SHELXT - integrated space-group and crystal-structure determination

A double stranded metal-organic assembly accommodating a pair of water trimers in the host cavity and catalysing Glaser coupling

A supramolecular compound, catena-poly{[Cu2(1,3-μ2-(1a))2(μ2-ter)2(H2O)2]n·(6H2O)n} (1) has been synthesized using (1a) [(1a = N(1),N(3),N(5)-trimethyl-N(1),N(3),N(5)-tris((pyridin-4-yl)methyl)-1,3,5-benzene tricarboxamide] and terephthalate (ter) as the pillaring unit by self-assembly. The terephthalate units are connected by copper(II) ions forming a single strand, while a pair of such strands are then linked by (1a) via two pyridyl terminal arms bound to copper(II) nodes on either side forming a one-dimensional double stranded assembly propagating along the c axis. The compound crystallizes in the Fdd2 space group. The cavity created in the interior of this double strand assembly trap six water molecules and are stabilized by hydrogen bonding with the host. The arrangement of the pair of acyclic water trimers in isolated cavities of (1) is such that it resembles a closed-bracket-like formation. The Hirshfeld surface analysis of (1) reveals the presence of strong intermolecular hydrogen-bonding interactions between one-dimensional ladder-like units and with the water trimer in the host cavity. The copper(II)-containing coordination polymer also acts as an efficient catalyst for the Glaser-Hay homo-coupling reaction.

Crystal structure of (n-but-yl)[2-(2,6-di-meth-oxy-phen-yl)-6-methyl-phen-yl](2-meth-oxy-phen-yl)phospho-nium chloride monohydrate

The title hydrated salt, C26H32O3P(+)·Cl(-)·H2O, contains four different substit-uents (H, alkyl, aryl, and biar-yl) on the P atom. The P-H hydrogen atom of the phospho-nium ion was located in a difference Fourier map and refined without imposing additional restraints. In the crystal, the Cl(-) ions and water mol-ecules are linked by pairs of Owater-H⋯Cl(-) hydrogen bonds and further linked to the phospho-nium cation by P-H(+)⋯Cl(-) and CAr/OMe-H⋯Owater hydrogen bonds to form an infinite one-dimensional chain along the [010] direction.

Crystal structures of (S)-(+)-5-(3-bromo/chloro-4-isopropoxyphen-yl)-5-methyl-imidazolidine-2,4-dione

In (S)-(+)-5-(3-bromo-4-isopropoxyphen-yl)-5-methyl-imidazolidine-2,4-dione, C13H15BrN2O3, (I), the hydantoin groups are connected via inter-molecular N-H⋯O hydrogen bonds, forming a terraced sheet structure. In the chloro analogue, (S)-(+)-5-(3-chloro-4-isopropoxyphen-yl)-5-methyl-imidazolidine-2,4-dione, C13H15ClN2O3, (II), the inter-molecular N-H⋯O hydrogen-bonding network forms a flat sheet. Comparison of the crystal structures reveals that (II) is more loosely packed than (I).

Crystal structure of (Na0.70)(Na0.70,Mn0.30)(Fe(3+),Fe(2+))2Fe(2+)(VO4)3, a sodium-, iron- and manganese-based vanadate with the alluaudite-type structure

The title compound, sodium (sodium,manganese) triiron(II,III) tris[vana-date(V)], (Na0.70)(Na0.70,Mn0.30)(Fe(3+),Fe(2+))2Fe(2+)(VO4)3, was prepared by solid-state reactions. It crystallizes in an alluaudite-like structure, characterized by a partial cationic disorder. In the structure, four of the 12 sites in the asymmetric unit are located on special positions, three on a twofold rotation axis (Wyckoff position 4e) and one on an inversion centre (4b). Two sites on the twofold rotation axis are entirely filled by Fe(2+) and V(5+), whereas the third site has a partial occupancy of 70% by Na(+). The site on the inversion centre is occupied by Na(+) and Mn(2+) cations in a 0.7:0.3 ratio. The remaining Fe(2+) and Fe(3+) atoms are statistically distributed on a general position. The three-dimensional framework of this structure is made up of kinked chains of edge-sharing [FeO6] octa-hedra stacked parallel to [10-1]. These chains are held together by VO4 tetra-hedral groups, forming polyhedral sheets perpendicular to [010]. Within this framework, two types of channels extending along [001] are present. One is occupied by (Na(+)/Mn(2+)) while the second is partially occupied by Na(+). The mixed site containing (Na(+)/Mn(2+)) has an octa-hedral coordination sphere, while the Na(+) cations in the second channel are coordinated by eight O atoms.

Crystal structure of zwitterionic 2-[bis-(2-meth-oxy-phen-yl)phosphanium-yl]-4-methyl-benzene-sulfonate monohydrate di-chloro-methane monosolvate

In the title compound, C21H21O5PS·H2O·CH2Cl2, the phospho-nium-sulfonate zwitterion has the acidic H atom located on the P atom rather than the sulfonate group. The S-O bond lengths [1.4453 (15)-1.4521 (14) Å] are essentially equal. In the crystal, the water mol-ecules bridge two zwitterions via Owater-H⋯Osulfonate hydrogen bonds into a centrosymmetric dimer. The dimers are further linked by weak CAr-yl-H⋯Osulfonate hydrogen bonds into chains extending along [100]. The PH(+) group is not involved in inter-molecular inter-actions.

Two new polytypes of 2,4,6-tri-bromo-benzo-nitrile

Three polymorphs of 2,4,6-tri-bromo-benzo-nitrile (RCN), C7H2Br3N, two of which are novel and one of which is a redetermination of the original structure first determined by Carter & Britton [(1972). Acta Cryst. B28, 945-950] are found to be polytypic. Each has a layer structure which differs only in the stacking of the layers. Each layer is composed of mol-ecules associated through C N⋯Br contacts which form R (2) 2(10) rings. Two such rings are associated with each N atom; one with each ortho-Br atom. No new polytypes of 1,3,5-tri-bromo-2-iso-cyano-benzene (RNC) were found but a re-determination of the original structure by Carter et al. [(1977). Cryst. Struct. Commun. 6, 543-548] is presented. RNC was found to be isostructural with one of the novel polytypes of RCN. Unit cells were determined for 23 RCN samples and 11 RNC samples. Polytypes could not be distinguished based on crystal habits. In all four structures, each mol-ecule of the asymmetric unit lies across a mirror plane.

Crystal structure of N-hy-droxy-picolinamide monohydrate

The crystal structure of the title compound, C6H6N2O2·H2O, consists of N-hy-droxy-picolinamide and water mol-ecules connected through O-H⋯O and N-H⋯N hydrogen bonds. The O-H⋯O inter-actions and π-π stacking inter-actions between the pyridine rings [centroid-centroid distance = 3.427 (1) Å] organize the components into columns extending along the b axis and the N-H⋯N hydrogen bonds link these columns into a two-dimensional framework parallel to (100). The N-hy-droxy-picolinamide mol-ecule adopts a strongly flattened conformation and only the O-H group H atom deviates significantly from the mol-ecule best plane. The dihedral angle between the hydroxamic group and the pyridine ring is 5.6 (2)°. The conformation about the hydroxamic group C-N bond is Z and that about the C-C bond between the pyridine and hydroxamic groups is E.

Crystal structure of an organic-inorganic supra-molecular salt based on a 4,4'-methyl-enebis(3,5-dimethyl-1H-pyrazol-2-ium) cation and a β-octa-molybdate anion

The asymmetric unit of the title compound, bis-[4,4'-methyl-enebis(3,5-dimethyl-1H-pyrazol-2-ium)] β-octa-molybdate, (C11H18N4)2[Mo8O26] or (H4mbdpz)2[Mo8O26], is composed of an H4mbdpz(2+) cation and half of the β-octa-molybdate anion which is completed by inversion symmetry. The organic mol-ecular units are engaged in a series of N-H⋯O hydrogen bonds with neighbouring anions, with N⋯O distances and N-H⋯O angles in the ranges 2.730 (2)-2.941 (2) Å and 122-166°, respectively. These inter-actions lead to the formation of a supra-molecular two-dimensional network parallel to the (010) plane.

(Acetato-κO){2-[(2-aminoethyl-κN)disulfanyl]ethanaminium}dichloridozinc(II)

In the title compound, [Zn(C4H13N2S2)(CH3COO)Cl2], the ZnIIion is in a tetrahedral coordination geometry, coordinated by one acetate, two chloride and one 2-[(2-aminoethyl)disulfanyl]ethanaminium ligand, with a Zn—O distance of 1.977 (3) Å, a Zn—N distance of 2.015 (3) Å and Zn—Cl distances of 2.2673 (18) and 2.2688 (15) Å. In the crystal, molecules are self-assembled by N—H...Cl hydrogen bonds, leading to a one-dimensional chain structure. The chains interact with each other through N—H...O, N—H...S, C—H...Cl and C—H...S hydrogen bonding, completing a three-dimensional hydrogen-bonding network structure.

2-Chloro-1-ferrocenylethanone

The title molecule, [Fe(C5H5)(C7H6ClO)], comprises a ferrocene unit with a 2-chloroethanone substituent on one of the cyclopentadienyl (Cp) rings. The two Cp rings are almost coplanar with an angle of 1.28 (1)° between them. In the crystal, C—H...Cl and C—H...O hydrogen bonds together with an edge-to-face C—H...π contact involving the unsubstituted Cp ring stack molecules along thec-axis direction.

2-Chloro-1-ferrocenylethanol

In the title compound, [Fe(C5H5)(C7H8ClO)], the ferrocene cyclopentadiene rings are slightly staggered and inclined to one another at an angle of 0.79 (13)°. In the crystal, C—H...Cl and C—H...O hydrogen bonds each form inversion dimers and these combine with an edge-to-face C—H...π hydrogen bond to stack the molecules along theb-axis direction.

6-Methyl-2-[(6-methylpyridin-2-yl)amino]pyridinium chloride chloroform monosolvate

In the title solvated molecular salt, C12H14N3+·Cl−·CHCl3, the aromatic rings of the cation are nearly coplanar [dihedral angle = 6.30 (5)°] and an intramolecular N—H...N hydrogen bond occurs. In the crystal, the chloride ion accepts an N—H...Cl hydrogen bond from the cation and a C—H...Cl interaction from the solvent molecule. These trimeric units are linked by cation-to-anion C—H...Cl interactions into chains that propagate in the [001] direction.

N,N,N-Triethylethanaminium 5,11,17,23-tetra-tert-butyl-25-cyanomethoxy-26,28-dihydroxy-27-oxido-2,8,14,20-tetrathiacalix[4]arene: a molecular salt

In the title molecular salt, C8H20N+·C42H48NO4S4−, the conformation of the anionic tetrathiacalix[4]arene, which is cone-shaped, is primarily determined by intramolecular O—H...O hydrogen bonds. There are also intramolecular C—H...O short contacts present. In the crystal, the anions (A) and cations (C) are linked by C—H...O and C—H...S hydrogen bonds, forming –A–C–A–C– chains along [001]. The chains are linkedviaC—H...Ncyanohydrogen bonds, forming ribbons along [001].

3,3′-[(Cyclohexane-1,4-diyl)bis(azanediyl)]bis(cyclohex-2-en-1-one)

The title compound, C18H26N2O2, crystallizes with two half-molecules in the asymmetric unit, both lying about inversion centres situated at the centers of the cyclohexane rings. In the crystal, the two molecules are linked by a pair of N—H...O hydrogen bonds, forming an inversion dimer with anR22(18) ring motif; the dimers are linked by a second pair of N—H...O hydrogen bonds, enclosing anR22(18) ring motif, forming chains along [1-10] which are linked by bifurcated C—H...(O,O) hydrogen bonds, forming slabs parallel to theabplane.

9-(5-Bromo-2-hydroxyphenyl)-10-(2-hydroxyethyl)-3,4,6,7-tetrahydroacridine-1,8(2H,5H,9H,10H)-dione

In the title compound, C21H22BrNO4, the tetrahydroacridine-1,8-dione unit has a bromohydroxyphenyl-substituent on the central carbon atom of the dihydropyridine ring and a 2-hydroxyethyl substituent on the nitrogen atom. An intramolecular O—H...O hydrogen bond forms between the hydroxyl substituent on the benzene ring and a carbonyl oxygen from the acridinedione, forming anS(8) ring. The hydroxyl group of the 2-hydroxyethyl residue is disordered over two sites with an occupancy ratio of 0.572 (6):0.428 (6). In the crystal structure O—H...O and C—H...O hydrogen bonds together with Br...O halogen bonds stack the molecules along theb-axis direction.

Polymeric structure of disodiump-terphenyl-4,4′′-disulfonate [Na2(O3S-C6H4-C6H4-C6H4-SO3]

In the title compound, 2Na+·C18H12O6S22−, the sodium ion is sevenfold coordinated by O atoms of five sulfonate groups (two in a chelating and three in a monodentate binding mode). They form (100) layers of edge-, corner- and face-sharing [NaO7] polyherdra which are interconnected by the terphenyl moieties. The asymmetric unit contains one sodium cation and onep-terphenyl-4,4′′-disulfonate anion on a centre of inversion.

Crystal structure and Hirshfeld analysis of the kryptoracemate: bis(mefloquinium) chloride p-fluorobenzenesulphonate

The crystal structure analysis of the bis(mefloquinium) chloride p-fluorobenzenesulphonate salt reveals a rare example of a kryptoracemate given that the cations exhibit a non-crystallographic enantiomeric relationship. The conformations of the cations are based on a skewed letter L with the (piperidinium-2-yl)methanol group sitting almost normal to and directed away from the quinolinyl residue. The most prominent feature of the molecular packing is the formation of supramolecular helical chains along the a-axis, being sustained by pairs of hydroxyl-O–H···O (sulphonate), piperidinium-N–H···O (sulphonate) and piperidinium-N–H···Cl hydrogen bonds. Geometric and Hirshfeld surface analyses of the crystal structure shows significant differences in supramolecular aggregation between the cations due to the presence of different anions and this is the likely reason for the observed kryptoracemic behaviour.

Mono- and Dinuclear Macrocyclic Calcium Complexes as Platforms for Mixed-Metal Complexes and Clusters

Mono- and dinuclear calcium complexes of the Schiff-base macrocycles H4L have been prepared and characterized spectroscopically and crystallographically. In the formation of Ca(THF)2(H2L(1)), Ca2(THF)2(μ-THF)(L(1)), and Ca2(THF)4(L(2)), the ligand framework adopts a bowl-shaped conformation instead of the conventional wedge, Pacman-shaped structure as seen with the anthracenyl-hinged complex Ca2(py)5(L(3)). The mononuclear calcium complex Ca(THF)2(H2L(1)) reacts with various equivalents of LiN(SiMe3)2 to form calcium/alkali metal clusters and dinuclear transition metal complexes when reacted subsequently with transition metal salts. The dinuclear calcium complex Ca2(THF)2(μ-THF)(L(1)), when reacted with various equivalents of NaOH, is shown to act as a platform for the formation of calcium/alkali metal hydroxide clusters, displaying alternate wedged and bowl-shaped conformations.

Dimethylammonium 2-amino-5-nitroterephthalate hemihydrate

The asymmetric unit of the title compound, C2H8N+·C8H5N2O6−·0.5H2O, comprises a monodeprotonated 2-amino-5-nitroterephthalate anion and a dimethylammonium counter-ion on general positions and a water molecule that lies on a twofold rotation axis. Extensive hydrogen bonding is observed between the carboxylate group and the dimethylammonium ion, the water molecule and the carboxylic acid group, as well as between the amino group, the water molecule and the carboxylic acid group (N—H...O and O—H...O hydrogen bonds are involved).

Nobiletin: a citrus flavonoid displaying potent physiological activity

Nobiletin [systematic name: 2-(3,4-dimethoxyphenyl)-5,6,7,8-tetramethoxy-4H-chromen-4-one; C21H22O8] is a flavonoid found in citrus peels, and has been reported to show a wide range of physiological properties, including anti-inflammatory, anticancer and antidementia activities. We have solved the crystal structure of nobiletin, which revealed that the chromene and arene rings of its flavone moiety, as well as the two methoxy groups bound to its arene ring, were coplanar. In contrast, the C atoms of the four methoxy groups bound to the chromene ring are out of the plane, making the molecule conformationally chiral. A comparison of the crystal structures of nobiletin revealed that it could adopt a variety of different conformations through rotation of the covalent bond between the chromene and arene rings, and the orientations of methoxy groups bound to the chromene ring.

Studies of a Large Odd-Numbered Odd-Electron Metal Ring: Inelastic Neutron Scattering and Muon Spin Relaxation Spectroscopy of Cr8 Mn

The spin dynamics of Cr₈Mn, a nine‐membered antiferromagnetic (AF) molecular nanomagnet, are investigated. Cr₈Mn is a rare example of a large odd‐membered AF ring, and has an odd‐number of 3d‐electrons present. Odd‐membered AF rings are unusual and of interest due to the presence of competing exchange interactions that result in frustrated‐spin ground states. The chemical synthesis and structures of two Cr₈Mn variants that differ only in their crystal packing are reported. Evidence of spin frustration is investigated by inelastic neutron scattering (INS) and muon spin relaxation spectroscopy (μSR). From INS studies we accurately determine an appropriate microscopic spin Hamiltonian and we show that μSR is sensitive to the ground‐spin‐state crossing from S=1/2 to S=3/2 in Cr₈Mn. The estimated width of the muon asymmetry resonance is consistent with the presence of an avoided crossing. The investigation of the internal spin structure of the ground state, through the analysis of spin‐pair correlations and scalar‐spin chirality, shows a non‐collinear spin structure that fluctuates between non‐planar states of opposite chiralities.

‘Frustrated’ hydrogen bond mediated amphiphile self-assembly – a solid state study

The effects of hydrogen bond donor acidity and counter cation within a ‘frustrated’ self-assembled, hydrogen bonded system.

Structural and morphological diversity of self-assembled synthetic γ-amino acid containing peptides

We report the synthesis of constrained amino acid building block gabapentin (Gpn) based hybrid peptides and their structural and morphological diversity in different conditions.

CH3-deprotonation of 9-methylanthracene under mild conditions

The chromophore building-block 9-methylanthracene is selectively deprotonated at the methyl group and activated for reactions with electrophiles.

PNPCB heterocycles via thermal and Lewis acid catalyzed trans-hydroborations

Reactions of iPr₂P(BH₃)N₃ and R₂PCCR affords compounds of the form R₂P(CCR)NP(BH₃)iPr₂ which undergo subsequent thermally induced or Lewis acid catalyzed intramolecular hydroboration to give PNPCB heterocycles R₂P(CCHPh)NP(BH₂)iPr₂.

Tri-, tetra-, and hexanuclear mixed-valence molybdenum clusters: structural diversity and catalysis of acetylene hydrogenation

A series of novel polynuclear molybdenum alkoxides was synthesized and explored in catalytic acetylene hydrogenation.

An unusual co-crystal [(μ2-dcpm)Ag2(μ2-O2CH)(η2-NO3)]2·[(μ2-dcpm)2Ag4(μ2-NO3)4] and its connection to the selective decarboxylation of formic acid in the gas phase

Binuclear silver cluster with μ₂-formate and μ₂-dcpm catalyses the decomposition of HCO₂H. This structural motif is present in the crystal.

Reaction environment and ligand lability in group 4 Cp2MXY (X, Y = Cl, OtBu) complexes

Ligand transfer during halide metathesis with group 4 metallocenes depends on whether a polar solvent is used or not.

Coordination of o-benzosemiquinonate, o-iminobenzosemiquinonate, 4,4′-di-tert-butyl-2,2′-bipyridine and 1,10-phenanthroline anion radicals to oxidovanadium(iv)

Coordination of semiquinonate and heterocyclic α-diimine anion radicals to oxidovanadium(iv) is authenticated.

Coordination compounds of a hydrazone derivative with Co(iii), Ni(ii), Cu(ii) and Zn(ii): synthesis, characterization, reactivity assessment and biological evaluation

Increasing inhibitory effect of Zn-Hp2DAP < Hp2DAP < Co-Hp2DAP on ABC transporter MDR1 drug efflux pump.

Crystal structure of catena-poly[N,N,N',N'-tetra-methyl-guanidinium [(chlorido-cadmate)-di-μ-chlorido]]

In the structure of the title salt, {(C5H14N3)[CdCl3]} n , the Cd(II) atom of the complex anion is five-coordinated by one terminal and four bridging Cl atoms. The corresponding coordination polyhedron is a distorted trigonal bipyramid, with Cd-Cl distances in the range 2.4829 (4)-2.6402 (4) Å. The bipyramids are condensed into a polyanionic zigzag chain extending parallel to [101]. The tetra-methyl-guanidinium cations are situated between the polyanionic chains and are linked to them through N-H⋯Cl hydrogen bonds, forming a layered network parallel to (010).

Guest-induced stereoselective self-assembly of quinoline-containing PdII and PtII metallacycles

The inclusion of aromatics within atropisomeric metallacycles induced stereoselectivity on the self-assembly. This selectivity is influenced by the size of the guests, the C–H⋯π interactions and the π-acceptor and hydrophobic character of the host.

Synthesis, structural characterization and biological evaluation of dinuclear gold(iii) complexes with aromatic nitrogen-containing ligands: antimicrobial activity in relation to the complex nuclearity

Dinuclear Au(iii) complexes with N-heterocycles have been synthesized and biologically evaluated.

Synthesis, X-ray characterization, DFT calculations and Hirshfeld surface analysis of thiosemicarbazone complexes of Mn+ ions (n = 2, 3; M = Ni, Cd, Mn, Co and Cu)

Herein we report the synthesis, X-ray characterization, DFT calculations and Hirshfeld surface analysis of seven complexes of transition metal ions with pyridine-based thiosemicarbazone ligands.

Synthesis and electronic structure determination of uranium(vi) ligand radical complexes

Pentagonal bipyramidal uranyl (UO₂²⁺) complexes of salen ligands were prepared and the electronic structure of the one-electron oxidized species[1a–c]+were investigated in solution.

Unexpected reactivity of an alkylaluminum complex of a non-innocent 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene ligand (dpp-bian)

The non-innocence of the bis-amido dpp-bian ligand has been documented by the reactions of compound 1 with acidic substrates, e.g. water.

Crystal structures of ethyl 6-(4-methyl-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate and ethyl 6-(4-fluoro-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate

The crystal structures of two chromone derivatives, viz. ethyl 6-(4-methyl-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate, C19H16O4, (1), and ethyl 6-(4-fluoro-phen-yl)-4-oxo-4H-chromene-2-carboxyl-ate C18H13FO4, (2), have been determined: (1) crystallizes with two mol-ecules in the asymmetric unit. A comparison of the dihedral angles beween the mean planes of the central chromone core with those of the substituents, an ethyl ester moiety at the 2-position and a para-substituted phenyl ring at the 6-position shows that each mol-ecule differs significantly from the others, even the two independent mol-ecules (a and b) of (1). In all three mol-ecules, the carbonyl groups of the chromone and the carboxyl-ate are trans-related. The supra-molecular structure of (1) involves only weak C-H⋯π inter-actions between H atoms of the substituent phenyl group and the phenyl group, which link mol-ecules into a chain of alternating mol-ecules a and b, and weak π-π stacking inter-actions between the chromone units. The packing in (2) involves C-H⋯O inter-actions, which form a network of two inter-secting ladders involving the carbonyl atom of the carboxyl-ate group as the acceptor for H atoms at the 7-position of the chromone ring and from an ortho-H atom of the exocyclic benzene ring. The carbonyl atom of the chromone acts as an acceptor from a meta-H atom of the exocyclic benzene ring. π-π inter-actions stack the mol-ecules by unit translation along the a axis.