Hydrothermal syntheses, characterizations and crystal structures of three new cadmium (II) amino-diphosphonates: effects of substitute groups on the structures of metal phosphonates

Hydrothermal reactions of cadmium(II) chloride with three amino-diphosphonic acids, C₆H₅CH₂N(CH₂PO₃H₂)₂ (H₄L¹), C₆H₅CH₂CH₂N(CH₂PO₃H₂)₂ (H₄L²) and 4-CH₃-C₆H₄CH₂N (CH₂PO₃H₂)₂) (H₄L³) resulted in three new metal amino-diphosphonates, namely, Cd(H₃L¹)₂, 1 Cd(H₃L²)₂·2H₂O 2 and Cd(H₃L³)₂3. In all three complexes, the Cd(II) ion is octahedrally coordinated by six phosphonate oxygen atoms from six ligands. Complexes 1 and 3 have a similar structure in which the CdO₆ octahedra are cross-linked by bridging ligands into a double chain along the c-axis, such double chains are further interlinked via hydrogen bonds between non-coordinated phosphonate oxygen atoms to form 〈100〉 and 〈200〉 layers with the phenyl groups of the ligands orientated toward the interlayer space. The structure of complex 2 features a 〈100〉 cadmium(II) diphosphonate layer. The effects of the substitute groups attached to the amine groups on the structures of the metal phosphonates are also discussed.     

Syntheses,structures, and photoluminescence of three cadmium(II) coordination polymers with flexible bis(benzimidazole) ligands

Three cadmium(II) coordination polymers, [CdBr₂(L₁)] _n (1), [CdI₂(L₂)] _n (2), and Cd₂Br₄(L₃)₂ (3), where L₁?=?1,3-bis(5,6-dimethylbenzimidazole)propane, L₂?=?1,4-bis(5,6-dimethylbenzimidazole)butane, and L₃?=?1,6-bis(5,6-dimethylbenzimidazole)hexane, have been synthesized by hydrothermal methods and characterized by elemental analyses, IR spectra, TGA, PXRD, and X-ray crystallographic diffraction. Complex 1 contains a 1-D helical chain in which CdBr₂ units are linked by L₁. For 2, each CdI₂ is connected by two different conformations of L₂ to form a 1-D zigzag chain. For 3, each CdBr₂ is linked by L₃ bridges to afford a binuclear structure. These results indicate that the spacer length of the ligands play important roles in assembly of Cd(II) coordination polymers. Thermogravimetric analyses and solid-state luminescent properties of the complexes have also been investigated.     

Two chiral cadmium carboxylate framework isomers generated by spontaneous resolution: synthesis,structures and properties

Two three-dimensional (3-D) chiral coordination polymers, [Cd(NDC)(DMF)]_n (1_L and 1_D: H₂NDC = 1,4-naphthalenedicarboxylic acid and DMF = N,N′-dimethylformamide), have been synthesized by introducing the rigid achiral dicarboxylic acid ligand under solvo-thermal conditions, without chiral template or additives. Both chiral Cd-CPs were characterized by single crystal X-ray crystallography, and structural analysis indicates that 1_L and 1_D are enantiomers based on the zigzag [Cd(COO)₂(DMF)]_n rod secondary building units, featuring the left- or right-hand 2₁ Cd-O-C-O-Cd helix chains and left- or right-hand 4₁ screw [Cd(NDC)]_n columns, respectively. The FT-IR, TGA, powder X-ray diffraction and solid-state luminescence of 1 have been investigated. It is intriguing that the evidence from the circular dichroism spectroscopies confirms enantiomeric excess in the whole spontaneous resolution crystallization.     

Two novel interpenetrated zinc(II) and cadmium(II) coordination polymers based on 4-imidazole-benzoate: Syntheses,crystal structures and properties

Two novel interpenetrated coordination polymers, [Zn(IBA)₂] _n (1) and {[Cd(IBA)₂(H₂O)]·4H₂O} _n (2), have been synthesized by using 4-imidazole-benzoic acid (HIBA) as ligand under hydrothermal conditions. Complex 1 crystallizes in a chiral space group and has a two-fold interpenetrated 2D network structure with (4,4) topology, while complex 2 is a 3D porous dia network with four nets interpenetrating each other. The SHG activity of 1 and the photoluminescent property of 2 have been investigated. Supported by the National Natural Science Foundation of China (Grant Nos. 20731004 & 20721002) and the National Basic Research Program of China (Grant No. 2007CB925103)     

Di-, tri-, tetranuclear clusters and polymeric cadmium compounds: Syntheses, structures and fluorescent properties with various linking fashions and high stability of orotates under the condition of strong bases

Assembly reactions of orotic acid (H₃dtpc ) and CdCl₂·2.5H₂O or CdSO₄·8H₂O yielded four new cadmium compounds {[Cd(H₂dtpc)(phen)(H₂O)₂]·(H₂dtpc)·4H₂O}₂ (1: solution reaction, pH=4-5, in addition of phen), [Cd₃(dtpc)₂(phen)₅]·13H₂O (2: hydrothermal reaction, initial pH=14, final pH=7.5), [Cd(Hdtpc)(H₂O)₃]₄ (3: solution reaction, initial pH=6.5, final pH=6.0), {[Cd(Hdtpc)(phen)(H₂O)]·H₂O}_n (4: hydrothermal reaction, initial pH=8; final pH=6.5), respectively. Compounds 1-4 have been characterized by IR, thermogravimetric analyses (TGA), photoluminescence analyses, single-crystal and powder X-ray diffraction (PXRD). Compound 1 is a binuclear, 2 is a trinuclear, 3 is a tetranuclear structure, and 4 possesses one-dimensional chain framework, respectively, in which the orotate ligands show seven different linking fashions in 1-4. The orotate ligands as trivalence anions are observed in the formation of orotate-compounds, in which the orotates show high stability under the extreme condition of strong basic solution, high temperature and pressure.     

Synthesis, Structure and Photoluminescence of Two Zinc Carboxyl－ate Polymers with Different Coordination Architectures

The hydrothermal reaction of ZnO with benzene‐1,4‐dicarboxylic add gave Zn·BDC·2H₂O (1) and Zn‐BDC·H₂O (2) (BDC = benzene‐1, 4‐dicarboxylate), respectively. Polymer 1 (C₄H₄O₃ZH_0.5) shows a one‐dimensional zigzag chain structure built up from the alternate connection of tetrahedral ZnO₄ and BDC units. Polymer 2 (C₄H₃O_2.5Zn_0.5) possesses a three‐dimensional framework containing infinite zigzag Zn·Zn·Zn pseudochains generated by five‐coordinate zinc centers and a rectangular channel system including three groups of different straight channels along the [001], [010] and [60–1] directions. The two metal‐organic polymeric compounds exhibit strong photoluminescent emission bands at 402 nm (λ_ex = 260 nm) (for 1) and at 344 nm and 385 nm (λ_ex = 279 nm) (for 2) in the solid state at room temperature.     

Calcium coordination compounds based on phenoxyacetic acids: microwave synthesis,thermostability and influences on the crystal structures of chlorine substituent group on ligands

Three calcium coordination compounds, [Ca(CPA)(H₂O)₄]·(CPA), 1, [Ca(MCPA)₂(H₂O)₂]·H₂O, 2, and [Ca(TCPA)₂(H₂O)₃]·2H₂O, 3 [HCPA = 3-chlorophenoxyacetic acid, HMCPA = 2-methyl-4-chlorophenoxyacetic acid, and HTCPA = 2,4,6-trichlorophenoxyacetic acid], have been synthesized by the microwave method with advantages that include shorter reaction times, lower energy consumption, and higher product yield. The structures have been characterized by IR, elemental analysis, and single-crystal X-ray diffraction. Influences on the crystal structures by changing the number and position of chlorine substituent group in phenoxyacetic acid are discussed. Steric hindrance effects involving the Cl and an ability to form the O–H?Cl hydrogen bonds enrich the structure diversity. TG analysis reveals that the thermostability for the three compounds is 3 > 1 > 2, which could be influenced by the existence of hydrogen bonds (O–H?Cl and O–H?O).     

Syntheses,crystal structures,and photoluminescence of two Cd(II) complexes with simple ligands

Two cadmium complexes, {[Cd₂(2,5-tda)₂(ip)₄]·4H₂O}_n (1) and {[Cd₂(4,4′-obb)₂(ip)₂·H₂O]·H₂O}_n (2) (2,5-tda?=?thiophene-2,5-dicarboxylic acid, 4,4′-obb?=?4,4′-oxybisbenzoic acid, ip?=?1H-imidazo[4,5-f][1, 10]-phenanthroline), were synthesized and characterized by IR, elemental analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. X-ray analysis revealed that 1 is a dinuclear complex with the 2,5-tda anion connecting two Cd ions in a μ₁-η¹:η⁰/μ₁-η¹:η⁰ coordination mode. Each dinuclear complex is further connected with neighboring complexes via hydrogen-bonding interactions. Compound 2 displays a 2-D layer structure with opened windows occupied by crystallographic water molecules. The layers are further packed via hydrogen-bonding interactions. Luminescent properties for 1 and 2 are also investigated in the solid state at room temperature.     

Cadmium iodide complexes with dimethylsulphoxide,and their crystal structures

The crystalline compounds [{CdI₂(dmso)}_n] ( 1 ,) and [Cd₂I₄(dmso)₄] ( 2 ,) provide a structural sequence illustrating the conversion of CdI₂ into the ionic derivatives [Cd(dmso)₆]²⁺ [Cd(dmso)I₃]₂^? · EtOH ( 3 ,) and [Cd(dmso)₆]²⁺ CdI₄^2? ( 4 ,), with increasing proportions of dmso. ( 1 ,) comprises polymeric chains with Cd centres linked by bridging iodide atoms, and alternately in four- and six-coordination. ( 2 ,) is a binuclear segment of the chains and can be seen as the structural forerunner of the ionic compounds ( 3 ,) and ( 4 ,). The ion packing in ( 3 ,) is loose, with lattice ethanol.     

Two 1-D metal-organic polymers constructed from bis-benzimidazole-based ligands: syntheses,crystal structures,and luminescent properties

By combination of Mn(II) and Hg(II) salts with a flexible building unit 1,1′-(1, 5-pentanediyl)bis-1H-benzimidazole (pbbm), two 1-D chain metal-organic polymers [Mn(SCN)₂(pbbm)₂] _n (1) and {[HgCl₂(pbbm)] · DMF} _n (2) have been prepared. The polymeric 1-D chains in 1 consist of parallel ribbons of rings, whereas 2 possesses a 1-D zig-zag chain framework based on tetrahedral mercury atoms bridged by pbbm molecules and terminally coordinated by two chlorides. The significant differences of these metal-organic frameworks indicate that the flexible pbbm ligand adjusts its conformation to meet the requirement of the coordination preference of the metal center. The photoluminescent properties of these new materials have been studied in the solid state at room temperature.     

Synthesis,characterisation and crystal structures of three trinuclear cadmium(II) complexes with multidentate Schiff base ligands

Three novel Schiff base Cd(II) trimeric complexes, [Cd₃(L¹)₂(SCN)₂(CF₃COO)₂] (1), [Cd₃(L¹)₂(SCN)₂(HCONMe₂)] (2) and [Cd₃(L²)₂{N(CN)₂}₂] (3) have been prepared from two different symmetrical Schiff bases H₂L¹ and H₂L² (where H₂L¹ = N¹,N³-bis(salicylideneimino)diethylenetriamine, a potentially pentadentate Schiff base with a N₃O₂ donor set, and H₂L² = N¹,N³-bis(3-methoxysalicylideneimino)diethylenetriamine, a potentially heptadentate Schiff base with a N₃O₄ donor set). All the complexes have been synthesised under similar synthetic procedures and their crystal structures have been established by single crystal X-ray diffraction methods. The ligands and their metal complexes have been characterised by analytical and spectroscopic techniques. Among the three complexes, 1 and 3 are linear whereas 2 is a cyclic trimer. In 1 and 3, all the doubly phenoxo bridged Cd(II) metal centres are in a distorted octahedral environment. In complex 2, two of the three Cd(II) centres reside in a distorted octahedral environment and the remaining one enjoys a monocapped octahedral geometry. Altogether the variety in the bridging mode of two new salen-type ligands has been established through these complexes.     

有机-无机复合杂多化合物的合成、结构及表征

利用常规水溶液法制备了三种基于饱和Keggin结构阴离子的有机-无机复合杂多化合物[Pr(pydc)(H2O)6]2H[PMo12O40]·4H2O(1)、[Nd(pydc)(H2O)6]2H[PMo12O40]·4H2O(2)和[Tb(pydc)(H2O)6]2H[PMo12O40]·4H2O(3)(pydc=2,6...     

Two 5-tetrazolylazo-8-hydroxyquinoline-based Zn(II) and Mn(II) complexes: syntheses,structures and optical properties

Two 5-tetrazolylazo-8-hydroxyquinoline (TTHQ) Zn²⁺ and Mn²⁺ complexes, [Zn(TTHQ)(en)]·2H₂O (en = ethylenediamine) (1) and [Mn₂(TTHQ)₂(H₂O)₆]·2H₂O (2), were synthesized and characterized by single-crystal X-ray diffraction analysis. Stacking (π–π) and hydrogen-bonding interactions are responsible for the stabilization of the supramolecular structures. UV–vis spectral changes and photoluminescent properties of TTHQ, 1 and 2 were investigated and a red emission was found. The hydrogen-bonding interaction energies in 1 and 2 were calculated using density functional theory at the WB97XD/6-31++G level.     

Two novel trinuclear cluster-based coordination polymers with 2,6-Di-imidazol-1-yl-pyridine: solvothermal syntheses,crystal structures,properties and Hirshfeld surface analysis

Two novel trinuclear cluster-based coordination polymers {[M₃(dip)(AcO)₆]·(X)}_n (1, M = Cu, X = CH₃OH; 2, M = Co, X = 2H₂O) (dip is 2,6-Di-imidazol-1-yl-pyridine), have been synthesised and structurally determined by single crystal X-ray diffraction, element analysis. Crystallographic unit of 1 consists of three Cu(II), six acetic ions, one dip ligand and one methanol molecule, which formed 1D chain through acetic bridges. The 1D chain further constructed 2-D network through dip ligand bridge which formed 3-D network through π···π interaction. Crystallographic unit of 2 consists of three Co(II), six acetic ions, one dip ligand and two water molecules. The trinuclear unit further formed a dimmer through dip ligand bridge which constructed 1-D through dip ligand bridge. The 1D chain further constructed 2-D network through π···π interaction. IR and UV–vis spectrum properties of 1 and 2 were studied. In addition, Hirshfeld surface analysis was also studied for 1.     

Syntheses,crystal structures and photoluminescence of three coordination polymers with 2,3-pyrazinedicarboxylic acid and N-donor ligands

The reactions between Cd(OAc)₂/Cu(NO₃)₂ and mixed ligands (2,3-pyrazinedicarboxylic acid (pzdc) and N-donor ligands) under different reaction conditions give the three title complexes 1, 2 and 3. There is a (4,8) net 2D network structure and a rectangular grid network structure in the cadmium complexes [Cd(pzdc)(phen)] · H₂O (1) and Cd₂(pzdc)₂(4,4′-bpy)(H₂O)₂ (2), respectively. The complex [Cu₄(pzdc)₄(phen)₂(H₂O)₄] · 10H₂O (3) has a 1D zigzag chain structure. The influences of coordination modes of the pzdc ligand and N-donor ligands on the superstructural diversity have been discussed. Complexes 1 and 2 exhibit strong fluorescent emission bands in the solid state at room temperature. The EPR spectrum of 3 is typical for a square-pyramidal geometry of copper (II) ions.     

Synthesis,crystal structures and fluorescence of cadmium(II) coordination polymers with derivatives of pyrazine-1,4-dioxide and thiocyanate as mixed-bridging ligands

Two Cd(II) coordination polymers have been synthesized with derivatives of pyrazine-1,4-dioxide and thiocyanate anion as bridging ligands and structurally determined by X-ray crystallography. Complex 1, [Cd(μ_1,3-SCN^?)₂(μ_1,6-L1)] _n (L1?=?2,5-dimethylpyrazine-1,4-dioxide), belongs to the triclinic, space group P 1 with a?=?5.7627(18)?Å, b?=?7.182(2)?Å, c?=?7.509(2)?Å, α?=?74.042(3)°, β?=?84.766(4)°, γ?=?88.162(4)°; complex 2, [Cd₂(μ_1,3-SCN^?)₄(μ₄-L2)] _n (L2?=?2,3,5,6-tetramethylpyrazine-1,4-dioxide), crystallizes in a monoclinic system with space group C2/m with a?=?10.194(4)?Å, b?=?13.491(6)?Å, c?=?8.140(3)?Å, β?=?120.372(4)°. Complex 1 shows a two-dimensional sheet structure, and in a direction the Cd(II) ions were coordinated by μ_1,3-SCN^? forming the one-dimensional chain and the L1 bridging ligand made the chains connect in the c direction leading to formation of a two-dimensional sheet on the ac plane. For 2 the one-dimensional chains in the a axis were constructed by coordination of μ_1,3-SCN^? bridging ligands with the Cd(II) ions, and in b and c directions the chains were joined by L2 bridging ligands leading to a three-dimensional structure. In 2 L2 displays a μ₄-bridging coordination mode. Both complexes exhibit strong fluorescence emission.     

Architectural diversity of six coordination compounds based on (S)-(+)-mandelic acid and different N-donor auxiliary ligands: syntheses,structures, and luminescent properties

Six transition metal coordination compounds with H₂mand and different N-donor ligands, [Co(Hmand)₂(2,2′-bipy)]·H₂O (1), [Ni(Hmand)₂(2,2′-bipy)]·H₂O (2), [Ni(Hmand)₂(bpe)] (3), [Zn(Hmand)₂(2,4′-bipy)(H₂O)]·2H₂O (4), [Zn(Hmand)(bpe)(H₂O)]_n[(ClO₄)]_n·nH₂O (5), and [Zn(Hmand)(4,4′-bipy)(H₂O)]_n[(ClO₄)]_n (6), were synthesized under different conditions (H₂mand = (S)-(+)-mandelic acid, bpe = 1,2-di(4-pyridyl)ethane, 4,4′-bipy = 4,4′-bipyridine, 2,4′-bipy = 2,4′-bipyridine, 2,2′-bipy = 2,2′-bipyridine). Their structures were determined by single-crystal X-ray diffraction analysis and further characterized by elemental analysis, infrared spectra, thermogravimetric analysis, powder X-ray diffraction, and circular dichroism. Compounds 1 and 2 are isostructural (0-D structures), which are extended to supramolecular 1-D chains by hydrogen bonding. Compound 3 exhibits 1-D straight chain structures, which are further linked via hydrogen bond interactions to generate a 3-D supramolecular architecture. Compound 4 displays a discrete molecular unit. Neighboring units are further linked by hydrogen bonds and π–π interactions to form a 3-D supramolecular architecture. Compound 5 displays a 2-D undulated network, further extended into a 3-D supramolecular architecture through hydrogen bond interactions. Compound 6 possesses a 2-D sheet structure. Auxiliary ligands and counteranions play an important role in the formation of final frameworks, and the hydrogen-bonding interactions and π–π stacking interactions contributed to the formation of the diverse supramolecular architectures. Compounds 1, 2, 4, 5, and 6 crystallize in chiral space groups, with the circular dichroism spectra exhibiting positive cotton effects. Furthermore, the luminescent properties of 4–6 have been examined in the solid state at room temperature, and the different crystal structures influence emission spectra significantly.     

Syntheses and crystal structures of new aurate salts of adenine or guanine nucleobases

Two new gold(III) complexes with adenine or guanine nitrogenous bases as counter‐cations were synthesized. These are 6‐amino‐7H‐purine‐1,9‐diium tetrachloridogold(III) chloride monohydrate, (C₅H₇N₅)[AuCl₄]Cl·H₂O, 1 , and 2‐amino‐6‐oxo‐6,7‐dihydro‐1H‐purin‐9‐ium tetrachloridogold(III) hemihydrate, (C₅H₆N₅O)[AuCl₄]·0.5H₂O, 2 . Their crystal structures were studied using single‐crystal X‐ray diffraction and FT–IR spectroscopic techniques. The arrangement of species in the studied crystal structures implies π‐stacking interactions, as well as concomitant C—H…π interactions, hydrogen bonds and other types of noncovalent interactions, which were studied qualitatively and quantitatively using the method of molecular Voronoi–Dirichlet polyhedra. The variation of the nitrogenous base from adenine to guanine results in evident differences in the packing of the species in the crystals of 1 and 2 . The splitting and shifting of bands in the FT–IR spectra of the title compounds reveals several features representative of noncovalent interactions in their crystal structures.     

基于三脚架羧酸和咪唑基配体的两种镉基配合物的合成、结构与荧光性质

通过水热法合成了2种镉基配位聚合物[Cd(Htatb)(1,4-bimb)]· H₂O (1)和[Cd(Htatb)(1,4-bib)( H₂O)]·DMF (2)(H3tatb=4,4′,4″-s-三嗪-2,4,6-三苯甲酸,1,4-bimb=1,4-双(咪唑-1-甲基)苯,1,4-bib=1,4-双(1-咪唑基)苯),并用X射线单晶衍射、热重分析、红外光谱和元素分析等手段对其进行了表征。1是一个2D层结构,这些层进一步通过O—H…O氢键连接,形成四重互穿3D结构。2也是2D层结构,通过O—H…O氢键进一步连接,形成二重穿插的3D结构。配合物1和2具有荧光性质。1通过不同的检测机制对硝基苯和Fe³⁺离子具有高度的选择性和敏感性,而2对2,4,6-三硝基苯酚和CrO₄^2-离子具有高度的选择性和敏感性。