An unusual polycatenating network self‐assembled by the 2D → 2D parallel → 3D parallel interpenetration of coordinative and hydrogen‐bonded (6,3) motifs

In the title coordination compound, catena‐poly[[[bis[diaquacadmium(II)]‐μ₂‐trans‐1,2‐bis(4‐pyridyl)ethene]bis{μ₂‐2,2′‐[(5‐carboxymethoxy‐m‐phenylene)dioxy]diacetato}] trans‐1,2‐bis(4‐pyridyl)ethene solvate dihydrate], {[Cd₂(C₁₂H₁₀O₉)₂(C₁₂H₁₀N₂)(H₂O)₄]·C₁₂H₁₀N₂·2H₂O}_n, (I), each Cd^II centre adopts a pentagonal–bipyramidal coordination geometry. The incompletely deprotonated 2,2′‐[(5‐carboxymethoxy‐m‐phenylene)dioxy]diacetate (TCMB) ligands and trans‐1,2‐bis(4‐pyridyl)ethene (bpe) ligands both act as bidentate bridges, linking the Cd^II centres into one‐dimensional ladders, which are connected into an undulating two‐dimensional (6,3) layer through O—H...N hydrogen bonds between the carboxylate groups of the TCMB ligands and the N atoms of the uncoordinated bpe ligands. Each undulating layer polycatenates two other identical layers, exhibiting the unusual combination of both 2D → 2D parallel and 2D → 3D parallel interpenetration (2D and 3D are two‐ and three‐dimensional, respectively).     

Crystal Structures,Magnetic Properties and Catecholase‐Like Activities of μ‐Alkoxo‐μ‐Carboxylato Double Bridged Dinuclear and Tetranuclear Copper(II) Complexes

One μ‐alkoxo‐μ‐carboxylato bridged dinuclear copper(II) complex, [Cu₂(L¹)(μ‐C₆H₅CO₂)] ( 1 )(H₃L¹ = 1,3‐bis(salicylideneamino)‐2‐propanol)), and two μ‐alkoxo‐μ‐dicarboxylato doubly‐bridged tetranuclear copper(II) complexes, [Cu₄(L¹)₂(μ‐C₈H₁₀O₄)(DMF)₂]·H₂O ( 2 ) and [Cu₄(L²)₂(μ‐C₅H₆O₄]·2H₂O·2CH₃CN ( 3 ) (H₃L² = 1,3‐bis(5‐bromo‐salicylideneamino)‐2‐propanol)) have been prepared and characterized. The single crystal X‐ray analysis shows that the structure of complex 1 is dimeric with two adjacent copper(II) atoms bridged by μ‐alkoxo‐μ‐carboxylato ligands where the Cu···Cu distances and Cu‐O(alkoxo)‐Cu angles are 3.5 11 Å and 132.8°, respectively. Complexes 2 and 3 consist of a μ‐alkoxo‐μ‐dicarboxylato doubly‐bridged tetranuclear Cu(II) complex with mean Cu‐Cu distances and Cu‐O‐Cu angles of 3.092 Å and 104.2° for 2 and 3.486 Å and 129.9° for 3 , respectively. Magnetic measurements reveal that 1 is strong antiferromagnetically coupled with 2J =‐210 cm^?1 while 2 and 3 exhibit ferromagnetic coupling with 2J = 126 cm^?1 and 82 cm^?1 (averaged), respectively. The 2J values of 1–3 are correlated to dihedral angles and the Cu‐O‐Cu angles. Dependence of the pH at 25 °C on the reaction rate of oxidation of 3,5‐di‐tert‐butylcatechol (3,5‐DTBC) to the corresponding quinone (3,5‐DTBQ) catalyzed by 1–3 was studied. Complexes 1–3 exhibit catecholase‐like active at above pH 8 and 25 °C for oxidation of 3,5‐di‐tert‐butylcatechol.     

A mixed‐valence chair‐like tetranuclear copper(I,II) cluster with three linking modes of the 3,5‐bis(2‐pyridyl)‐1,2,4‐triazole ligand

In the tetranuclear copper complex tetrakis[μ‐3,5‐bis(2‐pyridyl)‐1,2,4‐triazolido]bis[3,5‐bis(2‐pyridyl)‐1,2,4‐triazolido]dicopper(I)dicopper(II) dihydrate, [Cu^I₂Cu^II₂(C₁₂H₈N₅)₆]·2H₂O, the asymmetric unit is composed of one Cu^I center, one Cu^II center, three anionic 3,5‐bis(2‐pyridyl)‐1,2,4‐triazole (2‐BPT) ligands and one solvent water molecule. The Cu^I and Cu^II centers exhibit [Cu^IN₄] tetrahedral and [Cu^IIN₆] octahedral coordination environments, respectively. The three independent 2‐BPT ligands adopt different chelating modes, which link the copper centers to generate a chair‐like tetranuclear metallomacrocycle with metal–metal distances of about 4.4 × 6.2 Å disposed about a crystallographic inversion center. Furthermore, strong π–π stacking interactions and O—H...N hydrogen‐bonding systems link the tetracopper clusters into a two‐dimensional supramolecular network.     

Poly[di‐μ‐aqua‐μ‐1,2‐bis(pyridin‐4‐yl)ethene‐κ2N:N′‐tetrakis(4‐iodobenzoato‐κ2O,O′)dicadmium]

Colourless crystals of the title compound, [Cd₂(C₇H₄IO₂)₄(C₁₂H₁₀N₂)(H₂O)₂]_n, were obtained by the self‐assembly of Cd(NO₃)₂·4H₂O, 1,2‐bis(pyridin‐4‐yl)ethene (bpe) and 4‐iodobenzoic acid (4‐IBA). Each Cd^II atom is seven‐coordinated in a pentagonal–bipyramidal coordination environment by four carboxylate O atoms from two different 4‐IBA ligands, two O atoms from two water molecules and one N atom from a bpe ligand. The Cd^II centres are bridged by the aqua molecules and bpe ligands, which lie across centres of inversion, to give a two‐dimensional net. Topologically, taking the Cd^II atoms as nodes and the μ‐aqua and μ‐bpe ligands as linkers, the two‐dimensional structure can be simplified as a (6,3) network.     

Hydrogen bonding and π–π interactions in the cocrystal salt [Fe(bpe)2(H2O)4](TCEP)2·2(bpe) [bpe is trans‐1,2‐bis(pyridin‐4‐yl)ethene and TCEP is 1,1,3,3‐tetracyano‐2‐ethoxypropenide]

The cocrystal salt tetraaquabis[trans‐1,2‐bis(pyridin‐4‐yl)ethene‐κN]iron(II) bis(1,1,3,3‐tetracyano‐2‐ethoxypropenide)–trans‐1,2‐bis(pyridin‐4‐yl)ethene (1/2), [Fe(C₁₂H₁₀N₂)₂(H₂O)₄](C₉H₅N₄O)₂·2C₁₂H₁₀N₂, is a rare example of a mononuclear Fe^II compound with trans‐1,2‐bis(pyridin‐4‐yl)ethane (bpe) ligands. The complex cation resides on a crystallographically imposed inversion center and exhibits a tetragonally distorted octahedral coordination geometry. Both the symmetry‐independent bpe ligand and the cocrystallized bpe molecule are essentially planar. The 1,1,3,3‐tetracyano‐2‐ethoxypropenide counter‐ion is nonplanar and the bond lengths are consistant with significant electron delocalization. The extended structure exhibits an extensive O—H…N hydrogen‐bonding network with layers of complex cations joined by the cocrystallized bpe. Both the coordinated and the cocrystallized bpe are involved in π–π interactions. Hirshfeld and fingerprint plots reveal the important intermolecular interactions. Density functional theory was used to estimate the strengths of the hydrogen‐bonding and π–π interactions, and suggest that the O—H…N hydrogen bonds enhance the strength of the π‐interactions by increasing the polarization of the pyridine rings.     

A novel three‐dimensional tetranuclear CoII coordination polymer with water hexamers based on the V‐shaped tetracarboxylate ligand 4‐(2,4‐dicarboxylatophenoxy)phthalate

A new coordination polymer (CP), namely, poly[[diaquatris[μ₂‐1,4‐bis(1H‐imidazol‐1‐yl)benzene]bis[μ₆‐4‐(2,4‐dicarboxylatophenoxy)phthalato]tetracobalt(II)] hexahydrate], {[Co₄(C₁₆H₆O₉)₂(C₁₂H₁₀N₄)₃(H₂O)₂]·6H₂O}_n, has been synthesized by solvothermal reaction. The CP was fully characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, and powder and single‐crystal X‐ray diffraction. It presents a three‐dimensional (3D) structure based on tetranuclear Co^II secondary building units (SBUs) with a tfz‐d net and point symbol (4³)₂(4⁶·6¹⁸·8⁴). The 4‐(2,4‐dicarboxyphenoxy)phthalic acid (H₄dcppa) ligands are completely deprotonated and link {Co₄(COO)₄}^4? SBUs into two‐dimensional (2D) layers. Furthermore, adjacent layers are connected by 1,4‐bis(1H‐imidazol‐1‐yl)benzene (bib) ligands, giving rise to a 3D supramolecular architecture. Interestingly, there are numerous elliptical cavities in the CP where isolated unique discrete hexameric water clusters have been observed. The results of thermogravimetric and magnetic analyses are described in detail.     

A fourfold interpenetrating diamondoid three‐dimensional coordination polymer: poly[[[μ2‐1,2‐bis(pyridin‐4‐yl)ethene‐κ2N:N′](μ2‐5‐hydroxyisophthalato‐κ2O1:O3)zinc(II)] 1,2‐bis(pyridin‐4‐yl)ethene hemisolvate]

In the title compound, {[Zn(C₈H₄O₅)(C₁₂H₁₀N₂)]·0.5C₁₂H₁₀N₂}_n or {[Zn(HO‐BDC)(bpe)]·0.5bpe}_n [HO‐H₂BDC is 5‐hydroxyisophthalic acid and bpe is 1,2‐bis(pyridin‐4‐yl)ethene], the asymmetric unit contains a Zn^II atom, one HO‐BDC ligand, one coordinated bpe ligand and half a noncoordinating bpe molecule with crystallographic inversion symmetry. Each Zn^II centre is four‐coordinated by two O atoms from two distinct HO‐BDC ligands and two N atoms from two different bpe ligands in a ZnO₂N₂ coordination environment. The three‐dimensional topology of the title compound corresponds to a fourfold interpenetrating diamondoid coordination polymer network, with the uncoordinated bpe ligands located in the cavities, hydrogen bonded to the main network via the hydroxy group of the HO‐H₂BDC ligand.     

Syntheses,Structures, and Electrochemical Properties of Two Bis‐triazole‐bis‐amide‐based Copper(II) Pyridine‐2,3‐dicarboxylate Coordination Polymers

Abstract. Two bis‐triazole‐bis‐amide‐based copper(II) pyridine‐2,3‐dicarboxylate coordination polymers (CPs), [Cu(2,3‐pydc)(dtb)_0.5(DMF)] · 2H₂O ( 1 ) and [Cu(2,3‐pydc)(dth)_0.5(DMF)] · 2H₂O ( 2 ) (2,3‐H₂pydc = pyridine‐2,3‐dicarboxylic acid, dtb = N,N′‐bis(4H‐1,2,4‐triazole)butanamide, and dth = N,N′‐bis(4H‐1,2,4‐triazole)hexanamide), were synthesized under solvothermal conditions. CPs 1 and 2 show similar two‐dimensional (2D) structures. In 1 , the 2,3‐pydc anions bridge the Cu^II ions into a one‐dimensional (1D) chain. Such 1D chains are linked by the dtb ligands to form a 2D layer. The adjacent 2D layers are extended into a three‐dimensional (3D) supramolecular architecture by hydrogen‐bonding interactions. The electrochemical properties of 1 and 2 were investigated.     

A self‐penetrated three‐dimensional zinc(II) coordination framework based on 4,4′,4′′‐(1,3,5‐triazine‐2,4,6‐triyl)tribenzoic acid and 1,3‐bis[(imidazol‐1‐yl)methyl]benzene ligands: synthesis,structure and properties

With the rapid development of metal–organic frameworks (MOFs), a variety of MOFs and their derivatives have been synthesized and reported in recent years. Commonly, multifunctional aromatic polycarboxylic acids and nitrogen‐containing ligands are employed to construct MOFs with fascinating structures. 4,4′,4′′‐(1,3,5‐Triazine‐2,4,6‐triyl)tribenzoic acid (H₃TATB) and the bidentate nitrogen‐containing ligand 1,3‐bis[(imidazol‐1‐yl)methyl]benzene (bib) were selected to prepare a novel Zn^II‐MOF under solvothermal conditions, namely poly[[tris{μ‐1,3‐bis[(imidazol‐1‐yl)methyl]benzene}bis[μ₃‐4,4′,4′′‐(1,3,5‐triazine‐2,4,6‐triyl)tribenzoato]trizinc(II)] dimethylformamide disolvate trihydrate], {[Zn₃(C₂₄H₁₂N₃O₆)₂(C₁₄H₁₄N₄)₃]·2C₃H₇NO·3H₂O}_n ( 1 ). The structure of 1 was characterized by single‐crystal X‐ray diffraction, IR spectroscopy and powder X‐ray diffraction. The properties of 1 were investigated by thermogravimetric and fluorescence analysis. Single‐crystal X‐ray diffraction shows that 1 belongs to the monoclinic space group Pc. The asymmetric unit contains three crystallographically independent Zn^II centres, two 4,4′,4′′‐(1,3,5‐triazine‐2,4,6‐triyl)tribenzoate (TATB^3?) anions, three complete bib ligands, one and a half free dimethylformamide molecules and three guest water molecules. Each Zn^II centre is four‐coordinated and displays a distorted tetrahedral coordination geometry. The Zn^II centres are connected by TATB^3? anions to form an angled ladder chain with large windows. Simultaneously, the bib ligands link Zn^II centres to give a helical Zn–bib–Zn chain. Furthermore, adjacent ladders are bridged by Zn–bib–Zn chains to form a fascinating three‐dimensional self‐penetrated framework with the short Schläfli symbol 6⁵·7·8¹³·9·10. In addition, the luminescence properties of 1 in the solid state and the fluorescence sensing of metal ions in suspension were studied. Significantly, compound 1 shows potential application as a fluorescent sensor with sensing properties for Zr⁴⁺ and Cu²⁺ ions.     

Synthesis and crystal structure of a two‐dimensional sodium coordination polymer of 4,4′‐(diazenediyl)bis(1H‐1,2,4‐triazol‐5‐one)

The crystal engineering of coordination polymers has aroused interest due to their structural versatility, unique properties and applications in different areas of science. The selection of appropriate ligands as building blocks is critical in order to afford a range of topologies. Alkali metal cations are known for their mainly ionic chemistry in aqueous media. Their coordination number varies depending on the size of the binding partners, and on the electrostatic interaction between the ligands and the metal ions. The two‐dimensional coordination polymer poly[tetra‐μ‐aqua‐[μ₄‐4,4′‐(diazenediyl)bis(5‐oxo‐1H‐1,2,4‐triazolido)]disodium(I)], [Na₂(C₄H₂N₈O₂)(H₂O)₄]_n, (I), was synthesized from 4‐amino‐1H‐1,2,4‐triazol‐5(4H)‐one (ATO) and its single‐crystal structure determined. The mid‐point of the imino N=N bond of the 4,4′‐(diazenediyl)bis(5‐oxo‐1H‐1,2,4‐triazolide) (ZTO²⁻) ligand is located on an inversion centre. The asymmetric unit consists of one Na⁺ cation, half a bridging ZTO²⁻ ligand and two bridging water ligands. Each Na⁺ cation is coordinated in a trigonal antiprismatic fashion by six O atoms, i.e. two from two ZTO²⁻ ligands and the remaining four from bridging water ligands. The Na⁺ cation is located near a glide plane, thus the two bridging O atoms from the two coordinating ZTO²⁻ ligands are on adjacent apices of the trigonal antiprism, rather than being in an anti configuration. All water and ZTO²⁻ ligands act as bridging ligands between metal centres. Each Na⁺ metal centre is bridged to a neigbouring Na⁺ cation by two water molecules to give a one‐dimensional [Na(H₂O)₂]_n chain. The organic ZTO²⁻ ligand, an O atom of which also bridges the same pair of Na⁺ cations, then crosslinks these [Na(H₂O)₂]_n chains to form two‐dimensional sheets. The two‐dimensional sheets are further connected by intermolecular hydrogen bonds, giving rise to a stabile hydrogen‐bonded network.     

Two ZnII‐based MOFs constructed with biphenyl‐2,2′,5,5′‐tetracarboxylic acid and flexible N‐donor ligands: syntheses,structures and properties

Two new Zn²⁺‐based metal–organic frameworks (MOFs) based on biphenyl‐2,2′,5,5′‐tetracarboxylic acid, i.e. H₄(o,m‐bpta), and N‐donor ligands, namely, poly[[(μ₄‐biphenyl‐2,2′,5,5′‐tetracarboxylato)bis{[1,3‐phenylenebis(methylene)]bis(1H‐imidazole)}dizinc(II)] dimethylformamide monosolvate dihydrate], {[Zn₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂]·C₃H₇NO·2H₂O}_n or {[Zn₂(o,m‐bpta)(1,3‐bimb)₂]·C₃H₇NO·2H₂O}_n ( 1 ) {1,3‐bimb = [1,3‐phenylenebis(methylene)]bis(1H‐imidazole)}, and poly[[(μ₄‐biphenyl‐2,2′,5,5′‐tetracarboxylato)bis{[1,4‐phenylenebis(methylene)]bis(1H‐imidazole)}dizinc(II)] monohydrate], {[Zn₂(C₁₆H₆O₈)(C₁₄H₁₄N₄)₂]·H₂O}_n or {[Zn₂(o,m‐bpta)(1,4‐bimb)₂]·H₂O}_n ( 2 ) {1,4‐bimb = [1,4‐phenylenebis(methylene)]bis(1H‐imidazole)}, have been synthesized under solvothermal conditions. The complexes were characterized by IR spectroscopy, elemental analysis, single‐crystal X‐ray diffraction and powder X‐ray diffraction analysis. Structurally, the (o,m‐bpta)^4? ligands are fully deprotonated and combine with Zn²⁺ ions in μ₄‐coordination modes. Complex 1 is a (3,4)‐connected porous network with honeycomb‐like [Zn₂(o,m‐bpta)]_n sheets formed by 4‐connected (o,m‐bpta)^4? ligands. Complex 2 exhibits a (2,4)‐connected network formed by 4‐connected (o,m‐bpta)^4? ligands linking Zn²⁺ ions in left‐handed helical chains. The cis‐configured 1,3‐bimb and 1,4‐bimb ligands bridge Zn²⁺ ions to form multi‐membered [Zn₂(bimb)₂] loops. Optically, the complexes show strong fluorescence and display larger red shifts compared to free H₄(o,m‐bpta). Complex 2 shows ferroelectric properties due to crystallizing in the C_2v polar point group.     

Exploring the structural landscape of 2‐(thiophen‐2‐yl)‐1,3‐benzothiazole: high‐Z′ packing polymorphism and cocrystallization with calix[4]tube

We report here for the first time a cocrystal of the so‐called neutral calix[4]tube, which is two tail‐to‐tail‐arranged and partially deprotonated tetrakis(carboxymethoxy)calix[4]arenes, including three sodium ions, with 2‐(thiophen‐2‐yl)‐1,3‐benzothiazole, namely trisodium bis(carboxymethoxy)bis(carboxylatomethoxy)calix[4]arene tris(carboxymethoxy)(carboxylatomethoxy)calix[4]arene–2‐(thiophen‐2‐yl)‐1,3‐benzothiazole–dimethyl sulfoxide–water (1/1/2/2), 3Na⁺·C₃₆H₃₀O₁₂^2?·C₃₆H₃₁O₁₂^?·C₁₁H₇NS₂·2C₂H₆OS·2H₂O, which provides a new approach into the host–guest chemistry of inclusion complexes. Three packing polymorphs of the same benzothiazole with high Z′ (one with Z′ = 8 and two with Z′ = 4) were also discovered in the course of our desired cocrystallization. The inspection of these polymorphs and a previously known polymorph with Z′ = 2 revealed that Z′ increases as the strength of intermolecular contacts decreases. Also, these results expand the frontier of invoking calixarenes as a host for nonsolvent small molecules, besides providing knowledge on the rare formation of high‐Z′ packing polymorphs of simple molecules, such as the target benzothiazole.     

Synthesis and characterization of two one‐dimensional CdII coordination polymers (CPs) with 5‐amino‐2,4,6‐tribromoisophthalic acid and flexible N‐donor bipyridyl ligands

The bromo‐substituted aromatic dicarboxylic acid 5‐amino‐2,4,6‐tribromoisophthalic acid (H₂ATBIP) was used to assemble with Cd^II ions in the presence of the N‐donor flexible bipyridyl ligands 3,3′‐(diazene‐1,2‐diyl)dipyridine (mzpy) and 1,3‐bis(pyridin‐3‐ylmethyl)urea (3bpmu), leading to the formation of two chain coordination polymers by adopting solution methods, namely, catena‐poly[[[triaqua(5‐amino‐2,4,6‐tribromoisophthalato‐κO)cadmium(II)]‐μ‐3,3′‐(diazene‐1,2‐diyl)dipyridine‐κ²N¹:N^1′] dihydrate], {[Cd(C₈H₂Br₃NO₄)(C₁₀H₈N₄)(H₂O)₃]·2H₂O}_n or {[Cd(ATBIP)(mzpy)(H₂O)₃]·2H₂O}_n, ( 1 ), and catena‐poly[[[tetraaquacadmium(II)]‐μ‐1,3‐bis(pyridin‐3‐ylmethyl)urea‐κ²N¹:N^1′‐[diaquabis(5‐amino‐2,4,6‐tribromoisophthalato‐κO)cadmium(II)]‐μ‐1,3‐bis(pyridin‐3‐ylmethyl)urea‐κ²N¹:N^1′] octahydrate], {[Cd(C₈H₂Br₃NO₄)(C₁₂H₁₂N₄O)(H₂O)₃]·4H₂O}_n or {[Cd(ATBIP)(3bpmu)(H₂O)₃]·4H₂O}_n, ( 2 ). Both complexes were characterized by FT–IR spectroscopic analysis, thermogravimetric analysis (TGA), solid‐state diffuse reflectance UV–Vis spectroscopic analysis, and single‐crystal and powder X‐ray diffraction analysis (PXRD). The mzpy and 3bpmu ligands bridge the Cd^II metal centres in ( 1 ) and ( 2 ) into one‐dimensional chains, and the ATBIP²⁻ ligands show a monodentate coordination to the Cd^II centres in both coordination polymers. A discrete water tetramer exists in ( 1 ). Within the chains of ( 1 ) and ( 2 ), there are halogen bonds between adjacent ATBIP²⁻ and mzpy or 3bpmu ligands, as well as hydrogen bonds between the ATBIP²⁻ ligands and the coordinated water molecules. With the aid of weak interactions, the structures of ( 1 ) and ( 2 ) are further extended into three‐dimensional supramolecular networks. An analysis of the solid‐state diffuse reflectance UV–Vis spectra of ( 1 ) and ( 2 ) indicates that a wide indirect band gap exists in both complexes. Complexes ( 1 ) and ( 2 ) exhibit irreversible and reversible dehydration–rehydration behaviours, respectively, and the solid‐state fluorescence properties of both complexes have been studied.     

Two New Zinc(II) Coordination Polymers Based on 1, 6‐Bis(2‐methyl‐imidazole‐1‐yl)‐hexane Ligand: Synthesis,Structures, and Properties

Two coordination polymers based on 1, 6‐bis(2‐methyl‐imidazole‐1‐yl)‐hexane (bimh), namely {[Zn₃(BTC)₂(bimh)] · (bimh)}_n ( 1 ) and {[Zn(IPA)(bimh)] · (CH₃CH₂OH)_0.5}_n ( 2 ) (H₃BTC = trimesic acid, H₂IPA = isophthalic acid), were synthesized through hydrothermal reactions. In compound 1 , the zinc(II) ions are bridged by BTC^3– ligands to form an undulating infinite two‐dimensional (2D) polymeric network. The 3D networks of 1 show a twofold interpenetrating net. In compound 2 , zinc(II) ions are bridged by IPA^2– ligands to form one‐dimensional (1D) helical structures. The 2D structures of 2 are further assembled into 3D networks through aromatic π–π stacking interactions. Both compounds exhibit strong photoluminescence at room temperature and may be good candidates for potential luminescence materials.     

Investigation of commercial sodium cacodylate trihydrate: penta‐μ‐aqua‐disodium(I) bis(dimethylarsenate) and di‐μ‐aqua‐bis[triaquasodium(I)] bis(dimethylarsenate)

Crystals from commercial samples of sodium cacodylate trihydrate, NaO₂As(CH₃)₂·3H₂O, were analyzed by single‐crystal X‐ray diffraction and two phases were identified, viz. penta‐μ‐aqua‐disodium(I) bis(dimethylarsenate), {[Na₂(H₂O)₅](C₂H₆AsO₂)₂}_n, (I), and di‐μ‐aqua‐bis[triaquasodium(I)] bis(dimethylarsenate), [Na₂(H₂O)₈](C₂H₆AsO₂)₂, (II). Both (I) and (II) form layered structures in which hydrated Na⁺ ions form layers in the ab plane, the cacodylate ions being located in between the layers. In (I), the two non‐equivalent Na⁺ ions (located at twofold axes) and the three non‐equivalent aqua ligands (one of which also lies on a twofold axis) form infinite polymeric layers, but in (II), layers of discrete centrosymmetric [Na₂(H₂O)₈]²⁺ ions are present. One of the commercial samples analyzed contained almost exclusively crystals of the tetrahydrate (II), while another sample consisted of a mixture of the two phases.     

Synthesis,Structures, and Properties of Two Novel Supramolecular Architectures Constructed from [2,3‐f]Pyrazino[1,10]phenanthroline‐2,3‐dicarboxylic Acid

Two new compounds, [Ag(Hppdb)]_n ( 1 ) and {[Ag₂(Hppdb)₂(bpe)] · 5.5H₂O}_n( 2 ) [H₂ppdb = [2,3‐f]pyrazino[1,10]phenanthroline‐2,3‐dicarboxylic acid, bpe = trans‐1,2‐bis(4‐pyridyl)ethylene], were synthesized and characterized. In 1 , Hppdb^– ions link Ag^I cations to form an infinite 1D [–Ag–(Hppdb)–Ag–]_n chain, furthermore, the dimensionality is extended to 2D layers through synergistic π–π stacking, hydrogen‐bonding and weak Ag ··· O interactions. Correspondingly, the dimeric [(Ag)(Hppdb)]₂ subunits in 2 are connected by bpe ligands to generate a loop‐link‐shaped 1D chain motif, which is further joined through a R₂²(18)C–H ··· O hydrogen‐bonding ring to afford interesting diagonal/diagonal inclined catenation 2D + 2D → 3D supramolecular architectures. In addition, solid‐state properties such as photoluminescence and thermal stability of the two compounds were studied.     

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.     

Synthesis,Characterization, and Properties of Four Metal Complexes with Mulitdentate N‐Acyl‐Salicylhydrazide Ligands

The reactions of the new nitrilotriacetic acid N′,N′,N′‐tri(salicyloyl)trihydrazide (Ntash) with the corresponding metal salts gave four new complexes [Pb₄(bshz)₂] · 2DMF ( 1 ), [Co₂(bshz)(C₅H₅N)₆] · 2ClO₄ · (C₅H₅N) · 2H₂O ( 2 ), [Cu₃(fshz)₂(C₅H₅N)₂] ( 3 ), and [Zn₃(fshz)₂(C₅H₅N)₃]_n · 2DMF ( 4 ), in which two multidentate ligands, namely N,N′‐disalicyloylhydrazine (H₄bshz) and N‐formylsalicylhydrazide (H₃fshz) were generated in situ from Ntash. The structures of these complexes were determined by single‐crystal X‐ray diffraction analysis. Complex 1 presents a novel tetranuclear lead(II) cluster structure with the four lead(II) cations in “hemidirected” coordination spheres. The neighboring tetranuclear clusters of 1 are connected by DMF molecules through weak Pb–O bonds, forming one‐dimensional ribbons. Complexes 2 and 3 show dinuclear and linear trinuclear structures with the corresponding Co^III and Cu^II ions in distorted octahedral and square‐planar coordination environments, respectively. Complex 4 exhibits a one‐dimensional zigzag chain structure. The magnetic properties of 3 and the photoluminescent properties of 4 were also investigated.     

Synthesis,structure and properties of a new three‐dimensional interpenetrated metal–organic framework with 3,3′‐azodibenzoic acid (H2azdc) and 1,4‐bis(1H‐imidazol‐1‐yl)butane (bimb): {[Cd(azdc)(bimb)2]·H2O}n

A new three‐dimensional interpenetrated Cd^II–organic framework based on 3,3′‐azodibenzoic acid [3,3′‐(diazenediyl)dibenzoic acid, H₂azdc] and the auxiliary flexible ligand 1,4‐bis(1H‐imidazol‐1‐yl)butane (bimb), namely poly[[bis[μ₂‐1,4‐bis(1H‐imidazol‐1‐yl)butane‐κ²N³:N^3′][μ₂‐3,3′‐(diazenediyl)dibenzoato‐κ²O:O′]cadmium(II)] monohydrate], {[Cd(C₁₄H₈N₂O₄)(C₁₀H₁₄N₂)₂]·H₂O}_n, (1), was obtained by a typical solution reaction in mixed solvents (water and N,N′‐dimethylformamide). Each Cd^II centre is six‐coordinated by two O atoms of bis‐monodentate bridging carboxylate groups from two azdc²⁻ ligands and by four N atoms from four bimb ligands, forming an octahedral coordination environment. The Cd^II ions are connected by the bimb ligands, resulting in two‐dimensional (4,4) layers, which are further pillared by the azdc²⁻ ligands, affording a threefold interpenetrated three‐dimensional α‐Po topological framework with the Schläfli symbol 4¹²6³. The thermal stability and solid‐state fluorescence properties of (1) have been investigated.     

A new copper(II) supramolecular coordination polymer and a dinuclear compound with multifunctional 2‐amino‐5‐sulfobenzoic acid and flexible N‐donor ligands: synthesis,structure and characterization

Multifunctional 2‐amino‐5‐sulfobenzoic acid (H₂afsb) can exhibit a variety of roles during the construction of supramolecular coordination polymers. The pendant carboxylic acid, sulfonic acid and amino groups could not only play a role in directing bonding but could also have the potential to act as hydrogen‐bond donors and acceptors, resulting in extended high‐dimensional supramolecular networks. Two new Cu^II coordination compounds, namely catena‐poly[[[diaquacopper(II)]‐μ‐1,6‐bis(1H‐1,2,4‐triazol‐1‐yl)hexane‐κ²N⁴:N^4′] bis(3‐amino‐4‐carboxybenzenesulfonate) dihydrate], {[Cu(C₁₀H₁₆N₆)₂(H₂O)₂](C₇H₆NO₅S)₂·2H₂O}_n or {[Cu(bth)₂(H₂O)₂](Hafsb)₂·2H₂O}_n, (1), and bis(μ‐2‐amino‐5‐sulfonatobenzoato‐κ²O¹:O^1′)bis{μ‐1,2‐bis[(1H‐imidazol‐1‐yl)methyl]benzene‐κ²N³:N^3′}bis[aquacopper(II)] trihydrate, [Cu₂(C₇H₅NO₅S)₂(C₁₄H₁₄N₄)₂(H₂O)₂]·3H₂O or [Cu₂(afsb)₂(obix)₂(H₂O)₂]·3H₂O, (2), have been obtained through the assembly between H₂afsb and the Cu^II ion in the presence of the flexible N‐donor ligands 1,6‐bis(1H‐1,2,4‐triazol‐1‐yl)hexane (bth) and 1,2‐bis[(1H‐1,2,4‐triazol‐1‐yl)methyl]benzene (obix), respectively. Compound (1) consists of a cationic coordination polymeric chain and 3‐amino‐4‐carboxybenzenesulfonate (Hafsb⁻) anions. Compound (2) exhibits an asymmetric dinuclear structure. There are hydrogen‐bonded networks within the lattices of (1) and (2). Interestingly, both (1) and (2) exhibit reversible dehydration–rehydration behaviour.