Synthesis and Characterization of Novel 1‐Methyl‐3‐(4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)‐1H‐indazole Derivatives

A series of novel 1‐methyl‐3‐(4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)‐1H‐indazoles was synthesized in three steps from 5‐(1‐methyl‐1H‐indazol‐3‐yl)‐4‐phenyl‐2H‐1,2,4‐triazole‐3(4H)‐thiones. 5‐(1‐Methyl‐1H‐indazol‐3‐yl)‐4‐phenyl‐2H‐1,2,4‐triazole‐3(4H)‐thiones were converted into 1‐methyl‐3‐(5‐(methylsulfonyl)‐4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)‐1H‐indazoles upon methylation followed by treatment with aq. KMnO₄. The reaction of 1‐methyl‐3‐(5‐(methylsulfonyl)‐4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)‐1H‐indazoles with Raney nickel resulted in desulphonylation to afford corresponding 1‐methyl‐3‐(4‐phenyl‐4H‐1,2,4‐triazol‐3‐yl)‐1H‐indazoles. All the new synthesized compounds were characterized by spectral techniques.     

Synthesis and characterization of two novel bimetallic macrocyclic complexes generated from 1,2,4‐triazole‐containing semi‐rigid ligands and M(NO3)2 units (M = Ni and Zn)

Bimetallic macrocyclic complexes have attracted the attention of chemists and various organic ligands have been used as molecular building blocks, but supramolecular complexes based on semi‐rigid organic ligands containing 1,2,4‐triazole have remained rare until recently. It is easier to obtain novel topologies by making use of asymmetric semi‐rigid ligands in the self‐assembly process than by making use of rigid ligands. A new semi‐rigid ligand, 3‐[(pyridin‐4‐ylmethyl)sulfanyl]‐5‐(quinolin‐2‐yl)‐4H‐1,2,4‐triazol‐4‐amine (L), has been synthesized and used to generate two novel bimetallic macrocycle complexes, namely bis{μ‐3‐[(pyridin‐4‐ylmethyl)sulfanyl]‐5‐(quinolin‐2‐yl)‐4H‐1,2,4‐triazol‐4‐amine}bis[(methanol‐κO)(nitrato‐κ²O,O′)nickel(II)] dinitrate, [Ni₂(NO₃)₂(C₁₇H₁₄N₆S)₂(CH₃OH)₂](NO₃)₂, (I), and bis{μ‐3‐[(pyridin‐4‐ylmethyl)sulfanyl]‐5‐(quinolin‐2‐yl)‐4H‐1,2,4‐triazol‐4‐amine}bis[(methanol‐κO)(nitrato‐κ²O,O′)zinc(II)] dinitrate, [Zn₂(NO₃)₂(C₁₇H₁₄N₆S)₂(CH₃OH)₂](NO₃)₂, (II), by solution reactions with the inorganic salts M(NO₃)₂ (M = Ni and Zn, respectively) in mixed solvents. In (I), two Ni^II cations with the same coordination environment are linked by L ligands through Ni—N bonds to form a bimetallic ring. Compound (I) is extended into a two‐dimensional network in the crystallographic ac plane via N—H…O, O—H…N and O—H…O hydrogen bonds, and neighbouring two‐dimensional planes are parallel and form a three‐dimensional structure via π–π stacking. Compound (II) contains two bimetallic rings with the same coordination environment of the Zn^II cations. The Zn^II cations are bridged by L ligands through Zn—N bonds to form the bimetallic rings. One type of bimetallic ring constructs a one‐dimensional nanotube via O—H…O and N—H…O hydrogen bonds along the crystallographic a direction, and the other constructs zero‐dimensional molecular cages via O—H…O and N—H…O hydrogen bonds. They are interlinked into a two‐dimensional network in the ac plane through extensive N—H…O hydrogen bonds, and a three‐dimensional supramolecular architecture is formed via π–π interactions between the centroids of the benzene rings of the quinoline ring systems.     

Synthesis and Antifungal Activities of ω‐[4‐Aryl‐5‐(1‐phenyl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐1,2,4‐triazol‐3‐thio]‐ω‐(1H‐1,2,4‐triazol‐1‐yl)acetophenones

New 4‐aryl‐5‐(1‐phenyl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐1,2,4‐triazol‐3‐thiones 3 have been synthesized by the intramolecular cyclization of 4‐aryl‐1‐(1‐phenyl‐5‐methyl‐1,2,4‐triazol‐4‐formyl)thiosemicarbazides 2 with an 8% NaOH solution, and then 3 reacted with ω‐bromo‐ω‐(1H‐1,2,4‐triazol‐1‐yl)acetophenone to afford ω‐[4‐aryl‐5‐(1‐phenyl‐5‐methyl‐1,2,3‐triazol‐4‐yl)‐1,2,4‐triazol‐3‐thio]‐ω‐(1H‐1,2,4‐triazol‐1‐yl)‐acetophenones 4 . The preliminary biological test showed that the representative compounds possess some anti fungal activities.     

A novel two‐dimensional framework based on unprecedented cadmium(II) chains

The bent ligand 4‐[(1H‐1,2,4‐triazol‐1‐yl)methyl]benzoic acid (HL) has been used to create the novel two‐dimensional coordination polymer poly[μ₂‐aqua‐μ₂‐chlorido‐{μ₂‐4‐[(1H‐1,2,4‐triazol‐1‐yl)methyl]benzoato}cadmium(II)], [Cd(C₁₀H₈N₃O₂)Cl(H₂O)]_n, under hydrothermal reaction of HL with cadmium chloride. The crystallographically unique Cd atom is seven‐coordinated in an approximately pentagonal–bipyramidal environment of two carboxylate O atoms, two water O atoms, two Cl atoms and one triazole N atom. A notable feature is the presence of zigzag ...Cd...Cd... inorganic chains, in which neighboring Cd^II ions are doubly bridged by pairs of μ₂‐Cl atoms and μ₂‐H₂O ligands in an alternating fashion. To the authors' knowledge, this is the first example containing this bridging mode in a cadmium(II) framework. The chains are connected to one another through the bridging L⁻ ligand into a two‐dimensional undulating network. All of the two‐dimensional nets stack exactly together in an …AA… stacking sequence along the crystallographic b axis. Neighboring layers are further linked into a three‐dimensional framework via interlayer hydrogen‐bonding interactions.     

Synthesis of Novel Disubstituted Pyrazolo[1,5‐a]pyrimidines,Imidazo[1,2‐a]pyrimidines,and Pyrimido[1,2‐a]benzimidazoles Containing Thioether and Aryl Moieties

A series of novel 6‐[(1,3,4‐thiadiazol‐2‐yl)sulfanyl]‐7‐phenylpyrazolo[1,5‐a]pyrimidines, 5‐phenyl‐6‐[(1,3,4‐thiadiazol‐2‐yl)sulfanyl]imidazo[1,2‐a]pyrimidines, and 2‐phenyl‐3‐[(1,3,4‐thiadiazol‐2‐yl)sulfanyl]pyrimido[1,2‐a]benzimidazoles have been synthesized in four steps starting with 2‐hydroxyacetophenone. The intermediate 3‐[(1,3,4‐thiadiazol‐2‐yl)sulfanyl]‐4H‐1‐benzopyran‐4‐ones reacted with pyrazol‐3‐amines, 5‐methylpyrazol‐3‐amine, and 1H‐imidazol‐2‐amine, 1H‐benzimidazol‐2‐amine via a cyclocondensation to give the title compounds in the presence of MeONa as base, respectively. The approach affords the target compounds in acceptable‐to‐good yields. The new compounds were characterized by their IR, NMR, and HR mass spectra.     

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.     

The heterobifunctional ligand 5‐[4‐(1,2,4‐triazol‐4‐yl)phenyl]‐1H‐tetrazole and its role in the construction of a CdII metal–organic chain structure

5‐[4‐(1,2,4‐Triazol‐4‐yl)phenyl]‐1H‐tetrazole, C₉H₇N₇, (I), an asymmetric heterobifunctional organic ligand containing triazole (tr) and tetrazole (tz) termini linked directly through a 1,4‐phenylene spacer, crystallizes in the polar space group Pc. The heterocyclic functions, serving as single hydrogen‐bond donor (tz) or acceptor (tr) units, afford hydrogen‐bonded zigzag chains with no crystallographic centre of inversion. In the structure of catena‐poly[[diaquacadmium(II)]bis{μ₂‐5‐[4‐(1,2,4‐triazol‐4‐yl)phenyl]tetrazol‐1‐ido‐κ²N¹:N^1′}], [Cd(C₉H₆N₇)₂(H₂O)₂]_n, (II), the Cd^II dication resides on a centre of inversion in an octahedral {N₄O₂} environment. In the equatorial plane, the Cd^II polyhedron is built up from four N atoms of two kinds, namely of trans‐coordinating tr and tz fragments [Cd—N = 2.2926 (17) and 2.3603 (18) Å], and the coordinating aqua ligands occupy the two apical sites. The metal centres are separated at a distance of 11.1006 (7) Å by means of the double‐bridging tetrazolate anion, L⁻, forming a chain structure. The water ligands and tz fragments interact with one another, like a double hydrogen‐bond donor–acceptor synthon, leading to a hydrogen‐bonded three‐dimensional array.     

Design and synthesis of methyl 2‐{[4‐phenyl‐5‐(pyridin‐2‐yl)‐4H‐1,2,4‐triazol‐3‐yl]sulfanyl}acetate (phpy2NS) as a ligand for complexes of Group 12 elements: structural assessment and hydrogen‐bonded supramolecular assembly analysis

The reaction of 2‐cyanopyridine with N‐phenylthiosemicarbazide afforded 2‐[amino(pyridin‐2‐yl)methylidene]‐N‐phenylhydrazine‐1‐carbothioamide (Ham4ph) and crystals of 4‐phenyl‐5‐(pyridin‐2‐yl)‐2,4‐dihydro‐3H‐1,2,4‐triazole‐3‐thione (pyph3NS, 1 , C₁₃H₁₀N₄S). Crystals of methyl 2‐{[4‐phenyl‐5‐(pyridin‐2‐yl)‐4H‐1,2,4‐triazol‐3‐yl]sulfanyl}acetate (phpy2NS, 2 , C₁₆H₁₄N₄O₂S), derived from 1 , were obtained by the reaction of Ham4ph with chloroacetic acid, followed by the acid‐catalyzed esterification of the carboxylic acid with methyl alcohol. Crystals of bis(methanol‐κO)bis(methyl 2‐{[4‐phenyl‐5‐(pyridin‐2‐yl)‐4H‐1,2,4‐triazol‐3‐yl‐κ²N¹,N⁵]sulfanyl}acetato)zinc(II)/cadmium(II) hexabromidocadmate(II), [Zn_0.76Cd_0.24(C₁₆H₁₄N₄O₂S)₂(CH₃OH)₂][Cd₂Br₆] or [Zn_0.76Cd_0.24(phpy2NS)₂(MeOH)₂][Cd₂Br₆], 3 , and dichlorido(methyl 2‐{[4‐phenyl‐5‐(pyridin‐2‐yl)‐4H‐1,2,4‐triazol‐3‐yl‐κ²N¹,N⁵]sulfanyl}acetato)mercury(II), [HgCl₂(C₁₆H₁₄N₄O₂S)] or [Hg(phpy2NS)Cl₂], 4 , were synthesized using ligand 2 and CdBr₂ or HgCl₂, respectively. The molecular and supramolecular structures of the compounds were studied by X‐ray diffractometry. The asymmetric unit of 3 is formed from CdBr₃ and M(phpy2NS)(MeOH) units, where the metal centre M has a 76% occupancy of Zn^II and 24% of Cd^II. The M²⁺ centre of the cation, located on a crystallographic inversion centre, is hexacoordinated and appears as a slightly distorted octahedral [MN₄O₂]²⁺ cation. The Cd centre of the anion is coordinated by two terminal bromide ligands and two bridging bromide ligands that generate [Cd₂Br₆]^2? cadmium–bromide clusters. These clusters display crystallographic inversion symmetry forming two edge‐shared tetrahedra and serve as agents that direct the structure in the formation of supramolecular assemblies. In mononuclear complex 4 , the coordination geometry around the Hg²⁺ ion is distorted tetrahedral and comprises two chloride ligands and two N‐atom donors from the phpy2NS ligand, viz. one pyridine N atom and the other from triazole. In the crystal packing, all four compounds exhibit weak intermolecular interactions, which facilitate the formation of three‐dimensional architectures. Along with the noncovalent interactions, the structural diversity in the complexes can be attributed to the metal centre and to the coordination geometry, as well as to its ionic or neutral character.     

Metal‐directed supramolecular architectures based on the bifunctional ligand 2,5‐bis(1H‐1,2,4‐triazol‐1‐yl)terephthalic acid

By the solvothermal reactions of 2,5‐bis(1H‐1,2,4‐triazol‐1‐yl)terephthalic acid (H₂L) with transition‐metal ions, two novel polymeric complexes, namely, poly[diaqua[μ₄‐2,5‐bis(1H‐1,2,4‐triazol‐1‐yl)terephthalato]cobalt(II)], [Co(C₁₂H₆N₆O₄)(H₂O)₂]_n, ( 1 ), and poly[[diaqua[μ₄‐2,5‐bis(1H‐1,2,4‐triazol‐1‐yl)terephthalato]nickel(II)] dihydrate], {[Ni(C₁₂H₆N₆O₄)(H₂O)₂]·2H₂O}_n, ( 2 ), were isolated. Both polymers have been characterized by FT–IR spectroscopy, elemental analysis and single‐crystal X‐ray diffraction analysis. The complexes have similar two‐dimensional layered structures and coordination modes. Furthermore, the two‐dimensional layered structures bear distinct intermolecular hydrogen‐bonding interactions and π–π stacking interactions to form two different three‐dimensional supramolecular networks based on 4⁴‐subnets. The structural variation depends on the nature of the metal cations. The results of variable‐temperature magnetization measurements (χ_MT?T and χ_M^?1?T) show that complexes ( 1 ) and ( 2 ) display antiferromagnetic behaviour.     

In situ synthesis of mononuclear copper(II) complexes of the new tridentate ligand bis[(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)methyl]amine

Two mononuclear copper complexes, {bis[(3,5‐dimethyl‐1H‐pyrazol‐1‐yl‐κN²)methyl]amine‐κN}(3,5‐dimethyl‐1H‐pyrazole‐κN²)(perchlorato‐κO)copper(II) perchlorate, [Cu(ClO₄)(C₅H₈N₂)(C₁₂H₁₉N₅)]ClO₄, (I), and {bis[(3,5‐dimethyl‐1H‐pyrazol‐1‐yl‐κN²)methyl]amine‐κN}bis(3,5‐dimethyl‐1H‐pyrazole‐κN²)copper(II) bis(hexafluoridophosphate), [Cu(C₅H₈N₂)₂(C₁₂H₁₉N₅)](PF₆)₂, (II), have been synthesized by the reactions of different copper salts with the tripodal ligand tris[(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)methyl]amine (TDPA) in acetone–water solutions at room temperature. Single‐crystal X‐ray diffraction analysis revealed that they contain the new tridentate ligand bis[(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)methyl]amine (BDPA), which cannot be obtained by normal organic reactions and has thus been captured in the solid state by in situ synthesis. The coordination of the Cu^II ion is distorted square pyramidal in (I) and distorted trigonal bipyramidal in (II). The new in situ generated tridentate BDPA ligand can act as a meridional or facial ligand during the process of coordination. The crystal structures of these two compounds are stabilized by classical hydrogen bonding as well as intricate nonclassical hydrogen‐bond interactions.     

Green Synthesis of 1‐(1,2,4‐Triazol‐4‐yl)spiro[azetidine‐2,3′‐(3H)indole]‐2′,4′(1′H)‐diones as Potential Insecticidal Agents

One pot green synthesis of 1‐(1,2,4‐triazol‐4‐yl)spiro[azetidine‐2,3′‐(3H)‐indole]‐2′,4′(1′H)‐diones was carried out by the reaction of indole‐2,3‐diones,4‐amino‐4H‐1,2,4‐triazole and acetyl chloride/chloroacetyl chloride in ionic liquid [bmim]PF₆ with/without using a catalyst. It was also prepared by conventional method via Schiff's bases, 3‐[4H‐1,2,4‐triazol‐4‐yl]imino‐indol‐2‐one. Further, the corresponding phenoxy derivatives were obtained by the reaction of chloro group attached to azetidine ring with phenols. The synthesized compounds were characterized by analytical and spectral (IR, ¹H NMR, ¹³C NMR, and FAB mass) data. Evaluation for insecticidal activity against Periplaneta americana exhibited promising results.     

A one‐dimensional silver(I) coordination polymer based on the 2‐[2‐(pyridin‐4‐yl)‐1H‐benzimidazol‐1‐ylmethyl]phenol ligand exhibiting photoluminescence

A one‐dimensional Ag^I coordination complex, catena‐poly[[silver(I)‐μ‐{2‐[2‐(pyridin‐4‐yl)‐1H‐benzimidazol‐1‐ylmethyl]phenol‐κ²N²:N³}] perchlorate monohydrate], {[Ag(C₁₉H₁₅N₃O)]ClO₄·H₂O}_n, was synthesized by the reaction of 2‐[2‐(pyridin‐4‐yl)‐1H‐benzimidazol‐1‐ylmethyl]phenol (L) with silver perchlorate. In the complex, the L ligands are arranged alternately and link Ag^I cations through one benzimidazole N atom and the N atom of the pyridine ring, leading to an extended zigzag chain structure. In addition, the one‐dimensional chains are extended into a three‐dimensional supramolecular architecture via O—H...O hydrogen‐bond interactions and π–π stacking interactions. The complex exhibits photoluminescence in acetonitrile solution, with an emission maximum at 390 nm, and investigation of the thermal stability reveals that the network structure is stable up to 650 K.     

Synthesis and Fungicidal Activity of (1Z, 3Z)‐4,4‐Dimethyl‐1‐substitutedphenyl‐2‐(1H‐1,2,4‐triazol‐1‐yl)‐pent‐1‐en‐3‐one O‐[2,4‐dimethylthiazole(or 4‐methyl‐1,2,3‐thiadiazole)]‐5‐carbonyl Oximes

A series of novel (Z)‐1‐tert‐butyl (or phenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)‐ethanone O‐[2,4‐dimethylthiazole (or 4‐methyl‐1,2,3‐thiadiazole) ?5‐carbonyl] oximes 5a – 5c and (1Z, 3Z)‐4,4‐dimethyl‐1‐substitutedphenyl‐2‐(1H‐1,2,4‐triazol‐1‐yl)‐pent‐1‐en‐3‐one O‐[2,4‐dimethylthiazole (or 4‐methyl‐1,2,3‐thiadiazole)‐5‐carbonyl] oximes 6a – 6e were synthesized by the condensations of (Z)‐1‐tert‐butyl (or phenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)‐ethanone oximes 3 or (1Z, 3Z)‐4,4‐dimethyl‐1‐substitutedphenyl‐2‐(1H‐1,2,4‐triazol‐1‐yl)‐pent‐1‐en‐3‐one oximes 4 with 2,4‐dimethylthiazole‐5‐carbonyl chloride or 4‐methyl‐1,2,3‐thiadiazole‐5‐carbonyl chloride in the basic condition. Their structures were confirmed by IR, ¹H NMR, mass spectroscopy, and elemental analyses. The results of preliminary bioassays showed the title compounds 5 and 6 exhibited moderate to good fungicidal activities. For example, compound 6c possessed 86.4% inhibition against Fusarium oxysporum, and compound 6b exhibited 86.4 and 100% inhibition against Fusarium oxysporum and Cercospora arachidicola Hori at the concentration of 50 mg/L, respectively.     

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.     

Structural studies of (prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine hetero‐scorpionate copper complexes

The structures of five compounds consisting of (prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine complexed with copper in both the Cu^I and Cu^II oxidation states are presented, namely chlorido{(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ³N,N′,N′′}copper(I) 0.18‐hydrate, [CuCl(C₁₅H₁₇N₃)]·0.18H₂O, (1), catena‐poly[[copper(I)‐μ₂‐(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ⁵N,N′,N′′:C²,C³] perchlorate acetonitrile monosolvate], {[Cu(C₁₅H₁₇N₃)]ClO₄·CH₃CN}_n, (2), dichlorido{(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ³N,N′,N′′}copper(II) dichloromethane monosolvate, [CuCl₂(C₁₅H₁₇N₃)]·CH₂Cl₂, (3), chlorido{(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ³N,N′,N′′}copper(II) perchlorate, [CuCl(C₁₅H₁₇N₃)]ClO₄, (4), and di‐μ‐chlorido‐bis({(prop‐2‐en‐1‐yl)bis[(pyridin‐2‐yl)methylidene]amine‐κ³N,N′,N′′}copper(II)) bis(tetraphenylborate), [Cu₂Cl₂(C₁₅H₁₇N₃)₂][(C₆H₅)₄B]₂, (5). Systematic variation of the anion from a coordinating chloride to a noncoordinating perchlorate for two Cu^I complexes results in either a discrete molecular species, as in (1), or a one‐dimensional chain structure, as in (2). In complex (1), there are two crystallographically independent molecules in the asymmetric unit. Complex (2) consists of the Cu^I atom coordinated by the amine and pyridyl N atoms of one ligand and by the vinyl moiety of another unit related by the crystallographic screw axis, yielding a one‐dimensional chain parallel to the crystallographic b axis. Three complexes with Cu^II show that varying the anion composition from two chlorides, to a chloride and a perchlorate to a chloride and a tetraphenylborate results in discrete molecular species, as in (3) and (4), or a bridged bis‐μ‐chlorido complex, as in (5). Complex (3) shows two strongly bound Cl atoms, while complex (4) has one strongly bound Cl atom and a weaker coordination by one perchlorate O atom. The large noncoordinating tetraphenylborate anion in complex (5) results in the core‐bridged Cu₂Cl₂ moiety.     

Structural investigation of one‐ and two‐dimensional coordination polymers based on cobalt–bis(dioxolene) units and 1‐hydroxy‐1,2,4,5‐tetrakis(pyridin‐4‐yl)cyclohexane

The combination of cobalt, 3,5‐di‐tert‐butyldioxolene (3,5‐dbdiox) and 1‐hydroxy‐1,2,4,5‐tetrakis(pyridin‐4‐yl)cyclohexane (tpch) yields two coordination polymers with different connectivities, i.e. a one‐dimensional zigzag chain and a two‐dimensional sheet. Poly[[bis(3,5‐di‐tert‐butylbenzene‐1,2‐diolato)bis(1,5‐di‐tert‐butyl‐4‐oxocyclohexa‐2,5‐dien‐1‐yl‐3‐olato)[μ₄‐1‐hydroxy‐1,2,4,5‐tetrakis(pyridin‐4‐yl)cyclohexane]cobalt(III)]–ethanol–water 1/7/5], {[Co₂(C₁₄H₂₀O₂)₄(C₂₆H₂₄N₄O)]·7C₂H₅OH·5H₂O}_n or {[Co₂(3,5‐dbdiox)₄(tpch)}·7EtOH·5H₂O}_n, is the second structurally characterized example of a two‐dimensional coordination polymer based on linked {Co(3,5‐dbdiox)₂} units. Variable‐temperature single‐crystal X‐ray diffraction studies suggest that catena‐poly[[[(3,5‐di‐tert‐butylbenzene‐1,2‐diolato)(1,5‐di‐tert‐butyl‐4‐oxocyclohexa‐2,5‐dien‐1‐yl‐3‐olato)cobalt(III)]‐μ‐1‐hydroxy‐1,2,4,5‐tetrakis(pyridin‐4‐yl)cyclohexane]–ethanol–water (1/1/5)], {[Co(C₁₄H₂₀O₂)₂(C₂₆H₂₄N₄O)]·C₂H₅OH·5H₂O}_n or {[Co(3,5‐dbdiox)₂(tpch)]·EtOH·5H₂O}_n, undergoes a temperature‐induced valence tautomeric interconversion.     

Adsorption behaviour of a CdII–triazole MOF for butan‐2‐one in a single‐crystal‐to‐single‐crystal (SCSC) fashion: the role of hydrogen bonding and C—H…π interactions

The adsorption behaviour of the Cd^II–MOF {[Cd(L)₂(ClO₄)₂]·H₂O ( 1 ), where L is 4‐amino‐3,5‐bis[3‐(pyridin‐4‐yl)phenyl]‐1,2,4‐triazole, for butan‐2‐one was investigated in a single‐crystal‐to‐single‐crystal (SCSC) fashion. A new host–guest system that encapsulated butan‐2‐one molecules, namely poly[[bis{μ₃‐4‐amino‐3,5‐bis[3‐(pyridin‐4‐yl)phenyl]‐1,2,4‐triazole}cadmium(II)] bis(perchlorate) butanone sesquisolvate], {[Cd(C₂₄H₁₈N₆)₂](ClO₄)₂·1.5C₄H₈O}_n, denoted C₄H₈O@Cd‐MOF ( 2 ), was obtained via an SCSC transformation. MOF 2 crystallizes in the tetragonal space group P4₃2₁2. The specific binding sites for butan‐2‐one in the host were determined by single‐crystal X‐ray diffraction studies. N—H…O and C—H…O hydrogen‐bonding interactions and C—H…π interactions between the framework, ClO₄^? anions and guest molecules co‐operatively bind 1.5 butan‐2‐one molecules within the channels. The adsorption behaviour was further evidenced by ¹H NMR, IR, TGA and powder X‐ray diffraction experiments, which are consistent with the single‐crystal X‐ray analysis. A ¹H NMR experiment demonstrates that the supramolecular interactions between the framework, ClO₄^? anions and guest molecules in MOF 2 lead to a high butan‐2‐one uptake in the channel.     

Two different one‐dimensional supramolecular chains formed from the reaction of 2‐[1‐(pyridin‐4‐ylmethyl)‐1H‐benzimidazol‐2‐yl]quinoline with two different precursors,Co(NO3)2 and CoCl2

Two different one‐dimensional supramolecular chains with Co^II cations have been synthesized based on the semi‐rigid ligand 2‐[1‐(pyridin‐4‐ylmethyl)‐1H‐benzimidazol‐2‐yl]quinoline (L), obtained by condensation of 2‐(1H‐benzimidazol‐2‐yl)quinoline and 4‐(chloromethyl)pyridine hydrochloride. Starting from different Co^II salts, two new compounds have been obtained, viz. catena‐poly[[[dinitratocobalt(II)]‐μ‐2‐[1‐(pyridin‐4‐ylmethyl)‐1H‐benzimidazol‐2‐yl]quinoline] dichloromethane monosolvate acetonitrile monosolvate], {[Co(NO₃)₂(C₂₂H₁₆N₄)]·CH₂Cl₂·CH₃CN}_n, (I) and catena‐poly[[[dichloridocobalt(II)]‐μ‐2‐[1‐(pyridin‐4‐ylmethyl)‐1H‐benzimidazol‐2‐yl]quinoline] methanol disolvate], {[CoCl₂(C₂₂H₁₆N₄)]·2CH₃OH}_n, (II). In (I), the Co^II centres lie in a distorted octahedral [CoN₃O₃] coordination environment. {Co(NO₃)₂L}_n units form one‐dimensional helical chains, where the L ligand has different directions of twist. The helical chains stack together via interchain π–π interactions to form a two‐dimensional sheet, and another type of π–π interaction further connects neighbouring sheets into a three‐dimensional framework with hexagonal channels, in which the acetonitrile molecules and disordered dichloromethane molecules are located. In (II), the Co^II centres lie in a distorted trigonal–bipyramidal [CoCl₂N₃] coordination environment. {CoCl₂L}_n units form one‐dimensional chains. The chains interact via C—H...π and C—H...Cl interactions. The result is that two‐dimensional sheets are generated, which are further linked into a three‐dimensional framework via interlayer C—H...Cl interactions. When viewed down the crystallographic b axis, the methanol solvent molecules are located in an orderly manner in wave‐like channels.     

Poly[[{μ4‐3‐[(1H‐1,2,4‐triazol‐1‐yl)methyl]benzoato}zinc(II)] hemihydrate]: a novel two‐dimensional framework formed by self‐association of zinc(II) sulfate with 3‐[(1H‐1,2,4‐triazol‐1‐yl)methyl]benzoic acid

The title novel two‐dimensional coordination polymer, {[Zn₂(C₁₀H₈N₃O₂)₄]·H₂O}_n, features a {Zn₂L₂} bimetallic ring repeat unit {L is the 3‐[(1H‐1,2,4‐triazol‐1‐yl)methyl]benzoate ligand}. Each Zn^II cation of the bimetallic ring is further bonded to two other L ligands, resulting in a novel infinite two‐dimensional network structure with two channels of different sizes. The crystallographically unique Zn^II atom is thus six‐coordinated in a distorted octahedral environment of four carboxylate O atoms and two triazole N atoms. Two of these networks interpenetrate in an orthogonal arrangement to form the full three‐dimensional framework, with disordered water molecules located in the channels.     

Synthesis of 4‐(1‐phenyl‐1H‐pyrazol‐3‐yl)‐[1,2,4]triazolo[4,3‐a]quinoxalines and their 4‐halogenopyrazolyl analogs

Synthesis of {3‐[1‐(ethoxycarbonyl)‐[1,2,4]triazolo[4,3‐a]quinoxalin‐4‐yl]‐1‐phenyl‐1H‐pyrazol‐5‐yl}methyl ethyl oxalate ( 2 ), ethyl 4‐[5‐(acetoxymethyl)‐1‐phenyl‐1H‐pyrazol‐3‐yl]‐[1,2,4]triazolo[4,3‐a]quioxaline‐1‐carboxylate ( 4 ), [4‐halo‐1‐phenyl‐3‐(1‐phenyl‐[1,2,4]triazolo[4,3‐a]quioxalin‐4‐yl)‐1H‐pyrazol‐5‐yl]methyl acetate ( 11 ), {4‐halo‐3‐[1‐methyl‐[1,2,4]triazolo[4,3‐a]quinoxalin‐4‐yl]‐1‐phenyl‐1H‐pyraz‐ol‐5‐yl}methyl acetate ( 13 ), and [3‐([1,2,4]triazolo‐[4,3‐a]quinoxalin‐4‐yl)‐4‐halo‐1‐phenyl‐1H‐pyrazol‐5‐yl] methyl formate ( 15 ) was accomplished. The structural investigation of the new compounds is based on chemical and spectroscopic evidences. J. Heterocyclic Chem., (2011)