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.     

Preparation,Structure, and Optical Properties of the 1D Chain Red Luminescent Europium Coordination Polymer: {[Eu2L6(DMF)­(H2O)]·2DMF·H2O}n (L = C9H6ClO2–)

The 1D chain red luminescent europium coordination polymer: {[Eu₂L₆(DMF)(H₂O)] · 2DMF · H₂O}_n ( I ) (L = 4‐chloro‐cinnamic acid anion, C₉H₆ClO₂^–, DMF = N, N‐dimethylformamide) was synthesized by the reaction of Eu(OH)₃ and 4‐chloro‐cinnamic acid ligand. The structure of the coordination polymer was determined by single‐crystal X‐ray diffraction analysis. It reveals that there exists two crystallographically nonequivalent europium atoms in each unit of this coordination polymer and Eu³⁺ ions are connected by two alternating bridging modes to form an endless polymer structure. The luminescent properties and energy transfer process in the complex are investigated at room temperature.     

Poly[(N,N‐dimethylformamide‐κO)(μ3‐4,4′‐ethylenedibenzoato‐κ5O,O′:O′:O′′,O′′′)(pyrazino[2,3‐f][1,10]phenanthroline‐κ2N8,N9)lead(II)]

In the title Pb^II coordination polymer, [Pb(C₁₆H₁₀O₄)(C₁₄H₈N₄)(C₃H₇NO)]_n, each Pb^II atom is eight‐coordinated by two chelating N atoms from one pyrazino[2,3‐f][1,10]phenanthroline (L) ligand, one dimethylformamide (DMF) O atom and five carboxylate O atoms from three different 4,4′‐ethylenedibenzoate (eedb) ligands. The eedb dianions bridge neighbouring Pb^II centres through four typical Pb—O bonds and one longer Pb—O interaction to form a two‐dimensional structure. The C atoms from the L and eedb ligands form C—H...O hydrogen bonds with the O atoms of eedb and DMF ligands, which further stabilize the structure. The title compound is the first Pb^II coordination polymer incorporating the L ligand.     

Solvent‐Controlled Construction of Two 3D Manganese(II) Coordination Polymers Based on Flexible Tripodal Multicarboxylate Linker and Rod‐Shaped SBUs

To further explore the coordination possibilities of the flexible tripodal ligand, 4,4′,4′′‐(benzene‐1,3,5‐triyl‐tris(oxy))tribenzoic acid (H₃BTTB), two solvent‐controlled three‐dimensional (3D) manganese(II) coordination polymers, [Mn₃(BTTB)₂(H₂O)₄](H₂O)₂ ( 1 ) and [Mn₃(BTTB)₂(DMF)₂](DMF)₂ ( 2 ), were synthesized and characterized. Single crystal X‐ray diffraction analysis indicates that in the Mn^II complexes the BTTB ligands exhibit two coordination modes, which have not been reported previously. Complexes 1 and 2 involve different one‐dimensional (1D) rod‐shaped metal–carboxylate secondary building units (SBUs). The 1D SBUs are further extended to afford two different three‐dimensional (3D) frameworks with similar flu topology via linkage of the BTTB ligands. The results demonstrate that the reaction solvent as well as conformation and coordination mode of BTTB ligands play key roles on the formation of the final framework structures. Additionally, their luminescent properties were investigated.     

A one‐dimensional coordination polymer of 5‐[(imidazol‐1‐yl)methyl]benzene‐1,3‐dicarboxylic acid with CuII cations

5‐[(Imidazol‐1‐yl)methyl]benzene‐1,3‐dicarboxylic acid (H₂L) was synthesized and the dimethylformamide‐ and dimethylacetamide‐solvated structures of its adducts with Cu^II, namely catena‐poly[[copper(II)‐bis[μ‐3‐carboxy‐5‐[(imidazol‐1‐yl)methyl]benzoato]] dimethylformamide disolvate], {[Cu(C₁₂H₉N₂O₄)₂]·2C₃H₇NO}_n, (I), and catena‐poly[[copper(II)‐bis[μ‐3‐carboxy‐5‐[(imidazol‐1‐yl)methyl]benzoato]] dimethylacetamide disolvate], {[Cu(C₁₂H₉N₂O₄)₂]·2C₄H₉NO}_n, (II), the formation of which are associated with mono‐deprotonation of H₂L. The two structures are isomorphous and isometric. They consist of one‐dimensional coordination polymers of the organic ligand with Cu^II in a 2:1 ratio, [Cu(μ‐HL)₂]_n, crystallizing as the dimethylformamide (DMF) or dimethylacetamide (DMA) disolvates. The Cu^II cations are characterized by a coordination number of six, being located on centres of crystallographic inversion. In the polymeric chains, each Cu^II cation is linked to four neighbouring HL⁻ ligands, and the organic ligand is coordinated via Cu—O and Cu—N bonds to two Cu^II cations. In the corresponding crystal structures of (I) and (II), the coordination chains, aligned parallel to the c axis, are further interlinked by strong hydrogen bonds between the noncoordinated carboxy groups in one array and the coordinated carboxylate groups of neighbouring chains. Molecules of DMF and DMA (disordered) are accommodated at the interface between adjacent polymeric assemblies. This report provides the first structural evidence for the formation of coordination polymers with H₂Lvia multiple metal–ligand bonds through both carboxylate and imidazole groups.     

catena‐Poly[[[pyridinecopper(II)]bis[μ3‐4‐(2‐oxidobenzylideneamino)benzoato]] dimethylformamide disolvate], a polymer composed of dimeric dicopper building units

The title compound, {[Cu(C₁₄H₉NO₃)(C₅H₅N)]·C₃H₇NO}_n or {[Cu₂L₂(py)₂]·2DMF}_n [py is pyridine, L is 4‐(salicylideneamino)benzoate and DMF is dimethylformamide], is composed of dimeric dicopper [CuL(py)]₂ building units, which are interlinked into a one‐dimensional chain through the formation of Cu—O_COO bonds. The dimeric unit is centrosymmetric, containing two Cu^II atoms linked by bridging phenolate O atoms into a Cu₂O₂ plane with a chelating Cu—O bond length of 1.927 (2) Å and a bridging Cu—O bond length of 2.440 (2) Å. Interchain C—H...O and π–π stacking interactions are responsible for an extensive three‐dimensional structure in which the resulting channels are filled by DMF solvent molecules.     

A three‐dimensional coordination polymer of 3‐(3,5‐dicarboxybenzyloxy)benzoic acid with zinc

The synthesis is reported of the tricarboxylic acid 3‐(3,5‐dicarboxybenzyloxy)benzoic acid (H₃L) and the product of its reaction under solvothermal conditions with Zn^II cations, namely poly[[μ₆‐3‐(3,5‐dicarboxylatobenzyloxy)benzoato](dimethylformamide)‐μ₃‐hydroxido‐dizinc(II)], [Zn₂(C₁₆H₉O₇)(OH)(C₃H₇NO)]_n, the formation of which is associated with complete deprotonation of H₃L. Its crystal structure consists of a single‐framework coordination polymer of the organic L³⁻ ligand with Zn^II cations in a 1:2 ratio, with additional hydroxide and dimethylformamide (DMF) ligands coordinated to the Zn^II centres. The Zn^II cations are characterized by coordination numbers of 5 and 6, being bridged to each other by hydroxide ligands. In the polymeric framework, the carboxylate‐ and hydroxy‐bridged Zn^II cations are arranged in coordination‐tessellated columns, which propagate along the a axis of the crystal structure, and each L³⁻ ligand links to seven different Zn^II centres via Zn—O bonds of two different columns. The coordination framework, composed of [Zn₂(L)(OH)(DMF)]_n units, forms an open architecture, the channel voids within it being filled by the zinc‐coordinating DMF ligands. This report provides the first structural evidence for the formation of coordination polymers with H₃L via multiple metal–ligand bonds through its carboxylate groups.<!?tpb=21.5pt>     

Crystallization experiments with the dinuclear chelate ring complex di‐μ‐chlorido‐bis[(η2‐2‐allyl‐4‐methoxy‐5‐{[(propan‐2‐yloxy)carbonyl]methoxy}phenyl‐κC1)platinum(II)]

Crystallization experiments with the dinuclear chelate ring complex di‐μ‐chlorido‐bis[(η²‐2‐allyl‐4‐methoxy‐5‐{[(propan‐2‐yloxy)carbonyl]methoxy}phenyl‐κC¹)platinum(II)], [Pt₂(C₁₅H₁₉O₄)₂Cl₂], containing a derivative of the natural compound eugenol as ligand, have been performed. Using five different sets of crystallization conditions resulted in four different complexes which can be further used as starting compounds for the synthesis of Pt complexes with promising anticancer activities. In the case of vapour diffusion with the binary chloroform–diethyl ether or methylene chloride–diethyl ether systems, no change of the molecular structure was observed. Using evaporation from acetonitrile (at room temperature), dimethylformamide (DMF, at 313 K) or dimethyl sulfoxide (DMSO, at 313 K), however, resulted in the displacement of a chloride ligand by the solvent, giving, respectively, the mononuclear complexes (acetonitrile‐κN)(η²‐2‐allyl‐4‐methoxy‐5‐{[(propan‐2‐yloxy)carbonyl]methoxy}phenyl‐κC¹)chloridoplatinum(II) monohydrate, [Pt(C₁₅H₁₉O₄)Cl(CH₃CN)]·H₂O, (η²‐2‐allyl‐4‐methoxy‐5‐{[(propan‐2‐yloxy)carbonyl]methoxy}phenyl‐κC¹)chlorido(dimethylformamide‐κO)platinum(II), [Pt(C₁₅H₁₉O₄)Cl(C₂H₇NO)], and (η²‐2‐allyl‐4‐methoxy‐5‐{[(propan‐2‐yloxy)carbonyl]methoxy}phenyl‐κC¹)chlorido(dimethyl sulfoxide‐κS)platinum(II), determined as the analogue {η²‐2‐allyl‐4‐methoxy‐5‐[(ethoxycarbonyl)methoxy]phenyl‐κC¹}chlorido(dimethyl sulfoxide‐κS)platinum(II), [Pt(C₁₄H₁₇O₄)Cl(C₂H₆OS)]. The crystal structures confirm that acetonitrile interacts with the Pt^II atom via its N atom, while for DMSO, the S atom is the coordinating atom. For the replacement, the longest of the two Pt—Cl bonds is cleaved, leading to a cis position of the solvent ligand with respect to the allyl group. The crystal packing of the complexes is characterized by dimer formation via C—H…O and C—H…π interactions, but no π–π interactions are observed despite the presence of the aromatic ring.     

A binuclear zinc polymer with paddlewheel building units and intersecting helical chains based on a flexible 4‐[(carboxymethyl)sulfanyl]benzoic acid ligand

The asymmetric unit of the title compound, poly[{μ₄‐4‐[(carboxylatomethyl)sulfanyl]benzoato}(N,N‐dimethylformamide)zinc], [Zn(C₉H₆O₄S)(C₃H₇NO)]_n, consists of one crystallographically independent Zn^II cation, one 4‐[(carboxylatomethyl)sulfanyl]benzoate (L²⁻) ligand and one coordinated dimethylformamide (DMF) molecule. The zinc ion is coordinated by five O atoms from four separate L²⁻ ligands and one DMF molecule, and the ZnO₅ unit displays a distorted square‐based‐pyramidal geometry. Two ZnO₅ units form a binuclear zinc–tetracarboxylate paddlewheel cluster, and these are bridged by L²⁻ ligands to generate an intersecting helical chain (Zn²⁺ ions as nodes), which is composed of right‐handed (P) and left‐handed (M) helices. Weak C—H...O hydrogen bonds extend the one‐dimensional coordinated chain into a weakly bound three‐dimensional supramolecular architecture.     

Lagoden dimethylformamide hemisolvate dihydrate: absolute configuration,dipolar interactions and hydrogen‐bonding interactions

Lagoden (L·3H₂O, where L is Na⁺·C₂₀H₃₃O₆⁻; sodium 3β,16,18‐trihydroxy‐8,13‐epi‐9,13‐epoxylabdan‐15‐oate trihydrate) is widely used as an effective haemostatic agent. It has been crystallized from dimethylformamide (DMF) as sodium 3β,16,18‐trihydroxy‐8,13‐epi‐9,13‐epoxylabdan‐15‐oate dimethylformamide hemisolvate dihydrate, Na⁺·C₂₀H₃₃O₆⁻·0.5C₃H₇NO·2H₂O or L₂·DMF·4H₂O, and the asymmetric unit contains two of the latter formulation. The four symmetry‐independent Na⁺ cations and lagoden anions, one DMF molecule and six of the eight symmetry‐independent water molecules assemble into a one‐dimensional polymeric structure via dipolar and hydrogen‐bonding interactions. The lagoden anions coordinate to the Na⁺ cations via the carboxylate groups and the two primary hydroxy groups, whereas the secondary OH groups are solely involved in hydrogen bonding. Two of the four symmetry‐independent lagoden anions act in a chelating mode, forming seven‐membered chelate rings. The absolute structure, based on anomalous dispersion data collected at 130 K with Cu Kα radiation, confirms an inverted configuration at chiral centres C8 and C13 (labdane numbering) relative to the labdane skeleton.     

A new one‐dimensional coordination polymer of 5‐(1,3‐dioxo‐4,5,6,7‐tetraphenylisoindolin‐2‐yl)isophthalic acid with manganese

The coordination polymer catena‐poly[[(dimethylformamide‐κO)[μ₃‐5‐(1,3‐dioxo‐4,5,6,7‐tetraphenylisoindolin‐2‐yl)isophthalato‐κ⁴O¹,O^1′:O³:O^3′](methanol‐κO)manganese(III)] dimethylformamide monosolvate], {[Mn(C₄₀H₂₃NO₆)(CH₃OH)(C₃H₇NO)]·C₃H₇NO}_n, has been synthesized from the reaction of 5‐(1,3‐dioxo‐4,5,6,7‐tetraphenylisoindolin‐2‐yl)isophthalic acid and manganese(II) acetate tetrahydrate in a glass tube at room temperature by solvent diffusion. The Mn^II centre is hexacoordinated by two O atoms from one chelating carboxylate group, by two O atoms from two monodentate carboxylate groups and by one O atom each from a methanol and a dimethylformamide (DMF) ligand. The single‐crystal structure crystallizes in the triclinic space group P. Moreover, the coordination polymer shows one‐dimensional 2‐connected {0} uninodal chain networks, and free DMF molecules are connected to the chains by O—H...O hydrogen bonds. The thermogravimetric and photoluminescent properties of the compound have also been investigated.     

Syntheses,crystal structures and blue emission of three zinc(II) coordination polymers with a 4,4′‐dicarboxybiphenyl sulfone ligand

Three novel zinc complexes [Zn(dbsf)(H₂O)₂] ( 1 ), [Zn(dbsf)(2,2′‐bpy)(H₂O)]·(i‐C₃H₇OH) ( 2 ) and [Zn(dbsf)(DMF)] ( 3 ) (H₂dbsf = 4,4′‐dicarboxybiphenyl sulfone, 2,2′‐bpy = 2,2′‐bipyridine, i‐C₃H₇OH = iso‐propanol, DMF = N,N‐dimethylformamide) were first obtained and characterized by single crystal X‐ray crystallography. Although the results show that all the complexes 1–3 have one‐dimensional chains formed via coordination bonds, unique three‐dimensional supramolecular structures are formed due to different coordination modes and configuration of the dbsf^2? ligand, hydrogen bonds and π–π interactions. Iso‐propanol molecules are in open channels of 2 while larger empty channels are formed in 3 . As compared with emission band of the free H₂dbsf ligand, emission peaks of the complexes 1–3 are red‐shifted, and they show blue emission, which originates from enlarging conjugation upon coordination. Copyright © 2006 John Wiley & Sons, Ltd.     

Two terphenyl‐based diol hosts and corresponding solvent inclusions with dimethylformamide and acetonitrile

Having reference to an elongated structural modification of 2,2′‐bis(hydroxydiphenylmethyl)biphenyl, (I), the two 1,1′:4′,1′′‐terphenyl‐based diol hosts 2,2′′‐bis(hydroxydiphenylmethyl)‐1,1′:4′,1′′‐terphenyl, C₄₄H₃₄O₂, (II), and 2,2′′‐bis[hydroxybis(4‐methylphenyl)methyl]‐1,1′:4′,1′′‐terphenyl, C₄₈H₄₂O₂, (III), have been synthesized and studied with regard to their crystal structures involving different inclusions, i.e. (II) with dimethylformamide (DMF), C₄₄H₃₄O₂·C₂H₆NO, denoted (IIa), (III) with DMF, C₄₈H₄₂O₂·C₂H₆NO, denoted (IIIa), and (III) with acetonitrile, C₄₈H₄₂O₂·CH₃CN, denoted (IIIb). In the solvent‐free crystals of (II) and (III), the hydroxy H atoms are involved in intramolecular O—H...π hydrogen bonding, with the central arene ring of the terphenyl unit acting as an acceptor. The corresponding crystal structures are stabilized by intermolecular C—H...π contacts. Due to the distinctive acceptor character of the included DMF solvent species in the crystal structures of (IIa) and (IIIa), the guest molecule is coordinated to the host via O—H...O=C hydrogen bonding. In both crystal structures, infinite strands composed of alternating host and guest molecules represent the basic supramolecular aggregates. Within a given strand, the O atom of the solvent molecule acts as a bifurcated acceptor. Similar to the solvent‐free cases, the hydroxy H atoms in inclusion structure (IIIb) are involved in intramolecular hydrogen bonding, and there is thus a lack of host–guest interaction. As a result, the solvent molecules are accommodated as C—H...N hydrogen‐bonded inversion‐symmetric dimers in the channel‐like voids of the host lattice.     

A 2D coordination polymer assembled from a nickel(II) tetraazamacrocyclic cation and 4,4′‐(dimethylsilanediyl)diphthalate(3–) linker

The preformed nickel(II) complex of the 14‐membered macrocyclic ligand 1,4,8,11‐tetraazacyclotetradecane (cyclam, L), when treated with 4,4′‐(dimethylsilanediyl)diphthalic acid (H₄A) in a DMF/H₂O mixture (4:1 v/v) under heating, leads to [Ni(L)]₃(HA)₂·3DMF ( I·DMF ). Redissolution of this compound in a DMF/H₂O/MeOH mixture (4:1:30 v/v/v) with mild acidification under gentle heating results in the formation of a similar compound but containing water and methanol molecules of crystallization, [Ni(L)]₃(HA)₂·5H₂O·2MeOH ( II·H₂O ). At lower temperature and concentration of reactants and longer reaction time, single crystals of composition {[{Ni(L)}₃(HA)₂]·4CH₃OH}_n ( II·MeOH ) were isolated. Single‐crystal X‐ray diffraction analysis of this compound, which, according to PXRD is isostructural with II·H₂O but different from I·DMF , revealed its two‐dimensional (2D) polymeric structure, i.e. poly[[bis{μ₃‐4‐[(4‐carboxy‐3‐carboxylatophenyl)dimethylsilyl]benzene‐1,2‐dicarboxylato‐κ³O¹:O²:O^3′}tris(1,4,8,11‐tetraazacyclotetradecane‐κ⁴N)trinickel(II)] methanol tetrasolvate], {[Ni₃(C₁₈H₁₃O₈Si)₂(C₁₀H₂₄N₄)₃]·4CH₃OH}_n. It is built up of the monoprotonated tricarboxylate HA^3? ligand coordinated in a monodentate manner in the axial positions of two crystallographically independent Ni^II cations, one of which is located on a crystallographic inversion centre. Both metal ions adopt a slightly tetragonally elongated trans‐N₄O₂ octahedral geometry. The compound has a lamellar structure with polymeric layers oriented parallel to the (10) plane, which are in turn linked via hydrogen bonds involving protonated carboxylic acid groups of the ligand. Bulk compounds I·DMF and II·H₂O were characterized by FT–IR and diffuse reflectance spectroscopy and thermogravimetry, which provide evidence of their structural differences.     

Syntheses and structures of two novel fluorescent metal–organic frameworks generated from a tridentate donor–acceptor motif ligand

The tridentate organic ligand 4,4′,4′′‐(4,4,8,8,12,12‐hexamethyl‐8,12‐dihydro‐4H‐benzo[9,1]quinolizino[3,4,5,6,7‐defg]acridine‐2,6,10‐triyl)tribenzoic acid ( H₃L ) has been synthesized (as the methanol 1.25‐solvate, C₄₈H₃₉NO₆·1.25CH₃OH). As a donor–acceptor motif molecule, H₃L possess strong intramolecular charge transfer (ICT) fluorescence. Through hydrogen bonds, H₃L molecules construct a two‐dimensional (2D) network, which pack together into three‐dimensional (3D) networks with an ABC stacking pattern in the crystalline state. Based on H₃L and M(NO₃)₂ salts (M = Cd and Zn) under solvothermal conditions, two metal–organic frameworks (MOFs), namely, catena‐poly[[triaquacadmium(II)]‐μ‐10‐(4‐carboxyphenyl)‐4,4′‐(4,4,8,8,12,12‐hexamethyl‐8,12‐dihydro‐4H‐benzo[9,1]quinolizino[3,4,5,6,7‐defg]acridine‐2,6‐diyl)dibenzoato], [Cd(C₄₈H₃₇NO₆)(H₂O)₃]_n, I , and poly[[μ₃‐4,4′,4′′‐(4,4,8,8,12,12‐hexamethyl‐8,12‐dihydro‐4H‐benzo[9,1]quinolizino[3,4,5,6,7‐defg]acridine‐2,6,10‐triyl)tribenzoato](μ₃‐hydroxido)zinc(II)], [Zn₂(C₄₈H₃₆NO₆)(OH)]_n, II , were synthesized. Single‐crystal analysis revealed that both MOFs adopt a 3D structure. In I , partly deprotonated HL ^2? behaves as a bidentate ligand to link a Cd^II ion to form a one‐dimensional chain. In the solid state of I , the existence of weak interactions, such as O—H…O hydrogen bonds and π–π interactions, plays an essential role in aligning 2D nets and 3D networks with AB packing patterns for I . The deprotonated ligand L ^3? in II is utilized as a tridentate building block to bind Zn^II ions to construct 3D networks, where unusual Zn₄O₁₄ clusters act as connection nodes. As a donor–acceptor molecule, H₃L exhibits fluorescence with a photoluminescence quantum yield (PLQY) of 70% in the solid state. In comparison, the PL of both MOFs is red‐shifted with even higher PLQYs of 79 and 85% for I and II , respectively.     

A twofold interpenetrating two‐dimensional zinc(II) coordination polymer: synthesis,crystal structure and physical properties

A novel twofold interpenetrating two‐dimensional (2D) Zn^II coordination framework, poly[[(μ‐1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene‐κ²N³:N³)(μ‐naphthalene‐2,6‐dicarboxylato‐κ²O²:O⁶)zinc(II)] dimethylformamide monosolvate], {[Zn(C₁₂H₆O₄)(C₁₄H₁₄N₄)]·C₃H₇NO}_n or {[Zn(1,3‐BMIB)(NDC)]·DMF}_n (I), where H₂NDC is naphthalene‐2,6‐dicarboxylic acid, 1,3‐BMIB is 1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene and DMF is dimethylformamide, was prepared and characterized through IR spectroscopy, elemental analysis, thermal analysis and single‐crystal X‐ray diffraction. Single‐crystal X‐ray diffraction analysis revealed that (I) exhibits an unusual twofold interpenetrating 2D network. In addition, it displays strong fluorescence emissions and a high photocatalytic activity for the degradation of Rhodamine B (RhB) under UV‐light irradiation.     

A novel three‐dimensional zinc(II) coordination polymer based on 3,3′‐{[1,3‐phenylenebis(methylene)]bis(oxy)}dibenzoic acid and 1,4‐bis(pyridin‐4‐yl)benzene: synthesis,crystal structure and photocatalytic properties

A novel three‐dimensional (3D) Zn^II coordination polymer, namely, poly[[[1,4‐bis(pyridin‐4‐yl)benzene](μ₃‐3,3′‐{[1,3‐phenylenebis(methylene)]bis(oxy)}dibenzoato)zinc(II)] 1,4‐bis(pyridin‐4‐yl)benzene], {[Zn(C₂₂H₁₆O₆)(C₁₆H₁₂N₂)]·C₁₆H₁₂N₂}_n or {[Zn(PMBD)(DPB)]·DPB}_n, 1 , where H₂PMBD is 3,3′‐{[1,3‐phenylenebis(methylene)]bis(oxy)}dibenzoic acid and DPB is 1,4‐bis(pyridin‐4‐yl)benzene, has been synthesized by self‐assembly using zinc nitrate, a semi‐rigid dicarboxylic acid and a nitrogen‐containing ligand. The single‐crystal X‐ray structure determination indicates that 1 possesses an intriguing 3D architecture with a 4‐connected uninodal cds topology, which is constructed from dinuclear {Zn₂} clusters and V‐shaped PMBD^2? linkers. Compound 1 exhibits excellent photocatalytic activity on the degradation of the organic dyes Rhodamine B (RhB), Rhodamine 6G (Rh6G) and Methyl Red (MR).     

Studies on mono- and dinuclear bisoxime copper complexes with different coordination geometries

Two new mono- and dinuclear Cu(II) complexes, namely [CuL¹]·0.5H₂O (1) and [(Cu₂(L²)₂)(DMF)]·0.5DMF (2) (H₂L¹ = 1,2-bis{[(Z)-(3-methyl-5-oxo-1-phenyl-1H-pyrazolidin-4(4H)-yl)(phenyl)]methylene-aminooxy}ethane; H₂L² = 1,3-bis{[(Z)-(3-methyl-5-oxo-1-phenyl-1H-pyrazolidin-4(4H)-yl)(phenyl)] methyleneaminooxy}propane), have been synthesized and characterized by X-ray crystallography. The unit cell of complex 1 contains two crystallographically independent but chemically identical [CuL¹] molecules and one crystalline water molecule, showing a slightly distorted square-planar coordination geometry and forming a wave-like pattern running along the a-axis via hydrogen bonding and π···π stacking interactions. Complex 2 has a dinuclear structure, comprising two Cu(II) atoms, two completely deprotonated phenolate bisoxime (L²)²⁻ moieties (in the form of enol), and both coordinated and hemi-crystalline DMF molecules. Complex 2 has square-planar and square-pyramidal geometries around the two copper centers, whose basic coordination planes are almost perpendicular and form an infinite three-dimensional supramolecular network structure involving intermolecular C–H···N, C–H···O, and C–H···π(Ph) hydrogen bonding and π···π stacking interactions of neighboring pyrazole rings.     

Killing two birds with one stone: 2D+2D→3D parallel stacking and 3D self‐penetrating structures in one reaction and their crystal‐to‐crystal transformation

Reaction of the flexible phenolic carboxylate ligand 2‐(3,5‐dicarboxylbenzyloxy)benzoic acid (H₃L) with nickel salts in the presence of 1,2‐bis(pyridin‐4‐yl)ethylene (bpe) leads to the generation of a mixture of the two complexes under solvolthermal conditions, namely poly[[aqua[μ‐1,2‐bis(pyridin‐4‐yl)ethylene‐κ²N:N′]{μ‐5‐[(2‐carboxyphenoxy)methyl]benzene‐1,3‐dicarboxylato‐κ³O¹,O^1′:O³}nickel(II)] dimethylformamide hemisolvate monohydrate], {[Ni(C₁₆H₁₀O₇)(C₁₂H₁₀N₂)(H₂O)]·0.5C₃H₇NO·H₂O}_n or {[Ni(HL)(bpe)(H₂O)]·0.5DMF·H₂O}_n, 1 , and poly[[diaquatris[μ‐1,2‐bis(pyridin‐4‐yl)ethylene‐κ²N:N′]bis{μ‐5‐[(2‐carboxyphenoxy)methyl]benzene‐1,3‐dicarboxylato‐κ²O¹:O⁵}nickel(II)] dimethylformamide disolvate hexahydrate], {[Ni₂(C₁₆H₁₀O₇)₂(C₁₂H₁₀N₂)₃(H₂O)₂]·2C₃H₇NO·6H₂O}_n or {[Ni₂(HL)₂(bpe)₃(H₂O)₂]·2DMF·6H₂O}_n, 2 . In complex 1 , the Ni^II centres are connected by the carboxylate and bpe ligands to form two‐dimensional (2D) 4‐connected (4,4) layers, which are extended into a 2D+2D→3D (3D is three‐dimensional) supramolecular framework. In complex 2 , bpe ligands connect to Ni^II centres to form 2D layers with Ni₆(bpe)₆ metallmacrocycles. Interestingly, 2D+2D→3D inclined polycatenation was observed between these layers. The final 5‐connected 3D self‐penetrating structure was generated through further connection of Ni–carboxylate chains with these inclined motifs. Both complexes were fully characterized by single‐crystal analysis, powder X‐ray diffraction analysis, FT–IR spectra, elemental analyses, thermal analysis and UV–Vis spectra. Notably, an interesting metal/ligand‐induced crystal‐to‐crystal transformation was observed between the two complexes.     

Different coordination modes of trans‐2‐{[(2‐methoxyphenyl)imino]methyl}phenoxide in rare‐earth complexes: influence of the metal cation radius and the number of ligands on steric congestion and ligand coordination modes

A simple and effective synthetic route to homo‐ and heteroleptic rare‐earth (Ln = Y, La and Nd) complexes with a tridentate Schiff base anion has been demonstrated using exchange reactions of rare‐earth chlorides with in‐situ‐generated sodium (E)‐2‐{[(2‐methoxyphenyl)imino]methyl}phenoxide in different molar ratios in absolute methanol. Five crystal structures have been determined and studied, namely tris(2‐{[(2‐methoxyphenyl)imino]methyl}phenolato‐κ³O¹,N,O²)lanthanum, [La(C₁₄H₁₂NO₂)₃], ( 1 ), tris(2‐{[(2‐methoxyphenyl)imino]methyl}phenolato‐κ³O¹,N,O²)neodymium tetrahydrofuran disolvate, [La(C₁₄H₁₂NO₂)₃]·2C₄H₈O, ( 2 )·2THF, tris(2‐{[(2‐methoxyphenyl)imino]methyl}phenolato)‐κ³O¹,N,O²;κ³O¹,N,O²;κ²N,O¹‐yttrium, [Y(C₁₄H₁₂NO₂)₃], ( 3 ), dichlorido‐1κCl,2κCl‐μ‐methanolato‐1:2κ²O:O‐methanol‐2κO‐(μ‐2‐{[(2‐methoxyphenyl)imino]methyl}phenolato‐1κ³O¹,N,O²:2κO¹)bis(2‐{[(2‐methoxyphenyl)imino]methyl}phenolato)‐1κ³O¹,N,O²;2κ³O¹,N,O²‐diyttrium–tetrahydrofuran–methanol (1/1/1), [Y₂(C₁₄H₁₂NO₂)₃(CH₃O)Cl₂(CH₄O)]·CH₄O·C₄H₈O, ( 4 )·MeOH·THF, and bis(μ‐2‐{[(2‐methoxyphenyl)imino]methyl}phenolato‐1κ³O¹,N,O²:2κO¹)bis(2‐{[(2‐methoxyphenyl)imino]methyl}phenolato‐2κ³O¹,N,O²)sodiumyttrium chloroform disolvate, [NaY(C₁₄H₁₂NO₂)₄]·2CHCl₃, ( 5 )·2CHCl₃. Structural peculiarities of homoleptic tris(iminophenoxide)s ( 1 )–( 3 ), binuclear tris(iminophenoxide) ( 4 ) and homoleptic ate tetrakis(iminophenoxide) ( 5 ) are discussed. The nonflat Schiff base ligand displays μ₂‐κ³O¹,N,O²:κO¹ bridging, and κ³O¹,N,O² and κ²N,O¹ terminal coordination modes, depending on steric congestion, which in turn depends on the ionic radii of the rare‐earth metals and the number of coordinated ligands. It has been demonstrated that interligand dihedral angles of the phenoxide ligand are convenient for comparing steric hindrance in complexes. ( 4 )·MeOH has a flat Y₂O₂ rhomboid core and exhibits both inter‐ and intramolecular MeO—H…Cl hydrogen bonding. Catalytic systems based on complexes ( 1 )–( 3 ) and ( 5 ) have demonstrated medium catalytic performance in acrylonitrile polymerization, providing polyacrylonitrile samples with narrow polydispersity.