Copper(II) and cadmium(II) isothiocyanate coordination polymers with 4,4′‐bi‐1,2,4‐triazole

The coordination polymers catena‐poly[[[(4,4′‐bi‐1,2,4‐triazole‐κN¹)bis(thiocyanato‐κN)copper(II)]‐μ‐4,4′‐bi‐1,2,4‐triazole‐κ²N¹:N^1′] dihydrate], {[Cu(NCS)₂(C₄H₄N₆)₂]·2H₂O}_n, (I), and poly[tetrakis(μ‐4,4′‐bi‐1,2,4‐triazole‐κ²N¹:N^1′)bis(μ‐thiocyanato‐κ²N:S)tetrakis(thiocyanato‐κN)tricadmium(II)], [Cd₃(NCS)₆(C₄H₄N₆)₄]_n, (II), exhibit chain and two‐dimensional layer structures, respectively. The differentiation of the Lewis acidic nature of Cu^II and Cd^II has an influence on the coordination modes of the triazole and thiocyanate ligands, leading to topologically different polymeric motifs. In (I), copper ions are linked by bitriazole N:N′‐bridges into zigzag chains and the tetragonal–pyramidal CuN₅ environment is composed of two thiocyanate N atoms and three triazole N atoms [basal Cu—N = 1.9530 (18)–2.0390 (14) Å and apical Cu—N = 2.2637 (15) Å]. The structure of (II) contains two types of crystallographically unique Cd^II atoms. One type lies on an inversion center in a distorted CdN₆ octahedral environment, with bitriazole ligands in the equatorial plane and terminal isothiocyanate N atoms in the axial positions. The other type lies on a general position and forms centrosymmetric binuclear [Cd₂(μ‐NCS‐κ²N:S)₂(NCS)₂] units (tetragonal–pyramidal CdN₄S coordination). N:N′‐Bridging bitriazole ligands link the Cd centers into a flat (4,4)‐network.     

First‐row transition metal–pyridine (py)–sulfate [(py)xM](SO4) complexes (M = Ni,Cu and Zn): crystal field theory in action

The crystal structures of three first‐row transition metal–pyridine–sulfate complexes, namely catena‐poly[[tetrakis(pyridine‐κN)nickel(II)]‐μ‐sulfato‐κ²O:O′], [Ni(SO₄)(C₅H₅N)₄]_n, (1), di‐μ‐sulfato‐κ⁴O:O‐bis[tris(pyridine‐κN)copper(II)], [Cu₂(SO₄)₂(C₅H₅N)₆], (2), and catena‐poly[[tetrakis(pyridine‐κN)zinc(II)]‐μ‐sulfato‐κ²O:O′‐[bis(pyridine‐κN)zinc(II)]‐μ‐sulfato‐κ²O:O′], [Zn₂(SO₄)₂(C₅H₅N)₆]_n, (3), are reported. Ni compound (1) displays a polymeric crystal structure, with infinite chains of Ni^II atoms adopting an octahedral N₄O₂ coordination environment that involves four pyridine ligands and two bridging sulfate ligands. Cu compound (2) features a dimeric molecular structure, with the Cu^II atoms possessing square‐pyramidal N₃O₂ coordination environments that contain three pyridine ligands and two bridging sulfate ligands. Zn compound (3) exhibits a polymeric crystal structure of infinite chains, with two alternating zinc coordination environments, i.e. octahedral N₄O₂ coordination involving four pyridine ligands and two bridging sulfate ligands, and tetrahedral N₂O₂ coordination containing two pyridine ligands and two bridging sulfate ligands. The observed coordination environments are consistent with those predicted by crystal field theory.     

Synthesis,crystal structures and luminescence properties of seven mononuclear zinc(II), cadmium(II), cobalt(II) and nickel(II) complexes with 5‐(4‐methylphenyl)‐3‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazole

Due to their versatile coordination modes and metal‐binding conformations, triazolyl ligands can provide a wide range of possibilities for the construction of supramolecular structures. Seven mononuclear transition metal complexes with different structural forms, namely aquabis[3‐(4‐methylphenyl)‐5‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazolato‐κ²N ¹,N ⁵]zinc(II), [Zn(C₁₄H₁₁N₄)₂(H₂O)], (I), bis[5‐(4‐methylphenyl)‐3‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazole‐κ²N ³,N ⁴]bis(nitrato‐κO )zinc(II), [Zn(NO₃)₂(C₁₄H₁₂N₄)₂], (II), bis(methanol‐κO )bis[3‐(4‐methylphenyl)‐5‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazolato‐κ²N ¹,N ⁵]zinc(II), [Zn(C₁₄H₁₁N₄)₂(CH₄O)₂], (III), diiodidobis[5‐(4‐methylphenyl)‐3‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazole‐κ²N ³,N ⁴]cadmium(II), [CdI₂(C₁₄H₁₂N₄)₂], (IV), bis[5‐(4‐methylphenyl)‐3‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazole‐κ²N ³,N ⁴]bis(nitrato‐κO )cadmium(II), [Cd(NO₃)₂(C₁₄H₁₂N₄)₂], (V), aquabis[3‐(4‐methylphenyl)‐5‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazolato‐κ²N ¹,N ⁵]cobalt(II), [Co(C₁₄H₁₁N₄)₂(H₂O)], (VI), and diaquabis[3‐(4‐methylphenyl)‐5‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazolato‐κ²N ¹,N ⁵]nickel(II), [Ni(C₁₄H₁₁N₄)₂(H₂O)₂], (VII), have been prepared by the reaction of transition metal salts (Zn^II, Cd^II, Co^II and Ni^II) with 3‐(4‐methylphenyl)‐5‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazole (pymphtzH) under either ambient or hydrothermal conditions. These compounds have been characterized by elemental analysis, IR spectroscopy and single‐crystal X‐ray diffraction. All the complexes form three‐dimensional supramolecular structures through hydrogen bonds or through π–π stacking interactions between the centroids of the pyridyl or arene rings. The pymphtzH and pymphtz⁻ entities act as bidentate coordinating ligands in each structure. Moreover, all the pyridyl N atoms are coordinated to metal atoms (Zn, Cd, Co or Ni). The N atom in the 4‐position of the triazole group is coordinated to the Zn and Cd atoms in the crystal structures of (II), (IV) and (V), while the N atom in the 1‐position of the triazolate group is coordinated to the Zn, Co and Ni atoms in (I), (III), (VI) and (VII).     

Synthesis,crystal structure,and spectroscopic and thermal properties of the polymeric compound catena‐poly[[bis(2,4‐dichlorobenzoato)zinc(II)]‐μ‐isonicotinamide]

Zinc(II) carboxylates with O‐, S‐ and N‐donor ligands are interesting for their structural features, as well as for their antibacterial and antifungal activities. The one‐dimensional zinc(II) coordination complex catena‐poly[[bis(2,4‐dichlorobenzoato‐κO)zinc(II)]‐μ‐isonicotinamide‐κ²N¹:O], [Zn(C₇H₃Cl₂O₂)₂(C₆H₆N₂O)]_n, has been prepared and characterized by IR spectroscopy, single‐crystal X‐ray analysis and thermal analysis. The tetrahedral ZnO₃N coordination about the Zn^II cation is built up by the N atom of the pyridine ring, an O atom of the carbonyl group of the isonicotinamide ligand and two O atoms of two dichlorobenzoate ligands. Isonicotinamide serves as a bridge between tetrahedra, with a Zn...Zn distance of 8.8161 (7) Å. Additionally, π–π interactions between the planar benzene rings contribute to the stabilization of the extended structure. The structure is also stabilized by intermolecular hydrogen bonds between the amino and carboxylate groups of the ligands, forming a two‐dimensional network. During thermal decomposition of the complex, isonicotinamide, dichlorobenzene and carbon dioxide were evolved. The final solid product of the thermal decomposition heated up to 1173 K was metallic zinc.     

Binuclear and chain‐structure zinc(II) complexes constructed from 3,4‐dimethoxy‐trans‐cinnamic acid and N‐donor coligands 4‐(1H‐pyrazol‐3‐yl)pyridine and 4,4′‐bipyridine

3,4‐Dimethoxy‐trans‐cinnamic acid (Dmca) reacts with zinc sulfate in the presence of 4‐(1H‐pyrazol‐3‐yl)pyridine (L₁) or 4,4′‐bipyridine (L₂) under hydrothermal conditions to afford two mixed‐ligand coordination complexes, namely tetrakis(μ‐3,4‐dimethoxy‐trans‐cinnamato‐κ²O:O′)bis[[4‐(1H‐pyrazol‐3‐yl)pyridine]zinc(II)] heptahydrate, [Zn₂(C₁₁H₁₁O₄)₄(C₈H₇N₃)₂]·7H₂O or [Zn₂(Dmca)₄(L₁)₂]·7H₂O, (I), and catena‐poly[[bis(3,4‐dimethoxy‐trans‐cinnamato‐κO)zinc(II)]‐μ‐4,4′‐bipyridine‐κ²N:N′], [Zn(C₁₁H₁₁O₄)₂(C₁₀H₈N₂)]_n or [Zn(Dmca)₂(L₂)]_n, (II). The Zn^II centres in the two compounds display different coordination polyhedra. In complex (I), the Zn^II cation is five‐coordinated with a pseudo‐square‐pyramidal geometry, while in complex (II) the Zn^II cation sits on a twofold axis and adopts a distorted tetrahedral coordination environment. Complex (I) features a centrosymmetric binuclear paddle‐wheel‐like structure, while complex (II) shows a chain structure. This study emphasizes the significant effect of the coordination mode of both carboxylate‐group and N‐donor coligands on the formation of complex structures.     

More crystal field theory in action: the metal–4‐picoline (pic)–sulfate [M(pic)x]SO4 complexes (M = Fe,Co, Ni,Cu, Zn,and Cd)

Seven crystal structures of five first‐row (Fe, Co, Ni, Cu, and Zn) and one second‐row (Cd) transition metal–4‐picoline (pic)–sulfate complexes of the form [M(pic)_x]SO₄ are reported. These complexes are catena‐poly[[tetrakis(4‐methylpyridine‐κN)metal(II)]‐μ‐sulfato‐κ²O:O′], [M(SO₄)(C₆H₇N)₄]_n, where the metal/M is iron, cobalt, nickel, and cadmium, di‐μ‐sulfato‐κ⁴O:O‐bis[tris(4‐methylpyridine‐κN)copper(II)], [Cu₂(SO₄)₂(C₆H₇N)₆], catena‐poly[[bis(4‐methylpyridine‐κN)zinc(II)]‐μ‐sulfato‐κ²O:O′], [Zn(SO₄)(C₆H₇N)₂]_n, and catena‐poly[[tris(4‐methylpyridine‐κN)zinc(II)]‐μ‐sulfato‐κ²O:O′], [Zn(SO₄)(C₆H₇N)₃]_n. The Fe, Co, Ni, and Cd compounds are isomorphous, displaying polymeric crystal structures with infinite chains of M^II ions adopting an octahedral N₄O₂ coordination environment that involves four picoline ligands and two bridging sulfate anions. The Cu compound features a dimeric crystal structure, with the Cu^II ions possessing square‐pyramidal N₃O₂ coordination environments that contain three picoline ligands and two bridging sulfate anions. Zinc crystallizes in two forms, one exhibiting a polymeric crystal structure with infinite chains of Zn^II ions adopting a tetrahedral N₂O₂ coordination containing two picoline ligands and two bridging sulfate anions, and the other exhibiting a polymeric crystal structure with infinite chains of Zn^II ions adopting a trigonal bipyramidal N₃O₂ coordination containing three picoline ligands and two bridging sulfate anions. The structures are compared with the analogous pyridine complexes, and the observed coordination environments are examined in relation to crystal field theory.     

Phenanthroline complexes of zinc and calcium carbamates

Bis(N,N‐di‐n‐butyl­di­thio­carbamato‐κ²S,S′)(1,10‐phenanthroline‐κ²N,N′)­zinc(II) ethanol hemisolvate, [Zn(C₉H₁₈NS₂)₂(C₁₂H₈N₂)]·0.5C₂H₆O, (I), and bis(N,N‐di‐n‐hexyldithiocarbamato‐κ²S,S′)­bis(1,10‐phenanthroline‐κ²N,N′)calcium(II), [Ca(C₁₃H₂₆NS₂)₂(C₁₂H₈N₂)₂], (II), are mixed‐ligand com­plexes. In the first compound, the Zn atom has a distorted octahedral coordination, while in the second compound, the Ca atom is eight‐coordinate, with four S and four N atoms forming a highly distorted cube.     

Cobalt(II) chloride adducts with acetonitrile,propan‐2‐ol and tetrahydrofuran: considerations on nuclearity,reactivity and synthetic applications

High‐spin cobalt(II) complexes are considered useful building blocks for the synthesis of single‐molecule magnets (SMM) because of their intrinsic magnetic anisotropy. In this work, three new cobalt(II) chloride adducts with labile ligands have been synthesized from anhydrous CoCl₂, to be subsequently employed as starting materials for heterobimetallic compounds. The products were characterized by elemental, spectroscopic (EPR and FT–IR) and single‐crystal X‐ray diffraction analyses. trans‐Tetrakis(acetonitrile‐κN )bis(tetrahydrofuran‐κO )cobalt(II) bis[(acetonitrile‐κN )trichloridocobaltate(II)], [Co(C₂H₃N)₄(C₄H₈O)₂][CoCl₃(C₂H₃N)]₂, (1), comprises mononuclear ions and contains both acetonitrile and tetrahydrofuran (thf) ligands, The coordination polymer catena‐poly[[tetrakis(propan‐2‐ol‐κO )cobalt(II)]‐μ‐chlorido‐[dichloridocobalt(II)]‐μ‐chlorido], [Co₂Cl₄(C₃H₈O)₄], (2′), was prepared by direct reaction between anhydrous CoCl₂ and propan‐2‐ol in an attempt to rationalize the formation of the CoCl₂–alcohol adduct (2), probably CoCl₂(HOⁱPr)_m . The binuclear complex di‐μ‐chlorido‐1:2κ⁴Cl :Cl‐dichlorido‐2κ²Cl‐tetrakis(tetrahydrofuran‐1κO )dicobalt(II), [Co₂Cl₄(C₄H₈O)₄], (3), was obtained from (2) after recrystallization from tetrahydrofuran. All three products present cobalt(II) centres in both octahedral and tetrahedral environments, the former usually less distorted than the latter, regardless of the nature of the neutral ligand. Product (2′) is stabilized by an intramolecular hydrogen‐bond network that appears to favour a trans arrangement of the chloride ligands in the octahedral moiety; this differs from the cis disposition found in (3). The expected easy displacement of the bound solvent molecules from the metal coordination sphere makes the three compounds good candidates for suitable starting materials in a number of synthetic applications.     

Two isomorphous ZnII/CoII complexes with tri‐tert‐butoxysilanethiol and histamine,and (4‐hydroxymethyl‐1H‐imidazole‐κN)bis(tri‐tert‐butoxysilanethiolato‐κ2O,S)zinc(II)

The complexes [2‐(1H‐imidazol‐4‐yl‐κN³)ethylamine‐κN]bis(tri‐tert‐butoxysilanethiolato‐κS)cobalt(II), [Co(C₁₂H₂₇O₃SSi)₂(C₅H₉N₃)], and [2‐(1H‐imidazol‐4‐yl‐κN³)ethylamine‐κN]bis(tri‐tert‐butoxysilanethiolato‐κS)zinc(II), [Zn(C₁₂H₂₇O₃SSi)₂(C₅H₉N₃)], are isomorphous. The central Zn^II/Co^II ions are surrounded by two S atoms from the tri‐tert‐butoxysilanethiolate ligand and by two N atoms from the chelating histamine ligand in a distorted tetrahedral geometry, with two intramolecular N—H...O hydrogen‐bonding interactions between the histamine NH₂ groups and tert‐butoxy O atoms. Molecules of the complexes are joined into dimers via two intermolecular bifurcated N—H...(S,O) hydrogen bonds. The Zn^II atom in [(1H‐imidazol‐4‐yl‐κN³)methanol]bis(tri‐tert‐butoxysilanethiolato‐κ²O,S)zinc(II), [Zn(C₁₂H₂₇O₃SSi)₂(C₄H₆N₂O)], is five‐coordinated by two O and two S atoms from the O,S‐chelating silanethiolate ligand and by one N atom from (1H‐imidazol‐4‐yl)methanol; the hydroxy group forms an intramolecular hydrogen bond with sulfur. Molecules of this complex pack as zigzag chains linked by N—H...O hydrogen bonds. These structures provide reference details for cysteine‐ and histidine‐ligated metal centers in proteins.     

Two lanthanum(III) complexes containing η2‐pyrazolate and η2‐1,2,4‐triazolate ligands: intramolecular C—H...N/O interactions and coordination geometries

The lanthanum(III) complexes tris(3,5‐diphenylpyrazolato‐κ²N,N′)tris(tetrahydrofuran‐κO)lanthanum(III) tetrahydrofuran monosolvate, [La(C₁₅H₁₁N₂)₃(C₄H₈O)₃]·C₄H₈O, (I), and tris(3,5‐diphenyl‐1,2,4‐triazolato‐κ²N¹,N²)tris(tetrahydrofuran‐κO)lanthanum(III), [La(C₁₄H₁₀N₃)₃(C₄H₈O)₃], (II), both contain La^III atoms coordinated by three heterocyclic ligands and three tetrahydrofuran ligands, but their coordination geometries differ. Complex (I) has a mer‐distorted octahedral geometry, while complex (II) has a fac‐distorted configuration. The difference in the coordination geometries and the existence of asymmetric La—N bonding in the two complexes is associated with intramolecular C—H...N/O interactions between the ligands.     

Bis­(saccharinato‐κN)zinc(II) com­plexes with N,N′‐bidentate 2‐amino­methyl­pyridine and 2‐amino­ethylpyridine

The structures of trans‐bis[2‐(amino­methyl)­pyridine‐κ²N,N′]­bis­(saccharinato‐κN)­zinc(II), [Zn(C₇H₄NO₃S)₂(C₆H₈N₂)₂], (I), and [2‐(amino­ethyl)­pyridine‐κ²N,N′]bis­(saccharinato‐κN)­zinc(II), [Zn(C₇H₄NO₃S)₂(C₇H₁₀N₂)], (II), exhibit octa‐ and tetrahedrally coordinated Zn^II atoms, respectively. The di­amine ligands behave as N,N′‐bidentate ligands, while saccharinate (sac) is coordinated through the N atom. In (I), the complex lies about an inversion centre with the Zn atom disordered and displaced by 0.256 (2) Å from a centre of symmetry towards a sac N atom. The crystal structure of (I) is stabilized by N—H⋯O hydrogen bonds and the crystal packing of (II) is determined by hydrogen bonding as well as weak π–π stacking interactions between the sac ligands.     

Adducts of bis(acetylacetonato)zinc(II) with 1,10‐phenanthroline and 2,2′‐bipyridine

In each of the zinc(II) complexes bis(acetylacetonato‐κ²O,O′)(1,10‐phenanthroline‐κ²N,N′)zinc(II), [Zn(C₅H₇O₂)₂(C₁₂H₈N₂)], (I), and bis(acetylacetonato‐κ²O,O′)(2,2′‐bipyridine‐κ²N,N′)zinc(II), [Zn(C₅H₇O₂)₂(C₁₀H₈N₂)], (II), the metal center has a distorted octahedral coordination geometry. Compound (I) has crystallographically imposed twofold symmetry, with Z′ = 0.5. The presence of a rigid phenanthroline group precludes intramolecular hydrogen bonding, whereas the rather flexible bipyridyl ligand is twisted to form an intramolecular C—H...O interaction [the chelated bipyridyl ligand is nonplanar, with the pyridyl rings inclined at an angle of 13.4 (1)°]. The two metal complexes are linked by dissimilar C—H...O interactions into one‐dimensional chains. The present study demonstrates the distinct effects of two commonly used ligands, viz. 1,10‐phenanthroline and 2,2′‐bipyridine, on the structures of metal complexes and their assembly.     

Two zinc(II) coordination complexes based on an asymmetric multidentate ligand: syntheses,structures, selective fluorescence sensing of iron(III) ions and thermal analyses

The rational selection of ligands is vitally important in the construction of coordination complexes. Two novel Zn^II complexes, namely bis(acetato‐κO)bis[1‐(1H‐benzotriazol‐1‐ylmethyl)‐2‐propyl‐1H‐imidazole‐κN³]zinc(II) monohydrate, [Zn(C₁₃H₁₅N₅)₂(C₂H₃O₂)₂]·H₂O, ( 1 ), and bis(azido‐κN¹)bis[1‐(1H‐benzotriazol‐1‐ylmethyl)‐2‐propyl‐1H‐imidazole‐κN³]zinc(II), [Zn(C₁₃H₁₅N₅)₂(N₃)₂], ( 2 ), constructed from the asymmetric multidentate imidazole ligand, have been synthesized under mild conditions and characterized by elemental analyses, IR spectroscopy and single‐crystal X‐ray diffraction analysis. Both complexes exhibit a three‐dimensional supramolecular network directed by different intermolecular interactions between discrete mononuclear units. The complexes were also investigated by fluorescence and thermal analyses. The experimental results show that ( 1 ) is a promising fluorescence sensor for detecting Fe³⁺ ions and ( 2 ) is effective as an accelerator of the thermal decomposition of ammonium perchlorate.     

Three zinc(II) and cadmium(II) complexes containing 4‐amino‐3,5‐bis(pyridin‐2‐yl)‐1,2,4‐triazole and polynitrile ligands: synthesis,molecular and supramolecular structures,and photoluminescence properties

Three photoluminescent complexes containing either Zn^II or Cd^II have been synthesized and their structures determined. Bis[4‐amino‐3,5‐bis(pyridin‐2‐yl)‐1,2,4‐triazole‐κ²N ¹,N ⁵]bis(dicyanamido‐κN ¹)zinc(II), [Zn(C₁₂H₁₀N₆)₂(C₂N₃)₂], (I), bis[4‐amino‐3,5‐bis(pyridin‐2‐yl)‐1,2,4‐triazole‐κ²N ¹,N ⁵]bis(dicyanamido‐κN ¹)cadmium(II), [Cd(C₁₂H₁₀N₆)₂(C₂N₃)₂], (II), and bis[4‐amino‐3,5‐bis(pyridin‐2‐yl)‐1,2,4‐triazole‐κ²N ¹,N ⁵]bis(tricyanomethanido‐κN ¹)cadmium(II), [Cd(C₁₂H₁₀N₆)₂(C₄N₃)₂], (III), all crystallize in the space group P , with the metal centres lying on centres of inversion, but neither analogues (I) and (II) nor Cd^II complexes (II) and (III) are isomorphous. A combination of N—H…N and C—H…N hydrogen bonds and π–π stacking interactions generates three‐dimensional framework structures in (I) and (II), and a sheet structure in (III). The photoluminescence spectra of (I)–(III) indicate that the energies of the π–π* transitions in the coordinated triazole ligand are modified by minor changes of the ligand geometry associated with coordination to the metal centres.     

Two mononuclear octahedral complexes with benzimidazole‐2‐carboxylate: supramolecular networks constructed by hydrogen bonds

The title compounds, trans‐bis(1H‐benzimidazole‐2‐carboxylato‐κ²N³,O)bis(ethanol‐κO)cadmium(II), [Cd(C₈H₅N₂O₂)₂(C₂H₆O)₂], (I), and trans‐bis(1H‐benzimidazole‐κN³)bis(1H‐benzimidazole‐2‐carboxylato‐κ²N³,O)nickel(II), [Ni(C₈H₅N₂O₂)₂(C₇H₆N₂)₂], (II), are hydrogen‐bonded supramolecular complexes. In (I), the Cd^II ion is six‐coordinated by two O atoms from two ethanol molecules, and by two O and two N atoms from two bidentate benzimidazole‐2‐carboxylate (HBIC) ligands, giving a distorted octahedral geometry. The combination of O—H...O and N—H...O hydrogen bonds results in two‐dimensional layers parallel to the ab plane. In (II), the six‐coordinated Ni^II atom, which lies on an inversion centre, shows a similar distorted octahedral geometry to the Cd^II ion in (I); two benzimidazole molecules occupy the axial sites and the equatorial plane contains two chelating HBIC ligands. Pairs of N—H...O hydrogen bonds between pairs of HBIC anions connect adjacent Ni^II coordination units to form a one‐dimensional chain parallel to the a axis. Moreover, these one‐dimensional chains are further linked via N—H...O hydrogen bonds between HBIC anions and benzimidazole molecules to generate a three‐dimensional supramolecular framework. The two compounds show quite different supramolecular networks, which may be explained by the fact that different co‐ligands occupy the axial sites in the coordination units.     

Two ZnII coordination complexes assembled by trithiocyanuric acid and two different N‐donor auxiliary ligands

The dipyridyl‐type building blocks 4‐amino‐3,5‐bis(pyridin‐3‐yl)‐1,2,4‐triazole (3‐bpt) and 4,4′‐bipyridine (bpy) have been used to assemble with Zn^II in the presence of trithiocyanuric acid (ttcH₃) to afford two coordination compounds, namely bis[4‐amino‐3,5‐bis(pyridin‐3‐yl)‐1,2,4‐triazole‐κN³]bis(trithiocyanurato‐κ²N,S)zinc(II), [Zn(C₃H₂N₃S₃)₂(C₁₂H₁₀N₆)₂]·2H₂O, (1), and catena‐poly[[[bis(trithiocyanurato‐κ²N,S)zinc(II)]‐μ‐4,4′‐bipyridine‐κ²N:N′] 4,4′‐bipyridine monosolvate], {[Zn₂(C₃H₂N₃S₃)₄(C₁₀H₈N₂)₃]·C₁₀H₈N₂}_n, (2). Single‐crystal X‐ray analysis indicates that complex (1) is a mononuclear structure, while complex (2) presents a one‐dimensional chain coordination motif. In both complexes, the central Zn^II cation adopts an octahedral geometry, coordinated by four N‐ and two S‐donor atoms. Notably, trithiocyanurate (ttcH₂⁻) adopts the same bidentate chelating coordination mode in each complex and exists in the thione tautomeric form. The 3‐bpt co‐ligand in (1) adopts a monodentate coordination mode and serves as a terminal pendant ligand, whereas the 4,4′‐bipyridine (bpy) ligand in (2) adopts a bidentate–bridging coordination mode. The different coordination characters of the different N‐donor auxiliary ligands lead to structural diversity for complexes (1) and (2). Further analysis indicates that the resultant three‐dimensional supramolecular networks for (1) and (2) arise through intermolecular N—H...S and N—H...N hydrogen bonds. Both complexes have been further characterized by FT–IR spectroscopy and elemental analyses.     

A novel two‐dimensional zinc(II) coordination polymer with 6‐mercaptonicotinic acid

The novel title Zn^II coordination polymer, poly[bis(μ‐6‐thioxo‐1,6‐dihydropyridine‐3‐carboxylato‐κ²S:O)zinc(II)], [Zn(C₆H₄NO₂S)₂]_n, consists of two crystallographically independent zinc centers and two 6‐mercaptonicotinate (Hmna⁻) ligands. Each Zn^II atom is four‐coordinated and lies at the center of a distorted tetrahedral ZnS₂O₂ coordination polyhedron, bridged by four Hmna⁻ ligands to form a two‐dimensional (4,4)‐network. Each Hmna⁻ ion acts as a bridging bidentate ligand, coordinating to two Zn^II atoms through the S atom and a carboxyl O atom. The metal centers reside on twofold rotation axes. The coordination mode of the S atoms and N—H...O hydrogen‐bonding interactions between the protonated N atoms and the uncoordinated carboxyl O atoms give the extended structure a wavelike form.     

A polymeric zinc thio­sulfate complex containing anionic and cationic chains based on tetra­hedral and octa­hedral zinc sites

catena‐Poly[[[tetra­aqua­zinc(II)]‐μ‐4,4′‐bipyridine‐κ²N:N′] [[μ‐thio­sulfato‐κ²O:S‐bis­[(thio­sulfato‐κS)zinc(II)]]‐di‐μ‐4,4′‐pyridine‐κ⁴N:N′] dihydrate], {[Zn(C₁₀H₈N₂)(H₂O)₄][Zn₂(S₂O₃)₃(C₁₀H₈N₂)₂]·2H₂O}_n, is a polymeric zinc complex built up from thio­sulfate‐containing anionic chains, where the Zn atom is tetra­hedrally coordinated, and aqua‐containing cationic chains incorporating octa­hedrally coordinated Zn. In each type of chain, the 4,4′‐bipyridine units act as spacers, and the chains run along three non‐inter­secting almost orthogonal directions in space. The profusion of hydrogen‐bond donors (all the H atoms of the water mol­ecules) and acceptors (the thio­sulfate O and S atoms) generates a very complex hydrogen‐bonding scheme.