1D Double Chain Research Articles

Heteronuclear cadmium(II)/cobalt(III) cyanide coordination polymers with 1-methylimidazole and 1-ethylimidazole ligands: synthesis, characterization and catalytic activities

Two new heteronuclear Cd(II)/Co(III) compounds, {[Cd(1-meim)3Cd0.5(1-meim)Co(μ-CN)4(CN)2]}n (1) and {[Cd(1-etim)3Cd0.5(1-etim)2Co(μ-CN)3(CN)3]⋅H2O}n (2) (1-meim: 1-methylimidazole, 1-etim = 1-ethylimidazole), have been synthesized and characterized using elemental analysis, FT-IR and Raman spectroscopy, single-crystal X-ray diffraction techniques. The single crystal X-ray study shows that the compound 1 exhibited a 1D double chain structure and is further linked into 3D supramolecular architectures through CH⋅⋅⋅N and π⋅⋅⋅π interactions. Whereas the compound 2 displayed 2D network which is extended into a 3D supramolecular framework by OH⋅⋅⋅N hydrogen bonds and CH∙∙∙π interactions. In 1 and 2, each Co(III) ion is coordinated by six carbon atoms from cyanide ligands, thus showing an octahedral coordination geometry. Cd1 and Cd2 ions exhibited two different geometries, distorted trigonal bipyramidal and octahedral. Furthermore, phase purities, catalytic and thermal properties were investigated.

Syntheses, characterizations and photochromic properties of 1D→2D polycatenated cationic coordination polymers based on the flexible tripodal zwitterionic ligand

Two new coordination compounds, namely, {[ZnBr(µ3-tazna)]NO3·4H2O}n (1) and {[CdBr(µ3-tazna)]ClO4·2H2O}n (2) were solvothermally synthesized from the 1,1′,1′′-(((1,3,5-triazin-2,4,6-triyl)tris(benzene-4,1-diyl))tris(methylene))tris(3-carboxypyridin-1-ium) bromide (H3taznaBr3) ligand and characterized by IR spectroscopy, elemental analysis, X-ray single-crystal diffraction, X-ray powder diffraction (PXRD), and thermal analyses techniques. Single-crystal X-ray diffraction analysis reveals that compounds 1 and 2 crystallize in the triclinic system, P-1 space group. In 1 and 2, Zn(II) and Cd(II) centers are bridged by tazna ligands, displaying a rare 1D → 2D structure formed by the catenation of a 1D double chain. The photochromic behavior of compound 2 was investigated under 365 nm UV light, exhibiting a color change from white to yellow. Furthermore, the thermal and optical absorption properties of compounds 1 and 2 were investigated.

Solvent-controlled structural variation of two Cd(II) compounds derived from thiophene dicarboxylate and 4-imidazol-1-yl-pyridine mixed ligands

Two solvent-controlled Cd(II) compounds, formulated as {[Cd2(Htdc)4(µ-imyp)(H2O)4]} (1), [Cd2(µ 2-tdc)2(µ-imyp)(DMF)2(H2O)2]n (2) (H2tdc= 2,5-thiophenedicarboxylic acid, imyp = 4-imidazol-1-yl-pyridine and DMF = N,N-dimethylformamide) have been synthesized by reactions of Cd(NO3)2·4H2O and H2tdc with imyp in different solvents, respectively. Both compounds were then characterized by single-crystal X-ray diffraction and other physicochemical methods. In 1, partially deprotonated Htdc− anion as terminal ligand and µ-imyp ligand connect Cd2+ ions to generate a discrete structure. In 2, completely deprotonated µ 2 – tdc2− anions and µ-imyp ligand link Cd2+ ions into a 1D double chain structure. Both compounds display 3D supramolecular structures through hydrogen bonding interactions. The results provided interesting insights into solvent effects on the structural formation of compounds 1 and 2. In addition, the solid-state photoluminescent properties of compounds 1 and 2 were also investigated. Two solvent-controlled Cd(II) compounds have been synthesized by reactions of Cd(NO3)2·4H2O and 2,5-thiophenedicarboxylic acid with 4-imidazol-1-yl-pyridine in the different solvents. One compound is a discrete structure, while the other compound has a 1D double chain structure. The results provided interesting insights into solvent effects on the structural formation of compounds.

Synthesis, Characterization and Optical Properties of Two Novel Metal Borates

AbstractTwo novel metal borates, namely, Ag7B9O16(OH)2 (1) and AgCa2B7O11(OH)4 (2) were obtained under hydrothermal conditions. Ag7B9O16(OH)2 crystallizes into the centrosymmetric space group of C2/c in the monoclinic crystal system and displays a unique three‐dimensional (3D) framework built by 1D double borate chains further connected by Ag cations. AgCa2B7O11(OH)4 also belongs to monoclinic space group C2/c and it features borate chains with B8O8 8‐membered rings along the c axis which are further coordinated via AgO3 into 2D layers. These layers are bridged via CaO8 polyhedron into the final 3D framework. Two compounds were further characterized through thermogravimetric and optical analysis and density functional theory calculation have also been carried out, addressing their electronic structures.

Extending Unique 1D Double-Chains to 2D Layers with Birefringent Gain by Introducing a Hydroxyl Group.

It remains a significant hurdle for discovering birefringent materials in the deep ultraviolet (DUV, λ < 200 nm). It is well-known that the OH anions are recognized for their capability to eliminate the dangling bonds from terminal oxygen atoms, promoting the ultraviolet (UV) cutoff edge blueshift and regulating the crystal structure. Here, two new barium hydroxyborates, Ba3B11O18(OH)3(H2O) (BaBOH) and Na2BaB10O16(OH)2(H2O)2 (NaBaBOH), were designed and synthesized while displaying different dimensions. Remarkably, BaBOH presents novel one-dimensional (1D) [B22O37(OH)6]∞ double-chains formed by a new fundamental building block (FBB)[B11O21(OH)3]. NaBaBOH possesses a 2D [B10O16(OH)2]∞ layer with a less common FBB [B10O19(OH)2]. They enrich the structural diversity of hydroxyborates. Moreover, NaBaBOH exhibits a broad transparent window within the DUV spectral range (<190 nm) and possesses a favorable birefringence of 0.064. Furthermore, detailed summaries and structural comparisons have been implemented for all hydroxyborates containing alkali and alkaline-earth metals. This reveals that the OH group modulation strategy can be appropriately employed for the structural design.

Tuning the Emission of Homometallic DyIII, TbIII, and EuIII 1-D Coordination Polymers with 2,6-Di(1H-1,2,4-triazole-1-yl-methyl)-4-R-phenoxo Ligands: Sensitization through the Singlet State.

This work reports the structural characterization and photophysical properties of DyIII, TbIII, and EuIII coordination polymers with two phenoxo-triazole-based ligands [2,6-di(1H-1,2,4-triazole-1-yl-methyl)-4-R-phenoxo, LRTr (R = CH3; Cl)]. These ligands permitted us to obtain isostructural polymers, described as a 1D double chain, with LnIII being nona-coordinated. The energies of the ligand triplet (T1) states were estimated using low-temperature time-resolved emission spectra of YIII analogues. Compounds with LClTr present higher emission intensity than those with LMeTr. The emission of TbIII compounds was not affected by the different excitation wavelengths used and was emitted in the pure green region. In contrast, DyLMeTr emits in the blue-to-white region, while the luminescence of DyLClTr remains in the white region for all excitation wavelengths. On the other hand, EuIII compounds emit in the blue (ligand) or red region (EuIII) depending on the substituent of the phenoxo moiety and excitation wavelength. Theoretical calculations were employed to determine the excited states of the ligands by using time-dependent density functional theory. These calculations aided in modeling the intramolecular energy transfer and rationalizing the optical properties and demonstrated that the sensitization of the LnIII ions is driven via S1 → LnIII, a process that is less common as compared to T1 → LnIII.

First-Principles Thermodynamics of CsSnI3.

CsSnI3 is a promising ecofriendly solution for energy harvesting technologies. It exists at room temperature in either a black perovskite polymorph or a yellow 1D double-chain, which irreversibly deteriorates in the air. In this work, we unveil the relative thermodynamic stability between the two structures with a first-principles sampling of the CsSnI3 finite-temperature phase diagram, discovering how it is driven by anomalously large quantum and anharmonic ionic fluctuations. Thanks to a comprehensive treatment of anharmonicity, the simulations deliver a remarkable agreement with known experimental data for the transition temperatures of the orthorhombic, rhombohedral, and cubic perovskite structures and the thermal expansion coefficient. We disclose how the perovskite polymorphs are the ground state above 270 K and discover an abnormal decrease in heat capacity upon heating in the cubic black perovskite. Our results also significantly downplay the Cs+ rattling modes' contribution to mechanical instability. The remarkable agreement with experiments validates our methodology, which can be systematically applied to all metal halides.

Polyaromatic Group Embedded Cd(II)-Coordination Polymers for Microwave-Assisted Solvent-Free Strecker-Type Cyanation of Acetals.

In this work, two new 1D Cd(II) coordination polymers (CPs), [Cd(L1)(NMF)2]n (1) and [Cd(L2)(DMF)(H2O)2]n·n(H2O) (2), have been synthesized, characterized and employed as catalysts for the microwave-assisted solvent-free Strecker-type cyanation of different acetals. Solvothermal reaction between the pro-ligand, 5-{(pyren-1-ylmethyl)amino}isophthalic acid (H2L1) or 5-{(anthracen-9-ylmethyl)amino}isophthalic acid (H2L2), and Cd(NO3)2.6H2O in the presence of NMF or DMF:THF solvent, produces the coordination polymer 1 or 2, respectively. These frameworks were characterized by single-crystal and powder X-ray diffraction analyses, ATR-FTIR, elemental and thermogravimetry analysis. Their structural analysis revealed that both CPs show one-dimensional structures, but CP 1 has a 1D double chain type structure whereas CP 2 is a simple one-dimensional network. In CP 1, the dinuclear {Cd2(COO)4} unit acts as a secondary building unit (SBU) and the assembly of dinuclear SBUs with deprotonated ligand (L12-) led to the formation of a 1D double chain framework. In contrast, no SBU was observed in CP 2. To test the catalytic effectiveness of these 1D compounds, the solvent-free Strecker-type cyanation reactions of different acetals in presence of trimethylsilyl cyanide (TMSCN) was studied with CPs 1 and 2 as heterogenous catalysts. CP 1 displays a higher activity (yield 95%) compared to CP 2 (yield 84%) after the same reaction time. This is accounted for by the strong hydrogen bonding packing network in CP 2 that hampers the accessibility of the metal centers, and the presence of the dinuclear Cd(II) SBU in CP 1 which can promote the catalytic process in comparison with the mononuclear Cd(II) center in CP 2. Moreover, the recyclability and heterogeneity of both CPs were tested, demonstrating that they can be recyclable for at least for four cycles without losing their structural integrity and catalytic activity.

Multifunctional Cd-CP for fluorescence sensing of Cr(VI), MnO4−, acetylacetone and ascorbic acid in aqueous solutions

The development of multifunctional fluorescent chemosensors for the detection of multiple targets remains challenging but of great importance. In this paper, one novel coordination polymer (CP), denoted as [Cd2(edda)(phen)2]∙H2O (compound 1, H4edda = 5,5′ (ethane-1,2-diylbis(oxy)) diisophthalic acid, phen = 1,10-phenanthroline) is successfully designed and prepared under hydrothermal conditions. Structural analysis indicates that compound 1 possesses a one-dimensional (1D) double chain structure, then self-assembles into a three-dimensional (3D) supramolecular framework via π…π interactions between phen molecules. Interestingly, compound 1 is found to be tolerant in wide range of acidic to alkaline aqueous solutions (pH = 2–13). Fluorescent spectral investigations reveal that compound 1 exhibits highly selective and sensitive fluorescence responses toward MnO4−, Cr(VI) ions, acetylacetone (acac) and ascorbic acid (AA) by fluorescence quenching in the aqueous phase. The detection limits are in the very low range, reaching μM level for the detection of MnO4−, Cr(VI) ions, nM for AA and ppm for acac detection. The distinguished multi-responsive performance suggests compound 1 to be a potential multifunctional probe. Furthermore, the possible quenching mechanisms have also been systematically investigated in this work.

Synthesis, Characterization and The Effect of the Auxiliary Ligands on the Dimensionality of Two Cobalt(II)-Fumarate Coordination Polymers with Bis(imidazole) Ligands

Two new Co(II) coordination polymers, namely {[Co(m-fum)0.5(m-obix)2(H2O)](NO3)}n (1), {[Co(m-fum)0.5(m-mbix)2(H2O)](NO3)}n (2), (H2fum: fumaric acid, obix:1,2-bis(imidazol-1-yl-methyl)benzene, mbix: 1,3-bis(imidazol-1-yl-methyl)benzene), have been successfully synthesized under hydrothermal conditions. They have been structurally characterized by elemental analysis, IR spectra, single crystal X-ray diffraction, powder X-ray diffraction (PXRD), magnetic properties. Single-crystal X-ray analysis reveals that the asymmetric units of both CPs contain a Co(II) ion, half fumarate ligand, two bis(imidazole) ligands, one aqua ligand and a nitrate ion. While two symmetry-related Co1 ions are connected by one fumarate ligand to generate a dinuclear unit and obix ligand links adjacent dinuclear units through the nitrogen atoms to form a 1D double chains in 1, each mbix ligand links two Co1 ions to form 1D double chains, and the adjacent chains are further linked together by fumarate ligands to form a 2D network in 2. The effect of bis(imidazole) ligands, which are o- and m-isomers, on the dimensionality of the formed coordination polymer was investigated. The reason for this great effect of bis(imidazole) ligands is that adjustments in the framework occur result of the bending of the semi-rigid imidazole ligands. Thermal analysis shows that 1 and 2 possess similar thermal behaviors. The optical band gap energy values of 1 and 2 observed 3.24 eV and 3.21 eV, respectively. This small difference in the band gap energy may be due to the difference in structural arrangement.

Antiparallel π···π and C−H···H−C contacts in a novel Zn(II) coordination solid involving π-hole tetrel bonding interactions: A combined experimental and theoretical study, Hirshfeld surface analysis, molecular docking and potential drug property

A new Zn(II) coordination complex viz. [Zn(η2-Bz)(3-CNpy)(H2O)3]·Bz (1) [Bz = benzoate and 3-CNpy = 3-cyanopyridine] has been synthesized at room temperature and characterized by elemental analyses, electronic spectroscopy, FT-IR spectroscopy and single crystal X-ray diffraction.The molecules of 1 self-complimentarily assemble to form a 1D double-chain, stabilized by antiparallel π···π, C−H···H−C and π(nitrile)···π interactions along with other non-covalent interactions. These double-chains get interconnected through hydrogen bonding and π-hole tetrel bonding interactions to give a layered supramolecular architecture for 1. The interesting non-covalent interactions in 1 are studied by Hirshfeld surface analysis and different theoretical tools.The compound was docked with esterase as well as with glucosidase in order to check its biological potential. It was depicted from results that the compound 1 showed good docking score along interactions (2D and 3D) with amino acid residues located on the active sites of the selected enzymes. These in silico studies predicted that the synthesized compound may be effective against diseases related to these enzymes. To investigate the drug potential of 1, its pharmacokinetic and toxicokinetic properties were evaluated by ADMET calculations.

Highly selective detection of Fe3+ and nitro explosives by a bifunctional sensor based on Cd(II) complex

A cadmium fluorescence framework [Cd(sip)(dpa)(H2O)] n (1) (NaH2sip = sodium 5-sulfoisophthalate; dpa = 4,4’-dipyridylamine) has been successfully synthesized and characterized. Single crystal X-ray diffraction analysis reveals that complex 1 exhibits an infinite 1D double chain, the H-bonds extend the 1D chains into a 3D supermolecular framework. Fluorescent studies reveal that 1 can be used as a highly sensitive luminescent sensor for detecting Fe3+ ion in H2O and 4-nitrophenol (4-NP) in DMF within a few seconds through fluorescence quenching. The sensing mechanism for Fe3+ can be explained in terms of synergistic competitive absorption and coordination interactions between Fe3+ and the framework, while the mechanism for detecting 4-NP is mainly attributed to the competitive absorption between the excitation/emission of 1 and analytes.

Knoevenagel condensation reaction in supercritical carbon dioxide medium using a Zn(II) coordination polymer as catalyst

The replacement of conventional organic solvents by the so-called “green solvents” is a usual approach to more sustainable chemical processes. Supercritical carbon dioxide (scCO2) has been successfully regarded as a candidate for such a purpose. Moreover, it possesses moderate critical pressure and temperature conditions and may be easily separated from the catalytic system by a simple depressurization. In the present work, the new Zn(II) coordination polymer [Zn(L1)(NMeF)]n·n(NMeF) (Zn-CP 1) is reported, being prepared by the solvothermal reaction of 5-{(pyren-4-ylmethyl)amino}isophthalic acid (H2L1) with Zn(NO3)2·6H2O in N-methylformamide (NMeF). The SCXRD analysis revealed that Zn-CP 1 has a 1D double chain type of structure. Its potential as catalyst was studied in the Knoevenagel condensation of benzaldehyde and malononitrile as a model reaction under mild conditions, in scCO2 medium. An increasing trend was observed in the reaction yield as we moved from aprotic (THF) to protic (EtOH and H2O) polar co-solvents, reaching the full conversion in the case of water. It was found that scCO2, in the absence of a protic co-solvent, is not the most suitable medium for this reaction. The catalyst can be recycled without a considerable loss of activity; SEM, PXRD, FT-IR and TGA analyses indicate its high stability throughout the process.

A new Cu(II) metal–organic architecture driven by ether-bridged dicarboxylate: Photocatalytic properties and Hirshfeld surface analysis

A new Cu(II) coordination polymer with formula {[Cu(L)(bbi)(H2O)]•H2O}n (1) (H2L = 1,3-bis(3ˊ-carboxylatophenoxy)benzene, bbi = 1,1′-(1,4-butanediyl)bis(imidazole)), has been prepared and characterized using microanalysis, single crystal and powder X-ray diffraction techniques. The polymer 1 possess 1D double chain, which further extends into 2D layer through packing and hydrogen bond interactions. The polymer has been used as an effective photocatalyst for the photodisintegration of aromatic dyes viz. methyl violet (MV), Rhodamine B (Rh B) and methylene blue (MB). The results suggest that 1 is best photocatalyst for MB and decomposed 84.14% MB in 100 min following pseudo-first order reaction with rate constant k 0.01873 min−1. Furthermore, the possible photocatalytic mechanism exhibited by 1 for the catalytic degradation of MB was proposed using the trapping experiments and LC-MS methodology which suggested that ·OH is the main reactive oxygen species involved in photodecomposition of MB. In addition, band gap calculations and Hirshfeld surface analysis have been done to substantiate the photocatalytic mechanism.

Self-Assembly of 1D Double-Chain and 3D Diamondoid Networks of Lanthanide Coordination Polymers through In Situ-Generated Ligands: High-Pressure CO2 Adsorption and Photoluminescence Properties.

Two new lanthanide-based coordination polymers, [Sm2(bzz)(ben)6(H2O)3]·0.5H2O (1) and [Eu(bbz)(ben)3] (2), were synthesized and characterized. The described products were formed from in situ-generated benzoate (ben) and N’-benzoylbenzohydrazide (bbz) ligands, which were the products of transformation of originally added benzhydrazide (bzz) under hydrothermal conditions. Compound 1 exhibits a one-dimensional (1D) double-chain structure built up from the connection of the central Sm3+ ions with a mixture of bzz and ben ligands. On the other hand, 2 features a 3D network with a 4-connected (66) dia topology constructed from dinuclear [Eu2(ben)6] secondary building units and bbz linkers. High-pressure CO2 sorption studies of activated 1 show that maximum uptake increases to exceptionally high values of 376.7 cm3 g−1 (42.5 wt%) under a pressure of 50 bar at 298 K with good recyclability. Meanwhile, 2 shows a typical red emission in the solid state at room temperature with the decay lifetime of 1.2 ms.

Three new V‐shape dicarboxylate coordination polymers: syntheses, crystal structures and properties

AbstractThree new coordination polymers (CPs) with the formulas of [Zn2(SDBA)2(im)4]n (1), [CdCa(SDBA)2(DMA)(H2O)]n ⋅ 2n(DMA) (2) and [Cu(SDBA)0.5(μ2‐OH)]n (3) (H2SDBA=4,4’‐dicarboxybiphenyl sulfone, im=imidazole, DMA=N,N’‐dimethylacetamide) have been synthesized under hydro(solvo)thermal conditions and characterized by elemental analyses, powder x‐ray diffraction analyses, thermogravimetric analyses and single crystal X‐ray structural analyses. CP 1 displays a 1D double chain structure consolidated by N−H⋅⋅⋅O hydrogen bonds, which are further extended into a 3D supramolecular framework via the help of intermolecular N−H⋅⋅⋅O hydrogen bonds. CP 2 features a 2D layered structure based on 1D −[Cd−(COO)2−Ca]n− chains. Interestingly, in this 2D layer there exists large 1D channels that are occupied by the coordinated DMA molecules, coordinated water molecules and free DMA molecules. CP 3 has a 3D framework based on 1D −[Cu−(COO)(μ2‐OH)−Cu]n− chains. The luminescent properties of CPs 1 and 2, gas adsorption properties of 2 a (solvent‐free form of CP 2), and photocatalytic property of CP 3 were also investigated.

An unprecedented polyoxometalate-based 1D double chain compound with opposite charges enables conductivity improvement.

A POM-based one-dimensional (1D) chain compound, {BW12O40[Cu(2,2'-bipy)2]2[Cu(2,2'-bipy)(H2O)]}{BW12O40[Cu(2,2'-bipy)2][Cu(2,2'-bipy)(H2O)2]}·7H2O, has been synthesized and structurally characterized, which represents an unprecedented 1D double chain structure with opposite charges. In contrast to common POMs, this compound exhibits a relatively high electrical conductivity of 1.17 × 10-9 S cm-1 at 25 °C. In addition, its semiconducting properties have also been investigated by application of photoelectrochemical sensing of H2O2.

Synthesis, Structure and Luminescent Property of a 3D Layered-Pillared Cd(II) Metal–Organic Framework Derived from Mixed Rigid and Flexible Ligands

A new 3D Cd(II) metal–organic framework of [Cd2(HIDC)2(bibp)1.5]n (1) was synthesized hydrothermally by the reaction of imidazole-4,5-dicarboxylic acid (H2IDC) and 4,4′-bis(imidazol-1-ylmethyl)biphenyl (bibp) with Cd(NO3)2·4H2O. Single-crystal X-ray diffraction analysis reveals that this compound crystallizes in triclinic, space group Pī with a = 9.6610(3), b = 15.5866(5), c = 16.0228(6) Ǻ, α = 110.662(3), β = 101.521(3), γ = 107.115(3)˚, V = 2029.46(15) Ǻ3, Z = 2, Dc = 1.644 g cm−3, µ = 1.113 mm−1, F(000) = 1002, the final R1 = 0.0468 and wR2 = 0.0962 for 8932 observed reflections with I > 2σ(I). In 1, the alternately interconnection of Cd(II) ions by µ2-HIDC2− and µ3-HIDC2− anions resulted in the formation of 1D [Cd2(µ2-HIDC)(µ3-HIDC)]∞ with the right- and left-helical chains, which were further linked by the oxygen atoms derived from one of the carboxylate groups of µ3-HIDC2− anions, generating the 1D double helical chain structure of [Cd4(µ2-HIDC)2(µ3-HIDC)2]∞ along a axis. These adjacent 1D double chains are further linked by cis-µ2-bibp ligands to form a 2D network structure of [Cd4(µ2-HIDC)2(µ3-HIDC)2(cis-µ2-bibp)2]n, which are further pillared by trans-µ2-bibp ligands to generate a 3D layered-pillared metal–organic framework architecture of [Cd4(µ2-HIDC)2(µ3-HIDC)2(cis-µ2-bibp)2(trans-µ2-bibp)]n. Furthermore, the thermal stability and luminescent property of 1 have also been investigated. A 3D Cd(II) layered-pillared metal–organic framework was synthesized hydrothermally. This new compound displays high thermal stability and intense fluorescent emission.

PH-dependent two Cd(II) coordination architectures with methyl-3-hydroxy-5-carboxy-2-thiophenecarboxylate and 1,3-bis(4-pyridyl)propane mixed ligands: syntheses, crystal structures, and photoluminescent properties

ABSTRACTTwo new Sulfur-containing cadmium(II) coordination polymers {[Cd(HL)2](bpp)}n (1) and {[Cd(L)(bpp)(H2O)]}n (2) (H2L = methyl-3-hydroxy-5-carboxy-2-thiophenecarboxylate, and bpp = 1,3-bis(4-pyridyl)propane) have been synthesized under different pH conditions and structurally characterized by the single-crystal X-ray diffraction and other physicochemical techniques. Structural analyses reveal that compound 1 exhibits a 1D double chain structure based upon dimeric [Cd2(COO)2] subunit. Compound 2 features a 3D network which can be rationalized as a 3-fold 4-connected dia net. It is shown that the pH plays a crucial role in the formation of the resulting structures. Furthermore, solid photoluminescent properties of the two compounds make them potentially useful photoactive materials.

One-Dimensional Double Chains in Sodium-Based Quaternary Chalcogenides Displaying Intriguing Red Emission and Large Optical Anisotropy.

A new family of Na3AgSnQ4 (Q = S or Se) and Na3MIIInS4 (MII = Cd or Hg) was successfully synthesized in vacuum-sealed silica tubes for the first time. They exhibit similar isolated one-dimensional (1D) double chains {[AgSnQ4]n vs [(MII/In)S4]n} in their structures. After the detailed survey on the Inorganic Crystal Structure Database, title compounds can be described as the first discovered examples exhibiting novel 1D double-chain configurations in the known 171 (MIB and MIVA) or 48 (MIIB and MIIIA) element-based quaternary A-MIB/MIIB-MIVA/MIIIA-Q chalcogenides. In addition, their dimensionalities on the mode of connection between two anionic groups are closely related to the empirical A/(IB+IVA) and A/(IIB+IIIA) in the unit cell or the (IB+IVA)/Q and (IIB+IIIA)/Q ratios, which may produce a good way to predict and design new chalcogenides with low-dimensional structures. Photoluminescence measurement shows that Na3CdGaS4 and Na3CdInS4 display strong red emission (648 and 647 nm) at room temperature that also agrees well with the change in color from yellow to red under the irradiation of an ultraviolet lamp. Moreover, all of the title crystals exhibit a large optical anisotropy (Δn@1064 nm ≥ 0.13), and isolated 1D double chains may produce a huge effect to enhance optical anisotropy based on the first-principles calculations, which also gives us a feasible way to design new birefringent materials.