Temperature-controlled Hydrothermal Synthesis of Copper(I or II) Coordination Polymers via a Variety of Copper Coordination Modes

Two 1D coordination polymers Cu₂^I(C₆N₃H₄)₂(1) and Cu^II(C₆N₃H₄)₂·H₂O(2) based on benzotriazole(Bta) were hydrothermally synthesized by controlling the crystallization temperature. Single-crystal X-ray diffraction (XRD) analyses reveal that compound 1 is a 1D tubular structure constructed from two types of 1D chains {-Cu-N=N-N-}_n, where the Cu(I) ions adopt linear, triangular, and tetrahedral coordination modes to connect two types of Bta ligands via π-π interaction inside the tubular-like chain. For compound 2, the Cu(II) ions assume a quadrilateral coordination mode linking to the Bta ligands to give 1D straight chains, which stacks through π-π interactions to construct a 2D layer structure. Further characterizations including elemental analyses, infrared IR spectra, thermogravimetric(TG) analyses and luminescence properties have been done.     

Synthesis and Structural Characterization of Two New 2D Isophthalate‐bridged Copper(II) Polymers Based on Tricopper Units

Two new neutral polymeric layer compounds, [Cu₃(bpy)₂(Hip)₂(ip)₂] ( 1 ) and [Cu₃(phen)₂(Hip)₂(ip)₂] ( 2 ) (bpy = 2, 2′‐bipyridine, phen = 1, 10‐phenanthroline, ip = isophthalate), have been synthesized under hydrothermal conditions and characterized by X‐ray crystallography. Complex 1 crystallizes triclinic, P1¯ (No. 2), a = 10.352(5), b = 10.859(6), c = 11.602(6)Å, α = 83.25(1), β = 84.71(1), γ = 66.19(1)°, V = 1183.5(11)ų, Z = 1; 2 triclinic, P1¯ (No. 2), a = 10.375(1), b = 10.668(1), c = 11.758(1)Å, α = 83.179(2), β = 86.228(2), γ = 71.187(2)°, V = 1222.7(2)ų, Z = 1. The complexes consist of trinuclcear copper units that are bridged via two ip ligands forming zigzag polymeric chains. These chains are further extended into layers via aromatic π‐π interactions as well as hydrogen bonds between the free carboxyl groups and carboxylates.     

Solvent‐free Synthesis,Characterization and Solvent‐Vapor Interaction of Zinc(II) and Copper(II) Coordination Polymers containing Nitrogen‐donor Ligands

Coordination polymers of [Zn(INA)₂] ( 1 ) (INA = isonicotinate), [Cu₂(mal)₂(H₂O)₂(bipy)] ( 2 ) (mal = malonate, bipy = 4,4‐bipyridine), and [Zn₂(OAC)₄(bipy)₂] ( 3 ) (OAC = acetate) were prepared using mechanochemical grinding and heating methods. The materials were characterized with elemental analysis, FT‐IR spectroscopy, TGA, SEM, EI‐MS, BET, and PXRD. Comparison of PXRD patterns of the materials with patterns simulated from single‐crystal X‐ray diffraction data allowed identification of the products. Compared to conventional synthetic techniques such as solvothermal/hydrothermal solvent‐based methods, solvent‐free method was found to be simple, highly efficient, and environmentally friendly especially for the preparation of these coordination polymers on a large scale. Solvent‐vapor interaction properties of 1 , 2 , and 3 were investigated by exposure of the compounds to water and methanol at room temperature.     

Multi‐dimensional Copper(II) Coordination Polymers via Self‐assembly Induced by Sodium Ions

Two novel copper(II) coordination polymers, [CuNa₂(Hnta)₂]_n ( 1 ) and {[CuNa₂(pht)₂(H₂O)]·H₂O}_n ( 2 ) (H₃nta = nitrilotriacetate acid, H₂pht = o‐phthalic acid), have been synthesized and characterized.The sodium ions play an important role in the formation of the multi‐dimensional structures. The X‐ray structure of [CuNa₂(Hnta)₂]_n ( 1 ) is three‐dimensionally cross‐linked with building blocks [Cu(Hnta)₂]^2—connected by three sodium ions. The structure of {[CuNa₂(pht)₂(H₂O)]·H₂O}_n ( 2 ) can be described as pht units connected by Na ions via Na—O bonds to form chains, which are linked by Cu^II ions to make a 2D network. The IR spectra and thermal properties are also reported.     

Syntheses,Structures, and Catalytic Properties of Three Copper(II) Coordination Polymers Based on 2,3,5,6‐Tetrafluoro‐1,4‐bis(triazole‐ylmethyl)benzene and Benzene Carboxylate Ligands

Three new mixed‐ligand coordination polymers of Cu^II, namely, [Cu(Fbtx)(L1)(H₂O)]_n ( 1 ), [Cu(Fbtx)_0.5(HL2)(H₂O)₂]_n ( 2 ), and {[Cu(Fbtx)_1.5(HL3)(H₂O)] · H₂O}_n ( 3 ) [Fbtx = 2,3,5,6‐tetrafluoro‐1,4‐bis(1,2,4‐triazole‐1‐ylmethyl)benenze, H₂L1 = terephthalic acid, H₃L2 = trimesic acid, NaH₂L3 = 5‐sulfoisophthalic acid monosodium salt], were hydrothermally synthesized and structurally characterized by elemental analysis, IR spectra, and single‐crystal and powder X‐ray diffraction techniques. All the complexes have a two‐dimensional (2D) coordination layer structure. Of these, 1 displays a planar 4⁴‐ sql structure whereas both 2 and 3 are highly undulated 6³‐ hcb nets. Moreover, their thermal stability and catalytic behaviors in the aerobic oxidation of 4‐methoxybenzyl alcohol were also investigated as well. The results indicate that the benzene dicarboxylate ligands have an effective influence on the structures and catalytic properties of the resulting coordination polymers.     

[B(O–C6H4–CN)4]– based Silver and Copper Coordination Polymers

A series of new coordination polymers bearing the [B(O–C₆H₄–CN)₄]^– anion was synthesized. Two new, one dimensional coordination frameworks of the type M[B(O–C₆H₄–CN)₄] (M = Ag, Cu) were obtained by salt metathesis. The reactivity towards organic Lewis‐bases was studied. The reaction with bidentate ligands yielded two dimensional networks with the general formula [M(L)][B(O–C₆H₄–CN)₄] {L = 2,2′‐bipyridine, 4,4′‐bipyridine, 1,2‐bis(pyridyl)ethane, 1,4‐diazabicyclo[2.2.2]octane}. The synthesis, properties and single crystal structure are reported.     

Structural Diversity of Copper(II) Coordination Polymers Based on Tosylated Isophthalic Ligands

Two tosylated isophthalic ligands, namely, 5‐tosyloxy‐isophthalic acid (H₂toip) and 5‐tosylamino‐isophthalic acid (H₂taip) were synthesized. Self‐assembly of Cu^II ions with H₂toip and H₂taip ligands under different reaction conditions (temperature, solvents, and auxiliary ligands) gave rise to three coordination polymers formulated as [Cu(toip)(py)₂]_n ( 1 ), [Cu₆(toip)₆(H₂O)₆]_n · 8n(H₂O) ( 2 ), and [Cu₆(taip)₆(py)₄(dmf)₂]_n · n[(dmf)₆(MeOH)₂(H₂O)₂] ( 3 ) (py = pyridine, dmf = dimethylformamide). Compound 1 is a one‐dimensional (1D) coordination polymeric chain. Compounds 2 and 3 are two‐dimensional (2D) coordination networks featuring very similar Kagomé lattices based on the interconnection of paddle‐wheel [Cu₂(COO)₄] secondary building units (SBUs) and toip^2–/taip^2– ligands. However, the arrangement of adjacent Kagomé lattices in 2 and 3 are distinct, making them crystallize in different space groups and thereby have different crystal structures.     

Synthesis,Structure, and Magnetic Properties of a Copper(II) Metal‐Organic Framework with Biphenyl‐2,2′,4,4′‐tetracarboxylic Acid

The 2D Cu^II metal‐organic framework [Cu₂(bptc)(H₂O)₄]_n · 4nH₂O ( 1 ) (H₄bptc = biphenyl‐2,2′,4,4′‐tetracarboxylic acid) was hydrothermally synthesized and characterized by single‐crystal X‐ray diffraction and magnetic measurements. In the structure, bptc^4– serves as a twisted Π‐shaped organic building block to connect paddlewheel [Cu₂(COO)₄] dinuclear units and mononuclear units through 2‐/2′‐carboxylate and 4‐/4′‐carboxylate, respectively. According to the magnetic analysis using a dimer‐plus‐monomer model, strong antiferromagnetic coupling is operative within the dinuclear unit (J = –311 cm^–1 based on H = –J S ₁ S ₂), and the compound behaves like a mononuclear molecule at low temperature.     

Synthesis and Structure of Copper(II) Nitrate Complexes with 2, 6‐Bis(pyrazolyl)pyridine

Three mononuclear copper(II) complexes of copper nitrate with 2, 6‐bis(pyrazol‐1‐yl)pyridine ( bPzPy ) and 2, 6‐bis(3′,5′‐dimethylpyrazol‐1‐yl)pyridine ( bdmPzPy ), [Cu(bPzPy)(NO₃)₂] ( 1 ), [Cu(bPzPy)(H₂O)(NO₃)₂] ( 2 ) and [Cu(bdmPzPy)(NO₃)₂] ( 3 ) were synthesized by the reaction of copper nitrate with the ligand in ethanol solution. The complexes have been characterized through analytical, spectroscopic and EPR measurements. Single crystal X‐ray structure analysis of complexes 1 and 2 revealed a five‐coordinate copper atom in 1 , whereas 2 contains a six‐coordinate (4+2) Cu^II ion with molecular units acting as supramolecular nodes. These neutral nodes are connected through O–H ··· O(nitrate) hydrogen bonds to give couples of parallel linear strips assembled in 1D‐chains in a zipper‐like motif.     

Synthesis of a One‐dimensional Coordination Polymer Based on Copper(II) Nitrate and 1,2‐Bis(5‐monomethylhydrazinyl‐1H‐tetrazolyl)ethane

A one‐dimensional coordination polymer based on copper(II) nitrate and 1,2‐bis(5‐monomethylhydrazinyl‐1H‐tetrazolyl)ethane as ligand was prepared. The thermal and physical stability was determined by differential scanning calorimetry and BAM methods. The polymer was investigated by vibrational spectroscopy and single X‐ray diffraction. Moreover, the ligand itself and the 1,2‐bis(1H‐tetrazolyl)ethane were characterized as energetic material by bomb calorimetric measurements along with calculations using the EXPLO5 software. Both compounds have moderate energetic properties along with a high thermal and physical stability. These findings render these compounds into promising environment friendly gas generating agents.     

Synthesis and Characterization of [Zn2(4,4′‐bipy)n(AcO)4] – One‐dimensional Chain (n = 1) and One‐dimensional Double‐Chain (n = 2) Coordination Polymers

Two new Zn^II(μ‐4,4′‐bipy) coordination polymers with acetate anions, [Zn(4,4′‐bipy)(AcO)₂] ( 1 ) and [Zn₂(4,4′‐bipy)(AcO)₄] ( 2 ), have been synthesized. The compounds were characterized with elemental analysis, IR‐, ¹H NMR‐, ¹³C NMR spectroscopy and studied by thermal analysis, fluorescence measurements and x‐ray crystallography. The structural studies of compound 1 suggest the structure is a coordination polymer of zinc(II) consisting of linear double chains formed by bridging 4,4′‐bipy ligand and connection of the acetate‐bridged centrosymmetric [Zn₂(OAc)₂]²⁺ nodes.     

Crystal Structure and Characterization of Two Layered Copper(II) Coordination Polymers with Anions of 3‐Phosphonopropionic Acid and (RS)‐2‐Phosphonobutyric Acid

Blue single crystals of Cu[μ₃‐O₃P(CH₂)₂COOH] · 2H₂O ( 1 ) and Cu[(RS)‐μ₃‐O₃PCH(C₂H₅)COOH] · 3H₂O ( 2 ) were prepared in aqueous solutions (pH = 2.5–3.5). 1 crystallizes in space group Pbca (no. 61) with a = 812.5(2), b = 919.00(9), and c = 2102.3(2) pm. Cu²⁺ is fivefold coordinated by three oxygen atoms stemming from [O₃P(CH₂)₂COOH]^2– anions and two water molecules. The Cu–O bond lengths range from 194.0(3) to 231.8(4) pm. The connection between the [O₃P(CH₂)₂COOH]^2– anions and the Cu²⁺ cations yields a polymeric structure with layers parallel to (001). The layers are linked by hydrogen bonds. 2 crystallizes in space group Pbca (no. 61) with a = 1007.17(14), b = 961.2(3), c = 2180.9(4) pm. The copper cations are surrounded by five oxygen atoms in a square pyramidal fashion with Cu–O bonds between 193.6(4) and 236.9(4) pm. The coordination between [O₃PCH(C₂H₅)COOH]^2– and Cu²⁺ results in infinite puckered layers parallel to (001). The layers are not connected by any hydrogen bonds. Each layer contains both R and S isomers of the [O₃PCH(C₂H₅)COOH]^2– dianion. Water molecules not bound to Cu²⁺ are intercalated between the layers. UV/Vis spectra suggest three d–d transition bands at 743, 892, 1016 nm for 1 and four bands at 741, 838, 957, and 1151 nm for 2 , respectively. Magnetic measurements suggest a weak antiferromagnetic coupling between Cu²⁺ due to a super‐superexchange interaction. Thermoanalytical investigations in air show that the compounds are stable up to 95 °C ( 1 ) and 65 °C ( 2 ), respectively.     

3‐(Arylhydrazono)pentane‐2, 4‐diones and their Complexes with Copper(II) and Nickel(II) — Synthesis and Crystal Structures

A series of new 3‐(arylhydrazono)pentane‐2, 4‐diones ( 1 ‐ 6 ) synthesized from pentane‐2, 4‐dione and diazonium salts of respective anilines using the procedure of Japp‐Klingemann are described. Complexes with Cu^II and Ni^II salts are prepared ( 7 ‐ 10 , respectively). Spectroscopic properties of these compounds have been studied and X‐ray crystal structures of selected hydrazones ( 3 , 4 , 6 ) and of the hydrazone complexes ( 7 ‐ 10 ) are reported. The structures of the uncomplexed hydrazones feature an intramolecular N‐H···O interaction to yield a six‐membered H‐bond ring reflecting preference of the hydrazone tautomeric structure. All the complexes are mononuclear 2:1 (L:M) structures of six‐membered chelate type involving N₂O₂ binding sites that are quadratic arranged but differ in the entire coordination environment dependent on the metal and the ligand substitution including distorted octahedral and quadratic pyramidal coordination geometries in the Cu^II complexes 7 and 8 or nearly regular square planar coordination geometry in the Ni^II complexes 9 and 10 , respectively. In the crystal packings, strong and weak H‐bond interactions cause supramolecular network structures.     

Two‐Dimensional Monovalent Copper Halide Coordination Polymers Incorporating Anti‐Conformation 3,3′‐Bipyridine

Hydrothermal treatment of aqueous mixtures of copper(II) halides and 3,3′‐bipyridine (3,3′‐bpy) has afforded the coordination polymers [CuCl(3,3′‐bpy)]_n ( 1 ) and [Cu₂Br₂(3,3′‐bpy)]_n ( 2 ), which were analyzed via single crystal X‐ray diffraction, infrared spectroscopy, and elemental analysis. The structure of 1 consists of two‐dimensional (2‐D) layers constructed from the linkage of castellated one‐dimensional (1‐D) [CuCl]_n stepped chains through anti‐conformation 3,3′‐bpy tethers. Compound 2 presents a related 2‐D sheet motif, albeit built from infinite 1‐D [Cu₂Br₂]_n ladders strutted by 3,3′‐bpy ligands in anti conformation. In both cases neighboring 2‐D sheets stack into 3‐D via weak C–H···halogen interactions.     

Copper(I) Coordination Polymers with Alkanedithiol and ‐dinitrile Bridging Ligands

CuI‐based coordination polymers with 1, 2‐ethanedithiol, 3, 6‐dioxa‐1, 8‐octanedithiol and 3‐oxa‐1, 5‐pentanedinitrile as respectively μ‐S, S′ and μ‐N, N′ bridging ligands have been prepared by reaction of CuI with the appropriate alkane derivative in acetonitrile. equation/tex2gif-stack-1.gif[Cu(HSCH₂CH₂SH)₂]I ( 1 ) contains 4⁴ cationic nets, equation/tex2gif-stack-2.gif[(CuI)₂(HSCH₂CH₂OCH₂CH₂OCH₂CH₂SH)] ( 2 ) neutral layers in which stairlike CuI double chains are linked by dithiol spacers. In contrast to these 2D polymers, equation/tex2gif-stack-3.gif[CuI(NCCH₂CH₂OCH₂CH₂CN)] ( 3 ) and equation/tex2gif-stack-4.gif[(CuI)₄(NCCH₂CH₂OCH₂CH₂CN)₂] ( 4 ) both contain infinite chains with respectively (CuI)₂ rings and distorted (CuI)₄ cubes as building units. Solvothermal reaction of CuI with the thiacrown ether 1, 4, 10‐trithia‐15‐crown‐5 (1, 4, 10TT15C5) in acetonitrile affords the lamellar coordination polymer equation/tex2gif-stack-5.gif[(CuI)₃(1, 4, 10TT15C5)] ( 7 ) in which copper atoms of individual CuI double chains are bridged in a μ‐S1, S4 manner. The third sulphur atom S10 of the thiacrown ether coordinates a copper(I) atom from a parallel chain to generate a 2D network.     

Syntheses and Structures of Three New Copper(II) Coordination Polymers Involving 2, 2‐(4, 6‐Dinitro‐1, 3‐phenylenedioxy)­diacetic Acid

Three copper(II) coordination polymers, namely, {[CuL(H₂O)₂] · 4H₂O}_n( 1 ), [CuL(H₂O)(DMF)]_n( 2 ), and [CuL(2, 2′‐bipy)(DMSO)] · DMSO ( 3 ) [H₂L = 2, 2′‐(4, 6‐dinitro‐1, 3‐phenyl‐enedioxy)diacetic acid] were synthesized in different solvents (H₂O, DMF, and DMSO). X‐ray single crystal diffraction studies show that both complexes 1 and 3 belong to triclinic crystal system and P$\bar{1}$ space group and complex 2 belongs to the monoclinic crystal system and P2₁/c space group. In three complexes, all the central Cu^II ions coordinate with the ligand, forming a square pyramidal configuration. Both complexes 1 and 2 show similar 1D chain‐like structure and the chains are further connected by hydrogen bonds, forming 3D frameworks. Complex 3 exhibits a 0D structure due to the introduction of the ligand 2, 2′‐bipy. In addition, the luminescence properties of these complexes were investigated.     

Crystal Structures,Magnetism, and Dye Degradation Catalytic Properties of Copper 2‐Methoxycarboxybenzoate Coordination Complexes

Copper coordination complexes containing the 2‐methoxycarboxybenzoate (2‐mcob) ligand show different topologies depending on the nature of the dipyridyl coligand. [Cu₂(2‐mcob)₂(ebin)]_n ( 1 ) [ebin = ethanebis(isonicotinamide)] shows a ladder structure based on anti‐syn bridged [Cu(OCO)]_n chain motifs. [Cu₂(2‐mcob)₂(bbin)(H₂O)₂] ( 2 ) [bbin = butanebis(isonicotinamide)] displays a dimeric molecular structure. [Cu₂(2‐mcob)₂(hbin)]_n ( 3 ) [hbin = hexanebis(isonicotinamide)] manifests a ladder structure very similar to that of 1 . {[Cu(2‐mcob)(dpa)] · H₂O}_n ( 4 ) [dpa = bis(4‐pyridyl)amine] shows a chain coordination polymer structure. All four materials showed significant promise as heterogeneous degradation catalysts for Congo Red dye in aqueous suspension under ultraviolet irradiation. Variable temperature magnetic susceptibility experiments for 1 indicated the presence of weak antiferromagnetic exchange (g = 2.059(2), J = –0.84(2) cm^–1). Thermal degradation behavior is also discussed.     

Synthesis and Characterization of the Germanium Sulfonate Ge(CH3SO3)2 – a 3D Coordination Network Solid

The reaction of germanium(II)‐bis(2‐methoxyphenyl)methoxide with methanesulfonic acid provides the germanium(II) sulfonate Ge(CH₃SO₃)₂ ( 1 ), which was characterized by X‐ray diffraction, elemental analysis, NMR spectroscopy, and IR spectroscopy. The decomposition process of 1 was investigated by thermal gravimetric analysis (TGA) and temperature‐dependent X‐ray powder diffraction (PXRD) and both are consistent with the formation of GeO₂ as major final product. Single crystal X‐ray diffraction at 110 K revealed the chiral tetragonal space group P4₁2₁2 and formation of a three‐dimensional (3D) coordination network solid. The 3D network is composed of interconnected twenty four‐membered rings comprising bridging methanesulfonate groups, which link the germanium atoms.     

Network Motifs and Thermal Properties of Copper(I) Halide and Pseudohalide Coordination Polymers with 1, 7‐ and 4, 7‐Phenanthroline

The coordination polymers [CuBr(1, 7‐phen‐κN7)] ( 1a ), [CuI(1, 7‐phen)] ( 2a ) and [(CuI)₂(1, 7‐phen‐κN7)] ( 2b ) may be prepared by treatment of the appropriate copper(I) halide with 1, 7‐phenanthroline (1, 7‐phen) in acetonitrile. 1a exhibits staircase CuBr double chains, 2a novel quadruple CuI chains. Their thermal properties were investigated by DTA‐TG and temperature resolved powder X‐ray diffraction. On heating, both 1:1 compounds decompose to 2:1 polymers and then finally to CuBr or CuI. With 4, 7‐phenanthroline (4, 7‐phen), CuBr affords both 1:1 and 2:1 complexes ( 5a , 5b ), CuI 1:1 , 2:1 and 3:1 complexes( 6a , 6b , 6c ) in acetonitrile at 20 °C. 5a and 6a display lamellar coordination networks, with the former containing zigzag CuBr single chains, the latter 4‐membered (CuI)₂ rings. A second 2:1 complex [(CuI)₂(4, 7‐phen‐μ‐N4, N7)] ( 6b ′) with staircase CuI double chains can be obtained by reacting CuI with 4, 7‐phen in a sealed glass tube at 110 °C. Both 5a and 6a exhibit thermal decomposition pathways of the general type 1:1 → 2:1 → 3:1 → CuX, and novel CuX triple chains are proposed for the isostructural 3:1 polymers 5c and 6c . X‐ray structures are reported for complexes 1a , 2b , [(CuCN)₃(CH₃CN)(1, 7‐phen‐μ‐N1, N7)] ( 3c· CH₃CN), [CuSCN(1, 7‐phen‐κN7)] ( 4a ), 5a , 6a and [CuCN(4, 7‐phen‐μ‐N4, N7)] ( 7a ).     

Unprecedented ferromagnetic interaction in an erbium(III)–copper(II) coordination polymer

Two 3D Ln(III)–Cu(II) coordination polymers [Er₂Cu₃(pydc)₆(H₂O)₆]_n (1) and [Tb₂Cu₃(pydc)₆(H₂O)₆]_n (2) were hydrothermally prepared from pyridine-2,4-dicarboxylic acid (H₂pydc) and characterized by single-crystal X-ray diffraction analysis. The magnetic studies show that an unexpected ferromagnetic interaction between metal centers exists in 1 while 2 behaves as an antiferromagnet.