Crystal structure refinement with SHELXL

Di-μ3-chlorido-1:2:3κ3 Cl;2:3:4κ3 Cl-di-μ2-chlorido-1:2κ2 Cl;3:4κ2 Cl-tetra-kis-[(4-amino-1,5-dimethyl-2-phenyl-2,3-di-hydro-1H-pyrazol-3-one-κ2 N 4,O)chlorido-cadmium(II)] 1.7-hydrate: a new six-coordinate geometry index, τ6

The title centrosymmetric tetra-nuclear cadmium(II) com-plex of 4-amino-anti-pyrine and chloride ions, [Cd4Cl8(C11H13N3O)4]·1.7H2O, was synthesized using methanol as solvent. The two independent Cd2+ ions in the asymmetric unit have different geometries; the outer Cd atoms have fivefold CdONCl3 coordination spheres, while the inner Cd atoms have sixfold CdONCl4 coordination spheres. The com-plex is consolidated by intra-molecular N-H⋯O and N-H⋯Cl hy-dro-gen bonds. In the crystal, a combination of N-H⋯Cl and Ow-H⋯Cl (w = water) hy-dro-gen bonds link the com-ponents to form chains propagating along the a-axis direction. The chains are crosslinked by C-H⋯Cl and C-H⋯O hy-dro-gen bonds to form a three-dimensional structure. A new geometry index, τ6, is proposed to qu-anti-tatively estimate the geometry of a sixfold coordinated atom.

A Tetrazine-Based Synthesis for Accessing Underutilized Aza-Indole Analogues

Aza-indole functionalities fill an important role in drug discovery. While indoles are considered privileged scaffolds, aza-indoles allow for better pharmacological properties and on-target activities. Synthetic approaches to access aza-indoles are limited, with pyrazolopyridazines being some of the scarcest aza-indoles. To provide access to these underutilized cores, a synthetic approach utilizing a reaction cascade between a protected propargylhydrazine and dichlorotetrazine has been developed. In addition, a variety of methods were developed to access each position on the core for late-stage functionalization. This method offers an expedited synthetic route to a rare aza-indole scaffold with superior physiochemical properties when compared to indole analogues.

Redox-active inverse crowns for small molecule activation

Cyclic crown ethers bind metal cations to form host-guest complexes. Lesser-known inverse crowns are rings of metal cations that encapsulate anionic entities, enabling multiple deprotonation reactions, often with unusual selectivity. Self-assembly of a cycle of metal cations around the multiply charged carbanion during the deprotonation reaction is the driving force for this reactivity. Here we report the synthesis of a pre-assembled inverse crown featuring Na+ cations and a redox-active Mg0 centre. Reduction of N2O followed by N2 release and subsequent encapsulation of O2- demonstrates its reduce-and-capture functionality. Calculations reveal that this essentially barrier-free process involves a rare N2O2- dianion, embedded in the metalla-cycle. The inverse crown can adapt itself for binding larger anions like N2O22- through a self-reorganization process involving ring expansion. The redox-active inverse crown combines the advantages of a strong reducing agent with anion stabilizing properties provided by the ring of metal cations, leading to high reactivity and selectivity.

Crystal structure, Hirshfeld surface analysis and DFT studies of 4-amino-N'-[(1E)-1-(3-hy-droxyphen-yl)ethyl-idene]benzohydrazide

In the title compound, C15H15N3O2, (I), the aniline and phenol rings form a dihedral angle of 62.1 (1)°. Inter-molecular N-H⋯O and O-H⋯O hydrogen bonds lead to the formation of sheets extending parallel to (010). Inter-molecular inter-actions were qu-anti-fied and analysed using Hirshfeld surface analysis, revealing that H⋯H inter-actions contribute most to the crystal packing (42.2%). The mol-ecular structure was optimized by density functional theory (DFT) at the B3LYP/6-31 G(d,p) level and was compared with the experimentally determined mol-ecular structure in the solid state.

Novel organoruthenium complexes containing β-Diketonates: Synthesis, characterization, DNA/HSA interactions, and the impact of biocompatible ionic liquids on biological activities

In order to discover new dual-active agents, novel ruthenium (η6-p-cymene) complexes of the general formula [(η6-p-cym)Ru(OO)Cl] with O,O-diketo ester ligands ethyl 2-hydroxy-4-aryl-4-oxobut-2-enoate (1-3), were synthesized. The complexes 1-3 were characterized by spectral techniques (UV-Vis, IR, 1H and 13C NMR, and ESI-HRMS), elemental analysis, and X-ray crystallography. Based on in vitro DNA/HSA experiments, complex 1 exhibited the highest DNA/HSA-activity, suggesting that the presence of an alkene chain contributes to increased activity. The cytotoxic activity of 1-3 was evaluated in a panel of human cancer cell lines (A549, MDA-MB-231, LS-174, HeLa), and in one normal cell line (MRC-5), both in the absence and presence of biocompatible ionic liquids (BIO-ILs) such as cholinium glycinate (Cho-Gly), cholinium β-alaninate (Cho-Ala), and cholinium glutamate (Cho-Glu). Complex 1 exhibited the highest cytotoxicity and demonstrated selectivity toward HeLa cells. Additionally, its cytotoxicity was enhanced when combined with the BIO-ILs Cho-Gly and Cho-Ala. This study suggests that ionic liquids can influence the efficacy and selectivity of cancer treatments, highlighting the potential for enhancing therapeutic outcomes. However, it also emphasizes the need for a deeper understanding of BIO-IL interactions with cellular processes. Furthermore, compound 1 displayed strong antimicrobial activity against Staphylococcus aureus and Escherichia coli (MIC = 0.078 mg/mL). Among the assessed species, Candida albicans showed the highest sensitivity to antifungal activity. These results suggest that investigated compounds may have potential for further development as clinical candidates, pending additional studies.

An Ni-based coordination polymer with a bamboo-like crystal structure

An Ni-based coordination polymer, namely, poly[tetra-aqua-bis-[4,7-bis-(1H-pyrazol-4-yl)benzo[c][1,2,5]thia-diazole][μ4-5,5'-(1,3,6,8-tetra-oxo-1,3,6,8-tetra-hydro-benzo[lmn][3,8]phenanthroline-2,7-di-yl)diisophthalato]dinickel(II)], {[Ni2(C30H10N2O12)(C12H8N6S)2(H2O)4]·2C3H7NO·H2O} n or Ni-BIBT-BINDI, with a crystal structure reminiscent of bamboo has been synthesized, the Ni2+ ions exhibiting a slightly distorted octa-hedral coordination geometry with N atoms and O atoms. The bond lengths of the Ni-O bonds range from 2.032 to 2.121 Å, and those of the Ni-N bonds are approximately 2.080 Å. The BINDI ligands are connected to each other by the Ni-O bonds, which form the backbone of the bamboo, while the BIBT ligands are connected to the backbone of the bamboo through Ni-N bonds and grows on both sides of the bamboo, constituting the bamboo leaves.

Synthesis, crystal structure and Hirshfeld surface analysis of 2,2-di-chloro-3,3-dieth-oxy-1-(4-fluoro-phen-yl)propan-1-ol

The title mol-ecule, C13H17Cl2FO3, crystallizes in the ortho-rhom-bic space group P212121 with one mol-ecule in the asymmetric unit. The skeleton of the mol-ecule exhibits an anti conformation with a C-C-C-C(Ph) torsion angle of -174.97 (18)°. The species are weakly hy-dro-gen bonded to form a polymeric chain elongated in the direction of the b axis. This inter-action is realised by the hydroxyl group with an ether O atom of a symmetry-related species [O-H⋯O hy-dro-gen-bond distance of 2.975 (2) Å]. No π-stacking inter-action involving the fluoro-benzyl moiety is detected in the crystal structure. Hirshfeld surface analysis, confirming the O-H⋯O donor-acceptor inter-actions, indicates that the most important contributions to the surface contacts are H⋯H (47.0%), Cl⋯H (19.5%), C⋯H (12.1%) and F⋯H (10.7%).

Synthesis and crystal structure study of (R,R)-TMCDA ethanol derivatives doubly protonated with FeCl4 - and Cl- as counter-ions

The synthesis and structural characterization of the crystal forms of (R,R)-TMCDA and its ethanol derivative, both doubly protonated with FeCl4 - and Cl- as counter-ions, are reported, namely, (R,R)-N 1,N 1,N 2,N 2-tetra-methyl-cyclo-hexane-1,2-bis-(aminium) tetra-chlorido-ferrate chloride, (C10H24N2)[FeCl4]Cl (1a), and (R,R)-N 1-(2-hy-droxy-eth-yl)-N 1,N 2,N 2-tri-methyl-cyclo-hexane-1,2-bis-(aminium) tetra-chlorido-ferrate chloride (C11H26N2O)[FeCl4]Cl (2a). A notable feature across both synthesized compounds is the presence of N-H⋯Cl hydrogen bonds of moderate strength in the solid state. In the case of the ethanol derivative of (R,R)-TMCDA, the structure also reveals the formation of inter-molecular O-H⋯Cl hydrogen bonds.

Isoselenourea-Catalyzed Enantioselective Pyrazolo-Heterocycle Synthesis Enabled by Self-Correcting Amide and Ester Acylation

Pyrazole heterocycles are prevalent in a wide range of medicinal and agrochemical compounds, and as such, the development of methods for their enantioselective incorporation into molecular scaffolds is highly desirable. This manuscript describes the effective formation of fused pyrazolo-pyridones and -pyranones in high enantioselectivity (up to >99:1 er) via an isoselenourea (HyperSe) catalyzed enantioselective [3 + 3]-Michael addition-cyclization process using readily available pyrazolylsulfonamides or pyrazolones as pronucleophiles and α,β-unsaturated anhydrides as starting materials. Mechanistic analysis indicates an unusual self-correcting reaction pathway involving preferential [1,2]-addition of the pronucleophile to initially generate an intermediate amide or ester that can be intercepted by isoselenourea acylation, leading to productive formation of the fused heterocyclic products with high enantiocontrol. The scope and limitations of this process are developed across a range of examples, with insight into the factors leading to the observed enantioselectivity provided by density functional theory (DFT) analysis.

Stepwise Synthesis of Carboxyalumoxanes through Well-Defined Organoaluminum and Organogallium Carboxylatohydroxides Obtained by Controlled Hydrolysis

Alumoxanes are compounds of composition (R2AlOAlR2)n and (RAlO)n that are traditionally obtained by controlled hydrolysis of aluminum trialkyls, although nonhydrolytic approaches to alumoxanes are also used. To reduce the reactivity of alumoxanes in contact with air, in the 1990s, researchers attempted to replace alkyl groups with other substituents, leading to the synthesis of carboxyalumoxanes with bulky alkyl groups. In this paper, we report on the study of carboxy methylalumoxane synthesis and structural characterization. We present a two-step synthesis of carboxyalumoxane containing the (t-Bu2Al)2OAlMe2 alumoxane unit. The method involves the synthesis of carboxylatoaluminum hydroxides by the reaction of t-Bu3Al with carboxylic acid and water with a molar ratio of reagents of 2:1:1 in the first step, followed by the reaction with Me3Al. On the other hand, the one-step reaction of Me3Al with carboxylic acid and water in a molar ratio of 3:1:1 leads to the formation of a carboxy methylalumoxane incorporating a neutral Me6Al4O2 scaffold trapped by two carboxylate units. The reaction of carboxylatogallium hydroxides with Me3Al occurred with the exchange of t-Bu2Ga groups for Me2Al, leading to the formation of carboxyalumoxanes with a Me6Al4O2 scaffold. The molecular and crystal structures of the compounds were determined via single-crystal X-ray diffraction (SCXRD) crystallography.

Synthesis, X-ray diffraction, and computational studies of acyclovir and HBG analogs derived from Triazolyl-1,4-benzothiazine and their oxidized forms for breast cancer and SARS-CoV-2

This study presents a simple and efficient synthetic method for preparing a new series of acyclonucleosides derived from 1,4-benzothiazine and 1,4-benzothiazine-1,1-dioxide. These compounds feature the introduction of a 1,2,3-triazole-4-ylmethyl ring as a spacer between the heterocyclic bases and the pseudosugars of acyclovir (ACV) and hydroxybutylguanine (HBG). The acyclonucleosides were synthesized through copper-catalyzed 1,3-dipolar cycloaddition reactions between azides 8a and 8b and the N4-propargyl base 7. Following this, the deprotection of the acyclic chains and the oxidation of the sulfur to sulfone afforded the acyclonucleosides 9a,b-12a,b in satisfactory yields. The synthesized acyclonucleosides were characterized using 1H and 13C NMR spectroscopy. Moreover, the structure of 9b was confirmed by single-crystal X-ray diffraction analysis. The synthesized acyclonucleosides were evaluated through in silico studies, including network pharmacology for bioactivity, toxicity prediction, physicochemical properties, and ADMET analysis. Molecular docking studies revealed significant interactions, highlighting compound 11b's favorable binding with the target protein AKT1, achieving a binding energy of -6.43 kcal/mol, which is close to the Capivasertib standard. Similarly, compound 12b showed interactions akin to hydroxychloroquine, with a binding energy of -6.29 kcal/mol for the SARS-CoV-2 target protein. Molecular dynamics simulations further validated the stability of the ligand-protein complexes during 200 ns, as evidenced by acceptable RMSD and RMSF and Rg values. The post-dynamic, MMGBSA, PCA, FEL, PDF, and DCCM analyses of the AKT and SARS-CoV-2 protein-ligand complexes have provided comprehensive insights into their interactions with standard drugs, binding affinities, conformational dynamics, and structural stability. These studies are crucial for understanding the molecular mechanisms underlying drug efficacy and resistance, thereby informing the rational design of new inhibitors targeting AKT and SARS-CoV-2 proteins. Finally, the two most promising compounds, 11b and 12b, selected from the docking results, were analyzed using Density Functional Theory (DFT). These analyses revealed significant variations in their electronic properties, providing valuable insights into their reactivity, stability, and polarity.

Synthesis, crystal structure and thermal properties of di-aqua-bis-(4-methyl-pyridine-κN)bis-(thio-cyanato-κN)cobalt(II)

The reaction of Co(NCS)2 and 4-methyl-pyridine (C6H7N) in water leads to the formation of light-blue single crystals of the title compound, [Co(NCS)2(C6H7N)2(H2O)2]. The asymmetric unit consists of one CoII cation (site symmetry 1) as well as one thio-cyanate anion, one 4-methyl-pyridine coligand and one water mol-ecule in general positions to generate trans-CoN4O2 octa-hedra. In the crystal, the complexes are linked by O-H⋯S hydrogen bonds into a layered network. Powder X-ray diffraction (PXRD) shows that a pure sample has been obtained. Upon heating, the title compound loses its water mol-ecules and transforms into Co(NCS)2(C6H7N)2, which is already reported in the literature.

Formation and Metallomimetic Reactivity of a Transient Dicoordinate Alkylborylene

While existing literature has primarily focused on carbene-stabilized amino- and arylborylenes of the form [(carbene)BR] (R = substituent), herein we report the generation and metallomimetic reactivity of the first carbene-stabilized alkylborylene [(CAACMe)BCy] (CAACMe = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene, Cy = cyclohexyl). Furthermore, the transition metal-like decarbonylation reactions of a borylene complex, [(CAACMe)BCy(CO)], derived from borylene [(CAACMe)BCy] and CO, are described. Additional findings described include i) the identification of the coordination stages of the ligand to boron towards forming complexes [(CAACMe)BCyL] in the reduction route from starting material [(CAACMe)BCyBr2] and in the photolysis route from carbonyl complex [(CAACMe)BCy(CO], and ii) insights from quantum-chemical computations regarding the molecular and electronic structure of the borylene at various stages.

High-pressure synthesis of bilayer nickelate Sr3Ni2O5Cl2 with a tetragonal crystal structure

Motivated by a theoretical prediction of its potential superconductivity under ambient pressure, a novel oxychloride, Sr3Ni2O5Cl2, was synthesized for the first time. This synthesis utilized a high pressure of 10 GPa at 1673 K. Small single crystals were used to determine the crystal structure and measure the temperature dependence of electrical resistance. The crystal is isostructural with the recently discovered superconductor La3Ni2O7, in line with theoretical expectation.

Structure of ice VII with Hirshfeld atom refinement

In the refinement of the crystal structures of ice, the best results obtained so far have been with neutron diffraction because the most troublemaking aspects are the hydrogen atoms. In nine out of twenty ice structures, the hydrogen atoms are disordered, which makes proper refinement more difficult. In our previous paper describing the structure of ice VI we proved that, using Hirshfeld atom refinement (HAR) based on synchrotron X-ray data, it is possible to obtain results comparable with those from neutron experiments. In this work, we investigate another structure of high-pressure disordered ice, cubo-ice (ice VII). Single crystals of cubo-ice were grown under pressure in diamond anvil cells. X-ray diffraction measurements were conducted at a synchrotron source facility (APS, University of Chicago, USA) as well as on our regular in-house laboratory diffractometer with Ag radiation. The data collected were further refined with HAR. Comparison of the structural parameters obtained with those derived from neutron diffraction showed very good agreement in terms of bond lengths and fairly good agreement in terms of hydrogen atom ADPs. We were also able to perform unconstrained refinements with various split-atom models.

Crystal structure of bis-(diiso-propyl-amino)-fluoro-borane

The predominantly planar structure of a fluoro-substituted bis-(di-alkyl-amino)-borane, C12H28BFN2, was obtained from the reaction of boron trifluoride diethyl etherate with lithium diiso-propyl-amide and its structure is presented here. While the B-F bond length is in the typical range of single B-F bonds, the B-N bond length indicates a partial double-bond character. The sterically demanding isopropyl groups on both amides increase the N-B-N angle and enable inter-molecular van der Waals inter-actions.

Structure of (E)-4-amino-5-{[(1,5-dimethyl-3-oxo-2-phenyl-2,3-di-hydro-1H-pyrazol-4-yl)imino]-meth-yl}-1-methyl-2-phenyl-2,3-di-hydro-1H-pyrazol-3-one: aerial oxidation of 4-amino-anti-pyrine in di-methyl-formamide

The title compound, C22H22N6O2 (I), is the result of the aerial oxidation of the 5-methyl group of 4-amino-anti-pyrine to an aldehyde group followed by Schiff base formation with a second mol-ecule of 4-amino-anti-pyrine. The reaction only takes place in the presence of di-methyl-formamide. The central unit of the mol-ecule is close to planar, the pyrazole rings being inclined to each other by 3.74 (15)°. There is an intra-molecular N-H⋯N hydrogen bond enclosing an S(6) ring motif and there are two further S(6) rings involving weak C-H⋯O=C hydrogen bonds. The mol-ecule has an E configuration about the azomethine (-N=CH-) bond. In the crystal, inversion-related mol-ecules are linked by pairs of N-H⋯O hydrogen bonds, forming dimers enclosing R 2 2(10) loops. The dimers are linked by C-H⋯O hydrogen bonds and C-H⋯π inter-actions, leading to the formation of a three-dimensional supra-molecular network.

Models for the Anionic Polymerization of P═C Bonds: Cyclization of n-BuLi-Initiated MesP═CPh2 and Related Phosphaalkenes with H2C═CPh2

To model the first propagation step in the anionic polymerization of MesP═CPh2 we studied the addition of Li[MesP(Bu)-CPh2] (and related species) to nonpolymerizable H2C═CPh2. Addition proceeds via the o-CH3 of the P-Mes followed by unprecedented cyclization to C5P-rings with release of Li[CHPh2]. Further investigation of the aforementioned reaction using phosphaalkenes, RP═CAr2 (R ═ Mes, m-Xyl; R' ═ Ph, 4-FC6H4, 4-MeC6H4, 4-MeOC6H4), resulted in the observation of a relatively long-lived intermediate in two instances (R ═ Mes, R' = 4-MeC6H4, 4-MeOC6H4). For the latter, the intermediate was identified as n-BuP(CH(4-MeOC6H4)2)[C6(4,6-Me2)H2-(2-CH2CH2CPh2Li) by isolation of the oxidized, H+-quenched product. These observations provide intriguing clues into the complex mechanism of polymerization of P-Mes phosphaalkenes and the chiral cyclophosphane products are of interest as ligands for catalytic applications.

Catching Fullerenes: Synthesis of Molecular Nanogloves

Herein, we report the synthesis of a new series of rigid, all meta-phenylene, conjugated deep-cavity molecules, displaying high binding affinity towards buckyballs. A facile synthetic approach with an overall combined yield of approximately 53% in the last two steps has been developed using a templating strategy that combines the general structure of resorcin[4]arene and [12]cyclo-meta-phenylene. These two moieties are covalently linked via four acetal bonds, resulting in a glove-like architecture. 1H NMR titration experiments reveal fullerene binding affinities (Ka) exceeding ≥106 M-1. The size complementarity between fullerenes and these scaffolds maximizes CH⋯π and π⋯π interactions, and their host:guest adduct resembles a ball in a glove, hence their name as nanogloves. Fullerene recognition is tested by suspending carbon soot in a solution of nanoglove in 1,1,2,2-tetrachloroethane, where more than a dozen fullerenes are observed, ranging from C60 to C96.

TiNiSi-Type ALiAu (A = Ca, Sr, Ba, Eu, Yb) Compounds: Alternative Use of "Excess" Electrons

New TiNiSi-type compounds ALiAu (A = Ca, Sr, Ba, Eu, Yb) were obtained in the form of mm-sized single crystals by high-temperature centrifugation-aided filtration from lithium melt. They are the first examples of TiNiSi-type representatives containing Li and a transition metal. The metallic phases show paramagnetic (Ca) or diamagnetic (Sr, Ba, Yb) behavior or antiferromagnetic ordering below 19 K (Eu). A new structural description is based on a hexagonal close packing with A occupying all octahedral and Li occupying half of the tetrahedral voids in an ordered fashion. Chemical bonding analysis supports the structural description and reveals the formation of eight-atomic stella-quadrangula bonds pinned on the empty tetrahedral holes, a bonding picture known from elemental metals.

Structure, intermolecular interactions and charge-density distribution of 2-amino-4-methoxy-6-methylpyrimidine with methylsulfamic acid and 4-hydroxybenzoic acid: a combined experimental and theoretical study

The salts 2-amino-4-methoxy-6-methylpyrimidinium N-methylsulfamate, C6H10N3O+·CH4NO3S-, I, and 2-amino-4-methoxy-6-methylpyrimidinium 4-hydroxybenzoate, C6H10N3O+·C7H5O3-, II, have been synthesized and characterized by single-crystal X-ray diffraction. The protonation process takes place in both salts from acid to base. In both salts, the ring and amine N atoms, and the sulfoxide and carboxylate O atoms form eight-membered R22(8) ring motifs. The nature of the different types of interactions present in the crystals have been explored using Hirshfeld surface analysis. The percentage contributions of the different interactions in the crystal structures have been calculated using 2D fingerprint plots. The volumes of the voids present in salts I and II are 233.25 and 398.48 Å3, respectively. The band gap energies (ΔE) of salts I and II are 3.2022 and 3.5357 eV, respectively, as calculated by frontier molecular orbital (FMO) analysis. In Bader's quantum theory of atoms in molecules (QTAIM) analysis, the values of the electron density [ρ(rcp)] and the Laplacian of the electron density [∇2ρ(rcp)] at the protonated region of salt I are 0.261 e Å-3 and 2.889 e Å-5, respectively, and for salt II are 0.357 e Å-3 and 3.2 e Å-5. The pharmacokinetic properties and drug-like nature of the salts were confirmed by in-silico ADME (Absorption, Distribution, Metabolism and Excretion) prediction.

Synthesis, crystal structure and Hirshfeld surface analysis of 5,5-diphenyl-3-(prop-2-yn-1-yl)imidazolidine-2,4-dione

The new phenytoin analogue 5,5-diphenyl-3-(2-propyn-1-yl)imidazolidine-2,4-dione, C18H14N2O2 (3), was obtained through an alkyl-ation reaction with propargyl bromide via the phase-transfer catalysis method, and its structure was determined via single-crystal X-ray diffraction analysis. The asymmetric unit of 3 consists of two independent mol-ecules differing mainly in the orientation of the propynyl group. Each mol-ecule forms an inversion dimer through pairs of N2-H2⋯O2 hydrogen bonds. The crystal structure is further consolidated by C-H⋯O and C-H⋯π inter-actions. The contributions of the different inter-actions towards the crystal packing were further analysed using Hirshfeld surface and fingerprint plots, showing that the largest contribution comes from the H⋯H contacts (45%).

Synthesis and crystal structure of 2-(2,4-dioxo-6-methyl-pyran-3-yl-idene)-4-(4-hy-droxy-phen-yl)-2,3,4,5-tetra-hydro-1H-1,5-benzodiazepine

The title compound, C21H18N2O4, contains non-planar diazepine (in a boat-sofa conformation) and pyran (envelope) rings. In the crystal, O-H⋯O and N-H⋯O hydrogen bonds link the mol-ecules, enclosing R 2 2(16) and R 2 2(24) ring motifs, to generate [110] chains. Very weak π-π stacking inter-actions between the phenyl rings of adjacent mol-ecules with an inter-centroid distance of 4.0264 (9) Å help to consolidate a three-dimensional architecture. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (45.1%), H⋯O/O⋯H (23.2%) and H⋯C/C⋯H (19.2%) inter-actions.

Crystal structure, Hirshfeld surface analysis and DFT studies of 2-[4-(2-methyl-prop-yl)phen-yl]-N'-[(1Z)-1-(thio-phen-2-yl)ethyl-idene]propane-hydrazide

In the title compound C19H24N2OS, inter-molecular N-H⋯O hydrogen bonds generate R 2 2(8) ring motifs, forming dimers with an inter-action energy of -70.5 kJ mol-1. A short S⋯C inter-action produces another dimer with an inter-action energy of -30.6 kJ mol-1. The inter-molecular inter-actions were qu-anti-fied using Hirshfeld surface analysis. The two-dimensional fingerprint plots indicate that the major contributions to the crystal packing are from H⋯H (67.9%), C⋯H (13.7%), O⋯H (7.3%) and S⋯H (4.3%) inter-actions.

Crystal structure of a bis-4-aza-tetra-cyclo[5.3.2.02,6.08,10]dodec-11-ene-3,5-dione compound

In the molecule of 4-({3-[(3,5-dioxo-4-aza-tetra-cyclo-[5.3.2.02,6.08,10]dodec-11-en-4-yl)meth-yl]phen-yl}meth-yl)-4-aza-tetra-cyclo-[5.3.2.02,6.08,10]dodec-11-ene-3,5-dione, C30H28N2O4, which contains two substituted [2.2.2]bi-cyclo-octene ring systems linked through a m-xylenedi-amine ring, the six-membered rings of the bi-cyclo-octene ring systems adopt nearly perfect boat conformations as determined from Cremer-Pople analysis. Both ring systems are fused to a five-membered imide ring that is oriented endo to a bridgehead cyclo-propyl ring. The crystal structure features C=O⋯π inter-actions along with C-H⋯O hydrogen bonds.

Supramolecular coordination cages as crystalline sponges through a symmetry mismatch strategy

The crystalline sponge method enables single-crystal X-ray diffraction analysis of guests absorbed within single-crystalline porous materials. However, its application with large or highly polar guests remains challenging. In this study, we addressed some of these limitations using palladium-based octahedron-shaped M6L4 (Td) coordination cages as crystalline sponges. The key to facilitate the crystallization of the cage is the addition of large aromatic polysulfonates ('sticker' anions); the symmetry mismatch between the cage and the sticker (D2h) results in a low-symmetry space group (P1 ¯ ), preventing guest disorder and leading to the formation of guest-accessible channels in the crystal. Guests can be encapsulated either before or after cage crystallization. The size and host-guest properties of the cavity enable analysis of a broad range of compounds, including water-soluble molecules, large amphiphilic molecules (molecular weight of ~1,200) and molecular aggregates. We have demonstrated the versatility of the cage-sticker strategy through its application to a triaugmented triangular-prism-shaped M9L6 cage, extending the guest scope to medium-sized pharmaceutical molecules.

Crystallographic studies of piperazine derivatives of 5,5-dimethylhydantoin in the search for structural features of α1-adrenoreceptors antagonists

A number of piperazine derivatives of hydantoin display high affinity for α1-adrenoreceptors and antagonistic properties, which make them potent hypotensive agents. In order to study the correlations between affinity for α1-adrenoreceptors and molecular structures, the crystal structures of six piperazine derivatives of 5,5-dimethylhydantoin were determined by X-ray diffraction, namely, 4-(3-{3-[(2,4-dichlorophenyl)methyl]-5,5-dimethyl-2,4-dioxoimidazolidin-1-yl}-2-hydroxypropyl)-1-phenylpiperazine-1,4-diium dichloride monohydrate ethyl acetate hemisolvate, C25H32Cl2N4O32+·2Cl-·H2O·0.5C4H8O2 (1), 4-(2-cyanophenyl)-1-(3-{3-[(2,4-dichlorophenyl)methyl]-5,5-dimethyl-2,4-dioxoimidazolidin-1-yl}-2-hydroxypropyl)piperazin-1-ium chloride acetonitrile monosolvate, C26H30Cl2N5O3+·Cl-·C2H3N (2), 1-(3-{3-[(2,4-dichlorophenyl)methyl]-5,5-dimethyl-2,4-dioxoimidazolidin-1-yl}-2-hydroxypropyl)-4-(3,4-dimethylphenyl)piperazin-1-ium chloride, C27H35Cl2N4O3+·Cl- (3), 1-(3-{3-[(2,4-dichlorophenyl)methyl]-5,5-dimethyl-2,4-dioxoimidazolidin-1-yl}-2-hydroxypropyl)-4-(3-methoxyphenyl)piperazin-1-ium chloride, C26H33Cl2N4O4+·Cl- (4), 4-(2,3-dichlorophenyl)-1-(3-{3-[(2,4-dichlorophenyl)methyl]-5,5-dimethyl-2,4-dioxoimidazolidin-1-yl}-2-hydroxypropyl)piperazin-1-ium chloride 0.2-hydrate, C25H29Cl4N4O3+·Cl-·0.2H2O (5), and 3-[(2,4-dichlorophenyl)methyl]-1-{3-[4-(3,4-dichlorophenyl)piperazin-1-yl]-2-hydroxypropyl}-5,5-dimethylimidazolidine-2,4-dione, C25H28Cl4N4O3 (6). The compounds crystallize in the centrosymmetric triclinic space group, except for 2, which crystallizes in the monoclinic space group P21/c. For all six compounds, one molecule is observed in the asymmetric unit. The molecule of 1 is doubly protonated at both N atoms of the piperazine ring, whereas 2, 3, 4 and 5 are only protonated at one ring N atom. The protonated N atoms are engaged in charge-assisted hydrogen bonds with the chloride anions, and in 1 the N atom interacts with the chloride anion via the water molecule. The crystal packing in the protonated molecules (1-5) is in each case dominated by a network of N-H+...Cl-, O-H...Cl- and C-H...Cl- hydrogen bonds, while in the base molecule of 6, O-H...O hydrogen bonds dominate.

Crystal structure of poly[[aqua-(μ2-pyrazine-κ2 N:N')(μ2-2,3,5,6-tetra-chloro-benzene-1,4-di-car-boxyl-ato-κ2 O 1:O 4)copper(II)] hemihydrate]

The asymmetric unit of the title compound, {[Cu2(C8Cl4O4)2(C4H4N2)2(H2O)2]·H2O} n or {[Cu2(Cl4bdc)2(pyz)2(H2O)2]·H2O} n comprises of a CuII ion, one tetra-chloro-benzene-dicarboxyl-ate ion (Cl4bdc2-), one pyrazine ligand (pyz), and one and a half water mol-ecules. The CuII ion exhibits a five-coordinated square-pyramidal geometry with a CuN2O3 coordination environment comprising two oxygen atoms of the Cl4bdc2- ligands, one oxygen atom of a water mol-ecule, and two nitro-gen atoms of the pyz ligands. The carboxyl-ate group is almost perpendicular to the benzene ring and shows monodentate coordination to the CuII ion. The CuII ions of these units are bridged by both the Cl4bdc2- and pyz ligands to form two-dimensional (2D) layers, which are linked by alternating hydrogen-bonding and C-Cl⋯π inter-actions to yield a three-dimensional network.

Synthesis and crystal structure analysis of substituted bi-cyclo-[3.3.1]nona-nones

A set of novel bi-cyclo-[3.3.1]nona-nones, namely, 4-methoxybi-cyclo-[3.3.1]non-3-ene-2,9-dione, C10H12O3 (1), 4,9,9-tri-methoxybi-cyclo-[3.3.1]non-3-en-2-ol, C12H20O4 (2), 4-meth-oxy-6-methyl-1-(3-methyl-but-2-en-1-yl)-6-(4-methyl-pent-3-en-1-yl)bi-cyclo-[3.3.1]non-3-ene-2,9-dione, C22H32O3 (3) and 4-(tert-but-yl)-4-hy-droxy-2-meth-oxy-8-methyl-7-(3-methyl-but-2-en-1-yl)-8-(4-methyl-pent-3-en-1-yl)bi-cyclo-[3.3.1]non-2-en-9-one, C26H42O3 (4), were synthesized and structurally elucidated by NMR, HRMS and X-ray crystallography.

Uncertainties of recalculated bond lengths, angles and polyhedral volumes as implemented in the Crystal Palace program for parametric crystal structure analysis

Crystal Palace is a new Windows program for Parametric Analysis of Least-squares and Atomic Coordination with Estimated standard uncertainties (e.s.u.'s). The primary purpose of the program is to organize the refined structures from parametric structural studies (as a function of pressure or temperature or a series of compositions) for analysis of the structural trends, and the production of tables for publication without the risks associated with manual editing. The program reads structural information from one or more crystallographic information format (cif) files. It organizes the data by finding the structurally equivalent atoms in each structure and therefore can correctly organize structural information even if atom names or site occupancies are different, or the atom lists in the cif files are ordered differently. A major shortcoming of cif files as currently used is that they do not contain the full variance-covariance matrix from the structure refinement, but only the uncertainties of the individual positional parameters. Without the covariance of positional parameters, the e.s.u.'s of bond lengths and angles cannot be determined. Crystal Palace uses symmetry to estimate the major contributions to the covariance of atomic coordinates and thus realistic uncertainties of bond lengths, angles and polyhedral volumes. Crystal Palace also calculates various polyhedral distortion parameters and rigid-body corrections to bond lengths.

The origin of synthons and supramolecular motifs: beyond atoms and functional groups

A four-membered R22(4) supramolecular motif formed by S...S and S...I chalcogen-bonding interactions in the crystal structure of 4-iodo-1,3-dithiol-2-one (C3HIOS2, IDT) is analysed and compared with a similar R22(4) motif (stabilized by Se...Se and Se...O chalcogen bonds) observed in the previously reported crystal structure of selenaphthalic anhydride (C8H4O2Se, SePA) through detailed charge density analysis. Our investigation reveals that the chalcogen-bonding interactions participating in the R22(4) motifs observed in the two structures have the same characteristic orientation of local electrostatic electrophilic...nucleophilic interactions while involving different types of atoms. We carried out Cambridge Structural Database searches for synthons and supramolecular motifs involving chalcogen-, halogen- and hydrogen-bonding (ChB, XB and HB) interactions. Geometrical characterizations and topological analyses of the electron density ρ(r) and its negative Laplacian function [L(r) = -∇2ρ(r)] indicate that all the bonding interactions forming the motifs are driven by local electrophilic...nucleophilic interactions between complementary charge concentration (CC) and charge depletion (CD) sites present in the valence shells of the atoms, regardless of the atoms and functional groups involved. The graph-set assignment Gda(n) (G = C, R, D or S), formerly developed by Etter [Acc. Chem. Res. (1990), 23, 120-126] for HB interactions, is a convenient way to describe the connectivity in supramolecular motifs based on electrophilic...nucleophilic interactions (such as ChB, XB and HB interactions), exchanging the number of atomic acceptors (a) and donors (d) with the number of nucleophilic (n: CC) and electrophilic (e: CD) sites, and the number of atoms building the motif n by m, leading to the new graph-set assignment Gen(m) (G = C, R, D or S). Geometrical preferences in the molecular assembly of synthons and other supramolecular motifs are governed by the relative positions of CC and CD sites through CC...CD interactions that, in most cases, align with the internuclear directions within a <15° range despite low interaction energies. Accordingly, beyond atoms and functional groups, the origin of recurrent supramolecular structures embedded within different molecular environments is found in the local electrostatic complementarity of electrophilic and nucleophilic regions that are placed at particular geometries, driving the formation and the geometry of synthons and supramolecular motifs by directional and locally stabilizing electrostatic interactions.

Hydride Migration within RhH2Ag19 Superatom: A Combined Neutron Diffraction and DFT Analysis

An investigation combining neutron diffraction and DFT allows determining the most likely hydride migration pathway within the icosahedral metal framework of [RhH2Ag19{S2P(OnPr)2}12] (RhH2Ag19). Starting from the experimentally derived solid-state structures, a computational analysis is able to reveal an energetically favorable migration pathway with a maximum energy barrier of 4.2 kcal mol-1. The two hydrides migrate simultaneously within the Rh@Ag12 icosahedral core, traversing several positional isomers. This study expands the understanding of hydride dynamics in nanoclusters and provides critical insights into the structural flexibility of the superatom framework. These findings have significant implications for hydrogen storage, catalysis, and the design of advanced hydride-containing materials.

Orthosilicates with glaserite-type crystal structures: Na2BaZr[SiO4]2 and Na2BaHf[SiO4]2

Single crystal particles of Na2BaZr[SiO4]2 [systematic name: disodium barium zirconium bis-(orthosilicate)] and Na2BaHf[SiO4]2 [disodium barium hafnium bis-(orthosilicate)] were extracted from grain-grown polycrystals obtained by heating compacts of binary oxide mixtures at 1473 K. Single crystal X-ray diffraction analysis revealed that these are isostructural orthosilicates with a glaserite-type crystal structure, in which all sites of X, Y, M, and T in the general formula XY 2[M(TO4)2] are fully occupied by atoms of different elements. The crystal structures of the title compounds were refined in space group P3 under consideration of a two-component twin model. The SiO4 tetra-hedra are rotated approximately ±10.2° from the mirror plane of space group P3m around an axis parallel to [001].

Rapid and facile one-step microwave synthesis of macrobicyclic cryptands

Liquid-assisted grinding (LAG) and microwave synthesis are proposed as alternative routes for the synthesis of cryptands, with reaction times of up to 16 times faster than traditional methods. These rapid and facile techniques have the potential to replace traditional methods for a high-yield formation of clathrochelates, and other materials. The cryptand 6,16,25-tribenza-1,4,8,11,14,18,23,27-octa-aza-tri-cyclo-[9.9.9]nona-cosa-4,7,14,17,23,26-hexaene hexa-hydrate, C36H42N8·6H2O, (Ph3T2 ) was synthesized using this novel method. The crystal structure was redetermined by single-crystal X-ray diffraction using synchrotron radiation at 120 K. The structure exhibits disorder in the water mol-ecule of hydration.

Regulating photoreactivity in a polymorphic bi-component solid through large synthons

Polymorphism in bi-component crystals has received immense attention in recent times due to their potential in property engineering. Two polymorphs of a functional bi-component molecular solid are derived using Long-range Synthon Aufbau Modules (LSAM) by tuning the nature and position of substituents. The two polymorphs show distinct photochemical properties; Form I undergoes partial cis-trans isomerization, and Form II sustains a [2 + 2] photodimerization. The polymorphic forms also exhibit different photomechanical behaviors. While Form I shows differing photomechanical responses upon UV irradiation based on crystal morphology, Form II undergoes a solid-to-liquid transition upon photo-irradiation.

Construction of a 1,2-diazetidine core based on a multicomponent reaction of N,N'-(2,3-dimethylbutane-2,3-diyl)bis(hydroxylamine), arylglyoxals, and Meldrum's acid

Assembly of a 1,2-diazetidine moiety on the basis of vicinal bis(hydroxylamines) was implemented for the first time. This transformation was demonstrated using the multicomponent condensation of N,N'-(2,3-dimethylbutane-2,3-diyl)bis(hydroxylamine) (BHA) with various arylglyoxals and Meldrum's acid as an example. It was found that the investigated process leads to zwitterionic 1,2-diazetidines containing a 1,3-dioxane-4,6-dione moiety. As a result of the performed research, a facile approach for the synthesis of target products was developed. We show that the application of acetonitrile as a solvent is the distinctive feature of the proposed method. A one-step synthetic protocol involving readily available starting compounds, simple reaction conditions, atom economy, and a convenient preparative procedure without chromatographic purification are advantages of the presented approach. The structure of one of the synthesized compounds was unambiguously confirmed by X-ray analysis.

Fine-Tuning the Excited-State Dynamics of Heteroleptic Ruthenium(II) Polypyridyl Complexes with Systematic Variation of Benzazole-Substituted 8-Hydroxyquinolines

A series of structurally related bistridentate heteroleptic Ru(II) polypyridyl complexes, [RuII(ttpy)(8-HQLS/N/O)]+ (Ru1-Ru3), were synthesized, where ttpy = p-tolyl terpyridine and 8-HQLS/N/O are monoanionic N^N^O-donor tridentate ligands (8-HQLX), derived from 8-hydroxyquinoline (8-HQ), namely, 8-HQLS = 2-(2'-benzothiazole)-8-hydroxyquinoline, 8-HQLN = 2-(2'-benzimidazole)-8-hydroxyquinoline, and 8-HQLO = 2-(2'-benzoxazole)-8-hydroxyquinoline. The electronic structures of these rigid ligands were systematically tuned by varying the noncoordinating heteroatoms (S, O, NH) in the five-membered heterocyclic ring, impacting the electronic properties, redox potentials, excited-state lifetime/dynamics, and deactivation pathways and photophysical behavior of the corresponding Ru(II) complexes. Notably, [RuII(ttpy)(8HQLN)]+ (Ru2) exhibited an excited-state lifetime (τ > 1 ns in CH3CN at RT) surpassing that of the homoleptic complex [Ru(ttpy)2]2+ (τ ∼ 0.62 ns), despite its more distorted octahedral geometry. These heteroleptic complexes (Ru1-Ru3) showed extended excited-state lifetimes compared to their homoleptic counterpart Ru4. The complexes displayed absorption in the red region, which is favorable for phototherapeutic applications. Their relative singlet oxygen (1O2) quantum yields (ΦΔ) in CH3CN ranged from 0.03 to 0.10. Given their reasonable excited-state lifetimes and 1O2 generation ability, these Ru(II) complexes demonstrated potential as photocatalysts for organic substrates, as evidenced by their effectiveness in the photooxidation of PPh3 to Ph3P=O as a model reaction.

NMR-Based Rational Drug Design of G:G Mismatch DNA Binding Ligand Trapping Transient Complex via Disruption of a Key Allosteric Interaction

Small molecules that bind to mismatched DNA have been applied in various fields, including nanotechnology, bioimaging, and therapeutics. However, the intrinsic dynamic nature of mismatched DNA complicates the prediction of structural changes upon ligand binding, hindering rational ligand design. In this study, NMR was used for structure-based drug design, with a focus on the G:G mismatch binder ND and the structural dynamics of the DNA-ND complex. Through comprehensive NMR analysis with isotope labeling, two complex structures, the transient and stable complexes, were successfully determined. The nucleobase flip-outs and the distortion of the phosphate backbone of the complex structures were characterized by residual dipolar coupling (RDC) and 31P NMR, respectively. The RDC-refined stable complex structure suggested that the ligand linker-nucleobase interaction allosterically regulates a structural transition. This interaction was experimentally validated by 1H-15N HSQC spectra using a 15N-labeled ligand. Disruption of this key allosteric interaction facilitated the design of a new ligand, sND, that traps the transient complex structure. In conclusion, comprehensive NMR analysis using a weak binder aids in designing nucleic acid-binding ligands based on transient complex structures.

Probing the Framework Metal Dependent Properties of Actinide-Centered Polyoxoalkoxide Sandwich-Type Complexes

Development of a simple and scalable synthesis of (TBA)3[W5O18MoNO] provides for the formation of the mixed-metal lacunary polyoxoalkoxide, (TBA)2[W4O13(OMe)4MoNO][Na(MeOH)]. This complex was used to synthesize a series of polyoxoalkoxide sandwich-type complexes with the general formula (TBA)2[M{W4O13(OMe)4MoNO}2], where M = Zr(IV), Hf(IV), Th(IV), U(IV), and Np(IV). Compared to the analogous all-molybdenum complexes, the series have drastically different optical and redox properties. The results indicate that framework metal substitution acts as a tool for "orbital engineering", with Density Functional Theory (DFT) calculations revealing that the major consequence of incorporation of tungsten into the complexes is localization of LUMO and LUMO+1 on the molybdenum centers remaining in the molecule. The change in the distribution of the frontier orbitals translates to discrepancies in the electronic properties of the series. Given the rarity of polyoxometalate complexes featuring a U(V) ion, one electron oxidation of (TBA)2[U(IV){W4O13(OMe)4MoNO}2] was pursued. Isolation of the corresponding U(V) centered sandwich-type complex is reported, only the second example of U(V)-polyoxometalate complex described to date.

Monitoring α/β Particles Using a Copper Cluster Scintillator Detector

High-energy radiation is widely used in medicine, industry, and scientific research. Meanwhile, the detection of environmental ionizing radiation is essential to ensure the safe use of high-energy radiation. Among radiation detectors, scintillator detectors offer multiple advantages, including simple structure, high sensitivity, excellent environmental adaptability, and a favorable performance-to-price ratio. However, the development of high-performance scintillators that can provide highly sensitive responses to environmental radiation, especially α/β particles, remains a challenge. In this work, a copper cluster (Cu4I4(DPPPy)2) with excellent water-oxygen stability is prepared using a simple one-pot method at room temperature. Cu4I4(DPPPy)2 not only exhibits excellent X-ray excited luminescence (XEL) under X-ray irradiation but also demonstrates a highly sensitive scintillation response to α/β particles. By integrating Cu4I4(DPPPy)2 with a photomultiplier tube (PMT) and nuclear electronics, an α/β surface contamination monitor is successfully developed. This monitor enables the sensitive detection of excessive α/β particles in real-world environments. The detection frequency and signal intensity of Cu4I4(DPPPy)2 significantly surpass those of commercial scintillator of YAP:Ce, BGO, PbWO4, and anthracene under identical conditions, highlighting the promising application of metal clusters in low-dose environmental radiation detection.

Ternary Inclusion Co-Crystals for Efficient Photothermal Conversion and Solar-Driven Water Evaporation

Organic co-crystal engineering offers a convenient and efficient platform for preparing photothermal conversion (PTC) materials. However, current donor-acceptor (D-A) co-crystals generally have medium photothermal performance. Here, an inclusion co-crystal strategy is presented, i.e., host-guest encapsulation of small acceptor inside donor-type macrocycle's cavity, to enhance PTC efficiency through the promotion of D-A binding. A naphthyl-sidewall Tröger's base (TB[2]) molecular box donor is elaborately designed, which can encapsulate electron-deficient 7,7,8,8-tetracyanoquinodimethane (TCNQ) to form a 1:2 ternary inclusion charge-transfer (CT) co-crystal via the synergism of multiple noncovalent forces. Under 808 nm laser irradiation (0.7 W cm-2), the PTC efficiency of co-crystals is as high as 94.3%. The co-crystals are further introduced into the porous polymer of polyurethane (PU) to prepare an interfacial evaporator (TB-TCNQ@PU) for solar-driven water evaporation. Under 1 Sun irradiation, a high-water evaporation rate of 1.746 kg m-2 h-1 and a prominent solar-to-vapor efficiency of 93.8% are achieved. This work opens new avenues for the efficient PTC materials.

Insulator-metal transition induced by band-filling modulation in molecular Mott insulators

Metallic x-Li(Pc)Brx and x-Li(tbp)Ix were fabricated via halogen doping of the Mott insulators x-Li(Pc) and x-Li(tbp), where Pc and tbp denote the phthalocyaninato and tetrabenzoporphyrinato ligands, respectively. Crystal structure analyses revealed that halogen atoms in x-Li(Pc)Brx and x-Li(tbp)Ix penetrated the channels of the pristine x-Li(Pc) and x-Li(tbp) during the chemical oxidation of the ligands. Raman spectroscopy indicated that bromine and iodine exist as Br3- and I3-, whereas iodine in the previously reported x-Li(Pc)I exists as I5-. These findings suggest that band-filling modulation by halogen doping depends on both the halogen species and the π-ligand. Although x-Li(Pc)Brx was unstable during heat treatment, the dedoping process was successfully achieved using a reductant, demonstrating that the electronic states between the Mott insulating and metallic states can be chemically controlled.

Cobalt(II) and Cadmium(II) Metal-Organic Framework with Benzene-1,3,5-tricarboxylate and Viologen Guest: Stimuli-Responsive Photochromism, Volatile Amine Detection, and Hydrogen Generation

Two Co(II) and Cd(II) coordination polymers, {(Me2bipy)[Co5(btc)3(Hbtc)(OH)]·2DMF·9H2O} n (CoMOF) and {(Me2bipy)[Cd2(μ4-btc)2]} n (OGU-2), were synthesized and characterized using IR spectroscopy, elemental analysis, and powder and single-crystal X-ray diffraction techniques. The Cd1 ion is seven-coordinated, adopting a distorted monocapped trigonal prismatic geometry (CdO7). OGU-2 exhibits a 3D porous framework with a rare flu-3,6-C2/c topology. The framework contains one-dimensional channels along the c axis with dimensions of approximately 10 × 10 Å2. The photochromic behavior of OGU-2 was investigated, revealing excellent chromic properties in response to multiple external stimuli, including UV light, temperature, and organic amines. CoMOF, a coordination polymer reported previously, along with OGU-2, was evaluated as a catalyst for hydrogen gas production via the methanolysis reaction of NaBH4. The results demonstrated that these coordination polymers exhibited high catalytic activity for hydrogen production, comparable to the high values reported in the literature.

Support for the Anticipated Binding Mode of a Cytotoxic Dinuclear Copper Complex to Two Neighboring Phosphate Esters of the DNA Backbone

The cytotoxic dinuclear complex [(Htom6-Me){CuII(OAc)}2](OAc) (H2tom6-Me = 2,7-bis(di(6-methylpyridine-2-yl-methyl)aminomethyl)-1,8-naphthalenediol) binds to DNA, interferes with DNA synthesis in PCR at lower concentrations than cisplatin, and kills human cancer cells more efficiently than human stem cells of the same proliferation rate. It is supposed that the OAc- ligands dissociate in aqueous buffer, providing [(Htom6-Me){CuII(OH2)}2]3+, while the fragment [(Htom6-Me)CuII2]3+ binds to two neighboring phosphate diesters of the DNA backbone. Here, we report the hydrolysis of [(Htom6-Me){CuII(OAc)}2](OAc) in phosphate buffer providing the anticipated [(Htom6-Me){CuII(OH2)}2]3+. Moreover, the same reaction in H2O/CH3OH yields the complex [(Htom6-Me){CuII(H2PO4)}2]+. The molecular structures of [(Htom6-Me){CuII(OH2)}2]3+ and [(Htom6-Me){CuII(H2PO4)}2]+ show different coordination modes around the CuII ions demonstrating a significant flexibility of the fragment [(Htom6-Me)CuII2]3+ for binding to exogenous ligands despite its rigid naphthalene backbone. The coupling is weakly antiferromagnetic in [(Htom6-Me){CuII(H2PO4)}2]+, while that in tricationic [(Htom6-Me){CuII(OH2)}2]3+ is weakly ferromagnetic and can be attributed to the orthogonal orientation of the basal planes. UV-vis-NIR spectra of [(Htom6-Me){CuII(H2PO4)}2]+ but also of [(Htom6-Me){CuII(OAc)}2](OAc) in aqueous solution resemble that of [(Htom6-Me){CuII(OH2)}2]3+ demonstrating our earlier assumption that [(Htom6-Me){CuII(OH2)}2]3+ is the active species in buffer solutions for interaction with DNA. Moreover, the exchange of the OAc- ligands by H2PO4- ligands models the anticipated binding of [(Htom6-Me){CuII(OH2)}2]3+ to the phosphates of DNA.

Luminescent Indium Dicyanoaurate Coordination Polymers with Short Aurophilic Interactions

A series of coordination polymers were synthesized by combining In(OTf)3 (OTf = trifluoromethanesulfonate), 2,2';6',2"-terpyridine (Terpy) or its substituted analogues 4'-amino-2,2';6',2"-terpyridine (NH2-Terpy), 4'-chloro-2,2';6',2"-terpyridine (Cl-Terpy), and 4'-bromo-2,2';6',2"-terpyridine (Br-Terpy), with K[Au(CN)2]. All compounds consist of 1D chains of hydroxy-bridged [In2(OH)2(X-Terpy)2]4+ dimers connected to a 1D chain of [Au(CN)2]- units featuring very short aurophilic interactions (3.0106(3)-3.2155(4) Å). The distance of the aurophilic interaction is directly tunable through minor modifications of the ligand, with the Au(I)···Au(I) distance increasing as the size of the substituent on the Terpy ligand increases. The compounds display photoluminescence emission maxima ranging from 600 to 650 nm, which are significantly lower energy than for most [Au(CN)2]--based materials. The emission maxima shift to higher energy as the aurophilic interactions become longer. These results demonstrate the ability to tune the Au(I)···Au(I) distance, and in turn the luminescence, by varying the size of the substituent on the chelating ligand.

A Molecular Planetarium: Evidence for an Iodide Ligand Orbiting Two Gold(I) Ions in the Luminescent Cation, [Au2(μ-1,2-Bis(diphenylphosphino)methane)2I]. Inorg Chem 2025. [PMID: 40298146 DOI: 10.1021/acs.inorgchem.5c00396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Four new crystalline gold(I) complexes, [Au2(μ-dppm)2I][Au2(μ-dppm)2(μ-I)](AsF6)4·4CH2Cl2 (1), [Au2(μ-dppm)2(μ-I)]I·2CH2Cl2 (2), [Au2(μ-dppm)2(μ-I)](PF6)·CH2Cl2 (3), and [Au2(μ-dppm)2](AsF6)2·CH2Cl2 (4) where dppm is bis(diphenylphosphino)methane) have been prepared and structurally characterized by single crystal X-ray diffraction and nuclear magnetic resonance spectroscopy (NMR). Yellow crystals of [Au2(μ-dppm)2(μ-I)]I·2CH2Cl2 (2) and [Au2(μ-dppm)2(μ-I)](PF6)·CH2Cl2 (3) have a structure with two three-coordinate gold(I) ions held in close proximity by the dppm and bridging iodide ligands. Crystals of [Au2(μ-dppm)2I][Au2(μ-dppm)2(μ-I)](AsF6)4·4CH2Cl2 (1) have two different cations: one similar to complexes 2 and 3 and the other cation with a terminal iodide ligand in an unusual arrangement that binds a two-coordinate gold(I) ion to a three-coordinate gold(I) ion through an aurophilic interaction. In contrast, [Au2(μ-dppm)2](AsF6)2·CH2Cl2 (4) has no anion bound and only has the gold ions as two-coordinate centers. Each complex displays luminescence under UV irradiation in the solid and solution states. Remarkably, the NMR spectra of solutions of the iodide complexes (1), (2), and (3) suggest that the iodide ion is bound to the [Au2(μ-dppm)2]2+ core but is able to circulate around this core.

Application of a quantum crystallographic protocol to YLID, the world's most common crystal structure

2-Dimethylsulfuranylidene-l,3-indanedione (YLID) is the most common crystal structure in the world not because of its chemical or physical properties, but because of its use as a test crystal for commercial diffractometers by nearly all vendors for more than 50 years. We will use it as an example here to showcase how the application of modern quantum-crystallographic refinement techniques and new experiments can unravel a so-far hidden story, which puts the emphasis back on the interesting chemical and physical properties of this crystal structure. We present a new chiral form of orthorhombic YLID (the left-handed LS form) and describe the complicated relationship between helical crystal packing and molecular planar chirality. We investigate polymorphs of YLID with twisted and planar molecular configuration as a function of temperature (100 to 292 K) and external pressure (0 to 4 GPa). However, finally only chemical pressure, namely the insertion of water into the crystal structure, can transform the twisted into the planar structure. A combination of quantum crystallography and repeated measurements of the orthorhombic test crystal gives access to an estimate of reproducibility and reliability of refining both anomalous dispersion and Flack parameters. It appears that the chemical environment of covalently bonded atoms has an influence on the anomalous dispersion parameters.

Role of Hydrogen Bonding in Crystal Structure and Luminescence Properties of Melem Hydrates

In recent years, carbon nitride (CN) compounds, such as g-C3N4 and melem, have attracted attention as new visible light-driven photocatalysts with a variety of functions, including water splitting, organic decomposition, and dark photocatalysis. The building unit of these materials is the heptazine ring, and molecules with this structure have attracted considerable attention as luminescent materials. Melem is an organic molecule with amino groups at the three termini of its heptazine ring. Melem exhibits near-UV (NUV) emission with high quantum yield via thermally activated delayed fluorescence (TADF). Materials exhibiting TADF can achieve highly efficient luminescence without the use of heavy metals, generating interest in their potential as luminescent materials for organic electroluminescent devices. Compared to materials that emit in the visible-light region, there are few reports on TADF materials such as melem that exhibit NUV emissions. Melem hydrate is easily obtained by hydrothermal treatment of melem. Unlike melem crystals, melem hydrate (Mh) has a porous structure because of a hydrogen-bond network formed between melem and water molecules. To date, only one type of Mh has been well-investigated. Mhs are expected to exhibit novel properties, such as photocatalysis, molecular adsorption, and highly efficient NUV emission. Mh also provides an opportunity to investigate how hydrogen bonds between the melem molecule and crystal water affect the TADF NUV emissions. This provides clues to the mechanism of the TADF action exhibited by other melem compounds. In this study, we focus on a new melem hydrate with a parallelogram shape, Mhp, first reported by Dai et al. in 2022. The crystal structure of Mhp reportedly differs from that of Mh; however, the Mhp crystal structure has not been determined to date, and its physical properties have not been investigated. Therefore, in this study, we reexamined the conditions for growing single crystals of Mhp and succeeded in growing samples that could be used to measure physical properties. We also determined its crystal structure and investigated the role in crystal formation of the hydrogen bonds between melem and water molecules. We evaluated the thermal behavior and optical properties and discussed their correlation with the crystal structure. Similar to melem, Mhp displayed NUV luminescence in its photoluminescence (PL) spectrum. This luminescence was found to have high quantum yield and delayed fluorescence. At low temperatures, the PL of Mhp dramatically increased at a wavelength of approximately 350 nm. This behavior was attributed to a significant change in the hydrogen-bond network between melem and water molecules in the Mhp crystal at low temperatures. We found that distortion of the melem molecule in the excited state at low temperatures was suppressed by its strong hydrogen bonds with water molecules. As a result, the displacement of the atomic nuclei of the atoms that make up the melem molecules in the excited state produced by light absorption is small, and in the de-excitation process, radiative transitions to low-energy vibrational levels are promoted. At the same time, nonradiative deactivation was suppressed, resulting in high fluorescence quantum efficiency. The results of this research provide deep insight into the role of hydrogen bonds in the optical properties of hydrate crystals that exhibit highly efficient luminescence, including TADF.

Revisiting the structure and properties of mid-valent monopentamethylcyclopentadienylchromium complexes

The structure and properties of half-sandwich chromium complexes derived from the dinuclear chloride compound [{CrCp*(μ-Cl)}2] (1) (Cp* = η5-C5Me5) are revisited. Complex 1 does not react with H2 and N2 but cleaves the nitrogen-nitrogen bonds of azobenzene and 1,2-diphenylhydrazine at room temperature to give dinuclear chromium(IV) bis(imido) [{CrCp*Cl(μ-NPh)}2] (2) and chromium(III) bis(amido) [{CrCp*Cl(μ-NHPh)}2] (3) derivatives, respectively. Reactions of 1 with cyclopentyllithium [Li(C5H9)] in hexane or toluene under reflux conditions afford the previously reported tetranuclear chromium(II) hydride complex [{CrCp*(μ3-H)}4] (4) and the unsymmetrical chromium(I) sandwich compound [CrCp*(η6-C6H5Me)] (5) as crystals suitable for X-ray diffraction studies. While the treatment of 1 with excess LiBH4 leads to an analogous dinuclear complex [{CrCp*(μ-κ3-BH4)}2] (6), the reaction of the chromium(III) compound [{CrCp*Cl(μ-Cl)}2] with LiBH4 gives the mononuclear species [CrCp*(κ2-BH4)2] (7). Complex 6 cleanly reacts with the 2,6-lutidinium salt (LutH)(BPh4) to form the zwitterionic sandwich derivative [CrCp*(η6-C6H5-BPh3)] (8). Compounds 1 and 6 react with LiAlH4 to give a diamagnetic tetrachromium aggregate [(Al{(μ-H)4CrCp*})4] (9), which can be described as low-spin chromate(II) {CrCp*H4}3- units stabilizing the Al3+ ions primarily through Cr-H → Al interactions and weaker Cr → Al donation according to density functional theory (DFT) calculations. The thermal decomposition of 9 in benzene at 90 °C affords a mixed-valence CrII/CrI hexachromium species [(Al2{(μ-H)4CrCp*}{(μ3-H)4Cr2Cp*2})2] (10) with analogous interactions of {CrCp*H4}3- and {Cr2Cp*2H4}3- units with Al3+ ions.

Elucidation of an Unusually Long Pu-N Bond in a Plutonium(III)-Tetrazolate Complex

Four trivalent, f-element tetrazolate hydrate complexes [M(H2O)9](Hdtb)3·nH2O (Nd1, n = 7 and Pu1, n = 9; dtb2- = 1,3-di(tetrazolate-5-yl)benzene) and [M(Hdtb)(H2O)8](dtb)·11H2O (Nd2 and Pu2) were prepared using metathesis reactions. These complexes contain hydrated M(III) cations, but in the latter complexes, Nd2 and Pu2, one of the water molecules has been displaced by a long interaction between the M(III) cation and a Hdtb- anion. Notably, the Pu(III)-N bond in Pu2, representing the longest IXPu(III)-N (IX = nine coordinate) bond reported has a length of 2.8338(15) Å and is slightly shorter than the Nd(III)-N bond length of 2.8425(13) Å in Nd2. Analysis of bond lengths, Wiberg bond indices (WBI), natural localized molecular orbitals (NLMOs), and quantum theory of atoms in molecules (QTAIM) reveals that the metal contribution to the Pu(III)-N bond is marginally greater than that of the Pu(III)-OH2 bonds in Pu2 and the Nd(III)-N bond in Nd2. Thus, this rather long M-N interaction provides an example where the expectation that An(III) compounds exhibit greater covalency with soft donor ligands compared to harder ligands fails. The absorption spectra of Pu1 and Pu2 further support this observation, highlighting a surprising degree of similarity in their electronic structures.