Two novel mixed‐ligand complexes containing organosulfonate ligands

The structures reported herein, viz. bis(4‐aminonaphthalene‐1‐sulfonato‐κO)bis(4,5‐diazafluoren‐9‐one‐κ²N,N′)copper(II), [Cu(C₁₀H₈NO₃S)₂(C₁₁H₆N₂O)₂], (I), and poly[[[diaquacadmium(II)]‐bis(μ‐4‐aminonaphthalene‐1‐sulfonato)‐κ²O:N;κ²N:O] dihydrate], {[Cd(C₁₀H₈NO₃S)₂(H₂O)₂]·2H₂O}_n, (II), are rare examples of sulfonate‐containing complexes where the anion does not fulfill a passive charge‐balancing role, but takes an active part in coordination as a monodentate and/or bridging ligand. Monomeric complex (I) possesses a crystallographic inversion center at the Cu^II atom, and the asymmetric unit contains one‐half of a Cu atom, one complete 4‐aminonaphthalene‐1‐sulfonate (ans) ligand and one 4,5‐diazafluoren‐9‐one (DAFO) ligand. The Cu^II atom has an elongated distorted octahedral coordination geometry formed by two O atoms from two monodentate ans ligands and by four N atoms from two DAFO molecules. Complex (II) is polymeric and its crystal structure is built up by one‐dimensional chains and solvent water molecules. Here also the cation (a Cd^II atom) lies on a crystallographic inversion center and adopts a slightly distorted octahedral geometry. Each ans anion serves as a bridging ligand linking two Cd^II atoms into one‐dimensional infinite chains along the [010] direction, with each Cd^II center coordinated by four ans ligands via O and N atoms and by two aqua ligands. In both structures, there are significant π–π stacking interactions between adjacent ligands and hydrogen bonds contribute to the formation of two‐ and three‐dimensional networks.     

Three AgI,CuI and CdII coordination polymers based on the new asymmetrical ligand 2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole: syntheses,characterization and emission properties

The new asymmetrical organic ligand 2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole ( L , C₁₇H₁₃N₅O), containing pyridine and imidazole terminal groups, as well as potential oxdiazole coordination sites, was designed and synthesized. The coordination chemistry of L with soft Ag^I, Cu^I and Cd^II metal ions was investigated and three new coordination polymers (CPs), namely, catena‐poly[[silver(I)‐μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole] hexafluoridophosphate], {[Ag( L )]PF₆}_n, catena‐poly[[copper(I)‐di‐μ‐iodido‐copper(I)‐bis(μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole)] 1,4‐dioxane monosolvate], {[Cu₂I₂( L )₂]·C₄H₈O₂}_n, and catena‐poly[[[dinitratocopper(II)]‐bis(μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole)]–methanol–water (1/1/0.65)], {[Cd( L )₂(NO₃)₂]·2CH₄O·0.65H₂O}_n, were obtained. The experimental results show that ligand L coordinates easily with linear Ag^I, tetrahedral Cu^I and octahedral Cd^II metal atoms to form one‐dimensional polymeric structures. The intermediate oxadiazole ring does not participate in the coordination interactions with the metal ions. In all three CPs, weak π–π interactions between the nearly coplanar pyridine, oxadiazole and benzene rings play an important role in the packing of the polymeric chains.     

A new one‐dimensional CuII complex with a three‐dimensional supramolecular architecture incorporating benzene‐1,3‐dicarboxylate and 1‐[(1H‐benzotriazol‐1‐yl)methyl]‐1H‐imidazole

Subtle modifications of N‐donor ligands can result in complexes with very different compositions and architectures. In the complex catena‐poly[[bis{1‐[(1H‐benzotriazol‐1‐yl)methyl]‐1H‐imidazole‐κN ³}copper(II)]‐μ‐benzene‐1,3‐dicarboxylato‐κ³O ¹,O ^1′:O ³], {[Cu(C₈H₄O₄)(C₁₀H₉N₅)₂(H₂O)]·2H₂O}_n , each Cu^II ion is six‐coordinated by two N atoms from two crystallographically independent 1‐[(1H‐benzotriazol‐1‐yl)methyl]‐1H‐imidazole (bmi) ligands, by three O atoms from two symmetry‐related benzene‐1,3‐dicarboxylate (bdic²⁻) ligands and by one water molecule, leading to a distorted CuN₂O₄ octahedral coordination environment. The Cu^II ions are connected by bridging bdic²⁻ anions to generate a one‐dimensional chain. The bmi ligands coordinate to the Cu^II ions in monodentate modes and are pendant on opposite sides of the main chain. In the crystal, the chains are linked by O—H…O and O—H…N hydrogen bonds, as well as by π–π interactions, into a three‐dimensional network. A thermogravimetric analysis was carried out and the fluorescence behaviour of the complex was also investigated.     

The conformations of two copper(I) complexes of 1H‐benzimidazole‐2(3H)‐thione and thiosaccharinate

(Acetonitrile‐1κN)[μ‐1H‐benzimidazole‐2(3H)‐thione‐1:2κ²S:S][1H‐benzimidazole‐2(3H)‐thione‐2κS]bis(μ‐1,1‐dioxo‐1λ⁶,2‐benzothiazole‐3‐thiolato)‐1:2κ²S³:N;1:2κ²S³:S³‐dicopper(I)(Cu—Cu), [Cu₂(C₇H₄NO₂S₂)₂(C₇H₆N₂S)₂(CH₃CN)] or [Cu₂(tsac)₂(Sbim)₂(CH₃CN)] [tsac is thiosaccharinate and Sbim is 1H‐benzimidazole‐2(3H)‐thione], (I), is a new copper(I) compound that consists of a triply bridged dinuclear Cu—Cu unit. In the complex molecule, two tsac anions and one neutral Sbim ligand bind the metals. One anion bridges via the endocyclic N and exocyclic S atoms (μ‐S:N). The other anion and one of the mercaptobenzimidazole molecules bridge the metals through their exocyclic S atoms (μ‐S:S). The second Sbim ligand coordinates in a monodentate fashion (κS) to one Cu atom, while an acetonitrile molecule coordinates to the other Cu atom. The Cu^I—Cu^I distance [2.6286 (6) Å] can be considered a strong `cuprophilic' interaction. In the case of [μ‐1H‐benzimidazole‐2(3H)‐thione‐1:2κ²S:S]bis[1H‐benzimidazole‐2(3H)‐thione]‐1κS;2κS‐bis(μ‐1,1‐dioxo‐1λ⁶,2‐benzothiazole‐3‐thiolato)‐1:2κ²S³:N;1:2κ²S³:S³‐dicopper(I)(Cu—Cu), [Cu₂(C₇H₄NO₂S₂)₂(C₇H₆N₂S)₃] or [Cu₂(tsac)₂(Sbim)₃], (II), the acetonitrile molecule is substituted by an additional Sbim ligand, which binds one Cu atom via the exocylic S atom. In this case, the Cu^I—Cu^I distance is 2.6068 (11) Å.     

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.     

The coordination chemistry of two symmetric double‐armed oxadiazole‐bridged organic ligands with copper salts

Two new symmetric double‐armed oxadiazole‐bridged ligands, 4‐methyl‐{5‐[5‐methyl‐2‐(pyridin‐3‐ylcarbonyloxy)phenyl]‐1,3,4‐oxadiazol‐2‐yl}phenyl pyridine‐3‐carboxylate (L1) and 4‐methyl‐{5‐[5‐methyl‐2‐(pyridin‐4‐ylcarbonyloxy)phenyl]‐1,3,4‐oxadiazol‐2‐yl}phenyl pyridine‐4‐carboxylate (L2), were prepared by the reaction of 2,5‐bis(2‐hydroxy‐5‐methylphenyl)‐1,3,4‐oxadiazole with nicotinoyl chloride and isonicotinoyl chloride, respectively. Ligand L1 can be used as an organic clip to bind Cu^II cations and generate a molecular complex, bis(4‐methyl‐{5‐[5‐methyl‐2‐(pyridin‐3‐ylcarbonyloxy)phenyl]‐1,3,4‐oxadiazol‐2‐yl}phenyl pyridine‐3‐carboxylate)bis(perchlorato)copper(II), [Cu(ClO₄)₂(C₂₈H₂₀N₄O₅)₂], (I). In compound (I), the Cu^II cation is located on an inversion centre and is hexacoordinated in a distorted octahedral geometry, with the pyridine N atoms of two L1 ligands in the equatorial positions and two weakly coordinating perchlorate counter‐ions in the axial positions. The two arms of the L1 ligands bend inward and converge at the Cu^II coordination point to give rise to a spirometallocycle. Ligand L2 binds Cu^I cations to generate a supramolecule, diacetonitriledi‐μ₃‐iodido‐di‐μ₂‐iodido‐bis(4‐methyl‐{5‐[5‐methyl‐2‐(pyridin‐4‐ylcarbonyloxy)phenyl]‐1,3,4‐oxadiazol‐2‐yl}phenyl pyridine‐4‐carboxylate)tetracopper(I), [Cu₄I₄(CH₃CN)₂(C₂₈H₂₀N₄O₅)₂], (II). The asymmetric unit of (II) indicates that it contains two Cu^I atoms, one L2 ligand, one acetonitrile ligand and two iodide ligands. Both of the Cu^I atoms are four‐coordinated in an approximately tetrahedral environment. The molecule is centrosymmetric and the four I atoms and four Cu^I atoms form a rope‐ladder‐type [Cu₄I₄] unit. Discrete units are linked into one‐dimensional chains through π–π interactions.     

Two new isostructural mercury(II) complexes involving the N‐heterocyclic 1‐[(benzotriazol‐1‐yl)methyl]‐1H‐1,3‐imidazole ligand: syntheses,structures and properties

The unsymmetrical N‐heterocyclic ligand 1‐[(benzotriazol‐1‐yl)methyl]‐1H‐1,3‐imidazole (bmi) has three potential N‐atom donors and can act in monodentate or bridging coordination modes in the construction of complexes. In addition, the bmi ligand can adopt different coordination conformations, resulting in complexes with different structures due to the presence of the flexible methylene spacer. Two new complexes, namely bis{1‐[(benzotriazol‐1‐yl)methyl]‐1H‐1,3‐imidazole‐κN ³}dibromidomercury(II), [HgBr₂(C₁₀H₉N₅)₂], and bis{1‐[(benzotriazol‐1‐yl)methyl]‐1H‐1,3‐imidazole‐κN ³}diiodidomercury(II), [HgI₂(C₁₀H₉N₅)₂], have been synthesized through the self‐assembly of bmi with HgBr₂ or HgI₂. Single‐crystal X‐ray diffraction shows that both complexes are mononuclear structures, in which the bmi ligands coordinate to the Hg^II ions in monodentate modes. In the solid state, both complexes display three‐dimensional networks formed by a combination of hydrogen bonds and π–π interactions. The IR spectra and PXRD patterns of both complexes have also been recorded.     

A two‐dimensional mixed‐valence CuII/CuI coordination polymer constructed from 2‐(pyridin‐3‐yl)‐1H‐imidazole‐4,5‐dicarboxylate

Coordination polymers are a thriving class of functional solid‐state materials and there have been noticeable efforts and progress toward designing periodic functional structures with desired geometrical attributes and chemical properties for targeted applications. Self‐assembly of metal ions and organic ligands is one of the most efficient and widely utilized methods for the construction of CPs under hydro(solvo)thermal conditions. 2‐(Pyridin‐3‐yl)‐1H‐imidazole‐4,5‐dicarboxylate (HPIDC²⁻) has been proven to be an excellent multidentate ligand due to its multiple deprotonation and coordination modes. Crystals of poly[aquabis[μ₃‐5‐carboxy‐2‐(pyridin‐3‐yl)‐1H‐imidazole‐4‐carboxylato‐κ⁵N¹,O⁵:N³,O⁴:N²]copper(II)dicopper(I)], [Cu^IICu^I₂(C₁₀H₅N₃O₄)₂(H₂O)]_n, (I), were obtained from 2‐(pyridin‐3‐yl)‐1H‐imidazole‐4,5‐dicarboxylic acid (H₃PIDC) and copper(II) chloride under hydrothermal conditions. The asymmetric unit consists of one independent Cu^II ion, two Cu^I ions, two HPIDC²⁻ ligands and one coordinated water molecule. The Cu^II centre displays a square‐pyramidal geometry (CuN₂O₃), with two N,O‐chelating HPIDC²⁻ ligands occupying the basal plane in a trans geometry and one O atom from a coordinated water molecule in the axial position. The Cu^I atoms adopt three‐coordinated Y‐shaped coordinations. In each [CuN₂O] unit, deprotonated HPIDC²⁻ acts as an N,O‐chelating ligand, and a symmetry‐equivalent HPIDC²⁻ ligand acts as an N‐atom donor via the pyridine group. The HPIDC²⁻ ligands in the polymer serve as T‐shaped 3‐connectors and adopt a μ₃‐κ²N,O:κ²N′,O′:κN′′‐coordination mode, linking one Cu^II and two Cu^I cations. The Cu cations are arranged in one‐dimensional –Cu1–Cu2–Cu3– chains along the [001] direction. Further crosslinking of these chains by HPIDC²⁻ ligands along the b axis in a –Cu2–HPIDC²⁻–Cu3–HPIDC²⁻–Cu1– sequence results in a two‐dimensional polymer in the (100) plane. The resulting (2,3)‐connected net has a (12³)₂(12)₃ topology. Powder X‐ray diffraction confirmed the phase purity for (I), and susceptibilty measurements indicated a very weak ferromagnetic behaviour. A thermogravimetric analysis shows the loss of the apical aqua ligand before decomposition of the title compound.     

Preparation and characterization of two new CuII supramolecular coordination polymers incorporating sulfobenzoate and flexible heterocyclic ligands

The assembly of Cu^II with the multifunctional ligand 2‐amino‐4‐sulfobenzoic acid (H₂asba) in the presence of the auxiliary flexible ligands 1,4‐bis(triazol‐1‐ylmethyl)benzene (bbtz) and 1,4‐bis(imidazol‐1‐ylmethyl)benzene (bix) under ambient conditions resulted in two new supramolecular coordination polymers, namely poly[[(3‐amino‐4‐carboxybenzenesulfonato‐κO )aquabis[μ₂‐1,4‐bis(triazol‐1‐ylmethyl)benzene‐κ²N ⁴:N ^4′]copper(II)] 3‐amino‐4‐carboxybenzenesulfonate tetrahydrate], {[Cu(C₇H₆NO₅S)(C₁₂H₁₂N₆)₂(H₂O)](C₇H₆NO₅S)·4H₂O}_n , ( 1 ), and poly[[bis(μ₂‐2‐amino‐4‐sulfonatobenzoato‐κ³O ¹:N ,O ^1′)tetraaqua[μ₂‐1,4‐bis(triazol‐1‐ylmethyl)benzene‐κ²N ⁴:N ^4′]dicopper(II)] tetrahydrate], {[Cu₂(C₇H₅NO₅S)₂(C₁₄H₁₄N₄)(H₂O)₄]·4H₂O}_n , ( 2 ). Single‐crystal X‐ray structure diffraction analysis of ( 1 ) reveals that the bbtz ligand acts as a bridge, linking adjacent Cu^II ions into a two‐dimensional cationic (4,4) topological network, in which the coordinated 3‐amino‐4‐carboxybenzenesulfonate (Hasba⁻) anion uses its sulfonate group to bind with the Cu^II ion in a monodentate fashion and the carboxylate group remains protonated. The lattice Hasba⁻ anion resides in the two‐dimensional layer and balances the charge. The carboxylate group of the 2‐amino‐4‐sulfonatobenzoate (asba²⁻) ligand in ( 2 ) is involved in bidentate coordination, connecting adjacent Cu^II ions into carboxylate‐bridged chains which are further bridged by the auxiliary flexible bix ligand in a trans –gauche (TG) mode, resulting in the formation of a two‐dimensional network architecture. The amino group of the asba²⁻ ligand in ( 2 ) also takes part in the coordination with the central Cu^II ion. The six‐coordinated Cu^II centres in ( 1 ) and ( 2 ) exhibit distorted octahedral coordination geometries. Extensive hydrogen bonding exists in both ( 1 ) and ( 2 ). The interlayer hydrogen bonds in both compounds further extend adjacent two‐dimensional layers into three‐dimensional supramolecular network architectures. Furthermore, a detailed analysis of the solid‐state UV–Vis–NIR (NIR is near IR) diffuse reflectance data indicates that ( 1 ) and ( 2 ) may have potential as wide band gap indirect semiconductor materials. Compounds ( 1 ) and ( 2 ) show reversible and irreversible dehydration–rehydration behaviours, respectively.     

A novel luminescent ionic trinuclear Cu3I2 cluster cuprous complex supported by a P^N ligand: synthesis,structure characterization,properties and TD–DFT calculations

Luminescent cuprous complexes are an important class of coordination compounds due to their relative abundance, low cost and ability to display excellent luminescence. The title ionic trinuclear Cu₃I₂ complex, tris[μ₂‐diphenyl(pyridin‐2‐yl)phosphane‐κ²P:N]di‐μ₃‐iodido‐tricopper(I)(3 Cu—Cu) hexafluoridophosphate, [Cu₃I₂(C₃₉H₃₂NP)₃]PF₆, conventionally abbreviated as [Cu₃I₂(Ph₂PPy)₃]PF₆, is described. Each Cu^I atom is coordinated by two μ₃‐iodide ligands and by a P and an N atom from two Ph₂PPy ligands, giving rise to a CuI₂PN tetrahedral coordination geometry about each Cu^I centre. The electronic absorption and photoluminescence properties of this trinuclear cluster have been studied on as‐synthesized samples, which had been examined previously by powder X‐ray diffraction. A detailed time‐dependent density functional theory (TD–DFT) study was carried out and showed a green emission derived from a halide‐to‐ligand charge transfer and metal‐to‐ligand charge transfer ³(X+M)LCT excited state.     

Two new CoII coordination polymers with multifunctional 5‐amino‐2,4,6‐tribromoisophthalic acid and flexible isomeric bis(imidazole) ligands: preparation,crystal structure and characterization

Two new Co^II coordination polymers (CPs), namely, catena‐poly[[[(5‐amino‐2,4,6‐tribromobenzene‐1,3‐dicarboxylato‐κO)aquacobalt(II)]‐bis[μ‐1,3‐bis(imidazol‐1‐ylmethyl)benzene‐κ²N:N′]] 4.75‐hydrate], {[Co(C₈H₂Br₃NO₄)(C₁₄H₁₄N₄)₂(H₂O)]·4.75H₂O}_n, (1), and poly[(μ‐5‐amino‐2,4,6‐tribromobenzene‐1,3‐dicarboxylato‐κ²O¹:O³)[μ‐1,2‐bis(imidazol‐1‐ylmethyl)benzene‐κ²N:N′]cobalt(II)], [Co(C₈H₂Br₃NO₄)(C₁₄H₁₄N₄)]_n, (2), have been synthesized successfully by the assembly of multifunctional 5‐amino‐2,4,6‐tribromoisophthalic acid (H₂ATBIP) and Co^II ions in the presence of the flexible isomeric bis(imidazole) ligands 1,3‐bis(imidazol‐1‐ylmethyl)benzene (mbix) and 1,2‐bis(imidazol‐1‐ylmethyl)benzene (obix). The isomeric mbix and obix ligands have a big influence on the structures of CPs (1) and (2). CP (1) is composed of chains of nanometre‐sized elliptical rings, in which the Co^II atom exhibits a distorted octahedral coordination geometry and ATBIP²⁻ acts as a monodentate ligand. Two adjacent chains are interlinked by π–π stacking interactions and hydrogen bonds, resulting in a supramolecular double chain. Hydrogen‐bonded R₈⁶(16) rings extend adjacent supramolecular double chains into a two‐dimensional supramolecular layer. Halogen bonding and a hydrogen‐bonded R₄²(8) ring further link the two‐dimensional supramolecular layers, leading to the formation of a three‐dimensional supramolecular network. The Co^II ion in CP (2) is tetracoordinated, exhibiting a distorted tetrahedral configuration. The ATBIP²⁻ ligand exhibits a bis(monodentate) coordination bridging mode, linking adjacent Co^II ions into zigzag chains, which are further bridged by the auxiliary bridging obix ligand, resulting in a two‐dimensional (4,4) topological network. Interlayer hydrogen and halogen–halogen bonding further extend the two‐dimensional layers into a three‐dimensional supramolecular network. A detailed analysis of the solid‐state UV–Vis–NIR diffuse‐reflectance spectra of (1) and (2) indicates that a wide optical band gap exists in both (1) and (2). CP (1) exhibits an irreversible dehydration–rehydration behaviour.     

Cyano‐Bridged ‘Oximato’ Complexes: Synthesis,Structure, and Catalase‐Like Activities

The reaction of the ‘oximato’‐ligand precursor A (Fig. 1) and metal salts with KCN gave two mononuclear complexes [ML(CN)(H₂O)_n](ClO₄) ( 1 and 2 ; L={N‐(hydroxy‐κO)‐α‐oxo‐N′‐[(pyridin‐2‐yl‐κN)methyl[1,1′‐biphenyl]‐4‐ethanimidamidato‐κN′}; M=Co^II ( 1 ), Cu^II ( 2 ); n=2 for Co^II, n=0 for Cu^II; Figs. 2 and 3). The new cyano‐bridged pentanuclear ‘oximato’ complexes [{ML(H₂O)_n(NC)}₄M¹(H₂O)_x](ClO₄)₂ ( 3 – 6 ) and trinuclear complexes [{ML(H₂O)_n(NC)}₂M¹L](ClO₄) ( 7 – 10 ) ([M¹=Mn^II, Cu^II; x=2 for Mn^II, x=0 for Cu^II] were synthesized from mononuclear complexes and characterized by elemental analyses, magnetic susceptibility, molar conductance, and IR and thermal analysis. The four [ML(CN)(H₂O)_n]⁺ moieties are connected by a metal(II) ion in the pentanuclear complexe 3 – 6 , each one involving four cyano bridging ligands (Fig. 4). The central metal ion displays a square‐planar or octahedral geometry, with the cyano bridging ligands forming the equatorial plane. The axial positions are occupied by two aqua ligands in the case of the central Mn‐atom. The two [ML(CN)(H₂O)_n]⁺ moieties and an ‘oximato’ ligand are connected by a metal(II) ion in the trinuclear complexes 7 – 10 , each one involving two cyano bridging ligands (Fig. 5). The central metal ions display a distorted square‐pyramidal geometry, with two cyano bridging ligands and the donor atoms of the tridentate ‘oximato’ ligand. Moreover catalytic activities of the complexes for the disproportionation of hydrogen peroxide (H₂O₂) were also investigated in the presence of 1H‐imidazole. The synthesized homopolynuclear Cu^II complexes 6 and 10 displayed eficiency in disproportion reactions of H₂O₂ producing H₂O and dioxygen thus showing catalase‐like activity.     

Aqua­bis(3‐meth­oxy‐2‐pyridonato)­(2,2′:6′,2′′‐terpyridine)ruthenium(II)–acetonitrile–water (1/1/1)

The title compound, [Ru(C₆H₆NO₂)₂(C₁₅H₁₁N₃)(H₂O)]·CH₃CN·H₂O, is a transfer hydrogenation catalyst supported by nitro­gen‐donor ligands. This octa­hedral Ru^II complex features rare monodentate coordination of 3‐meth­oxy‐2‐pyridonate ligands and inter­ligand S(6)S(6) hydrogen bonding. Comparison of the title complex with a structural analog with unsubstituted 2‐pyridonate ligands reveals subtle differences in the orientation of the ligand planes.     

Weak Antiferromagnetism in Carboxylato Copper(II) Complexes of Bipyridines

Three new members of the copper/carboxylato/heterocyclic diimine family, namely [Cu(GLYO)(2, 2′‐bipy)]₂ · nH₂O (n = 4 ( 1 ) or 6 ( 2 ), H₂GLYO = glycolic acid, 2, 2′‐bipy = 2, 2′‐bipyridine) and {[Cu(AcO)₂(4, 4′‐bipy)] · 3H₂O}_n ( 3 ) (AcO = acetato, 4, 4′‐bipy = 4, 4‐bipyridine), have been synthesized and characterized by IR and electronic absorption spectroscopy, and the crystal structures have been determined by single crystal X‐ray analysis. 1 and 2 are composed of discrete dinuclear units in which each Cu^II atom is coordinated in a square pyramidal arrangement to the two nitrogen atoms of a bipyridine ligand, to bridging non‐carboxy oxygen atoms belonging to two glycolato ligands, and to one of the carboxy oxygen atoms of one of these glycolato ligands. The Cu··Cu distance is 3.0666(5)Å. Compound 3 consists of linear chains of dinuclear units in which each Cu^II is coordinated to one non‐bridging monodentate acetato ligand, to two acetato ligands that each bridge via a single oxygen atom, and to one nitrogen atom of each of two mutually trans bis‐monodentate 4, 4′‐bipyridine ligands that link the repeat units of the polymer. The coordination polyhedra are square pyramids, and the Cu··Cu distance within each dimeric repeat unit is 3.502(2)Å. The temperature dependence of their magnetic susceptibilities shows there to be weak antiferromagnetic interaction between the metal atoms of each dimer in all three complexes, with fitting parameter values of —2J = 1.3 cm^—1 and g = 2.09 for 1 and 2 , and —2J = 1.4 cm^—1 and g = 2.15 for 3 . The X‐band EPR spectra show signals corresponding to the dinuclear units.     

A twofold interpenetrating three‐dimensional CdII coordination framework: poly[[μ2‐1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene](μ3‐5‐nitrobenzene‐1,3‐dicarboxylato)cadmium(II)]

A twofold interpenetrating three‐dimensional Cd^II coordination framework, [Cd(C₈H₃NO₆)(C₁₄H₁₄N₄)]_n, has been prepared and characterized by IR spectroscopy, elemental analysis, thermal analysis and single‐crystal X‐ray diffraction. The asymmetric unit consists of a divalent Cd^II atom, one 1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene (1,3‐BMIB) ligand and one fully deprotonated 5‐nitrobenzene‐1,3‐dicarboxylate (NO₂‐BDC²⁻) ligand. The coordination sphere of the Cd^II atom consists of five O‐donor atoms from three different NO₂‐BDC²⁻ ligands and two imidazole N‐donor atoms from two different 1,3‐BMIB ligands, forming a distorted {CdN₂O₅} pentagonal bipyramid. The NO₂‐BDC ligand links three Cd^II atoms via a μ₁‐η¹:η¹ chelating mode and a μ₂‐η²:η¹ bridging mode. The title compound is a twofold interpenetrating 3,5‐connected network with the {4².6⁵.8³}{4².6} topology. In addition, the compound exhibits fluorescence emissions in the solid state at room temperature.     

A copper(I) coordination polymer incorporation the corrosion inhibitor 1H‐benzotriazole: poly[μ3‐benzotriazolato‐κ3N1:N2:N3‐copper(I)]

The title complex, [Cu(C₆H₄N₃)]_n, was synthesized by the reaction of cupric nitrate, 1H‐benzotriazole (BTAH) and aqueous ammonia under hydrothermal conditions. The asymmetric unit contains three crystallographically independent Cu^I cations and two 1H‐benzotriazolate ligands. Two of the Cu^I cations, one with a linear two‐coordinated geometry and one with a four‐coordinated tetrahedral geometry, are located on sites with crystallographically imposed twofold symmetry. The third Cu^I cation, with a planar three‐coordinated geometry, is on a general position. Two Cu^I cations are doubly bridged by two BTA⁻ ligands to afford a noncentrosymmetric planar [Cu₂(BTA)₂] subunit, and two [Cu₂(BTA)₂] subunits are arranged in an antiparallel manner to form a centrosymmetric [Cu₂(BTA)₂]₂ secondary building unit (SBU). The SBUs are connected in a crosswise manner via the sharing of four‐coordinated Cu^I cations, Cu—N bonding and bridging by two‐coordinate Cu^I cations, resulting in a one‐dimensional chain along the c axis. These one‐dimensional chains are further linked by C—H...π and weak van der Waals interactions to form a three‐dimensional supramolecular architecture.     

The first square‐planar copper(II) 1:2 complex with differently coordinated 2‐hydroxybenzaldehyde 4‐allylthiosemicarbazone ligands

The title compound, [(Z)‐4‐allyl‐2‐(2‐hydroxybenzylidene)thiosemicarbazide‐κS][(E)‐4‐allyl‐1‐(2‐oxidobenzylidene)thiosemicarbazidato‐κ³O,N¹,S]copper(II) monohydrate, [Cu(C₁₁H₁₁N₃OS)(C₁₁H₁₃N₃OS)]·H₂O, crystallized as a rotational twin in the monoclinic crystal system (space group Cc) with two formula unit (Z′ = 2) in the asymmetric unit, one of which contains an allyl substituent disordered over two positions. The Cu^II atom exhibits a distorted square‐planar geometry involving two differently coordinated thiosemicarbazone ligands. One ligand is bonded to the Cu^II atom in a tridentate manner via the phenolate O, azomethine N and thioamide S atoms, while the other coordinates in a monodentate manner via the S atom only. The complex is stabilized by an intramolecular hydrogen bond, which creates a six‐membered pseudo‐chelate metalla‐ring. The structure analysis indicates the presence of the E isomer for the tridentate ligand and the Z isomer for the monodentate ligand. The crystal structure contains a three‐dimensional network built from intermolecular O—H...O, N—H...O, O—H...N and N—H...S hydrogen bonds.     

Supramolecular Arrays of Cationic Complexes Containing Pyrazole Ligands and Tetrafluoroborate,Trifluoromethanesulfonate, or Nitrate as Counterions. Crystal Structure of Bis(3,5‐dimethyl‐4‐nitro‐1H‐pyrazole‐κN2)silver(1+) Nitrate ([Ag(HpzNO2)2](NO3))

The structures of [Pd(η³‐C₃H₅)(Hpz^R2)₂](BF₄) (Hpz^R2=Hpz^bp2=3,5‐bis(4‐butoxyphenyl)‐1H‐pyrazole, 1 ; Hpz^R2=Hpz^NO2=3,5‐dimethyl‐4‐nitro‐1H‐pyrazole=Hdmnpz, 2 ) and [Ag(Hpz^R2)₂](A) (Hpz^R2=Hpz^bp2, A= , 3 ; Hpz^R2=Hpz^NO2, A= , 4 ) were comparatively analyzed to determine the factors responsible for polymeric assemblies. In all cases, the H‐bonding interactions between the pyrazole moieties and the appropriate counterion and, in particular, the orientation of the NH groups of the pyrazole ligands are determinant of one‐dimensional polymeric arrays. In this context, the new compound [Ag(Hpz^NO2)₂](NO₃) ( 5 ) was synthesized and its structure analyzed by X‐ray diffraction (Fig. 4). The Hpz^NO2 serves as N‐monodentate ligand, which coordinates to the Ag^I center through its pyrazole N‐atom giving rise to an almost linear N Ag N geometry. The planar NO counterion bridges two adjacent Ag^I centers to form a one‐dimensional zigzag‐shaped chain which is also supported by the presence of N H⋅⋅⋅O bonds between the pyrazole NH group of adjacent cationic entities and the remaining O‐atom of the bridging NO (Fig. 5). The chains are further extended to a two‐dimensional layer‐like structure through additional Ag⋅⋅⋅O interactions involving the NO₂ substituents at the pyrazole ligands (Fig. 6).     

Bis(acesulfamato‐κ2N3,O4)bis­(2‐amino­pyrimidine‐κN1)copper(II)

In the crystal structure of the title compound, bis­(2‐amino­pyrimidine‐κN¹)bis­[6‐meth­yl‐1,2,3‐oxathia­zin‐4(3H)‐one 2,2‐dioxide(1−)‐κ²N³,O⁴]copper(II), [Cu(C₄H₄NO₄S)₂(C₄H₅N₃)₂], the first mixed‐ligand complex of acesulfame, the Cu^II centre resides on a centre of symmetry and has an octa­hedral geometry that is distorted both by the presence of four‐membered chelate rings and by the Jahn–Teller effect. The equatorial plane is formed by the N atoms of two amino­pyrimidine (ampym) ligands and by the weakly basic carbonyl O atoms of the acesulfamate ligands, while the more basic deprotonated N atoms of these ligands are in the elongated axial positions with a strong misdirected valence. The crystal is stabilized by pyrimidine ring stacking and by inter­molecular hydrogen bonding involving the NH₂ moiety of the ampym ligand and the carbon­yl O atom of the acesulfamate moiety.     

A novel mixed‐valence copper complex,poly[[μ2‐4,4′‐bipyridine‐μ3‐pyridine‐2,4,6‐tricarboxyl­ato‐di­copper(I,II)] monohydrate]

In the title novel mixed‐valence copper complex, {[Cu₂(C₈H₂NO₆)(C₁₀H₈N₂)]·H₂O}_n, the Cu^I and Cu^II ions are linked by 4,4′‐bipyridine (bpy) and pyridine‐2,4,6‐tricarboxyl­ate (ptc) ligands into corrugated layers, which are assembled via inter­layer C—H⋯O hydrogen bonds to give a three‐dimensional supra­molecular architecture.