Synthesis,Characterization, and Magnetic Behaviour of Dinuclear Nickel(II) Complexes of N,N′‐Substituted Dithiooxamides derived from α‐Amino Acids

New dinuclear complexes of the types [Ni₂(L)(H₂O)₂] and [Ni₂(L)(H₂O)₆] [H₄L = N,N′‐bis(carboxymethyl) dithiooxamide (H₄GLYDTO), N,N′‐bis(1‐carboxyethyl) dithiooxamide (H₄ALADTO), N,N′‐bis(1‐carboxy‐2‐methylpropyl) dithiooxamide (H₄VALDTO) and N,N′‐bis(1‐carboxy‐3‐methylbutyl) dithiooxamide (H₄LEUDTO)] have been prepared and characterized by IR and electronic absorption spectroscopy, and the structure of [Ni₂(ALADTO)(H₂O)₆] crystals has been determined by single crystal X‐ray analysis. This compound is composed of discrete dinuclear units in which two Ni^II atoms with NO₄S kernels are linked by a single [ALADTO]^4– group that coordinates through its carboxylato oxygen, amino nitrogen and thiolato sulphur atoms. In each dimer unit the two nickel(II) ions in distorted octahedral coordination are separated by 5.863(2) Å The temperature dependence of the magnetic susceptibility of the new compounds was measured over the range 2 to 300 K. In the complexes of [GLYDTO]^4– and [ALADTO]^4– the two Ni atoms are antiferromagnetically coupled, with J = –23.51(4) and –20.95(8) cm^–1, respectively. By constrast, [Ni₂(VALDTO)(H₂O)₂], [Ni₂(VALDTO)(H₂O)₆] and [Ni₂(LEUDTO)(H₂O)₂] remain paramagnetic down to 2 K, with magnetic moment values between 2.8 and 3.3 M.B.     

New Examples of Metal Coordination Architectures of 3,3′,4,4′‐Biphenyltetracarboxylic Acid – Syntheses,Crystal Structures,and Physical Properties

Four new metal‐organic frameworks [Cu₂(2,2′‐bipy)₂(ox)(H₂O)₂]·(H₂bptc) ( 1 ), [Cu(bptc)_0.5(phen)(H₂O)]·H₂O ( 2 ), Co₂(bptc)(bmb)_1.5 ( 3 ) and [Cd₂(bptc) (bmb)]·3H₂O ( 4 ) (H₄bptc = 3,3′,4,4′‐biphenyltetracarboxylic acid, ox = oxalate, phen = 1,10‐phenanthroline, 2,2′‐bipy = 2,2′‐bipyridine and bmb = 4,4′‐bis((1H‐imidazol‐1‐yl)methyl)biphenyl), were obtained by reactions of the corresponding metal salts with H₄bptc and N‐containing auxiliary ligands and their structures were determined by single‐crystal X‐ray diffraction. The results reveal that 1 has a 0‐D structure consisting of discrete ionic entities, while 2 features a 1‐D ladder structure. Additionally, there exist π‐π stacking and intermolecular hydrogen‐bonding interactions in 1 and 2 , respectively, forming 3‐D supramolecular structures. In 3 ‐ 4 , undulating 2‐D metal‐bptc layer structures are formed with two different coordination modes of bptc carboxylate groups, respectively, which are further extended by bmb into 3‐D structures. Magnetic properties of 1 and 3 have been studied. The photoluminescence property of 4 has also been investigated. Moreover, nonlinear optical measurements showed that 4 displayed a second‐harmonic‐generation (SHG) response of 0.7 times of that for urea.     

Poly[(μ4‐biphenyl‐3,3′,4,4′‐tetracarboxylato)bis[μ2‐1,4‐bis(imidazol‐1‐ylmethyl)benzene]dicobalt(II)]

The asymmetric unit of the title two‐dimensional coordination polymer, [Co₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂]_n, contains one Co²⁺ ion, half of a biphenyl‐3,3′,4,4′‐tetracarboxylate (bptc) anion lying about an inversion centre and one 1,4‐bis(imidazol‐1‐ylmethyl)benzene (bix) ligand. The Co^II atom is coordinated by three carboxylate O atoms from two different bptc ligands and two N atoms from two bix ligands constructing a distorted square pyramid. Each Co²⁺ ion is interlinked by two bptc anions, while each bptc anion coordinates to four Co atoms as a hexadentate ligand so that four Co^II atoms and four bptc anions afford a larger 38‐membered ring. These inorganic rings are further extended into a two‐dimensional undulated network in the (10) plane. Two Co^II atoms in adjacent 38‐membered rings are joined together by pairs of bix ligands forming a 26‐membered [Co₂(bix)₂] ring that is penetrated by a bptc anion; these components share a common inversion centre.     

Poly­[[di­aqua­tris(μ6‐benzene‐1,2,4,5‐tetra­carboxyl­ato)­tris(μ2‐4,4′‐bi­pyridine)­hexacopper(II)] dihydrate]

The hydro­thermal reaction of an aqueous solution of Cu(CH₃COO)₂·H₂O, 1,2,4,5‐benzene­tetra­carboxylic acid and 4,4′‐bi­pyridine gave rise to the interesting title three‐dimensional polymer {[Cu₆(btec)₃(4,4′‐bpy)₃(H₂O)₂]·2H₂O}_n (btec is 1,2,4,5‐benzene­tetra­carboxyl­ate, C₁₀H₂O₈⁴⁻, and 4,4′‐bpy is 4,4′‐bi­pyridine, C₁₀H₈N₂), in which each btec ligand links six copper(II) cations into a lamellar [Cu₆(btec)₃(H₂O)₂]_n sub­polymer framework. There are two distinct diamine units and two distinct carboxylate units, with one of each lying across an inversion centre.     

catena‐Poly[[(2,2′‐diamino‐4,4′‐bithiazole){μ3‐cis‐N‐(2‐carboxylatophenyl)‐N′‐[3‐(dimethylamino)propyl]oxamidato(3−)}dicopper(II)] nitrate 0.6‐hydrate]

The title complex, {[Cu₂(C₁₄H₁₆N₃O₄)(C₆H₆N₄S₂)]NO₃·0.6H₂O}_n, is a one‐dimensional copper(II) coordination polymer bridged by cis‐oxamide and carboxylate groups. The asymmetric unit is composed of a dinuclear copper(II) cation, [Cu₂(dmapob)(dabt)]⁺ {dmapob is N‐(2‐carboxylatophenyl)‐N′‐[3‐(dimethylamino)propyl]oxamidate and dabt is 2,2′‐diamino‐4,4′‐bithiazole}, one nitrate anion and one partially occupied site for a solvent water molecule. The two Cu^II ions are located in square‐planar and square‐pyramidal coordination environments, respectively. The separations of the Cu atoms bridged by oxamide and carboxylate groups are 5.2053 (3) and 5.0971 (4) Å, respectively. The complex chains are linked by classical hydrogen bonds to form a layer and then assembled by π–π stacking interactions into a three‐dimensional network. The influence of the terminal ligand on the structure of the complex is discussed.     

Poly[[diaqua‐μ‐4,4′‐bipyridine‐dinitratodi‐μ‐l‐tyrosinato‐dicopper(II)]: a chiral two‐dimensional coordination polymer

The title compound, [Cu₂(C₉H₁₀NO₃)₂(NO₃)₂(C₁₀H₈N₂)(H₂O)₂]_n, contains Cu^II atoms and l ‐tyrosinate (l ‐tyr) and 4,4′‐bipyridine (4,4′‐bipy) ligands in a 2:2:1 ratio. Each Cu atom is coordinated by one amino N atom and two carboxylate O atoms from two l ‐tyr ligands, one N atom from a 4,4′‐bipy ligand, a monodentate nitrate ion and a water molecule in an elongated octahedral geometry. Adjacent Cu atoms are bridged by the bidentate carboxylate groups into a chain. These chains are further linked by the bridging 4,4′‐bipy ligands, forming an undulated chiral two‐dimensional sheet. O—H...O and N—H...O hydrogen bonds connect the sheets in the [100] direction. This study offers useful information for the engineering of chiral coordination polymers with amino acids and 4,4′‐bipy ligands by considering the ratios of the metal ion and organic components.     

Poly[diaqua(μ‐4,4′‐bipyridine‐κ2N:N′)bis(μ‐cyanido‐κ2C:N)bis(cyanido‐κC)nickel(II)copper(II)]: a metal–organic cyanide‐bridged framework

The structure of the title compound, [NiCu(CN)₄(C₁₀H₈N₂)(H₂O)₂]_n or [{Cu(H₂O)₂}(μ‐C₁₀H₈N₂)(μ‐CN)₂{Ni(CN)₂}]_n, was shown to be a metal–organic cyanide‐bridged framework, composed essentially of –Cu–4,4′‐bpy–Cu–4,4′‐bpy–Cu– chains (4,4′‐bpy is 4,4′‐bipyridine) linked by [Ni(CN)₄]²⁻ anions. Both metal atoms sit on special positions; the Cu^II atom occupies an inversion center, while the Ni^II atom of the cyanometallate sits on a twofold axis. The 4,4′‐bpy ligand is also situated about a center of symmetry, located at the center of the bridging C—C bond. The scientific impact of this structure lies in the unique manner in which the framework is built up. The arrangement of the –Cu–4,4′‐bpy–Cu–4,4′‐bpy–Cu– chains, which are mutually perpendicular and non‐intersecting, creates large channels running parallel to the c axis. Within these channels, the [Ni(CN)₄]²⁻ anions coordinate to successive Cu^II atoms, forming zigzag –Cu—N[triple‐bond]C—Ni—C[triple‐bond]N—Cu– chains. In this manner, a three‐dimensional framework structure is constructed. To the authors' knowledge, this arrangement has not been observed in any of the many copper(II)–4,4′‐bipyridine framework complexes synthesized to date. The coordination environment of the Cu^II atom is completed by two water molecules. The framework is further strengthened by O—H...N hydrogen bonds involving the water molecules and the symmetry‐equivalent nonbridging cyanide N atoms.     

Hydrothermal Synthesis of Five New Coordination Polymers Based on Benzophenone‐2, 4′‐dicarboxylic Acid and N‐Donor Spacers

Five new coordination polymers, namely, [Ni₂(L)₂(4, 4′‐bipy)₃)] · H₂O]_n ( 1 ), [Ni₂(L)₂(O) (bpp)₂]_n ( 2 ), [Zn(L)(bib)_0.5]_n ( 3 ), [Zn(L)(PyBIm)]_n ( 4 ), and [Zn₃(L)₂(OH)(im)]_n ( 5 ) [H₂L = benzophenone‐2, 4′‐dicarboxylic acid, 4, 4′‐bipy = 4, 4′‐bipyridine, bpp = 1, 3‐bis(4‐pyridyl)propane, PyBIm = 2‐(4‐pyridyl)benzimidazole, and im = imidazole] were synthesized under hydrothermal conditions. Structure determination revealed that compound 1 is a 3D network and exhibits a 4‐connected metal‐organic framework with (4².6³.8) topology, whereas compounds 2 , 3 , 4 , and 5 are two‐dimensional layer structures. In compounds 2 – 4 , dinuclear metal clusters are formed through carboxylic groups. In compound 5 , trinuclear metal clusters are formed through μ₃‐OH and carboxylic groups. The carboxylic groups exhibit three coordination modes in compounds 1 – 5 : monodentately, bidentate‐chelating, and bis‐monodentately. Furthermore, the luminescent properties for compounds 3 , 4 , and 5 were investigated.     

Syntheses,Crystal Structures,and Magnetic Properties of Three Metal‐Nitroxide Complexes with the V‐shaped 4, 4′‐Oxybis(benzoate)

Three new metal–nitroxide complexes {[Ni(NIT4Py)₂(obb)(H₂O)₂] · 1.5H₂O}_n ( 1 ), {[Co(NIT4Py)₂(obb)(H₂O)₂] · 2H₂O}_n ( 2 ), and [Co(IM4Py)₂(obb)₂(H₂O)₂][Co(IM4Py)₂(H₂O)₄] · 10H₂O ( 3 ) with the V‐shaped 4,4′‐oxybis(benzoate) [NIT4Py = 2‐(4′‐pyridyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide, IM4Py = 2‐(4′‐pyridyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxide, and obb = 4, 4′‐oxybis(benzoate) anion] were synthesized and structurally characterized. Single‐crystal X‐ray analyses indicate that complexes 1 and 2 crystallize in neutral one‐dimensional (1D) zigzag chains, in which the nitroxide–metal–nitroxide units are linked by the V‐shaped 4,4′‐oxybis(benzoate) anions, whereas complex 3 consists of isolated mononuclear [Co(IM4Py)₂(obb)₂(H₂O)₂]^2– anions and [Co(IM4Py)₂(H₂O)₄]²⁺ ions. Magnetic measurements show that complexes 1 and 2 both exhibit weak antiferromagnetic interactions between the metal ions and the nitroxides.     

catena‐Poly[bis(μ‐2,2′‐bipyridin‐6‐olato)‐κ3N,N′:O;O:N,N′‐dicopper(I,II) [[tetrafluoridoniobium(V)]‐μ‐oxido]]

A novel copper–niobium oxyfluoride, {[Cu₂(C₁₀H₇N₂O)₂][NbOF₄]}_n, has been synthesized by a hydrothermal method and characterized by elemental analysis, EDS, IR, XPS and single‐crystal X‐ray diffraction. The structural unit consists of one C₂‐symmetric [NbOF₄]⁻ anion and one centrosymmetric coordinated [Cu₂(obpy)₂]⁺ cation (obpy is 2,2′‐bipyridin‐6‐olate). In the [NbOF₄]⁻ anion, each Nb^V metal centre is five‐coordinated by four F atoms and one O atom in the first coordination shell, forming a square‐pyramidal coordination geometry. These square pyramids are then further connected to each other via trans O atoms [Nb—O = 2.187 (3) Å], forming an infinite linear {[NbOF₄]⁻}_n polyanion. In the coordinated [Cu₂(obpy)₂]⁺ cation, the oxidation state of each Cu site is disordered, which is confirmed by the XPS results. The disordered Cu sites are coordinated by two N atoms and one O atom from two different obpy ligands. The [NbOF₄]⁻ and [Cu₂(obpy)₂]⁺ units are assembled via weak C—H...F hydrogen bonds, resulting in the formation of a three‐dimensional supramolecular structure. π–π stacking interactions between the pyridine rings [centroid–centroid distance = 3.610 (2) Å] may further stabilize the crystal structure.     

Double End‐On Azido Copper(II) Dinuclear Complex with Oxazoline Ligand: Synthesis,Structure, Magnetic Properties and Theoretical Study

A double azido‐bridged Cu^II dinuclear complex with the chelating chiral ligand, [Cu₂(L)₂(N₃)₄] ( 1 ) [L = (+)‐2, 2′‐isopropylidene‐bis((4R)‐4‐benzyl‐2‐oxazoline)] was synthesized and characterized by single‐crystal X‐ray diffraction, IR spectroscopy, magnetic measurements, and theoretical studies. The asymmetric double end‐on azido bridges in complex 1 lead to a weak antiferromagnetic behavior with J = –7.4 cm^–1. The exchange interactions in complex 1 were investigated by DFT calculations, and the calculated exchange interaction (J = –8.0 cm^–1) is in good agreement with the experimental value.     

A novel one‐dimensional coordination polymer,catena‐poly[[diaquacobalt(II)]‐μ‐(2,2′‐bipyridyl‐3,3′‐dicarboxylato‐κ4N,N′:O,O′)]

The title compound, [Co(C₁₂H₆N₂O₄)(H₂O)₂]_n, has been hydro­thermally synthesized and structurally characterized. It consists of polymeric chains of [Co{μ‐(2,2′‐bipyridyl‐3,3′‐di­carboxyl­ato‐κ⁴N,N′:O,O′)}(H₂O)₂] units, in which each Co^II cation is octahedrally coordinated by two chelating pyridyl N atoms, two chelating carboxyl O atoms from different carboxylate groups of another bipyridyl ligand, and two water mol­ecules as terminal ligands. A crystallographic twofold axis parallel to the chain axis, passes through the Co atom.     

Cobalt(II) and cadmium(II) square grids supported with 4,4′‐bipyrazole and accommodating 3‐carboxyadamantane‐1‐carboxylate

In poly[[bis(μ‐4,4′‐bi‐1H‐pyrazole‐κ²N²:N^2′)bis(3‐carboxyadamantane‐1‐carboxylato‐κO¹)cobalt(II)] dihydrate], {[Co(C₁₂H₁₅O₄)₂(C₆H₆N₄)₂]·2H₂O}_n, (I), the Co²⁺ cation lies on an inversion centre and the 4,4′‐bipyrazole (4,4′‐bpz) ligands are also situated across centres of inversion. In its non‐isomorphous cadmium analogue, {[Cd(C₁₂H₁₅O₄)₂(C₆H₆N₄)₂]·2H₂O}_n, (II), the Cd²⁺ cation lies on a twofold axis. In both compounds, the metal cations adopt an octahedral coordination, with four pyrazole N atoms in the equatorial plane [Co—N = 2.156 (2) and 2.162 (2) Å; Cd—N = 2.298 (2) and 2.321 (2) Å] and two axial carboxylate O atoms [Co—O = 2.1547 (18) Å and Cd—O = 2.347 (2) Å]. In both structures, interligand hydrogen bonding [N...O = 2.682 (3)–2.819 (3) Å] is essential for stabilization of the MN₄O₂ environment with its unusually high (for bulky adamantanecarboxylates) number of coordinated N‐donor co‐ligands. The compounds adopt two‐dimensional coordination connectivities and exist as square‐grid [M(4,4′‐bpz)₂]_n networks accommodating monodentate carboxylate ligands. The interlayer linkage is provided by hydrogen bonds from the carboxylic acid groups via the solvent water molecules [O...O = 2.565 (3) and 2.616 (3) Å] to the carboxylate groups in the next layer [O...O = 2.717 (3)–2.841 (3) Å], thereby extending the structures in the third dimension.     

Structure and Magnetic Properties of a 2D Paddle‐wheel Dinuclear[Cu2] Cluster‐based Polymer with 1,1‐Cyclohexanediacetate Ligand

One new two‐dimensional (2D) Cu^II polymer [Cu(CHDA)(H₂O)]_n ( 1 ) was synthesized solvothermally based on 1,1‐cyclohexanediacetic acid (H₂CHDA) ligand. Single‐crystal X‐ray diffraction analysis reveals that 1 has a 2D framework structure consisting of paddle‐wheel dinuclear [Cu₂] cluster unit and CHDA^2– connector, which bears a 4‐connected sql network with Schläfli symbol of (4⁴.6²). Magnetic studies indicate the presence of strong antiferromagnetic coupling (J = –302 cm^–1) between the two Cu^II ions in the paddle‐wheel dicopper(II) entity.     

One‐dimensional CuII coordination polymers containing C2h‐symmetric 1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylate linkers

Two new one‐dimensional Cu^II coordination polymers (CPs) containing the C_2h‐symmetric terphenyl‐based dicarboxylate linker 1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylate (3,3′‐TPDC), namely catena‐poly[[bis(dimethylamine‐κN)copper(II)]‐μ‐1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylato‐κ⁴O,O′:O′′:O′′′] monohydrate], {[Cu(C₂₀H₁₂O₄)(C₂H₇N)₂]·H₂O}_n, (I), and catena‐poly[[aquabis(dimethylamine‐κN)copper(II)]‐μ‐1,1′:4′,1′′‐terphenyl‐3,3′‐dicarboxylato‐κ²O³:O^3′] monohydrate], {[Cu(C₂₀H₁₂O₄)(C₂H₇N)₂(H₂O)]·H₂O}_n, (II), were both obtained from two different methods of preparation: one reaction was performed in the presence of 1,4‐diazabicyclo[2.2.2]octane (DABCO) as a potential pillar ligand and the other was carried out in the absence of the DABCO pillar. Both reactions afforded crystals of different colours, i.e. violet plates for (I) and blue needles for (II), both of which were analysed by X‐ray crystallography. The 3,3′‐TPDC bridging ligands coordinate the Cu^II ions in asymmetric chelating modes in (I) and in monodenate binding modes in (II), forming one‐dimensional chains in each case. Both coordination polymers contain two coordinated dimethylamine ligands in mutually trans positions, and there is an additional aqua ligand in (II). The solvent water molecules are involved in hydrogen bonds between the one‐dimensional coordination polymer chains, forming a two‐dimensional network in (I) and a three‐dimensional network in (II).     

catena‐Poly[disodium [[diformato­tricopper(II)]‐di‐μ3‐formato‐tetra‐μ2‐formato]]: a new mode of bridging between binuclear and mononuclear formate–copper(II) units

The novel title polymeric copper(II) complex, {Na₂[Cu₃‐(CHO₂)₈]}_n, consists of sodium cations and infinite anionic chains, in which neutral dinuclear [Cu₂(O₂CH)₄] moieties alternate with dianionic [Cu(O₂CH)₄]²⁻ units. Both metal‐containing moieties are located on crystallographic inversion centers. The syn–syn bridging configuration between the mononuclear and dinuclear components yields a structure that is significantly more dense than the structures previously reported for mononuclear–dinuclear copper(II) carboxyl­ates with syn–anti or anti–anti bridging modes.     

μ‐2,2′,6,6′‐Tetramethyl‐4,4′‐bipyridine‐κ2N1:N1′‐bis[(diethylenetriamine‐κ3N,N′,N′′)palladium(II)] tetranitrate

The title compound, [Pd₂(C₄H₁₃N₃)₂(C₁₄H₁₆N₂)](NO₃)₄, comprises discrete tetracationic dumbbell‐type dinuclear complex molecules and noncoordinating nitrate anions. Two Pd(dien)²⁺ moieties (dien is diethylenetriamine) are joined by the rigid linear exo‐bidentate bridging 2,2′,6,6′‐tetramethyl‐4,4′‐bipyridine ligand to form the dinuclear complex, which lies across a centre of inversion in the space group P2₁/n, so that the rings in the 2,2′,6,6′‐tetramethyl‐4,4′‐bipyridine bridging ligand are parallel. In the crystal, the primary and secondary amino groups of the dien ligand act as hydrogen‐bond donors towards the nitrate anions to form a three‐dimensional hydrogen‐bond network.     

A Series of Transition Metal Coordination Polymers Bearing 1,4‐Phenylenediacetate

The reactions of transition metal salts or hydroxide with 1,4‐phenylenediacetic acid (H₂PDA) in the presence of ancillary ligands 4,4′‐bipyridine (4,4′‐bpy) or imidazole (Im) produced five coordination polymers with the empirical formula [M(PDA)(4,4′‐bpy)(H₂O)₂]_n [M = Mn ( 1 ), Ni ( 2 )], [Cu(PDA)(4,4′‐bpy)]_n · 2nH₂O ( 3 ), [Ni(PDA)(Im)₂(H₂O)₂]_n · nH₂O ( 4 ), and [Cu(PDA)(Im)₂]_n · 2nH₂O ( 5 ). Their structures were determined by single‐crystal X‐ray diffraction analyses. The isomorphous 1 and 2 present a two‐dimensional sheet constructed by two kinds of one‐dimensional chains of –Ni^II–PDA^2––Ni^II– and –Ni^II–4,4′‐bpy–Ni^II–. Compound 3 features dinuclear subunits, which are further connected by two PDA^2– ligands and two 4,4′‐bpy ligands along (001) and (011) directions, respectively, to build a two‐dimensional sheet with the topology (4².6⁷.8)(4².6) different from those of 1 and 2 . Both 4 and 5 show one‐dimensional chain structure. The difference of compound 4 and 5 is that the two carboxylato groups of PDA^2– in 4 adopt monodentate coordination modes, whereas the two carboxylato groups of PDA^2– in 5 chelate to the metal ions. Magnetic susceptibility data of 1 were measured. Magnetically, 1 presents a one‐dimensional chain with a weak antiferromagnetic interaction (J =–0.064 cm^–1) between the intrachain Mn^II atoms mediated by 4,4′‐bpy.     

由4，4＇-联二吡啶桥联α,β-不饱和酸铜形成铜（II）的一维配位聚合物

A methanol solution of 4,4‘-bipyridine reacts with Cu2A4(H2O)2 to yield coordination polymers of general formula: [Cu2A4(bipy)]n [A: CH2=C(Me)CO2^- (1), CH2=CHCO2^- (2); bipy: 4,4‘-bipyridine]. They were characterized by elemental analyses, IR spectra and thermal analyses. The X-ray structure analyses of 1 show a one-dimensional chain structure where the binuclear structural units Cu2[CH2=C(Me)CO2]4 are bridged by 4,4‘-bipyridine molecules. Furthermore, the binuclear units between adjacent layers can form micropores. The temperature-dependent magnetic susceptibility of 1 indicates that the strong antiferromagnetic interaction exists between copper(Ⅱ) atoms in the binuclear units.     

Syntheses,Structures, and Luminescence of Metal(II) Coordination Polymers based on Flexible 1,1′‐(1,4‐Butanediyl)bis(imidazole) and Tetrachlorobenzene‐1,4‐dicarboxylate Ligands

The coordination polymers, {[Co(bbim)₂(H₂O)₂](tcbdc) · 2H₂O}_n ( 1 ), {[Ni(tcbdc)(bbim)(H₂O)₂] · 2DMF}_n ( 2 ), and {[Cu₂(tcbdc)₂(bbim)₄] · 4H₂O}_n ( 3 ) [bbim = 1,1′‐(1,4‐butanediyl)bis(imidazole) and tcbdc^2– = tetrachlorobenzene‐1,4‐dicarboxylate] were synthesized and characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, luminescence, and single‐crystal X‐ray diffraction analysis. Complex 1 has a double‐stranded chain structure through doubly bridged [Co(bbim)₂] units. Complex 2 exhibits two‐dimensional square grid, whereas complex 3 has a three‐dimensional porous network structure with an unprecedented 4⁴ · 6¹¹ topological structure through interpenetrating square grid. The water molecules in complex 3 occupy the vacancy through three kinds of hydrogen bond interactions. Upon excitation at 370 nm, complexes 1 – 3 present solid‐state luminescence at room temperature.