A novel two‐dimensional MnII coordination polymer with 1,2‐bis­(imidazol‐1‐yl)­ethane

In the crystal structure of the title complex, poly­[[di­azido­manganese(II)]‐di‐μ‐1,2‐bis­(imidazol‐1‐yl)­ethane‐κ⁴N³:N^3′], [Mn(N₃)₂(C₈H₁₀N₄)₂]_n or [Mn(N₃)₂(bim)₂]_n, where bim is 1,2‐­bis(imidazol‐1‐yl)­ethane, each Mn^II atom is six‐coordinated in a distorted octahedral coordination environment to four N atoms from four bim ligands and two N atoms from two azide ligands. The Mn^II atoms, which lie on inversion centres, are bridged by four bim ligands to form a two‐dimensional (4,4)‐network. The azide ligands are monodentate (terminal).     

Six Coordination Polymers based on 4‐(1H‐Imidazol‐1‐yl)phthalic Acid: Structural Diversities,Magnetism and Luminescence Properties

The coordination polymers (CPs), [Ni(L)(H₂O)₄]_n ( 1 ), [Co(HL)₂(H₂O)₂]_n ( 2 ), {[Cu(L)(H₂O)₃] · H₂O}_n ( 3 ), [Mn(L)(H₂O)₂]_n ( 4 ), [Cd(L)(H₂O)₂]_n ( 5 ), and {[Zn₂(L)₂] · H₂O}_n ( 6 ), were solvothermally synthesized by employing the imidazol‐carboxyl bifunctional ligand 4‐(1H‐imidazol‐1‐yl) phthalic acid (H₂L). Single‐crystal X‐ray diffraction indicated that the L^2–/HL^– ligands display various coordination modes with different metal ions in 1 – 6 . Complexes 1 and 2 show one‐dimensional (1D) chain structures, whereas complexes 3 – 6 show 2D layered structures. The magnetic properties of these complexes were investigated. Complexes 1 and 3 indicate weak ferromagnetic interactions, whereas complexes 2 and 4 demonstrate antiferromagnetic interactions. In addition, luminescence properties of 5 and 6 were measured and studied in detail.     

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

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

A concise and efficient synthesis of amino‐substituted (1H‐benzo[d]imidazol‐1‐yl)pyrimidine hybrids: synthetic sequence and the molecular and supramolecular structures of six examples

A concise and efficient synthesis of a series of amino‐substituted benzimidazole–pyrimidine hybrids has been developed, starting from the readily available N⁴‐(2‐aminophenyl)‐6‐methoxy‐5‐nitrosopyrimidine‐2,4‐diamine. In each of N⁵‐benzyl‐6‐methoxy‐4‐(2‐phenyl‐1H‐benzo[d]imidazol‐1‐yl)pyrimidine‐2,5‐diamine, C₂₅H₂₂N₆O, (I), 6‐methoxy‐N⁵‐(4‐methoxybenzyl)‐4‐[2‐(4‐methoxyphenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidine‐2,5‐diamine, C₂₇H₂₆N₆O₃, (III), 6‐methoxy‐N⁵‐(4‐nitrobenzyl)‐4‐[2‐(4‐nitrophenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidine‐2,5‐diamine, C₂₅H₂₀N₈O₅, (IV), the molecules are linked into three‐dimensional framework structures, using different combinations of N—H…N, N—H…O, C—H…O, C—H…N and C—H…π hydrogen bonds in each case. Oxidative cleavage of 6‐methoxy‐N⁵‐(4‐methylbenzyl)‐4‐[2‐(4‐methylphenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidine‐2,5‐diamine, (II), with diiodine gave 6‐methoxy‐4‐[2‐(4‐methylphenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidine‐2,5‐diamine, which crystallized as a monohydrate, C₁₉H₁₈N₆O·H₂O, (V), and reaction of (V) with trifluoroacetic acid gave two isomeric products, namely N‐{5‐amino‐6‐methoxy‐6‐[2‐(4‐methylphenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidin‐2‐yl}‐2,2,2‐trifluoroacetamide, which crystallized as an ethyl acetate monosolvate, C₂₁H₁₇F₃N₆O₂·C₄H₈O₂, (VI), and N‐{2‐amino‐6‐methoxy‐4‐[2‐(4‐methylphenyl)‐1H‐benzo[d]imidazol‐1‐yl]pyrimidin‐5‐yl}‐2,2,2‐trifluoroacetamide, which crystallized as a methanol monosolvate, C₂₁H₁₇F₃N₆O₂·CH₄O, (VIIa). For each of (V), (VI) and (VIIa), the supramolecular assembly is two‐dimensional, based on different combinations of O—H…N, N—H…O, N—H…N, C—H…O and C—H…π hydrogen bonds in each case. Comparisons are made with some related structures.     

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.     

Syntheses and Structures of Coordination Polymers Constructed by Semi‐Rigid Bicarboxylic Acid Ligands

The complexes [Co(L¹)(mpy)] ( 1 ), [Ni(L¹)(mpy)] ( 2 ), [Co(L¹)(tbpy)] · 2H₂O ( 3 ), [Ni₂(L¹)₂(tbpy)₂] · 5H₂O ( 4 ), [Mn₂(L¹)₂(tbpy)₂] · 3H₂O ( 5 ), [Mn(L¹)(biim‐3)] ( 6 ), [Ni₂(L¹)₂(btb)₂(H₂O)] · 2H₂O ( 7 ), [Cu(L²)(mpy)] · 7H₂O ( 8 ), [Co(L²)(tbpy)(H₂O)] ( 9 ), [Ni(L²)(tbpy)(H₂O)] · H₂O ( 10 ), [Cu(L²)(bib)] · 2H₂O ( 11 ), and [Cu(L²)(btb)] · 2H₂O ( 12 ) [H₂L¹ = (3‐carboxyl‐phenyl)‐(4‐(2′‐carboxyl‐phenyl)‐benzyl)ether, H₂L² = 3‐carboxy‐1‐(4′‐carboxybenzyl)‐2‐oxidopyridinium, mpy = 2‐(4‐(4′‐methylphenyl)‐6‐(pyrindin‐2‐yl)pyridin‐2‐yl)pyridine), tbpy = 2‐(4‐(4′‐tert‐butylphenyl)‐6‐(pyrindin‐2‐yl)pyridin‐2‐yl)pyridine), biim‐3 = 1,3‐bis(imidazol‐1′‐yl)propane, btb = 1,4‐bis(1,2,4‐triazol‐1‐ylmethyl)benzene, bib = 1,4‐bis(imidazol‐1′‐ylmethyl)benzene] were synthesized. Compounds 1 – 6 have similar 1D chain structures, which are further linked by π–π interactions to generate supramolecular double chains for 1 and 2 , and supramolecular layers for 3 – 6 . Compound 7 displays a 3D 6‐connected framework with (4⁴ · 6¹¹) topology. Compound 8 features a monomolecular structure, which is further linked by hydrogen bonds between the lattice water molecules and carboxylate oxygen atoms of L² anions to form a 2D supramolecular layer. The monomolecular structures of 9 and 10 are connected by hydrogen bonds and π–π interactions simultaneously to generate supramolecular layers. Compounds 11 and 12 show layer structures.     

A concise,efficient and versatile synthesis of amino‐substituted benzo[b]pyrimido[5,4‐f]azepines: synthesis and spectroscopic characterization,together with the molecular and supramolecular structures of three products and one intermediate

A concise, efficient and versatile synthesis of amino‐substituted benzo[b]pyrimido[5,4‐f]azepines is described: starting from a 5‐allyl‐4,6‐dichloropyrimidine, the synthesis involves base‐catalysed aminolysis followed by intramolecular Friedel–Crafts cyclization. Four new amino‐substituted benzo[b]pyrimido[5,4‐f]azepines are reported, and all the products and reaction intermediates have been fully characterized by IR, ¹H and ¹³C NMR spectroscopy and mass spectrometry, and the molecular and supramolecular structures of three products and one intermediate have been determined. In each of N,2,6,11‐tetramethyl‐N‐phenyl‐6,11‐dihydro‐5H‐benzo[b]pyrimido[5,4‐f]azepin‐4‐amine, C₂₂H₂₄N₅, (III), 4‐(1H‐benzo[d]imidazol‐1‐yl)‐6,11‐dimethyl‐6,11‐dihydro‐5H‐benzo[b]pyrimido[5,4‐f]azepine, which crystallizes as a 0.374‐hydrate, C₂₁H₁₉N₅·0.374H₂O, (VIIIa), and 6,7,9,11‐tetramethyl‐4‐(5‐methyl‐1H‐benzo[d]imidazol‐1‐yl)‐6,11‐dihydro‐5H‐benzo[b]pyrimido[5,4‐f]azepine, C₂₄H₂₅N₅, (VIIIc), the azepine ring adopts a boat conformation, but with a different configuration at the stereogenic centre in (VIIIc), as compared with (III) and (VIIIa). In the intermediate 5‐allyl‐6‐(1H‐benzo[d]imidazol‐1‐yl)‐N‐methyl‐N‐(4‐methylphenyl)pyrimidin‐4‐amine, C₂₂N₂₁N₅, (VIIb), the immediate precursor of 4‐(1H‐benzo[d]imidazol‐1‐yl)‐6,8,11‐trimethyl‐6,11‐dihydro‐5H‐benzo[b]pyrimido[5,4‐f]azepine, (VIIIb), the allyl group is disordered over two sets of atomic sites having occupancies of 0.688 (5) and 0.312 (5). The molecules of (III) are linked into chains by a C—H…π(pyrimidine) hydrogen bond, and those of (VIIb) are linked into complex sheets by three hydrogen bonds, one of the C—H…N type and two of C—H…π(arene) type. The molecules of the organic component in (VIIIa) are linked into a chain of rings by two C—H…π(arene) hydrogen bonds, and these chains are linked into sheets by the water components; a single weak C—H…N hydrogen bond links molecules of (VIIIc) into centrosymmetric R₂²(10) dimers. Comparisons are made with some related compounds.     

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.     

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.     

3D semiconducting Co–MOFs based on 5‐(hydroxymethyl)isophthalic acid and imidazole derivatives: syntheses and crystal structures

Two three‐dimensional cobalt‐based metal–organic frameworks with 5‐(hydroxymethyl)isophthalic acid (H₂HIPA), namely poly[[μ₂‐1,4‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene‐κ²N³:N^3′][μ₂‐5‐(hydroxymethyl)isophthalato‐κ²O¹:O³]cobalt(II)], [Co(C₉H₆O₅)(C₁₄H₁₄N₄)]_n ( 1 ), and poly[tris[μ₂‐1,4‐bis(1H‐imidazol‐1‐yl)benzene‐κ²N³:N^3′]bis[μ₃‐5‐(hydroxymethyl)isophthalato‐κ²O¹:O³:O⁵]dicobalt(II)], [Co₂(C₉H₆O₅)₂(C₁₂H₁₀N₄)₃]_n ( 2 ), were synthesized under similar hydrothermal conditions. Single‐crystal X‐ray diffraction analyses revealed that 5‐(hydroxymethyl)isophthalate (HIPA^2?) and 1,4‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene (1,4‐BMIB) are simple linkers connecting cobalt centres to build a fourfold interpenetration dia framework in complex 1 . However, complex 2 is a pillared‐layer framework with a (3,6)‐connected network constructed by 1,4‐bis(1H‐imidazol‐1‐yl)benzene (1,4‐DIB) linkers, 3‐connected HIPA^2? ligands and 6‐connected Co^II centres. The above significant structural differences can be ascribed to the introduction of the different auxiliary N‐donor ligands. Moreover, UV–Vis spectroscopy and Mott–Schottky measurements confirmed that complexes 1 and 2 are typical n‐type semiconductors.     

Green Synthesis of 6‐Aryl‐5,6‐dihydrobenzo[4,5]imidazo[1,2‐c]quinazoline Derivatives in Ionic Liquid under Catalyst‐free Conditions

Using ionic liquids as green media, a series of 6‐arylbenzo[4,5]imidazo[1,2‐c]quinazoline derivatives is synthesized via a reaction of 2‐(1H‐benzo[d]imidazol‐2‐yl)aniline and benzaldehydes in the air. While the intermediate products of 6‐aryl‐5,6‐dihydrobenzo[4,5]imidazo[1,2‐c]quinazolines were obtained in high yields at the same conditions under nitrogen protection.     

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.     

A new two‐dimensional ZnII coordination polymer based on 1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene and 5‐nitrobenzene‐1,3‐dicarboxylic acid: synthesis,crystal structure and physical properties

A novel two‐dimensional (2D) Zn^II coordination framework, poly[[μ‐1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene](μ‐5‐nitrobenzene‐1,3‐dicarboxylato)zinc(II)], [Zn(C₈H₃NO₆)(C₁₄H₁₄N₄)]_n or [Zn(NO₂‐BDC)(1,3‐BMIB)]_n [1,3‐BMIB is 1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene and NO₂‐H₂BDC is 5‐nitrobenzene‐1,3‐dicarboxylic acid], has been prepared and characterized by IR, elemental analysis, thermal analysis and single‐crystal X‐ray diffraction. Single‐crystal X‐ray diffraction analysis revealed that the compound is a new 2D polymer with a 6³ topology parallel to the (10) crystal planes based on left‐handed helices, right‐handed helical NO₂‐BDC–Zn chains and [Zn₂(1,3‐BMIB)₂]_n clusters. In the crystal, adjacent layers are further connected by C—H…O hydrogen bonds, C—H…π interactions, C—O…π interactions and N—O…π interactions to form a three‐dimensional structure in the solid state. In addition, the compound exhibits strong fluorescence emissions in the solid state at room temperature.     

2,5‐Bis[4‐methyl‐3‐(pyridin‐3‐yl)phenyl]‐1,3,4‐oxadiazole and its one‐dimensional polymeric complex with ZnCl2

2,5‐Bis[4‐methyl‐3‐(pyridin‐3‐yl)phenyl]‐1,3,4‐oxadiazole (L), C₂₆H₂₀N₄O, forms one‐dimensional chains via two types of intermolecular π–π interactions. In catena‐poly[[dichloridozinc(II)]‐μ‐2,5‐bis[4‐methyl‐3‐(pyridin‐3‐yl)phenyl]‐1,3,4‐oxadiazole], [ZnCl₂(C₂₆H₂₀N₄O)]_n, synthesized by the combination of L with ZnCl₂, the Zn^II centres are coordinated by two Cl atoms and two N atoms from two L ligands. [ZnCl₂L]_n forms one‐dimensional P (plus) and M (minus) helical chains, where the L ligand has different directions of twist. The helical chains stack together via interchain π–π and C—H...π interactions.     

Two new NiII and ZnII metal–organic frameworks of glutarate and 1,4‐bis[(2‐methyl‐1H‐imidazol‐1‐yl)methyl]benzene ligands: syntheses,structures and luminescence sensing properties

Two new metal–organic frameworks (MOFs), namely, three‐dimensional poly[diaquabis{μ₂‐1,4‐bis[(2‐methyl‐1H‐imidazol‐1‐yl)methyl]benzene}bis(μ₂‐glutarato)dinickel(II)] monohydrate], {[Ni₂(C₅H₆O₄)₂(C₁₆H₁₈N₄)₂(H₂O)₂]·H₂O}_n or {[Ni₂(Glu)₂(1,4‐mbix)₂(H₂O)₂]·H₂O}_n, ( I ), and two‐dimensional poly[[{μ₂‐1,4‐bis[(2‐methyl‐1H‐imidazol‐1‐yl)methyl]benzene}(μ₂‐glutarato)zinc(II)] tetrahydrate], {[Zn(C₅H₆O₄)(C₁₆H₁₈N₄)]·4H₂O}_n or {[Zn(Glu)(1,4‐mbix)]·4H₂O}_n ( II ), have been synthesized hydrothermally using glutarate (Glu^2?) mixed with 1,4‐bis[(2‐methyl‐1H‐imidazol‐1‐yl)methyl]benzene (1,4‐mbix), and characterized by single‐crystal X‐ray diffraction, IR and UV–Vis spectroscopy, powder X‐ray diffraction, and thermogravimetric and photoluminescence analyses. Ni^II MOF ( I ) shows a 4‐connected 3D framework with point symbol 6⁶, but is not a typical dia network. Zn^II MOF ( II ) displays a two‐dimensional 4⁴‐ sql network with one‐dimensional water chains penetrating the grids along the c direction. The solid‐state photoluminescence analysis of ( II ) was performed at room temperature and the MOF exhibits highly selective sensing toward Fe³⁺ and Cr₂O₇^2? ions in aqueous solution.     

Mannich Reaction as a New Route for the Synthesis of Tetrahydro Pyrimido Benzimidazolyl Coumarins

Condensation of coumarin‐4‐acetic acids ( 1 ) with ortho‐phenylenediamine ( 2 ) in anhydrous phosphoric acid afforded 4‐((1H‐benzo[d]imidazol‐2‐yl)methyl)‐2H‐chromen‐2‐ones ( 3 ). Attempted Mannich reaction of 3 with formalin and primary amines resulted in 4‐(2‐phenyl‐1,2,3,4‐tetrahydrobenzo[4,5]imidazo[1,2‐c]pyrimidin‐4‐yl)‐2H‐chromen‐2‐ones ( 6 ). The structures of synthesized compounds were elucidated by analyses including 2D HETCOR and DEPT experiments. Synthesized compounds have been subjected for anti‐inflammatory activity. Compound 6j exhibited promising anti‐inflammatory activity.     

Metal Ion Induced Assembly of Two Coordination Polymers with Different Topological Nets: Syntheses,Crystal Structures,and Luminescent Properties

The coordination polymers [Zn₂(NDA)(HNDA)₂(IPT)₂]_n ( 1 ) and [Mn(NDA)(IPT)]_n ( 2 ) [H₂NDA = naphthalene‐1,4‐dicarboxylic acid and IPT = 4′‐(4‐(1H‐imidazol‐1‐yl)phenyl)‐4,2′:6′,4′′‐terpyridine] were synthesized under hydrothermal conditions and characterized by single‐crystal X‐ray diffraction. Complex 1 features a one‐dimensional ladder‐like chain, whereas complex 2 shows a three‐dimensional CdS topology. The different coordination modes for organic ligands and topological nets for complexes 1 and 2 are mainly related with the metal ions.     

Three AgI,CuI and CdII coordination polymers based on the new asymmetrical ligand 2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole: syntheses,characterization and emission properties

The new asymmetrical organic ligand 2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole ( L , C₁₇H₁₃N₅O), containing pyridine and imidazole terminal groups, as well as potential oxdiazole coordination sites, was designed and synthesized. The coordination chemistry of L with soft Ag^I, Cu^I and Cd^II metal ions was investigated and three new coordination polymers (CPs), namely, catena‐poly[[silver(I)‐μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole] hexafluoridophosphate], {[Ag( L )]PF₆}_n, catena‐poly[[copper(I)‐di‐μ‐iodido‐copper(I)‐bis(μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole)] 1,4‐dioxane monosolvate], {[Cu₂I₂( L )₂]·C₄H₈O₂}_n, and catena‐poly[[[dinitratocopper(II)]‐bis(μ‐2‐{4‐[(1H‐imidazol‐1‐yl)methyl]phenyl}‐5‐(pyridin‐4‐yl)‐1,3,4‐oxadiazole)]–methanol–water (1/1/0.65)], {[Cd( L )₂(NO₃)₂]·2CH₄O·0.65H₂O}_n, were obtained. The experimental results show that ligand L coordinates easily with linear Ag^I, tetrahedral Cu^I and octahedral Cd^II metal atoms to form one‐dimensional polymeric structures. The intermediate oxadiazole ring does not participate in the coordination interactions with the metal ions. In all three CPs, weak π–π interactions between the nearly coplanar pyridine, oxadiazole and benzene rings play an important role in the packing of the polymeric chains.     

ZnII and CuII complexes generated from 5‐(pyridin‐4‐yl)‐3‐[2‐(pyridin‐4‐yl)ethyl]‐1,3,4‐oxadiazole‐2(3H)‐thione

A new 1,3,4‐oxadiazole‐containing bispyridyl ligand, namely 5‐(pyridin‐4‐yl)‐3‐[2‐(pyridin‐4‐yl)ethyl]‐1,3,4‐oxadiazole‐2(3H)‐thione (L), has been used to create the novel complexes tetranitratobis{μ‐5‐(pyridin‐4‐yl)‐3‐[2‐(pyridin‐4‐yl)ethyl]‐1,3,4‐oxadiazole‐2(3H)‐thione}zinc(II), [Zn₂(NO₃)₄(C₁₄H₁₂N₄OS)₂], (I), and catena‐poly[[[dinitratocopper(II)]‐bis{μ‐5‐(pyridin‐4‐yl)‐3‐[2‐(pyridin‐4‐yl)ethyl]‐1,3,4‐oxadiazole‐2(3H)‐thione}] nitrate acetonitrile sesquisolvate dichloromethane sesquisolvate], {[Cu(NO₃)(C₁₄H₁₂N₄OS)₂]NO₃·1.5CH₃CN·1.5CH₂Cl₂}_n, (II). Compound (I) presents a distorted rectangular centrosymmetric Zn₂L₂ ring (dimensions 9.56 × 7.06 Å), where each Zn^II centre lies in a {ZnN₂O₄} coordination environment. These binuclear zinc metallocycles are linked into a two‐dimensional network through nonclassical C—H...O hydrogen bonds. The resulting sheets lie parallel to the ac plane. Compound (II), which crystallizes as a nonmerohedral twin, is a coordination polymer with double chains of Cu^II centres linked by bridging L ligands, propagating parallel to the crystallographic a axis. The Cu^II centres adopt a distorted square‐pyramidal CuN₄O coordination environment with apical O atoms. The chains in (II) are interlinked via two kinds of π–π stacking interactions along [01]. In addition, the structure of (II) contains channels parallel to the crystallographic a direction. The guest components in these channels consist of dichloromethane and acetonitrile solvent molecules and uncoordinated nitrate anions.     

A new one‐dimensional ZnII coordination polymer based on 2‐[(1H‐imidazol‐1‐yl)methyl]‐1H‐benzimidazole and benzene‐1,2‐dicarboxylate

Multidentate N‐heterocyclic compounds form a variety of metal complexes with many intriguing structures and interesting properties. The title coordination polymer, catena‐poly[zinc(II)‐bis{μ‐2‐[(1H‐imidazol‐1‐yl)methyl]‐1H‐benzimidazole}‐κ²N³:N^3′;N^3′:N³‐zinc(II)‐bis(μ‐benzene‐1,2‐dicarboxylato)‐κ²O¹:O²;κ³O¹,O^1′:O²], [Zn₂(C₈H₄O₄)₂(C₁₁H₁₀N₄)₂]_n, has been synthesized by the reaction of Zn(NO₃)₂ with 2‐[(1H‐imidazol‐1‐yl)methyl]‐1H‐benzimidazole (imb) and benzene‐1,2‐dicarboxylic acid (H₂bdic) under hydrothermal conditions. There are two crystallographically distinct imb ligands [imb(A) and imb(B)] in the structure which adopt very similar coordination geometries. The imb(A) ligand bridges two symmetry‐related Zn1 ions, yielding a binuclear [(Zn1)₂{imb(A)}₂] unit, and the imb(B) ligand bridges two symmetry‐related Zn2 ions resulting in a binuclear [(Zn2)₂{imb(B)}₂] unit. The above‐mentioned binuclear units are further connected alternately by pairs of bridging bdic²⁻ ligands, forming an infinite one‐dimensional chain. These one‐dimensional chains are further connected through N—H...O hydrogen bonds, leading to a two‐dimensional layered structure. In addition, the title polymer exhibits good fluorescence properties in the solid state at room temperature.