A one‐dimensional heterometallic coordination polymer with a three‐dimensional supramolecular framework: poly[μ2‐aqua‐diaqua(2,2′‐bipyridyl)(μ5‐2‐sulfonatobutanedioato)copper(II)sodium(I)]

The title compound, [CuNa(C₄H₃O₇S)(C₁₀H₈N₂)(H₂O)₃]_n, consists of one Cu^II cation, one Na^I cation, one 2‐sulfonatobutanedioate trianion (SSC³⁻), one 2,2′‐bipyridyl (bpy) ligand and three coordinated water molecules as the building unit. The coordination of the Cu^II cation is composed of two pyridyl N atoms, one water O atom and two carboxylate O atoms in a distorted square‐pyramidal coordination geometry with an axial elongation. The Na^I cation is six‐coordinated by three water molecules and three carboxylate O atoms from three SSC³⁻ ligands in a distorted octahedral geometry. Two SSC³⁻ ligands link two Cu^II cations to form a Cu₂(SSC)₂(bpy)₂ macrocyclic unit lying across an inversion centre, which is further linked by Na^I cations via Na—O bonds to give a one‐dimensional chain. Interchain hydrogen bonds link these chains to form a two‐dimensional layer, which is further extended into a three‐dimensional supramolecular framework through π–π stacking interactions. The thermal stability of the title compound has also been investigated.     

Two different one‐dimensional CdII halide coordination polymers constructed through bridging carboxylate ligands

Two cadmium halide complexes, catena‐poly[[chloridocadmium(II)]‐di‐μ‐chlorido‐[chloridocadmium(II)]‐bis[μ₂‐4‐(dimethylamino)pyridin‐1‐ium‐1‐acetate]‐κ³O:O,O′;κ³O,O′:O], [CdCl₂(C₉H₁₂N₂O₂)]_n, (I), and catena‐poly[1‐cyanomethyl‐1,4‐diazoniabicyclo[2.2.2]octane [[dichloridocadmium(II)]‐μ‐oxalato‐κ⁴O¹,O²:O^1′,O^2′] monohydrate], {(C₈H₁₅N₃)[CdCl₂(C₂O₄)]·H₂O}_n, (II), were synthesized in aqueous solution. In (I), the Cd^II cation is octahedrally coordinated by three O atoms from two carboxylate groups and by one terminal and two bridging chloride ligands. Neighbouring Cd^II cations are linked together by chloride anions and bridging O atoms to form a one‐dimensional zigzag chain. Hydrogen‐bond interactions are involved in the formation of the two‐dimensional network. In (II), each Cd^II cation is octahedrally coordinated by four O atoms from two oxalic acid ligands and two terminal Cl⁻ ligands. Neighbouring Cd^II cations are linked together by oxalate groups to form a one‐dimensional anionic chain, and the water molecules and organic cations are connected to this one‐dimensional zigzag chain through hydrogen‐bond interactions.     

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.     

Crystal structure,shape analysis and bioactivity of new LiI,NaI and MgII complexes with 1,10‐phenanthroline and 2‐(3,4‐dichlorophenyl)acetic acid

Reactions of 1,10‐phenanthroline (phen) and 2‐(3,4‐dichlorophenyl)acetic acid (dcaH) with M_n(CO₃) (M = Li^I, Na^I and Mg^II; n = 1 and 2) in MeOH yield the mononuclear lithium complex aqua[2‐(3,4‐dichlorophenyl)acetato‐κO](1,10‐phenanthroline‐κ²N,N′)lithium(I), [Li(C₈H₅Cl₂O₂)(C₁₂H₈N₂)(H₂O)] or [Li(dca)(phen)(H₂O)] ( 1 ), the dinuclear sodium complex di‐μ‐aqua‐bis{[2‐(3,4‐dichlorophenyl)acetato‐κO](1,10‐phenanthroline‐κ²N,N′)sodium(I)}, [Na₂(C₈H₅Cl₂O₂)₂(C₁₂H₈N₂)₂(H₂O)₂] or [Na₂(dca)₂(phen)₂(H₂O)₂] ( 2 ), and the one‐dimensional chain magnesium complex catena‐poly[[[diaqua(1,10‐phenanthroline‐κ²N,N′)magnesium]‐μ‐2‐(3,4‐dichlorophenyl)acetato‐κ²O:O′] 2‐(3,4‐dichlorophenyl)acetate monohydrate], {[Mg(C₈H₅Cl₂O₂)(C₁₂H₈N₂)(H₂O)₂](C₈H₅Cl₂O₂)·H₂O}_n or {[Mg(dca)(phen)(H₂O)₂](dca)·H₂O}_n ( 3 ). In these complexes, phen binds via an N,N′‐chelate pocket, while the deprotonated dca^? ligands coordinate either in a monodentate (in 1 and 2 ) or bidentate (in 3 ) fashion. The remaining coordination sites around the metal ions are occupied by water molecules in all three complexes. Complex 1 crystallizes in the triclinic space group P with one molecule in the asymmetric unit. The Li⁺ ion adopts a four‐coordinated distorted seesaw geometry comprising an [N₂O₂] donor set. Complex 2 crystallizes in the triclinic space group P with half a molecule in the asymmetric unit, in which the Na⁺ ion adopts a five‐coordinated distorted spherical square‐pyramidal geometry, with an [N₂O₃] donor set. Complex 3 crystallizes in the orthorhombic space group P2₁2₁2₁, with one Mg²⁺ ion, one phen ligand, two dca^? ligands and three water molecules in the asymmetric unit. Both dcaH ligands are deprotonated, however, one dca^? anion is not coordinated, whereas the second dca^? anion coordinates in a bidentate fashion bridging two Mg²⁺ ions, resulting in a one‐dimensional chain structure for 3 . The Mg²⁺ ion adopts a distorted octahedral geometry, with an [N₂O₄] donor set. Complexes 1 – 3 were evaluated against urease and α‐glucosidase enzymes for their inhibition potential and were found to be inactive.     

A novel two‐dimensional CuSCN network templated by 2,2′‐dimethyl‐1,1′‐(butane‐1,4‐diyl)bis(1H‐imidazol‐3‐ium) cations

The cation‐templated self‐assembly of 1,4‐bis(2‐methyl‐1H‐imidazol‐1‐yl)butane (bmimb) with CuSCN gives rise to a novel two‐dimensional network, namely catena‐poly[2,2′‐dimethyl‐1,1′‐(butane‐1,4‐diyl)bis(1H‐imidazol‐3‐ium) [tetra‐μ₂‐thiocyanato‐κ⁴S:S;κ⁴S:N‐dicopper(I)]], {(C₁₂H₂₀N₄)[Cu₂(NCS)₄]}_n. The Cu^I cation is four‐coordinated by one N and three S atoms, giving a tetrahedral geometry. One of the two crystallographically independent SCN⁻ anions acts as a μ₂‐S:S bridge, binding a pair of Cu^I cations into a centrosymmetric [Cu₂(NCS)₂] subunit, which is further extended into a two‐dimensional 4⁴‐sql net by another kind of SCN⁻ anion with an end‐to‐end μ₂‐S:N coordination mode. Interestingly, each H₂bmimb dication, lying on an inversion centre, threads through one of the windows of the two‐dimensional 4⁴‐sql net, giving a pseudorotaxane‐like structure. The two‐dimensional 4⁴‐sql networks are packed into the resultant three‐dimensional supramolecular framework through bmimb–SCN N—H...N hydrogen bonds.     

Soft scorpionate coordination at alkali metals

Reported here are the single‐crystal X‐ray structure analyses of bis‐μ‐methanol‐κ⁴O:O‐bis{[hydrotris(3‐phenyl‐2‐sulfanylidene‐2,3‐dihydro‐1H‐1,3‐imidazol‐1‐yl)borato‐κ³H,S,S′](methanol‐κO)sodium(I)}, [Na₂(C₂₇H₂₂BN₆S₃)₂(CH₄O)₄] (NaTm^Ph), bis‐μ‐methanol‐κ⁴O:O‐bis{[hydrotris(3‐isopropyl‐2‐sulfanylidene‐2,3‐dihydro‐1H‐1,3‐imidazol‐1‐yl)borato‐κ³H,S,S′](methanol‐κO)sodium(I)}–diethyl ether–methanol (1/0.3333/0.0833), [Na₂(C₁₈H₂₈BN₆S₃)₂(CH₄O)₄]·0.3333C₄H₁₀O·0.0833CH₃OH (NaTm^iPr), and a novel anhydrous form of sodium hydrotris(methylthioimidazolyl)borate, poly[[μ‐hydrotris(3‐methyl‐2‐sulfanylidene‐2,3‐dihydro‐1H‐1,3‐imidazol‐1‐yl)borato]sodium(I)], [Na(C₁₂H₁₆BN₆S₃)] ([NaTm^Me]_n). NaTm^iPr and NaTm^Ph have similar dimeric molecular structures with κ³H,S,S′‐bonding, but they differ in that NaTm^Ph is crystallographically centrosymmetric (Z′ = 0.5) while NaTm^iPr contains one crystallographically centrosymmetric dimer and one dimer positioned on a general position (Z′ = 1.5). [NaTm^Me]_n is a one‐dimensional coordination polymer that extends along the a direction and which contains a hitherto unseen side‐on η²‐C=S‐to‐Na bond type. An overview of the structural preferences of alkali metal soft scorpionate complexes is presented. This analysis suggests that these thione‐based ligands will continue to be a rich source of interesting alkali metal motifs worthy of isolation and characterization.     

A three‐dimensional polymeric potassium complex of 5‐sulfonobenzene‐1,2,4‐tricarboxylic acid: poly[μ‐aqua‐aqua‐μ9‐(2,4‐dicarboxy‐5‐sulfonatobenzoato)‐dipotassium(I)]

The asymmetric unit in the structure of the title compound, [K₂(C₉H₄O₉S)(H₂O)₂]_n, consists of two eight‐coordinated K^I cations, one 2,4‐dicarboxy‐5‐sulfonatobenzoate dianion (H₂SBTC²⁻), one bridging water molecule and one terminal coordinated water molecule. One K^I cation is coordinated by three carboxylate O atoms and three sulfonate O atoms from four H₂SBTC²⁻ ligands and by two bridging water molecules. The second K^I cation is coordinated by four sulfonate O atoms and three carboxylate O atoms from five H₂SBTC²⁻ ligands and by one terminal coordinated water molecule. The K^I cations are linked by sulfonate groups to give a one‐dimensional inorganic chain with cage‐like K₄(SO₃)₂ repeat units. These one‐dimensional chains are bridged by one of the carboxylic acid groups of the H₂SBTC²⁻ ligand to form a two‐dimensional layer, and these layers are further linked by the remaining carboxylate groups and the benzene rings of the H₂SBTC²⁻ ligands to generate a three‐dimensional framework. The compound displays a photoluminescent emission at 460 nm upon excitation at 358 nm. In addition, the thermal stability of the title compound has been studied.     

Two two‐dimensional MnII and NaI coordination polymers constructed by the flexible benzene‐1,4‐dioxy­acetate ligand

Two new two‐dimensional coordination polymers, poly­[[[aqua(2,2′‐bi­pyridine‐κ²N,N′)manganese(II)]‐μ₃‐p‐phenyl­enebis­(oxy­acet­ato)‐κ³O:O′:O′′] dihydrate], {[Mn(C₁₀H₈O₆)(C₁₀H₈N₂)(H₂O)]·2H₂O}_n, (I), and poly­[[di‐μ‐aqua‐bis­[aqua­sodium(I)]]‐μ₄‐p‐phenyl­enebis­(oxy­acetato)‐κO:O′,O′′:O′′′,O′′′′:O′′′′′], [Na₂(C₁₀H₈O₆)(H₂O)₄]_n, (II), have been synthesized and characterized by X‐ray single‐crystal diffraction. In (I), there are two 1,4‐BDOA²⁻ [p‐phenyl­enebis­(oxy­acetate) or, more commonly, benzene‐1,4‐dioxy­acetate] ligands, each lying about inversion centres, while in (II), there is one such ligand and it also has crystallographically imposed inversion symmetry. In (I), each Mn^II atom displays an octahedral MnN₂O₄ configuration, defined by three carboxyl O atoms of different 1,4‐BDOA²⁻ groups, two N atoms of one 2,2′‐bi­pyridine ligand and one water mol­ecule. In (II), each Na^I atom is octahedrally coordinated by one ether O atom, two carboxyl O atoms of different 1,4‐BDOA²⁻ ligands and three water mol­ecules. The metal ions in complexes (I) and (II) are bridged by 1,4‐BDOA²⁻ groups into two‐dimensional layer structures. Furthermore, three‐dimensional supramolecular networks are constructed via hydrogen bonds in (I) and (II), and by additional π–π stacking interactions in (I).     

A three‐dimensional cadmium(II) coordination polymer with unequal homochiral double‐stranded concentric helical chains

A homochiral helical three‐dimensional coordination polymer, poly[[(μ₂‐acetato‐κ³O,O′:O)(hydroxido‐κO)(μ₄‐5‐nicotinamido‐1H‐1,2,3,4‐tetrazol‐1‐ido‐κ⁵N¹,O:N²:N⁴:N⁵)(μ₃‐5‐nicotinamido‐1H‐1,2,3,4‐tetrazol‐1‐ido‐κ⁴N¹,O:N²:N⁴:N⁵)dicadmium(II)] 0.75‐hydrate], {[Cd₂(C₇H₅N₆O)₂(CH₃COO)(OH)]·0.75H₂O}_n, was synthesized by the reaction of cadmium acetate, N‐(1H‐tetrazol‐5‐yl)isonicotinamide (H‐NTIA), ethanol and H₂O under hydrothermal conditions. The asymmetric unit contains two crystallographically independent Cd^II cations, two deprotonated 5‐nicotinamido‐1H‐1,2,3,4‐tetrazol‐1‐ide (NTIA⁻) ligands, one acetate anion, one hydroxide anion and three independent partially occupied water sites. The two Cd^II cations, with six‐coordinated octahedral and seven‐coordinated pentagonal bipyramidal geometries are located on general sites. The tetrazole group of one symmetry‐independent NTIA⁻ ligand links one of the independent Cd^II cations into 6₁ helical chains, while the other NTIA⁻ ligand links the other independent Cd^II cations into similar but unequal 6₁ helical chains. These chains, with a pitch of 24.937 (5) Å, intertwine into a double‐stranded helix. Each of the double‐stranded 6₁ helices is further connected to six adjacent helical chains through an acetate μ₂‐O atom and the tetrazole group of the NTIA⁻ ligand into a three‐dimensional framework. The helical channel is occupied by the isonicotinamide groups of NTIA⁻ ligands and two helices are connected to each other through the pyridine N and carbonyl O atoms of isonicotinamide groups. In addition, N—H...O and O—H...N hydrogen bonds exist in the complex.     

A novel three‐dimensional AgI coordination polymer based on mixed naphthalene‐1,5‐disulfonate and aminoacetate ligands

The three‐dimensional coordination polymer poly[[bis(μ₃‐2‐aminoacetato)di‐μ‐aqua‐μ₃‐(naphthalene‐1,5‐disulfonato)‐hexasilver(I)] dihydrate], {[Ag₆(C₁₀H₆O₆S₂)(C₂H₄NO₂)₄(H₂O)₂]·2H₂O}_n, based on mixed naphthalene‐1,5‐disulfonate (L1) and 2‐aminoacetate (L2) ligands, contains two Ag^I centres (Ag1 and Ag4) in general positions, and another two (Ag2 and Ag3) on inversion centres. Ag1 is five‐coordinated by three O atoms from one L1 anion, one L2 anion and one water molecule, one N atom from one L2 anion and one Ag^I cation in a distorted trigonal–bipyramidal coordination geometry. Ag2 is surrounded by four O atoms from two L2 anions and two water molecules, and two Ag^I cations in a slightly octahedral coordination geometry. Ag3 is four‐coordinated by two O atoms from two L2 anions and two Ag^I cations in a slightly distorted square geometry, while Ag4 is also four‐coordinated by two O atoms from one L1 and one L2 ligand, one N atom from another L2 anion, and one Ag^I cation, exhibiting a distorted tetrahedral coordination geometry. In the crystal structure, there are two one‐dimensional chains nearly perpendicular to one another (interchain angle = 87.0°). The chains are connected by water molecules to give a two‐dimensional layer, and the layers are further bridged by L1 anions to generate a novel three‐dimensional framework. Moreover, hydrogen‐bonding interactions consolidate the network.     

Mercury(II) thiolate complexes of two flexible benzimidazole‐based ligands

The structure of catena‐poly[[{bis[4‐(trimethylammonio)benzenethiolate‐κS]mercury(II)}‐μ‐1,1′‐(ethane‐1,2‐diyl)bis(1H‐benzimidazole)‐κ²N³:N^3′] bis(hexafluoridophosphate) 0.25‐hydrate], {[Hg(C₁₆H₁₄N₄)(C₉H₁₃NS)₂](PF₆)₂·0.25H₂O}_n, contains a one‐dimensional zigzag chain. The Hg^II cation is coordinated by two S atoms of two 4‐(trimethylammonio)benzenethiolate (Tab) ligands and by two N atoms from two different 1,1′‐(ethane‐1,2‐diyl)bis(1H‐benzimidazole) ligands, forming a distorted seesaw‐shaped coordination geometry. The F atoms of the hexafluoridophosphate anion interact with the H atoms of the Tab ligand, generating a two‐dimensional network. Furthermore, this layer is connected to neighbouring layers via H...π interactions, thereby forming a three‐dimensional hydrogen‐bonded structure. In catena‐poly[[{[4‐(trimethylammonio)benzenethiolate‐κS]mercury(II)}bis[μ‐4‐(trimethylammonio)benzenethiolate‐κ²S:S]{[4‐(trimethylammonio)benzenethiolate‐κS]mercury(II)}‐μ‐1,1′‐(hexane‐1,6‐diyl)bis(1H‐benzimidazole)‐κ²N³:N^3′] tetrakis(hexafluoridophosphate)], {[Hg₂(C₂₀H₂₂N₄)(C₉H₁₃NS)₄](PF₆)₄}_n, each Hg^II cation is coordinated by two S atoms of two Tab ligands and one N atom of the 1,1′‐(hexane‐1,6‐diyl)bis(1H‐benzimidazole) (hbbm) ligand, forming a distorted T‐shaped coordination geometry, while longer secondary Hg...S bonds join two such units across a centre of inversion to give the tetravalent cation. Adjacent {[Hg(Tab)₂]₂(μ‐hbbm)}⁴⁺ cations are linked through the centrosymmetric hbbm ligands to afford a one‐dimensional chain extending along the b axis. Several F atoms interact with the H atoms of the Tab and hbbm ligands, while the S atom interacts with an aromatic H atom of a different Tab ligand, to afford a complex intra‐ and intermolecular hydrogen‐bonding arrangement in a three‐dimensional structure.     

Poly[tetra‐μ2‐l‐lactato‐indium(III)sodium(I)]

The asymmetric unit of the title compound, [InNa(C₃H₅O₃)₄]_n, consists of one In^III ion, one Na^I ion and four crystallographically independent l ‐lactate monoanions. The coordination of the In^III ion is composed of five carboxylate O and two hydroxy O atoms in a distorted pentagonal–bipyramidal coordination geometry. The Na^I ion is six‐coordinated by four carboxylate O atoms and two hydroxy O atoms from four l ‐lactate ligands in a distorted octahedral geometry. Each In^III ion is coordinated by four surrounding l ‐lactate ligands to form an [In(l ‐lactate)₄]⁻ unit, which is further linked by Na^I ions through Na—O bonds to give a two‐dimensional layered structure. Hydrogen bonds between the hydroxy groups and carboxylate O atoms are observed between neighbouring layers.     

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.     

The first compound with an unusual type of anion, [Li(SR)2]–: bis­(μ2‐aqua‐d2)tetra­kis(aqua‐d2)dilithium(I) bis­[bis­(tri‐tert‐butoxy­silanethiol­ato‐κ2O,S)lithate(I)] dihydrate‐d2

The title complex, [Li₂(D₂O)₆][Li(C₉H₂₇SSiO₃)₂]₂·2D₂O, is the first compound with an S—M bond (M = alkali metal) within an unusual type of lithate anion, [Li(SR)₂]⁻ {where R is Si[OC(CH₃)₃]₃}. There is a centre of symmetry located in the middle of the Li₂O₂ ring of the cation. All Li atoms are four‐coordinate, with LiO₄ (cations) and LiO₂S₂ (anions) cores. The singly charged [Li(SR)₂]⁻ anions are well separated from the doubly charged [Li₂(D₂O)₆]²⁺ cations; the distance between Li atoms from differently charged ions is greater than 5 Å. Both ion types are held within an extended network of O—D⋯O and O—D⋯S hydrogen bonds.     

Two Cd and Hg peroxodisulfate complexes with aromatic amines

The crystal structures of two complexes containing the peroxodisulfate anion are reported, namely μ‐peroxodisulf­ato‐1κO:2κO′‐bis­[(acetato‐κ²O,O′)aqua­(2,2′:6′,2′′‐terpyridine‐κ³N,N′,N′′)cadmium(II)] hepta­hydrate, [Cd₂(C₂H₃O₂)₂(S₂O₈)(C₁₅H₁₁N₂)₂(H₂O)₂]·7H₂O, (I), and catena‐poly[[[bis(2,2′‐bipy­ridine‐κ²N,N′)mercury(II)]‐μ‐peroxodisulfato‐κ²O:O′] 0.4‐hy­drate], {[Hg(C₁₀H₈N₂)₂(S₂O₈)]·0.4H₂O}_n, (II). In both structures, the anion behaves as a bridge, linking neighbouring coordination polyhedra in two different ways, either tightly bound to the hepta­coordinated Cd²⁺ cation forming neatly separated dimeric entities in (I) or across a shorter O—S—O path producing weakly connected chains by way of `semi­coordination' to the Hg²⁺ cations in (II).     

Mononuclear and dinuclear bromide–nitrite cadmium(II) complexes with related 1,4‐diazabicyclo[2.2.2]octane ligands

The title compounds, di‐μ‐bromido‐bis[bromido(1‐carboxymethyl‐4‐aza‐1‐azoniabicyclo[2.2.2]octane‐κN⁴)(nitrito‐κ²O,O′)cadmium(II)] dihydrate, [Cd₂Br₄(C₈H₁₅N₂O₂)₂(NO₂)₂]·2H₂O, (I), and aquabromido(1‐cyanomethyl‐4‐aza‐1‐azoniabicyclo[2.2.2]octane‐κN⁴)bis(nitrito‐κ²O,O′)cadmium(II) monohydrate, [CdBr(C₈H₁₄N₃)(NO₂)₂(H₂O)]·H₂O, (II), are two‐dimensional hydrogen‐bonded metal–organic hybrid complexes. In (I), the complex is situated on a centre of inversion so that each symmetry‐related Cd^II atom is coordinated by two bridging Br atoms, one monodentate Br atom, one chelating nitrite ligand and one organic ligand, yielding a significantly distorted octahedral geometry. The combination of O—H...O and O—H...Br hydrogen bonds produces centrosymmetric R₆⁶(16) ring motifs, resulting in two‐dimensional layers parallel to the ab plane. In contrast, the complex molecule in (II) is mononuclear, with the Cd^II atom seven‐coordinated by two bidentate nitrite groups, one N atom from the organic ligand, one monodentate Br atom and a water O atom in a distorted pentagonal–bipyramidal environment. The combination of O—H...O and O—H...Br hydrogen bonds produces R₅⁴(14) and R₃³(8) rings which lead to two‐dimensional layers parallel to the ac plane.     

Poly[bis(μ2‐2‐aminopyrazine‐κ2N1:N4)(μ2‐nitrato‐κ2O:O)(nitrato‐κ2O,O′)disilver(I)]: an achiral two‐dimensional coordination polymer forming chiral crystals

The solution reaction of AgNO₃ and 2‐aminopyrazine (apyz) in a 1:1 ratio gives rise to the title compound, [Ag₂(NO₃)₂(C₄H₅N₃)₂]_n, (I), which possesses a chiral crystal structure. In (I), both of the crystallographically independent Ag^I cations are coordinated in tetrahedral geometries by two N atoms from two apyz ligands and two O atoms from nitrate anions; however, the Ag^I centers show two different coordination environments in which one is coordinated by two O atoms from two different symmetry‐related nitrate anions and the second is coordinated by two O atoms from a single nitrate anion. The crystal structure consists of one‐dimensional Ag^I–apyz chains, which are further extended by μ₂‐κ²O:O nitrate anions into a two‐dimensional (4,4) sheet. N—H...O and C_apyz—H...O hydrogen bonds connect neighboring sheets to form a three‐dimensional supramolecular framework.     

Chiral one‐ and two‐dimensional silver(I)–biotin coordination polymers

Reaction of biotin {C₁₀H₁₆N₂O₃S, HL; systematic name: 5‐[(3aS,4S,6aR)‐2‐oxohexahydro‐1H‐thieno[3,4‐d]imidazol‐4‐yl]pentanoic acid} with silver acetate and a few drops of aqueous ammonia leads to the deprotonation of the carboxylic acid group and the formation of a neutral chiral two‐dimensional polymer network, poly[[{μ₃‐5‐[(3aS,4S,6aR)‐2‐oxohexahydro‐1H‐thieno[3,4‐d]imidazol‐4‐yl]pentanoato}silver(I)] trihydrate], {[Ag(C₁₀H₁₅N₂O₃S)]·3H₂O}_n or {[Ag(L)]·3H₂O}_n, (I). Here, the Ag^I cations are pentacoordinate, coordinated by four biotin anions via two S atoms and a ureido O atom, and by two carboxylate O atoms of the same molecule. The reaction of biotin with silver salts of potentially coordinating anions, viz. nitrate and perchlorate, leads to the formation of the chiral one‐dimensional coordination polymers catena‐poly[[bis[nitratosilver(I)]‐bis{μ₃‐5‐[(3aS,4S,6aR)‐2‐oxohexahydro‐1H‐thieno[3,4‐d]imidazol‐4‐yl]pentanoato}] monohydrate], {[Ag₂(NO₃)₂(C₁₀H₁₆N₂O₃S)₂]·H₂O}_n or {[Ag₂(NO₃)₂(HL)₂]·H₂O}_n, (II), and catena‐poly[bis[perchloratosilver(I)]‐bis{μ₃‐5‐[(3aS,4S,6aR)‐2‐oxohexahydro‐1H‐thieno[3,4‐d]imidazol‐4‐yl]pentanoato}], [Ag₂(ClO₄)₂(C₁₀H₁₆N₂O₃S)₂]_n or [Ag₂(ClO₄)₂(HL)₂]_n, (III), respectively. In (II), the Ag^I cations are again pentacoordinated by three biotin molecules via two S atoms and a ureido O atom, and by two O atoms of a nitrate anion. In (I), (II) and (III), the Ag^I cations are bridged by an S atom and are coordinated by the ureido O atom and the O atoms of the anions. The reaction of biotin with silver salts of noncoordinating anions, viz. hexafluoridophosphate (PF₆⁻) and hexafluoridoantimonate (SbF₆⁻), gave the chiral double‐stranded helical structures catena‐poly[[silver(I)‐bis{μ₂‐5‐[(3aS,4S,6aR)‐2‐oxohexahydro‐1H‐thieno[3,4‐d]imidazol‐4‐yl]pentanoato}] hexafluoridophosphate], {[Ag(C₁₀H₁₆N₂O₃S)₂](PF₆)}_n or {[Ag(HL)₂](PF₆)}_n, (IV), and catena‐poly[[[{5‐[(3aS,4S,6aR)‐2‐oxohexahydro‐1H‐thieno[3,4‐d]imidazol‐4‐yl]pentanoato}silver(I)]‐μ₂‐{5‐[(3aS,4S,6aR)‐2‐oxohexahydro‐1H‐thieno[3,4‐d]imidazol‐4‐yl]pentanoato}] hexafluoridoantimonate], {[Ag(C₁₀H₁₆N₂O₃S)₂](SbF₆)}_n or {[Ag(HL)₂](SbF₆)}_n, (V), respectively. In (IV), the Ag^I cations have a tetrahedral coordination environment, coordinated by four biotin molecules via two S atoms, and by two carboxy O atoms of two different molecules. In (V), however, the Ag^I cations have a trigonal coordination environment, coordinated by three biotin molecules via two S atoms and one carboxy O atom. In (IV) and (V), neither the ureido O atom nor the F atoms of the anion are involved in coordination. Hence, the coordination environment of the Ag^I cations varies from AgS₂O trigonal to AgS₂O₂ tetrahedral to AgS₂O₃ square‐pyramidal. The conformation of the valeric acid side chain varies from extended to twisted and this, together with the various anions present, has an influence on the solid‐state structures of the resulting compounds. The various O—H...O and N—H...O hydrogen bonds present result in the formation of chiral two‐ and three‐dimensional networks, which are further stabilized by C—H...X (X = O, F, S) interactions, and by N—H...F interactions for (IV) and (V). Biotin itself has a twisted valeric acid side chain which is involved in an intramolecular C—H...S hydrogen bond. The tetrahydrothiophene ring has an envelope conformation with the S atom as the flap. It is displaced from the mean plane of the four C atoms (plane B) by 0.8789 (6) Å, towards the ureido ring (plane A). Planes A and B are inclined to one another by 58.89 (14)°. In the crystal, molecules are linked via O—H...O and N—H...O hydrogen bonds, enclosing R₂²(8) loops, forming zigzag chains propagating along [001]. These chains are linked via N—H...O hydrogen bonds, and C—H...S and C—H...O interactions forming a three‐dimensional network. The absolute configurations of biotin and complexes (I), (II), (IV) and (V) were confirmed crystallographically by resonant scattering.     

A three‐dimensional mixed‐valence CuII/CuI coordination polymer constructed from biphenyl‐3,4′,5‐tricarboxylate and 1,4‐bis(1H‐imidazol‐1‐yl)benzene ligands

Coordination polymers (CPs) built by coordination bonds between metal ions/clusters and multidentate organic ligands exhibit fascinating structural topologies and potential applications as functional solid materials. The title coordination polymer, poly[diaquabis(μ₄‐biphenyl‐3,4′,5‐tricarboxylato‐κ⁴O³:O^3′:O^4′:O⁵)tris[μ₂‐1,4‐bis(1H‐imidazol‐1‐yl)benzene‐κ²N³:N^3′]dicopper(II)dicopper(I)], [Cu^II₂Cu^I₂(C₁₅H₇O₆)₂(C₁₂H₁₀N₄)₃(H₂O)₂]_n, was crystallized from a mixture of biphenyl‐3,4′,5‐tricarboxylic acid (H₃bpt), 1,4‐bis(1H‐imidazol‐1‐yl)benzene (1,4‐bib) and copper(II) chloride in a water–CH₃CN mixture under solvothermal reaction conditions. The asymmetric unit consists of two crystallographically independent Cu atoms, one of which is Cu^II, while the other has been reduced to the Cu^I ion. The Cu^II centre is pentacoordinated by three O atoms from three bpt³⁻ ligands, one N atom from a 1,4‐bib ligand and one O atom from a coordinated water molecule, and the coordination geometry can be described as distorted trigonal bipyramidal. The Cu^I atom exhibits a T‐shaped geometry (CuN₂O) coordinated by one O atom from a bpt³⁻ ligand and two N atoms from two 1,4‐bib ligands. The Cu^II atoms are extended by bpt³⁻ and 1,4‐bib linkers to generate a two‐dimensional network, while the Cu^I atoms are linked by 1,4‐bib ligands, forming one‐dimensional chains along the [20] direction. In addition, the completely deprotonated μ₄‐η¹:η¹:η¹:η¹ bpt³⁻ ligands bridge one Cu^I and three Cu^II cations along the a (or [100]) direction to form a three‐dimensional framework with a (10³)₂(10)₂(4².6.10².12)₂(4².6.8².10)₂(8) topology via a 2,2,3,4,4‐connected net. An investigation of the magnetic properties indicated a very weak ferromagnetic behaviour.     

Two‐dimensional ZnII and one‐dimensional CoII coordination polymers based on benzene‐1,4‐dicarboxylate and pyridine ligands

Coordination polymers constructed from metal ions and organic ligands have attracted considerable attention owing to their diverse structural topologies and potential applications. Ligands containing carboxylate groups are among the most extensively studied because of their versatile coordination modes. Reactions of benzene‐1,4‐dicarboxylic acid (H₂BDC) and pyridine (py) with Zn^II or Co^II yielded two new coordination polymers, namely, poly[(μ₄‐benzene‐1,4‐dicarboxylato‐κ⁴O:O′:O′′:O′′′)(pyridine‐κN)zinc(II)], [Zn(C₈H₄O₂)(C₅H₅N)]_n, (I), and catena‐poly[aqua(μ₃‐benzene‐1,4‐dicarboxylato‐κ³O:O′:O′′)bis(pyridine‐κN)cobalt(II)], [Co(C₈H₄O₂)(C₅H₅N)₂(H₂O)]_n, (II). In compound (I), the Zn^II cation is five‐coordinated by four carboxylate O atoms from four BDC²⁻ ligands and one pyridine N atom in a distorted square‐pyramidal coordination geometry. Four carboxylate groups bridge two Zn^II ions to form centrosymmetric paddle‐wheel‐like Zn₂(μ₂‐COO)₄ units, which are linked by the benzene rings of the BDC²⁻ ligands to generate a two‐dimensional layered structure. The two‐dimensional layer is extended into a three‐dimensional supramolecular structure with the help of π–π stacking interactions between the aromatic rings. Compound (II) has a one‐dimensional double‐chain structure based on Co₂(μ₂‐COO)₂ units. The Co^II cations are bridged by BDC²⁻ ligands and are octahedrally coordinated by three carboxylate O atoms from three BDC²⁻ ligands, one water O atom and two pyridine N atoms. Interchain O—H…O hydrogen‐bonding interactions link these chains to form a three‐dimensional supramolecular architecture.