Highly dynamic 1D coordination polymers for adsorption and separation applications

Roles of Water Molecules in the Structures and Magnetic Properties of Coordination Polymers with a Dicarboxylate Ligand

Three new coordination polymers, {[M(nbpdc)(DMF)(H2O)2]·H2O}∞ (M = Co and Ni) and [Zn(nbpdc)(DMF)(H2O)]∞, were synthesized from 2-nitrobiphenyl-4,4'-dicarboxylate (nbpdc2-). The isomorphous Co(II) and Ni(II) compounds exhibited a two-dimensional coordination network in which the chains with single-water bridges and the chains with single-nbpdc2- bridges intersected each other by sharing the metal ions. The coordination networks were connected with uncoordinated water molecules through hydrogen bonds. The rarely identified single-water-bridged coordination chain was reinforced by water-based intrachain hydrogen bonds. The single-water bridges mediated modest antiferromagnetic superexchange in both Co(II) and Ni(II) compounds and afforded a spin-canting structure for the Co(II) compound at low temperatures. Water molecules played a distinct structural role in the Zn(II) compound, which was a one-dimensional coordination polymer with single-nbpdc2- bridges. Instead of bridging metal ions, each water molecule was coordinated to one metal ion and hydrogen-bonded to the coordination spheres of other two metal ions, resulting to an infinite ladderlike hydrogen-bonding motif. The ladders interlinked the nbpdc-bridged chains into a three-dimensional supramolecular architecture featuring the 5-conneted {44.64} net.

Coordination Polymers of Vanadium and Selected Metal Ions with N,O-Donor Schiff Base Ligands-Synthesis, Crystal Structure, and Application

This review provides an overview of the synthesis, characterization and application of coordination polymers based on N,O-donor Schiff base ligands. The coordination polymers (CPs) represent a novel class of inorganic-organic hybrid materials with tunable compositions and fascinating structures. They are composed of metal ions and organic ligands. Therefore, the nature of the metal ion and type of organic ligand is the most significant factor in constructing targeted coordination polymers with the desired properties. Due to the versatile coordination modes, N,O-donor Schiff base ligands are also used to construct various CPs.

Semiconducting Cu(I) Framework for Room Temperature NO2 Sensing via Efficient Charge Transfer

Efficient room-temperature sensors for toxic gases are essential to ensure a safe and healthy life. Conducting frameworks have shown great promise in advancing gas sensing technologies. In this study, two new organic-inorganic frameworks [Cu2X2(PPh3)2(L)]n, CP1 (X = I) and CP2 (X = Br) have been synthesized using (pyridin-4-yl)-N-(4H-1,2,4-triazol-4-yl)methanimine (L) and triphenylphosphine. These frameworks exhibit distinct structural arrangements to generate 1D coordination polymers (CPs). Due to their semiconducting properties, both CPs are fabricated into conventional interdigitated electrodes by drop-casting. Benefitting from the higher electron density of the Cu(I) center, CP1 demonstrates selective sensing for NO2 gas with excellent sensitivity and reversibility. The material offers one of the best room temperature NO2 chemiresistive sensing performances among the MOF/CP-based materials with ultrafast response time (15.5 s @10 ppm). Additionally, convenient synthesis and ease of device fabrication for sensing give the material a distinct advantage. The experimental and theoretical findings collectively suggest that the adsorption of NO2 on the material's surface and the concomitant effective charge transfer between Cu(I) and NO2 are key to its efficacious gas sensing capabilities.

Silver 4,4'-Vinylenedipyridine Coordination Polymers: Linker Effects on Formation Thermodynamics and Anion Exchange

Four new and one previously reported silver 4,4'-vinylenedipyridine (Vpe) coordination polymers were tested as anion exchange materials to assess their potential for pollutant sequestration and compared to analogous silver 4,4'-bipyridine (bipy) coordination polymers. The materials were synthesized using nitrate, tetrafluoroborate, perchlorate, perrhenate, or chromate as the anion to produce cationic coordination polymers with solubilities ranging from 0.0137(7) to 0.21(5) mM. These values are much lower than silver bipy coordination polymers [0.045(3) to 5.5(5) mM] and agree with thermochemical calculations. [Ag(Vpe)+][BF4-], [Ag2(Vpe)2.52+][CrO42-]·5H2O, and [Ag(Vpe)+][ReO4-]·2H2O structures are reported. Perrhenate and chromate ions in an equimolar solution were fully adsorbed by [Ag(Vpe)+][NO3-]·3H2O [620(2) and 137.1(6) mg/g, respectively] as well as by [Ag(Vpe)+][BF4-] [661.8(3) and 190(3) mg/g, respectively] via anion exchange. DFT calculations show that torsional energetics play a significant role in the formation thermodynamics by reducing the energy cost by as much as 4.8 kJ/mol when bipy is replaced with Vpe in silver-based coordination polymers. The results obtained with the flat Vpe ligand highlight the potential role of coordination polymers in practical anion exchange.

Diamagnetic Carrier-Doping-Induced Continuous Electronic and Magnetic Crossover in One-Dimensional Coordination Polymers

The potential to introduce tunable electrical conductivity and molecular magnetism through carrier doping in metal-organic coordination polymers is particularly promising for nanoelectronics applications. Precise control of the doping level is essential for determining the electronic and magnetic properties. In this study, we present a series of one-dimensional coordination polymers, {(HNEt3)0.5[CuxCo(1-x)(L)]}n (HNEt3 = triethylammonium, L = 1,2,4,5-tetrakis(methanesulfonamido)benzene), doped with diamagnetic Cu1+ carriers. Through comprehensive characterization of the structural, optical, and magnetic properties, we observed continuous electronic and magnetic crossover as the doping level was gradually increased. When x < 0.5, the doped compounds exhibit ferromagnetic insulating behavior with very high energy barriers (Ueff up to 560 K) and excellent slow relaxation of magnetization. At x = 0.5, {(HNEt3)0.5[Cu0.5Co0.5(L)]}n functions as a paramagnetic semiconductor at high temperatures and a single-molecule magnet at low temperatures. When x > 0.5, the doped compounds act as diluted antiferromagnetic semiconductors with narrow band gaps (Ea = 0.2 eV). The emergence of such rich electronic and magnetic crossovers is ascribed to the cooperation of the strong electron-donating ability of the ligand and the pronounced crystal-field effects. Our findings indicate that one-dimensional (1D) coordination polymers are promising for the design of novel low-dimensional magnetic semiconductors.

Dynamic Interchain Motion in 1D Tetrathiafulvalene-Based Coordination Polymers for Highly Sensitive Molecular Recognition

The application of electrically conductive 1D coordination polymers (1D CPs) in nanoelectronic molecular recognition is theoretically promising yet rarely explored due to the challenges in their synthesis and optimization of electrical properties. In this regard, two tetrathiafulvalene-based 1D CPs, namely [Co(m-H2TTFTB)(DMF)2(H2O)]n (Co-m-TTFTB), and {[Ni(m-H2TTFTB)(CH3CH2OH)1.5(H2O)1.5]·(H2O)0.5}n (Ni-m-TTFTB) are successfully constructed. The shorter S···S contacts between the [M(solvent)3(m-H2TTFTB)]n chains contribute to a significant improvement in their electrical conductivities. The powder X-ray diffraction (PXRD) under different organic solvents reveals the flexible and dynamic structural characteristic of M-m-TTFTB, which, combined with the 1D morphology, lead to their excellent performance for sensitive detection of volatile organic compounds. Co-m-TTFTB achieves a limit of detection for ethanol vapor down to 0.5 ppm, which is superior to the state-of-the-art chemiresistive sensors based on metal-organic frameworks or organic polymers at room temperature. In situ diffuse reflectance infrared Fourier transform spectroscopy, PXRD measurements and density functional theory calculations reveal the molecular insertion sensing mechanism and the corresponding structure-function relationship. This work expands the applicable scenario of 1D CPs and opens a new realm of 1D CP-based nanoelectronic sensors for highly sensitive room temperature gas detection.

2D coordination polymers of cadmium(II) and zinc(II) derived from N,N'-bis(glycinyl)pyromellitic diimide: microwave-assisted synthesis, structures, spectroscopic properties and influence of metal-ion size

Two new two-dimensional (2D) coordination polymers (CPs), namely, poly[diaqua[μ4-2,2'-(1,3,5,7-tetraoxo-1,2,3,5,6,7-hexahydropyrrolo[3,4-f]isoindole-2,6-diyl)diacetato-κ4O:O':O'':O''']cadmium(II)], [Cd(C14H6N2O8)(H2O)2]n (1), and poly[[tetraaqua[μ4-2,2'-(1,3,5,7-tetraoxo-1,2,3,5,6,7-hexahydropyrrolo[3,4-f]isoindole-2,6-diyl)diacetato-κ4O:O':O'':O'''][μ2-2,2'-(1,3,5,7-tetraoxo-1,2,3,5,6,7-hexahydropyrrolo[3,4-f]isoindole-2,6-diyl)diacetato-κ2O:O']dizinc(II)] dihydrate], {[Zn(C14H6N2O8(H2O)2]·H2O}n (2), have been synthesized by the microwave-irradiated reaction of Cd(CH3COO)2·2H2O and Zn(CH3COO)2·2H2O, respectively, with N,N'-bis(glycinyl)pyromellitic diimide {BGPD, namely, 2,2'-(1,3,5,7-tetraoxo-1,2,3,5,6,7-hexahydropyrrolo[3,4-f]isoindole-2,6-diyl)diacetic acid, H2L}. In the crystal structure of 1, the CdII ion is six-coordinated by four carboxylate O atoms from four symmetry-related L2- dianions and two coordinated water molecules, furnishing an octahedral coordination geometry. The bridging L2- dianion links four symmetry-related CdII cations into a 2D layer-like structure with a 3,4-connected bex topology. In the crystal structure of 2, the ZnII ion is five-coordinated by three carboxylate O atoms from three different L2- dianions and two coordination water molecules, furnishing a trigonal bipyramidal coordination geometry. Two crystallographically independent ligands serve as μ4- and μ2-bridges, respectively, to connect the ZnII ions, thereby forming a 2D layer with a 3,3-connected hcb topology. Crystal structure analysis reveals the presence of n→π* interactions between two carbonyl groups of the pyromellitic diimide moieties in 1 and 2. CP 1 exhibits an enhanced fluorescence emission compared with free H2L. The framework of 2 decomposes from 720 K, indicating its high thermal stability. A comparative analysis of a series of structures based on the BGPD ligand indicates that the metal-ion size has a great influence on the connection modes of the metal ions due to different steric effects, which, in turn, affects the structures of the SBUs (secondary building units) and frameworks.

Bispidine Based Hg(II) 1D Coordination Polymers of Helical Topology: Stability, Selective Adsorption and 1D to 2D Dimensionality Change Via SC-to-SC Transformation

Bispidine based Hg(II) coordination polymers of helical topology CP-MeOH and CP-EtOH are almost isostructural (they mainly differ for the solvent included in their lattice and by a small % in unit cell parameters) but they differ for everything else: i) their intrinsic stability, ii) their ability to adsorb solvents upon prior evacuation, iii) their accessible structural transformations. In particular, one of the two starting materials, once evacuated, is capable to adsorb methanol from atmospheres containing binary and ternary mixtures of volatile organic compounds (MeOH, CHCl3 and EtOH) under ambient conditions (25 °C, 1 atm) and with a marked selectivity. The other one is not, but undergoes a 1D to 2D dimensionality change which can be monitored in situ by SC-XRD through a SC-to-SC process.

Solvent-induced structural transformation in a one-dimensional coordination polymer

We have rationally designed a one-dimensional coordination polymer (1D CP), termed 1D-DGIST-18, that exhibits intrinsic structural flexibility. This 1D CP enables its expansion into a three-dimensional network through supramolecular interactions involving coordinated solvents and/or ligands. The strategic selection of solvents for solvent exchange, prior to drying, significantly influences the structures of 1D-DGIST-18 by removing certain coordinating solvents and modulating π-π stacking. Consequently, a hierarchical porosity emerges, ranging from micro- to meso- to macroporous structures, which is attributed to its inherent structural dynamics. Additionally, the formation of excimers endows 1D-DGIST-18, when immersed in acetone, with 'turn-on' fluorescence, as evidenced by fluorescence decay profiles. These structural transitions within 1D-DGIST-18 are further elucidated using single-crystal X-ray diffractometry. The insights from this study provide a foundation for the design of materials with structural dynamics and tunable properties.

In Situ Conversion of Ligand to a Coordination Polymer via a Core@Shell Crystal: A Multi-Step Phase-Dependent Structural Transformation

Two pseudopolymorphic 1D coordination polymers of the formulas [Cd(3,3'-pytz)(CH3OH)2(ClO4)2]n (1) and [Cd(3,3'-pytz)(CH3CN)2(ClO4)2]n (2) have been prepared using the electron-deficient 3,6-bis(pyridin-3-yl)-1,2,4,5-tetrazine (3,3'-pytz) ligand and cadmium perchlorate in the chloroform/methanol and chloroform/acetonitrile solvent system, respectively. It was observed that compounds 1 and 2 experienced one-step (CPreagent → CPproduct) single-crystal-to-powder structural transformation to the pure water-coordinated compound [Cd(3,3'-pytz)(H2O)2(ClO4)2]n (3) by absorbing water vapor from air (solid-gas phase transformation). Interestingly, compounds 1, 2, and 3 undergo a different transformation path and show an in situ unique three-step (CPreagent → CPproduct → Ligandintermediate → CPproduct) single-crystal-to-single-crystal (SCSC) structural transformation process through soaking in deionized water (solid-liquid phase transformation). In this fascinating transformation, we report for the first time the direct conversion of a ligand into a coordination polymer by a rare core-shell pathway in a solid-liquid phase transformation. In this process, we obtained compound {[Cd(3,3'-pytz)(H2O)4](3,3'-pytz)2(ClO4)2(H2O)6}n (4) (single-crystal = S, crystal = C, or microcrystal = P) as mixed compounds of core-shell L@4C and 4S or core-shell L@4P and 4P for compounds (1 and 2) and 3, respectively.

Dynamic Cages-Towards Nanostructured Smart Materials

The interest in capsular assemblies such as dynamic organic and coordination cages has blossomed over the last decade. Given their chemical and structural variability, these systems have found applications in diverse fields of research, including energy conversion and storage, catalysis, separation, molecular recognition, and live-cell imaging. In the exploration of the potential of these discrete architectures, they are increasingly being employed in the formation of more complex systems and smart materials. This Review highlights the most promising pathways to overcome common drawbacks of cage systems (stability, recovery) and discusses the most promising strategies for their hybridization with systems featuring various dimensionalities. Following the description of the most recent advances in the fabrication of zero to three-dimensional cage-based systems, this Review will provide the reader with the structure-dependent relationship between the employed cages and the properties of the materials.

Macroscopic handedness inversion of terbium coordination polymers achieved by doping homochiral ligand analogues

Inspired by natural biological systems, chiral or handedness inversion by altering external and internal conditions to influence intermolecular interactions is an attractive topic for regulating chiral self-assembled materials. For coordination polymers, the regulation of their helical handedness remains little reported compared to polymers and supramolecules. In this work, we choose the chiral ligands R-pempH2 (pempH2 = (1-phenylethylamino)methylphosphonic acid) and R-XpempH2 (X = F, Cl, Br) as the second ligand, which can introduce C-H⋯π and C-H⋯X interactions, doped into the reaction system of the Tb(R-cyampH)3·3H2O (cyampH2 = (1-cyclohexylethylamino)methylphosphonic acid) coordination polymer, which itself can form a right-handed superhelix by van der Waals forces, and a series of superhelices R-1H-x, R-2F-x, R-3Cl-x, and R-4Br-x with different doping ratios x were obtained, whose handedness is related to the second ligand and its doping ratio, indicating the decisive role of interchain interactions of different strengths in the helical handedness. This study could provide a new pathway for the design and self-assembly of chiral materials with controllable handedness and help the further understanding of the mechanism of self-assembly of coordination polymers forming macroscopic helical systems.

Selective Gas Sensing under a Mixed Gas Flow with a One-Dimensional Copper Coordination Polymer

Structural changes of the coordination polymer associated with gas adsorption (gate opening-type adsorption) can be linked to bulk physical properties such as magnetism, electrical conductivity, and dielectric properties. To enable real-space sensing applications, it is imperative to have a system where the selective adsorption of mixed gases can be correlated with physical properties. In this report, we demonstrate that a crystalline sample of one-dimensional (1D) coordination polymer exhibits selective CO2 adsorption while simultaneously displaying dielectric switching behavior in a mixed N2/CO2 gas environment. In the crystal of {[Cu2(2-TPA)4(pz)]·CH3CN}n (1·CH3CN), where 2-TPA and pz are 2-thiophencarboxylate and pyrazine, respectively, paddle wheel-type units of [Cu2(2-TPA)4] are bridged by pz, forming a 1D chain structure. One of the two crystallographically independent 2-TPA units was interacted with the pz moiety of the adjacent 1D chain by π···π interactions, forming a two-dimensional (2D) layer parallel to the ab plane. Activated 1 shows selective CO2 adsorption by a gate opening-type adsorption mechanism, indicating that the CO2 adsorption process is accompanied by a structural change. The change in the real part of dielectric permittivity (ε') under the mixed N2/CO2 gas flow is a result of the selective CO2 adsorption, which was supported by the enthalpy changes (ΔH) associated with CO2 adsorption in two methods: CO2 adsorption isotherms and temperature-dependent measurements of ε' under a mixed N2/CO2 gas flow. The calculated ΔH values were found to be in good agreement across both methods. The CO2 ratio in the mixed N2/CO2 gas flow increased, and the switching ratio of ε' (Δε') also increased. Notably, Δε' exhibited a marked increase beyond the pressure required for gate opening adsorption.

Catalytic activity and mechanistic investigation of 1D 2-Picolinic acid based Cu(II) coordination polymer in the selective construction of 1,4-disubstituted triazoles

The catalytic activity of 1D 2-Picolinic acid based Cu (II) coordination polymer (CP1) in click reaction was evaluated to generate 1,4-disubstituted 1,2,3-triazoles selectively. The CP1 catalyst loading of 2 mol% was applied successfully in the reaction for primary azides with diverse functionalities of terminal alkynes in green solvent (EG/H2O). Moreover, the one-pot, multicomponent click reaction involving benzyl bromide, sodium azide, and phenylacetylene was also catalyzed by CP1. The findings show that 1D 2-Picolinic acid based Cu (II) coordination polymer catalytic systems are highly efficient for green click triazoles synthesis. DFT calculation supported the plausible mechanism involved in the CP1 catalyzed click reaction.

Coordination-Guided Conformational Locking of 1D Metal-Organic Frameworks for a Tunable Stimuli-Responsive Luminescence Region

One-dimensional (1D) metal-organic frameworks (MOFs) have shown great potential for designing more sensitive and smart stimuli-responsive photoluminescence metal-organic frameworks (PL-MOFs). Herein, we propose a strategy for constructing the 1D MOFs with tunable stimuli-responsive luminescence regions based on coordination-guided conformational locking. Two flexible 1D MOF microcrystals with trans- and cis-coordination modes, respectively, were synthesized by controlling the spatial constraint of solvents. The two 1D frameworks possess different conformation lockings of gain ligands, which have a great influence on the rotating restrictions and corresponding excited-state behaviors, generating the remarkably distinct color-tunable ranges (cyan-blue to green and cyan-blue to yellow, respectively). On this basis, the two 1D MOF materials, benefiting from the varied stimuli-responsive ranges, have displayed great potential in fulfilling the anticounterfeiting and information encryption applications. These results provide valuable guidance for the development of smart MOF-based stimuli-responsive materials in information identification and data encryption.

Separation of pyrrolidine from tetrahydrofuran by using pillar[6]arene-based nonporous adaptive crystals

Pyrrolidine, an important feedstock in the chemical industry, is commonly produced via vapor-phase catalytic ammoniation of tetrahydrofuran (THF). Obtaining pyrrolidine with high purity and low energy cost has extremely high economic and environmental values. Here we offer a rapid and energy-saving method for adsorptive separation of pyrrolidine and THF by using nonporous adaptive crystals of per-ethyl pillar[6]arene (EtP6). EtP6 crystals show a superior preference towards pyrrolidine in 50 : 50 (v/v) pyrrolidine/THF mixture vapor, resulting in rapid separation. The purity of pyrrolidine reaches 95% in 15 min of separation, and after 2 h, the purity is found to be 99.9%. Single-crystal structures demonstrate that the selectivity is based on the stability difference of host-guest structures after uptake of THF or pyrrolidine and non-covalent interactions in the crystals. Besides, EtP6 crystals can be recycled efficiently after the separation process owing to reversible transformations between the guest-free and guest-loaded EtP6.

Different Topologies of Hg(II)-Bispidine 1D Coordination Polymers: Dynamic Behavior in Solvent Adsorption and Exchange Processes

One-dimensional (1D) coordination polymers (CPs) featuring three different topologies, comprising zig-zag, ribbon-like and poly-[n]-catenane structures, were obtained by reaction of Hg(II) ions with a novel bispidine ligand L3, and structurally characterized by SC- and P-XRD methods. The CPs obtained in the form of microcrystalline powders were tested for their ability to undergo solvent adsorption and exchange by P-XRD and 1 H NMR spectroscopy. The extent of their dynamic behavior was then correlated to their structural features, highlighting the role of interchain interactions established among their constituting linear arrays. Zig-zag CPs proved to be resilient to external chemical stimuli, while they differently respond to thermal treatments, depending on the solvent originally included within the CP. In the case of polycatenated structures, we observed transformations where the original topology was maintained upon guest exchange, but also cases where it changed to zig-zag, even under solid/vapor conditions (i. e., no complete dissolution of the CP). Given the presence of linear interconnected 1D channels, 3 ⋅ ClBz-polycatenanePwd is also able to trap volatile guests such as n-hexane when exposed to its vapors.

Polyaromatic Carboxylate Ligands Based Zn(II) Coordination Polymers for Ultrasound-Assisted One-Pot Tandem Deacetalization–Knoevenagel Reactions

Solvothermal reactions between the polyaromatic group containing carboxylic acid pro-ligands 5-{(pyren-1-ylmethyl)amino}isophthalic acid (H2L1) and 5-{(anthracen-9-ylmethyl)amino}isophthalic acid (H2L2) with Zn(NO3)2·6H2O led to the formation of the new 1D coordination polymer [Zn(L1)(NMF)]n (1) and four other coordination polymers, [Zn(L1)(DMF)]n (2), [Zn(L1)(4,4′-Bipy)]n (3), [Zn(L2)(DMF)(H2O)2]n·n(H2O) (4) and [Zn2(L2)2(DMF)(CH3OH)]n (5), which were previously reported by our group. Single crystal X-ray diffraction analyses revealed that the CP 1 has a one-dimensional (1D) double-chain-type structure similar to that of CP 2. For CP 3, the assembly of the Zn(II) ion with a deprotonated L12− ligand and 4,4′-bipyridine produces a 3D network. CP 4 and 5 exhibit 1D linear and 2D layered-type structures. The ultrasound-assisted tandem reactions promoted by CPs have not yet been well studied. Thus, in the present work, we have investigated the catalytic activities of the newly synthesized CP 1, as well as of the other CPs 2–5, towards the tandem deacetalization–Knoevenagel condensation reactions of various acetals under ultrasonic irradiation. They proved to be highly efficient, with special emphasis on catalyst 1, which completely converted the substrate (benzaldehyde dimethyl acetal) into the desired product (2-benzylidenemalononitrile) after 2 h. The stability of the catalysts, namely regarding the action of ultrasonic radiation, was demonstrated by their reuse, where only a slight loss of activity was observed after four cycles. Heterogeneity was also demonstrated, and no leaching was detected over the various cycles.

Phosphorus or Nitrogen - The first Phosphatriptycene in Coordination Polymer Chemistry

Phosphasilatriptycene, a phenylene spacer and a pyridyl moiety represent the building blocks of TRIP-Py, the first heteroditopic ligand featuring a phoshatriptycene scaffold. The P and N donor sites located at...

Distinct Fold-Mode Formation of Crystalline Cu(I) Helical Coordination Polymers with Alternation of the Solid-State Emission Using Shape of the Counter Anions

One-dimensional cationic coordination polymers have been a promising platform for designing solid-state physical properties through diverse coordination geometries. In particular, the folding mode of the coordination polymers that form a helical structure directly determines the metal-centered coordination environment. Herein, we report N-heterocyclic carbene (NHC) Cu(I) cationic coordination polymers with pyrazine as the linker, which construct a 4-fold or 3-fold helical column in luminescent crystals using octahedral anions (SbF₆^- and PF₆^-) or a tetrahedral anion (BF₄^-), respectively. Single-crystal XRD studies revealed that the folding modes depend on the structural shape of the counteranions, which form H-F interactions between ligands and anions. Indeed, the folding mode change from 4-fold to 3-fold by including a different shape of the counteranions, resulting in red-shifted emission from approximately 580 to 687 nm, which is difficult to modulate in the solid state.

Homochiral Dysprosium Phosphonate Nanowires: Morphology Control and Magnetic Dynamics

Controllable synthesis of uniformly distributed nanowires of coordination polymers with inherent physical functions is highly desirable but challenging. In particular, the combination of chirality and magnetism into nanowires has potential applications in multifunctional materials and spintronic devices. Herein, we report four pairs of enantiopure coordination polymers with formulae S-, R-Dy(cyampH)₃  ⋅ CH₃ COOH ⋅ 2H₂ O (S-1, R-1), S-, R-Dy(cyampH)₃  ⋅ 3H₂ O (S-2, R-2), S-, R-Dy(cyampH)₂ (C₂ H₅ COO) ⋅ 3H₂ O (S-3, R-3) and S-, R-Dy(cyampH)₃  ⋅ 0.5C₂ H₅ COOH ⋅ 2H₂ O (S-4, R-4) [cyampH₂ =S-, R-(1-cyclohexylethyl)aminomethylphosphonic acids], which were obtained depending on the pH of the reaction mixtures and the specific carboxylic acid used as pH regulator. Interestingly, compounds 3 were obtained as superlong nanowires, showing 1D neutral chain structure which contains both phosphonate and propionate anion ligands. While compounds 1, 2 and 4 appeared as block-like crystals, superhelices and nanorods, respectively, and exhibited similar neutral chain structures containing only phosphonate ligand. Slow magnetization relaxation characteristic of single-molecule magnet (SMM) behavior was observed for compounds S-1 and S-3. Theoretical calculations were performed to rationalize the magneto-structural relationships.

Structural and Thermal Investigations of Co(II) and Ni(II) Coordination Polymers Based on biphenyl-4,4'-dioxydiacetate Linker

Two coordination polymers, [Co(µ₄-L)(H₂O)₂]_n (1) and [Ni(µ-L)(H₂O)₄]_n (2), were solvothermally assembled from the corresponding metal(II) chlorides and biphenyl-4,4-dioxydiacetic acid (H₂L) as a flexible dicarboxylate linker. The cobalt(II) compound 1 featured a layer-pillared 3D metal-organic network with a cds topology, while the nickel(II) derivative 2 represented a linear chain 1D coordination polymer with a 2C1 topology. The µ₄₋ and µ-L²⁻ linkers exhibited different denticity and coordination modes in the synthesized compounds, thus contributing to their structural diversity. The dimensionality of 1 and 2 had an influence on their thermal stability and decomposition processes, which were investigated in detail by TG-DSC and TG-FTIR methods. Thermal decomposition products of coordination polymers were also analyzed by PXRD, confirming the formation of Co₃O₄/CoO and NiO as final materials. The obtained compounds broaden a family of coordination polymers assembled from flexible dicarboxylate linkers.

Selective guest inclusion of linear C6 hydrocarbons in a Zn(ii) 1D coordination polymer

Trapping of volatile unbranched C₆ hydrocarbons (hexane, 1-hexene, and 1-hexyne) in a 1D coordination polymer is reported.