Tetrakis(2,2′‐bipyridine‐κ2N,N′)­tetrakis(μ‐salicyl­ato‐κ3O,O′:O′′)‐quadro‐tetrazinc(II) decahydrate

The title compound, [Zn₄(C₇H₄O₃)₄(C₁₀H₈N₂)₄]·10H₂O, crystallizes as a centrosymmetric tetranuclear cyclic complex containing four Zn^II atoms bridged by four carboxyl­ate groups from salicyl­ate ligands, with a syn–anti configuration. Each Zn^II atom has a distorted trigonal–bipyramidal coordination geometry, formed by two N atoms of a 2,2′‐bipyridine ligand and three O atoms from two salicyl­ate ligands. The complex is stabilized by intramolecular π–π interactions between pairs of bi­pyridine rings and a 16‐membered gear‐wheel‐shaped cyclic framework. The hydrogen‐bonding network is formed via the water mol­ecules.     

The infinite double‐stranded chain polymer catena‐poly­[[bis­(dicyan­amido)­zinc(II)]‐di‐μ‐1,2‐bis(1,2,4‐triazol‐1‐yl)­ethane‐κ4N4:N4′]

The coordination geometry of the Zn^II atom in the title complex, [Zn(C₂N₃)₂(C₆H₈N₆)₂]_n or [Zn(dca)₂(bte)₂]_n, where bte is μ‐1,2‐bis(1,2,4‐triazol‐1‐yl)­ethane and dca is dicyan­amide, is distorted compressed octahedral, in which the Zn^II atom lies on an inversion center and coordinates four N atoms from the triazole rings of four symmetry‐related bte ligands and two N atoms from two symmetry‐related monodentate dca ligands. The structure is polymeric, with 18‐membered spiro‐fused rings extending in the b direction and each 18‐membered ring involving two inversion‐related bte mol­ecules.     

A novel parallel interpenetrating two‐dimensional (4,4) network: poly[[μ2‐1,4‐bis(imidazol‐1‐ylmethyl)benzene](μ2‐naphthalene‐1,4‐dicarboxylato)zinc(II)]

In the title coordination compound, [Zn(C₁₂H₆O₄)(C₁₄H₁₄N₄)]_n, the two Zn^II centers exhibit different coordination environments. One Zn^II center is four‐coordinated in a distorted tetrahedral environment surrounded by two carboxylate O atoms from two different naphthalene‐1,4‐dicarboxylate (1,4‐ndc) anions and two N atoms from two distinct 1,4‐bis(imidazol‐1‐ylmethyl)benzene (1,4‐bix) ligands. The coordination of the second Zn^II center comprises two N atoms from two different 1,4‐bix ligands and three carboxylate O atoms from two different 1,4‐ndc ligands in a highly distorted square‐pyramidal environment. The 1,4‐bix ligand and the 1,4‐ndc anion link adjacent Zn^II centers into a two‐dimensional four‐connected (4,4) network. The two (4,4) networks are interpenetrated in a parallel mode.     

Poly[[{μ4‐3‐[(1H‐1,2,4‐triazol‐1‐yl)methyl]benzoato}zinc(II)] hemihydrate]: a novel two‐dimensional framework formed by self‐association of zinc(II) sulfate with 3‐[(1H‐1,2,4‐triazol‐1‐yl)methyl]benzoic acid

The title novel two‐dimensional coordination polymer, {[Zn₂(C₁₀H₈N₃O₂)₄]·H₂O}_n, features a {Zn₂L₂} bimetallic ring repeat unit {L is the 3‐[(1H‐1,2,4‐triazol‐1‐yl)methyl]benzoate ligand}. Each Zn^II cation of the bimetallic ring is further bonded to two other L ligands, resulting in a novel infinite two‐dimensional network structure with two channels of different sizes. The crystallographically unique Zn^II atom is thus six‐coordinated in a distorted octahedral environment of four carboxylate O atoms and two triazole N atoms. Two of these networks interpenetrate in an orthogonal arrangement to form the full three‐dimensional framework, with disordered water molecules located in the channels.     

A novel dimeric zinc(II) complex: bis­[μ‐1,2‐bis­(1H‐1,2,4‐triazol‐1‐yl)­ethane‐κ2N4:N4′]­bis­[diisothio­cyanato­zinc(II)]

The coordination geometry of the Zn^II atom in the title complex, [Zn₂(NCS)₄(C₆H₈N₆)₂], is that of a distorted tetra­hedron, in which the Zn^II atom is coordinated by four N atoms from the triazole rings of two symmetry‐related 1,2‐bis­(1,2,4‐triazol‐1‐yl)ethane ligands and two thio­cyanate ligands. Two Zn^II atoms are bridged by two organic ligands to form a dimer. The dimer lies about an inversion center.     

A novel 8‐carboxyindeno[1,2‐b]quinoxalin‐11‐one thio­semi­carbazone zinc(II) Schiff base complex

In the novel title binuclear zinc(II) Schiff base complex, bis­(μ‐11‐thio­semicarbazonoindeno[1,2‐b]quinoxaline‐8‐carboxylato)bis­[(dimethyl sulfoxide)zinc(II)] dimethyl sulfoxide tri­solvate, [Zn₂(C₁₇H₉N₅O₂S)₂(C₂H₆OS)₂]·3C₂H₆OS, each Zn^II atom is five‐coordinated and situated in a distorted square‐pyramidal environment, coordinated by two L²⁻ ligands and one dimethyl sulfoxide mol­ecule. Each L²⁻ ligand, which coordinates to two Zn^II atoms, has two parts. One part, acting in a tridentate chelating mode, coordinates to one Zn^II atom through two N atoms and one S atom, while another part coordinates to another Zn^II atom through a monodentate carboxylate group. The whole complex has a dimeric structure. The coordination mode of the nearly planar L²⁻ ligand is quite different from the most common mode for Schiff bases.     

A three‐dimensional ZnII coordination framework: poly[[μ2‐(E)‐1,2‐bis(pyridin‐4‐yl)ethene][μ4‐(E)‐2,2′‐(diazene‐1,2‐diyl)dibenzoato][μ2‐(E)‐2,2′‐(diazene‐1,2‐diyl)dibenzoato]dizinc(II)]

In the title coordination polymer, [Zn₂(C₁₄H₈N₂O₄)₂(C₁₂H₁₀N₂)]_n, the asymmetric unit contains one Zn^II cation, two halves of 2,2′‐(diazene‐1,2‐diyl)dibenzoate anions (denoted L²⁻) and half of a 1,2‐bis(pyridin‐4‐yl)ethene ligand (denoted bpe). The three ligands lie across crystallographic inversion centres. Each Zn^II centre is four‐coordinated by three O atoms of bridging carboxylate groups from three L²⁻ ligands and by one N atom from a bpe ligand, forming a tetrahedral coordination geometry. Two Zn^II atoms are bridged by two carboxylate groups of L²⁻ ligands, generating a [Zn₂(CO₂)₂] ring. Each loop serves as a fourfold node, which links its four equivalent nodes via the sharing of four L²⁻ ligands to form a two‐dimensional [Zn₂L₄]_n net. These nets are separated by bpe ligands acting as spacers, producing a three‐dimensional framework with a 4⁶6⁴ topology. Powder X‐ray diffraction and solid‐state photoluminescence were also measured.     

catena‐Poly[[[diaqua­bis(pyridine‐4‐carboxamide‐κN)copper(II)]‐μ2‐squarato‐κO1:O3] dihydrate]

The asymmetric unit of the title compound, {[Cu(C₄O₄)(C₆H₆N₂O)₂(H₂O)₂]·2H₂O}_n, consists of one pyridine‐4‐carbox­amide (isonicotinamide or ina) ligand, one‐half of a squarate dianion, a coordinated aqua ligand and a solvent water mol­ecule. Both the Cu^II and the squarate ions are located on inversion centers. The Cu^II ions are octa­hedrally surrounded by four O atoms of two water mol­ecules and two squarate anions, and by two N atoms of the isonicotinamide ligands. The crystal structure contains chains of squarate‐1,3‐bridged Cu^II ions. These chains are held together by N—H⋯O and O—H⋯O inter­molecular hydrogen‐bond inter­actions, forming an extensive three‐dimensional network.     

Di‐μ‐acetato‐bis­{[2,4‐dichloro‐6‐(2‐pyridylmethyl­imino­meth­yl)­phenol­ato]zinc(II)} and di‐μ‐thio­cyanato‐bis­{[2,4‐dichloro‐6‐(2‐pyridylmethyl­imino­meth­yl)phenolato]copper(II)}

The two title complexes, [Zn₂(C₁₃H₉Cl₂N₂O)₂(C₂H₃O₂)₂], (I), and [Cu₂(C₁₃H₉Cl₂N₂O)₂(NCS)₂], (II), are dinuclear Schiff base compounds. Both mol­ecules are located on crystallographic centres of inversion. In (I), the Zn^II atom is five‐coordinated in a trigonal–bipyramidal coordination, with one imine N atom of one Schiff base and two acetate O atoms defining the basal plane, and one O atom and one pyridine N atom of the Schiff base occupying the axial positions, while in (II), the Cu^II atom is five‐coordinated in a square‐pyramidal coordination, with one O and two N atoms of one Schiff base and one terminal N atom of a bridging thio­cyanate ligand defining the basal plane, and one terminal S atom of another bridging thio­cyanate ligand occupying the apical position. The different bridging ligands lead to the different coordinations of the complexes.     

catena‐Poly[[dicyanamido(5,5′‐dimethyl‐2,2′‐bipyridine‐κ2N,N′)copper(II)]‐μ‐dicyanamido‐κ2N1:N5]

In the crystal structure of the title compound, [Cu(C₂N₃)₂(C₁₂H₁₂N₂)]_n, the Cu^II atom adopts a distorted square‐pyramidal geometry, the basal plane of which is formed by two N atoms of the bi­pyridine ligand, one N atom of a bidentate dicyan­amide anion and one N atom of a monodentate dicyan­amide anion [Cu—N = 1.9760 (15)–2.0157 (15) Å]. The apical position is occupied by an N atom of a bidentate dicyan­amide anion, located 2.2468 (16) Å from the Cu atom, thus forming a one‐dimensional polymeric chain.     

Bis(μ‐5‐carboxybenzene‐1,3‐dicarboxylato‐κ2O1:O3)bis[(2,2′‐bi‐1H‐imidazole‐κ2N3,N3′)zinc]

The title compound, [Zn₂(C₉H₄O₆)₂(C₆H₆N₄)₂], consists of two Zn^II ions, two 5‐carboxybenzene‐1,3‐dicarboxylate (Hbtc²⁻) dianions and two 2,2′‐bi‐1H‐imidazole (bimz) molecules. The Zn^II centre is coordinated by two carboxylate O atoms from two Hbtc²⁻ ligands and by two imidazole N atoms of a bimz ligand, in a distorted tetrahedral coordination geometry. Two neighbouring Zn^II ions are bridged by a pair of Hbtc²⁻ ligands, forming a discrete binuclear [Zn₂(Hbtc)₂(bimz)₂] structure lying across an inversion centre. Hydrogen bonds between carboxyl H atoms and carboxylate O atoms and between imidazole H atoms and carboxylate O atoms link the binuclear units. These binuclear units are further extended into a three‐dimensional supramolecular structure through extensive O—H...O and N—H...O hydrogen bonds. Moreover, the three‐dimensional nature of the crystal packing is reinforced by the π–π stacking. The title compound exhibits photoluminescence in the solid state, with an emission maximum at 415 nm.     

Poly[[tetrachlorido{μ4‐tetrakis[(pyridin‐4‐yl)oxymethyl]methane‐κ4N:N′:N′′:N′′′}dizinc(II)] dimethylformamide tetrasolvate]

A novel metal–organic framework, {[Zn₂Cl₄(C₂₅H₂₄N₄O₄)]·4C₃H₇NO}_n, has been synthesized solvothermally by assembling the semi‐rigid tetrahedral ligand tetrakis[(pyridin‐4‐yl)oxymethyl]methane (tpom) and zinc nitrate in dimethylformamide (DMF). The crystal structure is noncentrosymmetric (P2₁c). Each Zn^II cation has a tetrahedral coordination environment (C₂ symmetry), which is formed by two chloride ligands and two pyridine N atoms from two tpom ligands. The tetrahedral tetradentate tpom linker has a quaternary C atom located on the crystallographic axis. This linker utilizes all the peripheral pyridine N atoms to connect four Zn^II cations, thereby forming a wave‐like two‐dimensional sheet along the c axis. The two‐dimensional layer can be topologically simplified as a typical uninodal 4‐connected sql/Shubnikov net, which is represented by the Schläfli symbol {4⁴,6²}. Adjacent layers are further packed into a three‐dimensional structure by C—H...Cl hydrogen bonds.     

2,6‐Bis(1‐benzyl‐1H‐1,2,3‐triazol‐4‐yl)pyridine and its octahedral copper complex

In the tridentate ligand 2,6‐bis(1‐benzyl‐1H‐1,2,3‐triazol‐4‐yl)pyridine, C₂₃H₁₉N₇, both sets of triazole N atoms are anti with respect to the pyridine N atom, while in the copper complex aqua[2,6‐bis(1‐benzyl‐1H‐1,2,3‐triazol‐4‐yl)pyridine](pyridine)(tetrafluoroborato)copper(II) tetrafluoroborate, [Cu(BF₄)(C₅H₅N)(C₂₃H₁₉N₇)(H₂O)]BF₄, the triazole N atoms are in the syn–syn conformation. The coordination of the Cu^II atom is distorted octahedral. The ligand structure is stabilized through intermolecular C—H...N interactions, while the crystal structure of the Cu complex is stabilized through water‐ and BF₄‐mediated hydrogen bonds. Photoluminiscence studies of the ligand and complex show that the ligand is fluorescent due to triazole–pyridine conjugation, but that the fluorescence is quenched on complexation.     

catena‐Poly[[diaquadiisothiocyanatoiron(II)]‐μ‐4,4′‐bi‐1,2,4‐triazole]: a one‐dimensional coordination polymer

In the title complex, [Fe(NCS)₂(C₄H₂N₆)₂(H₂O)₂]_n, the Fe^II atom is on an inversion centre and the 4,4′‐bi‐1,2,4‐triazole (btr) group is bisected by a twofold axis through the central N—N bond. The coordination geometry of the Fe^II atom is elongated distorted FeN₄O₂ octahedral, where the cation is coordinated by two N atoms from the triazole rings of two btr groups, two N atoms from NCS⁻ ligands and two water molecules. Btr is a bidentate ligand, coordinating one Fe^II atom through a peripheral N atom of each triazole ring, leading to a one‐dimensional polymeric (chain) structure extending along [101]. The chains are further connected through a network of O—H...N and C—H...S hydrogen bonds.     

Metal(II) Ion Complexes with 5‐(Pyrazin‐2‐yl)‐2,4‐dihydro‐3H‐1,2,4‐triazole‐3‐thione; Synthesis,Structural Characterization,Acid‐base,and Complexing Properties in Solution

The study reports the synthesis of complexes Co(HL)Cl₂ ( 1 ), Ni(HL)Cl₂ ( 2 ), Cu(HL)Cl₂ ( 3 ), and Zn(HL)₃Cl₂ ( 4 ) with the title ligand, 5‐(pyrazin‐2‐yl)‐1,2,4‐triazole‐5‐thione (HL), and their characterization by elemental analyses, ESI‐MS (m/z), FT‐IR and UV/Vis spectroscopy, as well as EPR in the case of the Cu^II complex. The comparative analysis of IR spectra of the metal ion complexes with HL and HL alone indicated that the metal ions in 1 , 2 , and 3 are chelated by two nitrogen atoms, N(4) of pyrazine and N(5) of triazole in the thiol tautomeric form, whereas the Zn^II ion in 4 is coordinated by the non‐protonated N(2) nitrogen atom of triazole in the thione form. pH potentiometry and UV/Vis spectroscopy were used to examine Co^II, Ni^II, and Zn^II complexes in 10/90 (v/v) DMSO/water solution, whereas the Cu^II complex was examined in 40/60 (v/v) DMSO/water solution. Monodeprotonation of the thione triazole in solution enables the formation of the L:M = 1:1 species with Co^II, Ni^II and Zn^II, the 2:1 species with Co^II and Zn^II, and the 3:1 species with Zn^II. A distorted tetrahedral arrangement of the Cu^II complex was suggested on the basis of EPR and Vis/NIR spectra.     

A one‐dimensional zinc(II) coordination polymer incorporating [1,1′‐biphenyl]‐4,4′‐dicarboxylate and N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide ligands

In the title compound, catena‐poly[[[N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide]chloridozinc(II)]‐μ‐[1,1′‐biphenyl]‐4,4′‐dicarboxylato‐[[N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide]chloridozinc(II)]‐μ‐[N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide]], [Zn₂(C₁₄H₈O₄)Cl₂(C₂₆H₂₂N₄O₂)₃]_n, the Zn^II centre is four‐coordinate and approximately tetrahedral, bonding to one carboxylate O atom from a bidentate bridging dianionic [1,1′‐biphenyl]‐4,4′‐dicarboxylate ligand, to two pyridine N atoms from two N,N′‐bis(pyridin‐3‐ylmethyl)‐[1,1′‐biphenyl]‐4,4′‐dicarboxamide ligands and to one chloride ligand. The pyridyl ligands exhibit bidentate bridging and monodentate terminal coordination modes. The bidentate bridging pyridyl ligand and the bridging [1,1′‐biphenyl]‐4,4′‐dicarboxylate ligand both lie on special positions, with inversion centres at the mid‐points of their central C—C bonds. These bridging groups link the Zn^II centres into a one‐dimensional tape structure that propagates along the crystallographic b direction. The tapes are interlinked into a two‐dimensional layer in the ab plane through N—H...O hydrogen bonds between the monodentate ligands. In addition, the thermal stability and solid‐state photoluminescence properties of the title compound are reported.     

Poly[[tetraaqua(μ7‐pyridine‐2,3,5,6‐tetracarboxylato)dicadmium(II)] monohydrate]

The title compound, {[Cd₂(C₉HNO₈)(H₂O)₄]·H₂O}_n, consists of two crystallographically independent Cd^II cations, one tetrabasic pyridine‐2,3,5,6‐tetracarboxylate (pdtc) anion, four coordinated water molecules and one solvent water molecule. The Cd^II cations have distorted square‐antiprismatic (one pyridine N, six carboxylate O and one water O atom) and octahedral (three carboxylate O and three water O atoms) coordination environments. Each pdtc ligand employs its pyridine and carboxylate groups to chelate and bridge seven Cd^II cations. The square‐antiprismatic coordinated Cd^II cations are linked by pdtc ligands into a lamellar framework structure, while the octahedral coordinated Cd^II cations are bridged by the μ₂‐carboxylate O atoms and the pdtc ligands into a chain network that further joins neighbouring lamellae into a three‐dimensional porous network. The cavities are filled with solvent water molecules that are linked to the host through complex hydrogen bonding.     

Bromidobis[2‐(pyridin‐2‐yl)methanol‐κ2N,O]copper(II) bromide monohydrate

The title compound, [CuBr(C₆H₇NO)₂]Br·H₂O, is an ionic mononuclear complex in which the [CuBr(C₆H₇NO)₂]⁺ cation possesses distorted square‐pyramidal geometry. The Cu^II centre is coordinated by two neutral 2‐(pyridin‐2‐yl)methanol (2‐pyMeOH) ligands and a terminal bromide ligand. The 2‐pyMeOH ligands are coordinated in a bidentate chelating manner through the pyridine N and hydroxy O atoms, forming a five‐membered chelate ring with the Cu^II centre. The planes of the pyridine rings are twisted by 58.71 (14)° with respect to each other. The charge is balanced by a noncoordinating bromide anion which, together with a solvent water molecule, links the components through hydrogen bonds into infinite chains propagating along the a axis. The mononuclear cations appear to associate in pairs through weak interactions between the metal atom of one cation and the halogen atom of an adjacent cation.     

Poly[bis(μ‐4‐benzoyl‐1‐isonicotinoylthiosemicarbazide‐κ2N:S)dichloridocadmium(II)]

The asymmetric unit of the title complex, [CdCl₂(C₁₄H₁₂N₄O₂S)₂]_n, consists of one Cd^II ion located on the crystallographic inversion centre, one 4‐benzoyl‐1‐isonicotinoylthiosemicarbazide ligand and one chloride ligand. The central Cd^II ion adopts a distorted octahedral coordination geometry formed by two pyridyl N atoms of two ligands, two S atoms of two other ligands and two chloride ligands. The thiosemicarbazide ligands act as bridges, linking the metal ions into a two‐dimensional layered structure parallel to the bc plane. Intermolecular N—H...O hydrogen bonds and C—H...π interactions exist between adjacent layers.     

Di­aqua(2,2′‐bi­pyridine)­malonato­manganese(II)

In the crystal structure of the title compound, [Mn(C₃H₂O₄)(C₁₀H₈N₂)(H₂O)₂], the Mn^II atom demonstrates a distorted octahedral geometry, being coordinated by two N atoms of a 2,2′‐bi­pyridine ligand, two O atoms from the carboxyl­ate groups of the chelating malonate dianion and two O atoms of two cis water mol­ecules. The complex mol­ecules are linked to form a three‐dimensional supramolecular array by both hydrogen‐bonding interactions between coordinated water and the carboxyl­ate groups of neighboring mol­ecules and aromatic π–π‐stacking interactions of the bi­pyridine rings.