Anion‐directed Silver(I) Coordination Assemblies Based on 1‐(2‐Pyridyl)‐2‐(4‐pyridyl)‐1,2,4‐triazolewith Diverse Supramolecular Networks and Dichromate Removal Capabilities

A series of silver(I) supramolecular complexes, namely, {[Ag(L²⁴)](NO₃)}_n ( 1 ), [Ag₂(L²⁴)(NO₂)₂]_n ( 2 ), and {[Ag_1.25(L²⁴)(DMF)](PF₆)_1.25}_n ( 3 ) were prepared by the reactions of 1‐(2‐pyridyl)‐2‐(4‐pyridyl)‐1,2,4‐triazole (L²⁴) and silver(I) salts with different anions (AgNO₃, AgNO₂, AgPF₆). Single‐crystal X‐ray diffraction indicates that 1 – 3 display diverse supramolecular networks. The structure of dinuclear complex 1 is composed of a six‐membered Ag₂N₄ ring with the Ag ··· Ag distance of 4.4137(3) Å. In complex 2 , the adjacent Ag^I centers are interlinked by L²⁴ ligands into a 1D chain, the adjacent of which are further extended by the bridged nitrites to construct a 2D coordination architecture. Complex 3 shows a 3D (3,4)‐connected framework, which is generated by the linkage of L²⁴ ligands. All complexes were characterized by IR spectra, elemental analysis, and powder X‐ray diffraction. Notably, a structural comparison of the complexes demonstrates that their structures are predominated by the nature of anions. Additionally, 1 and 2 show efficient dichromate (Cr₂O₇^2–) capture in water system, which can be ascribed to the anion‐exchange.     

Synthesis,Crystal Structures,and Properties of Copper(II), Zinc(II), and Cadmium(II) Coordination Polymers Based on 5‐Nitro‐isophthalate and 1,2‐(2‐Pyridyl)‐1,2,4‐triazole

Three coordination polymers, namely {[Cu(5‐nipa)(L²²)](H₂O)₂}_n ( 1 ), [Zn(5‐nipa)(L²²)(H₂O)]_n ( 2 ), and {[Cd₂(5‐nipa)₂(L²²)(H₂O)₃](H₂O)_3.6}_n ( 3 ), were prepared under similar synthetic method based on 1,2‐(2‐pyridyl)‐1,2,4‐triazole (L²²) and ancillary ligand 5‐nitro‐isophthalic acid (5‐H₂nipa) with Cu^II, Zn^II, and Cd^II perchlorate, respectively. All the complexes were characterized by IR spectroscopy, elemental analysis, and powder X‐ray diffraction (PXRD) patterns. Single‐crystal X‐ray diffraction indicates that complexes 1 and 2 show similar 1D chain structures, whereas complex 3 exhibits the 2D coordination network with hcb topology. The central metal atoms show distinct coordination arrangements ranging from distorted square‐pyramid for Cu^II in 1 , octahedron for Zn^II in 2 , to pentagonal‐bipyramid for Cd^II in 3 . The L²² ligand adopts the same (η³,μ₂) coordination fashion in complexes 1 – 3 , while the carboxyl groups of co‐ligand 5‐nipa^2– adopt monodentate fashion in 1 and 2 and bidentate chelating mode in 3 . These results indicate that the choice of metal ions exerts a significant influence on governing the target complexes. Furthermore, thermal stabilities of complexes 1 – 3 and photoluminescent properties of 2 and 3 were also studied in the solid state.     

Synthesis,Crystal Structure and Photoluminescence Property of Zinc(II), Cadmium(II), and Lead(II) Complexes with Bidentate Ligand: 1‐(1‐Imidazolyl)‐4‐(imidazol‐1‐ylmethyl)benzene (IIMB)

Assembly of bidentate ligand 1‐(1‐imidazolyl)‐4‐(imidazol‐1‐ylmethyl)benzene (IIMB) with varied metal salts of Zn^II, Cd^II and Pb^II provide three new complexes, [Zn(IIMB)₂](ClO₄)₂·2H₂O ( 1 ), [Cd(IIMB)₂(SCN)₂] ( 2 ) and [Pb(IIMB)₂(SCN)](SCN) ( 3 ). Single crystal X‐ray diffraction studies revealed that complexes 1 and 2 display a similar one‐dimensional double stranded chain structure, while complex 3 is a slight distorted rhombohedral grid network with (4,4) topology. The results indicate that the coordination geometry of the metal ion and the counter anion have great impact on the structure of the complexes. In addition, the photoluminescence properties of ligand IIMB and complexes 1 – 3 were studied in the solid state at room temperature.     

Synthesis,structural characterization and cytotoxic activity of diorganotin(IV) complexes of N‐(5‐halosalicylidene)tryptophane

Four new diorganotin(IV) complexes of N‐(5‐halosalicylidene)tryptophane, R₂Sn[5‐X‐2‐OC₆H₃CH?NCH(CH₂Ind)COO] [Ind = 3‐indolyl; R, X = Et, Cl ( 1 ); Et, Br( 2 ); n‐Bu, Cl ( 3 ); n‐Bu, Br ( 4 )], were synthesized and characterized by elemental analysis, IR and NMR (¹H, ¹³C and ¹¹⁹Sn) spectra. The crystal structures of complexes 1 – 3 were determined by X‐ray single crystal diffraction and showed that the tin atoms are in a distorted trigonal bipyramidal geometry and form five‐ and six‐membered chelate rings with the tridentate ligand. Intermolecular weak interactions in 1–3 link molecules, respectively, into a two‐dimensional array, a one‐dimensional infinite chain and a one‐dimensional double‐chain supramolecular structure. Bioassay results of the compounds indicated that the dibutyltin complexes 3 and 4 have potent in vitro cytotoxic activity against two human tumor cell lines, CoLo205 and Bcap37, while the diethyltin complexes 1 and 2 display weak cytotoxic activity. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis,Characterization, and Crystal Structure of Three Coordination Polymers from 5‐(Pyridin‐2‐ylmethyl)aminoisophthalic Acid

Three new complexes: [M(L)(H₂O)] [M = Zn ( 1 ), Co ( 2 ), Ni ( 3 ); H₂L = 5‐(pyridin‐2‐ylmethyl)aminoisophthalic acid] were synthesized under hydrothermal conditions at 180 °C and were characterized by elemental analysis, FT‐IR spectroscopy, single‐crystal X‐ray diffraction, and thermogravimetric analysis (TGA). The results of X‐ray diffraction analysis reveal that complexes 1 – 3 are isostructural and crystallize in the monoclinic system with space group P2₁/c. Each of the complexes displays a (3,3′)‐connected two‐dimensional (2D) wave‐like network with (4,8²) topology, within which five‐membered uncoplanar N,N‐chelated metallacycles are shaped. Delicate N–H ··· O and O–H ··· O hydrogen bonding interactions exist in complexes 1 – 3 . Adjacent 2D layers are linked by intermolecular interactions, resulting in the construction of extended metal‐organic frameworks (MOFs) in complexes 1 and 2 .     

Homoleptic Zinc(II) Complexes Based on 4′‐(2‐Thienyl)‐terpyridine: Preparation,Structures, and Properties

The homoleptic complexes Zn^II(4′‐(2‐(5‐R‐thienyl))‐terpyridine)₂(ClO₄)₂ [R = hydrogen ( 1 ), bromo ( 2 ), methyl ( 3 ), and methoxy ( 4 )] were prepared. Their structures were determined by single‐crystal X‐ray diffraction analyses, and further characterized by high resolution mass, infrared spectra (IR), and elemental analyses. Single crystal X‐ray diffraction analysis showed that Zn^II ions in the complexes are both six‐coordinate with N₆ coordination sphere, displaying distorted octahedral arrangements. The absorption and emission spectra of the homoleptic Zn^II complexes were investigated and compared to those of the parent complex Zn^II(4′‐(2‐thienyl))‐terpyridine)₂(ClO₄)₂. The UV/Vis absorption spectra showed that the complexes all exhibit strong absorption component in UV region, moreover, complex 4 has an absorption component in the visible region. Thus, the photocatalytic activities of the complexes in degradation of organic dyes were investigated under UV and visible irradiation.     

Synthesis,crystal structures and luminescence properties of seven mononuclear zinc(II), cadmium(II), cobalt(II) and nickel(II) complexes with 5‐(4‐methylphenyl)‐3‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazole

Due to their versatile coordination modes and metal‐binding conformations, triazolyl ligands can provide a wide range of possibilities for the construction of supramolecular structures. Seven mononuclear transition metal complexes with different structural forms, namely aquabis[3‐(4‐methylphenyl)‐5‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazolato‐κ²N ¹,N ⁵]zinc(II), [Zn(C₁₄H₁₁N₄)₂(H₂O)], (I), bis[5‐(4‐methylphenyl)‐3‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazole‐κ²N ³,N ⁴]bis(nitrato‐κO )zinc(II), [Zn(NO₃)₂(C₁₄H₁₂N₄)₂], (II), bis(methanol‐κO )bis[3‐(4‐methylphenyl)‐5‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazolato‐κ²N ¹,N ⁵]zinc(II), [Zn(C₁₄H₁₁N₄)₂(CH₄O)₂], (III), diiodidobis[5‐(4‐methylphenyl)‐3‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazole‐κ²N ³,N ⁴]cadmium(II), [CdI₂(C₁₄H₁₂N₄)₂], (IV), bis[5‐(4‐methylphenyl)‐3‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazole‐κ²N ³,N ⁴]bis(nitrato‐κO )cadmium(II), [Cd(NO₃)₂(C₁₄H₁₂N₄)₂], (V), aquabis[3‐(4‐methylphenyl)‐5‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazolato‐κ²N ¹,N ⁵]cobalt(II), [Co(C₁₄H₁₁N₄)₂(H₂O)], (VI), and diaquabis[3‐(4‐methylphenyl)‐5‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazolato‐κ²N ¹,N ⁵]nickel(II), [Ni(C₁₄H₁₁N₄)₂(H₂O)₂], (VII), have been prepared by the reaction of transition metal salts (Zn^II, Cd^II, Co^II and Ni^II) with 3‐(4‐methylphenyl)‐5‐(pyridin‐2‐yl)‐1H‐1,2,4‐triazole (pymphtzH) under either ambient or hydrothermal conditions. These compounds have been characterized by elemental analysis, IR spectroscopy and single‐crystal X‐ray diffraction. All the complexes form three‐dimensional supramolecular structures through hydrogen bonds or through π–π stacking interactions between the centroids of the pyridyl or arene rings. The pymphtzH and pymphtz⁻ entities act as bidentate coordinating ligands in each structure. Moreover, all the pyridyl N atoms are coordinated to metal atoms (Zn, Cd, Co or Ni). The N atom in the 4‐position of the triazole group is coordinated to the Zn and Cd atoms in the crystal structures of (II), (IV) and (V), while the N atom in the 1‐position of the triazolate group is coordinated to the Zn, Co and Ni atoms in (I), (III), (VI) and (VII).     

Syntheses,Structures, and Luminescence of Metal(II) Coordination Polymers based on Flexible 1,1′‐(1,4‐Butanediyl)bis(imidazole) and Tetrachlorobenzene‐1,4‐dicarboxylate Ligands

The coordination polymers, {[Co(bbim)₂(H₂O)₂](tcbdc) · 2H₂O}_n ( 1 ), {[Ni(tcbdc)(bbim)(H₂O)₂] · 2DMF}_n ( 2 ), and {[Cu₂(tcbdc)₂(bbim)₄] · 4H₂O}_n ( 3 ) [bbim = 1,1′‐(1,4‐butanediyl)bis(imidazole) and tcbdc^2– = tetrachlorobenzene‐1,4‐dicarboxylate] were synthesized and characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, luminescence, and single‐crystal X‐ray diffraction analysis. Complex 1 has a double‐stranded chain structure through doubly bridged [Co(bbim)₂] units. Complex 2 exhibits two‐dimensional square grid, whereas complex 3 has a three‐dimensional porous network structure with an unprecedented 4⁴ · 6¹¹ topological structure through interpenetrating square grid. The water molecules in complex 3 occupy the vacancy through three kinds of hydrogen bond interactions. Upon excitation at 370 nm, complexes 1 – 3 present solid‐state luminescence at room temperature.     

Rhodium(I) and Silver(I) Complexes of 4, 5‐Dicyano‐1, 3‐dimesityl‐ and 4, 5‐Dicyano‐1, 3‐dineopentylimidazol‐2‐ylidene

The new N‐heterocyclic carbene (NHC) precursors 4, ‐dicyano‐1, ‐dimesityl‐ ( 9 ) and 4, 5‐dicyano‐1, 3‐dineopentyl‐2‐(pentafluorophenyl)imidazoline ( 14 ) were synthesized. The structure of 9 could be determined by X‐ray crystallography. With the 2‐pentafluorophenyl‐substituted imidazolines 9 and 14 , the [AgCl(NHC)], [RhCl(COD)(NHC)], and [RhCl(CO)₂(NHC)] complexes [NHC = 4, 5‐dicyano‐1, 3‐dimesitylimidazol‐2‐ylidene ( 3 ) and 4, 5‐dicyano‐1, 3‐dineopentylimidazol‐2‐ylidene ( 4 )] were obtained. Crystal structures of [AgCl( 3 )] ( 15 ), [RhCl(COD)( 3 )] ( 17 ), [RhCl(COD)( 4 )] ( 18 ), and [RhCl(CO)₂( 3 )] ( 19 ) were solved and with the crystal data of 19 , the percent buried volume ( %V_bur) of 31.8(±0.1) % was determined for NHC 3 . Infrared spectra of the imidazolines 9 and 14 and of the complexes 15 – 20 were recorded and the CO stretching frequencies of complexes 19 and 20 were used to determine the Tolman electronic parameters of the newly obtained NHCs 3 (TEP: 2060 cm^–1) and 4 (TEP: 2061 cm^–1), thus proving that 1, 3‐substitution of maleonitrile‐NHCs does not have a significant effect for the high π‐acceptor strength of these carbenes.     

Structure and cytotoxicity of zinc (II) and cobalt (II) complexes based on 1,3,5‐tris(1‐imidazolyl) benzene

Three novel complexes, [Zn (tib)₂·(H₂O)₂]·(NO₃)₂ ( 1 ), [Co (tib)₂]·2NO₃ ( 2 ) and [Co₂(tib)₂(btc)]·H₂O ( 3 ) [H₄btc = 1,2,4,5‐benzenetetracarboxylic acid; H₂tib = 1,3,5‐tris(1‐imidazolyl)benzene], were synthesized and characterized by single‐crystal X‐ray, IR and elemental analysis. The interaction of these complexes with FS‐DNA (fish sperm DNA) was monitored, and binding constants were determined using UV/Vis, which revealed that they have the ability to bind to FS‐DNA. DNA‐binding constants (K) for the three complexes were 2.2 × 10⁴ m ^?1, 0.7 × 10⁴ m ^?1 and 0.09 × 10⁴ m ^?1, respectively. The interaction capacity of the complexes with FS‐DNA has been investigated by fluorescence spectroscopy. Stern–Volmer quenching plot values for complexes 1 , 2 and 3 were 0.3784, 0.1028 and 0.076, respectively. The viscosity measurement suggested that complexes 1 , 2 and 3 interact with DNA in an intercalation mode. In addition, anti‐cancer activities of these complexes investigated through MTT assays in vitro indicated that the complexes showed good cytotoxic activity against cancer cell lines. Cytotoxic activity of test complexes against two different cancer cell lines (HeLa and KB cells) showed significant cancer cell inhibition rates. Flow cytometry experiments and morphological apoptosis studies showed that the complexes induced apoptosis of HeLa tumor cell lines. Finally, a further molecular docking technique was employed to confirm the binding of the complexes toward the molecular target DNA.     

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.     

Novel Approach for Rapid and Efficient Synthesis of 2‐(3‐(4‐Aryl)‐1‐isonicotinoyl‐4,5‐dihydro‐1H‐pyrazol‐4‐yl)‐3‐phenylthiazolidin‐4‐one Derivatives and Screened Their Antimicrobial Activity

A series of compounds, viz. 2‐(3‐(4‐aryl)‐1‐isonicotinoyl‐4,5‐dihydro‐1H‐pyrazol‐4‐yl)‐3‐phenylthiazolidin‐4‐one 4 ( a – n ), have been synthesized by reaction of 3 ( a – n ) with thioglycolic acid in the presence of zinc chloride. Compounds 3 ( a – n ) have been synthesized by amination of formylated pyrazoles 2 ( A – B ), which were synthesized by formylation of 1 ( A – B ) by Vilsmeier–Haack reagent (POCl₃/DMF). Compounds 1 ( A – B ) were synthesized by condensation of hydrazide and substituted acetophenones under conventional method and microwave irradiation method. These compounds were identified on the basis of melting point range, Rf values, infrared, ¹H NMR, and mass spectral analysis. These compounds were evaluated for their in vitro antimicrobial activity, and their minimum inhibitory concentration was determined. Among them, compound 4b and compound 4l possess appreciable antimicrobial and antifungal activities. Antibacterial activity results showed that compounds containing electron‐withdrawing groups were more active than compounds containing electron‐releasing groups.     

Synthesis,Crystal Structure,and Spectral Properties of Two Manganese(II) and Zinc(II) Complexes with 3,4‐Dimethyl‐5‐(2‐pyridyl)‐1,2,4‐triazole

Two complexes, cis‐[MnL₂(NCS)₂] ( 1 ) and cis‐[ZnL₂(NCS)₂] ( 2 ) with asymmetrical substituted triazole ligands [L = 3,4‐dimethyl‐5‐(2‐pyridyl)‐1,2,4‐triazole], were synthesized and characterized by elemental analysis, UV/Vis and FT‐IR spectroscopy as well as thermogravimetric analyses (TGA), powder XRD, and single‐crystal X‐ray diffraction. In the complexes, each L molecule adopts a chelating bidentate mode by the nitrogen atoms of pyridyl and triazole. Both complexes have a similar distorted octahedral [MN₆] core (M = Mn²⁺ and Zn²⁺) with two NCS^– ions in the cis position.     

(Azido‐κN)bis­(di‐2‐pyridylamine)­copper(II) hexa­fluoro­phosphate and (azido‐κN)bis­(di‐2‐pyridylamine)­copper(II) chloride tetra­hydrate

The two new title complexes, [Cu(N₃)(dpyam)₂]PF₆ (dpyam is di‐2‐pyridylamine, C₁₀H₁₁N₃), (I), and [Cu(N₃)(dpyam)₂]Cl·4H₂O, (II), respectively, have been characterized by single‐crystal X‐ray diffraction. Both complexes display a distorted square‐pyramidal geometry. Each Cu atom is coordinated in the basal plane by three dpyam N atoms and one azide N atom in equatorial positions, and by another N atom from the dpyam group in the apical position. In complex (I), the one‐dimensional supra­molecular architecture is assembled via hydrogen‐bonding inter­actions between the amine N atom and terminal azide N atoms and the F atoms of the PF₆⁻ anion. For complex (II), hydrogen‐bonding inter­actions between the amine N atom, the Cl⁻ anion and water O atoms result in a two‐dimensional lattice.     

Synthesis and structures of photoactive manganese–carbonyl complexes derived from 2‐(pyridin‐2‐yl)‐1,3‐benzothiazole and 2‐(quinolin‐2‐yl)‐1,3‐benzothiazole

PhotoCORMs (photo‐active CO‐releasing molecules) have emerged as a class of CO donors where the CO release process can be triggered upon illumination with light of appropriate wavelength. We have recently reported an Mn‐based photoCORM, namely [MnBr(pbt)(CO)₃] [pbt is 2‐(pyridin‐2‐yl)‐1,3‐benzothiazole], where the CO release event can be tracked within cellular milieu by virtue of the emergence of strong blue fluorescence. In pursuit of developing more such trackable photoCORMs, we report herein the syntheses and structural characterization of two Mn^I–carbonyl complexes, namely fac‐tricarbonylchlorido[2‐(pyridin‐2‐yl)‐1,3‐benzothiazole‐κ²N ,N ′]manganese(I), [MnCl(C₁₂H₈N₂S)(CO)₃], (1), and fac‐tricarbonylchlorido[2‐(quinolin‐2‐yl)‐1,3‐benzothiazole‐κ²N ,N ′]manganese(I), [MnCl(C₁₆H₁₀N₂S)(CO)₃], (2). In both complexes, the Mn^I center resides in a distorted octahedral coordination environment. Weak intermolecular C—H…Cl contacts in complex (1) and Cl…S contacts in complex (2) consolidate their extended structures. These complexes also exhibit CO release upon exposure to low‐power broadband visible light. The apparent CO release rates for the two complexes have been measured to compare their CO donating capacity. The fluorogenic 2‐(pyridin‐2‐yl)‐1,3‐benzothiazole and 2‐(quinolin‐2‐yl)‐1,3‐benzothiazole ligands provide a convenient way to track the CO release event through the `turn‐ON' fluorescence which results upon de‐ligation of the ligands from their respective metal centers following CO photorelease.     

Synthesis and Structure of a Series of New Molybdenum(VI) Complexes with the Esters of 2‐Mercaptonicotinic Acid

The novel dioxomolybdenum(VI) complexes with methyl ( 1 ), ethyl ( 2 ), n‐propyl ( 3 ), i‐propyl ( 4 ), n‐butyl ( 5 ) and cyclohexyl ( 6 ) ester of 2‐mercaptonicotinic acid have been prepared in the reactions of MoO₂Cl₂ and MoO₂(acac)₂ (acac = 2,4‐pentandionate) with mercaptonicotinic acid in corresponding alcohol. The esterification reaction was catalyzed by Mo^V originated from the reduction of Mo^VI with mercaptonicotinic ‐SH group with simultaneous formation of S–S bond resulting from the condensation of two 2‐mercaptonicotinic molecules. The presence of Mo^V was proved by ESR spectra. The molecular and crystal structures of 1 , 2 , 3 and 4 as well as of the by‐products 1,1′‐dithio‐2,2′‐n‐butylnicotinoate ( 7 ) and tetramethylammonium hexachloromolybdate(V) ( 8 ) have been determined by a X‐ray single crystal diffraction. The complexes 1 – 4 contain MoO₂²⁺ core with octahedral coordination of each molybdenum atom complexed by two 2‐mercaptonicotinato N and S donor atoms.     

Synthesis,structure and property of diorganotin N‐[(3‐methoxy‐2‐oxyphenyl)methylene]tyrosinates

Five new diorganotin N‐[(3‐methoxy‐2‐oxyphenyl)methylene] tyrosinates, R₂Sn[2‐O‐3‐MeOC₆H₃CH=NCH (CH₂C₆H₄OH‐4)COO] (R = Me, 1 ; Et, 2 ; Bu, 3 ; Cy, 4 ; Ph, 5 ), have been synthesized and characterized by elemental analysis, IR, NMR (¹H, ¹³C and ¹¹⁹Sn) spectra, and the X‐ray single crystal diffraction. In non‐coordinated solvent, complexes 1 – 5 have penta‐coordinated tin atom. In the solid state, 1 – 3 are centrosymmetric dimmers in which each tin atom is seven‐coordinated in a distorted pentagonal bipyramid, and 4 displays discrete molecular structure with distorted trigonal bipyramidal geometry, and the tin atom of 5 is hexa‐coordinated and possess the distorted octahedral geometry with a coordinational methanol molecule. The intermolecular O‐H???O hydrogen bonds in 1 – 4 link molecules into the different one‐dimensional supramolecular chain with R₂² (30) or R₂² (20) macrocycles, and the molecules of 5 are joined into a two‐dimensional supramolecular network containing R₄⁴ (24) and R₄⁴ (28) two macrocycles. Bioassay results against human tumour cell HeLa indicated that 3 ‐ 5 belonged to the efficient cytostatic agents and the activity decreased in the order 4 > 3 > 5 > 2 > 1. The fluorescence determinations show the complexes may be explored for potential luminescent materials.     

Pseudohalide‐directed Assembly of Two Zinc(II) Coordination Polymers with a 3,4‐Bis(3‐pyridyl)‐5‐(4‐pyridyl)‐1,2,4‐triazole Tecton

The zinc(II) pseudohalide complexes {[Zn(L³³⁴)(SCN)₂(H₂O)](H₂O)₂}_n ( 1 ) and [Zn(L³³⁴)(dca)₂]_n ( 2 ) were synthesized and characterized using the ligand 3,4‐bis(3‐pyridyl)‐5‐(4‐pyridyl)‐1,2,4‐triazole (L³³⁴) and ZnCl₂ in presence of thiocyanate (SCN^–) and dicynamide [dca, N(CN)₂^–] respectively. Single‐crystal X‐ray structural analysis revealed that the central Zn^II atoms in both complexes have similar octahedral arrangement. Compound 1 has a 2D sheet structure bridged by bidentate L³³⁴ and double μ_N,S‐thiocyanate anions, whereas complex 2 , incorporating with two monodentate dicynamide anions, displays a two‐dimensional coordination framework bridged by tetradentate L³³⁴ ligand. Structural analysis demonstrated that the influence of pseudohalide anions plays an important role in determining the resultant structure. Both complexes were characterized by IR spectroscopy, microanalysis, and powder X‐ray diffraction techniques. In addition, the solid fluorescence and thermal stability properties of both complexes were investigated.     

(Z)‐3‐(1H‐Indol‐3‐yl)‐2‐(3‐thienyl)­acrylo­nitrile and (Z)‐3‐[1‐(4‐tert‐butyl­benzyl)‐1H‐indol‐3‐yl]‐2‐(3‐thienyl)­acrylo­nitrile

(Z)‐3‐(1H‐Indol‐3‐yl)‐2‐(3‐thienyl)­acrylo­nitrile, C₁₅H₁₀N₂S, (I), and (Z)‐3‐[1‐(4‐tert‐butyl­benzyl)‐1H‐indol‐3‐yl]‐2‐(3‐thienyl)­acrylo­nitrile, C₂₆H₂₄N₂S, (II), were prepared by base‐catalyzed reactions of the corresponding indole‐3‐carbox­aldehyde with thio­phene‐3‐aceto­nitrile. ¹H/¹³C NMR spectral data and X‐ray crystal structures of compounds (I) and (II) are presented. The olefinic bond connecting the indole and thio­phene moieties has Z geometry in both cases, and the mol­ecules crystallize in space groups P2₁/c and C2/c for (I) and (II), respectively. Slight thienyl ring‐flip disorder (ca 5.6%) was observed and modeled for (I).     

Mononuclear Co(III), Ni(II) and Cu(II) complexes of 2‐(2,4‐dichlorobenzamido)‐N'‐(3,5‐di‐tert‐butyl‐2‐hydroxybenzylidene)benzohydrazide: Structural insight and biological assay

A series of mononuclear metal complexes of Co(III), Ni(II) and Cu(II) with 2‐(2,4‐dichlorobenzamido)‐N′‐(3,5‐di‐tert‐butyl‐2‐hydroxybenzylidene)benzohydrazide ( LH ₃ ) have been synthesized and characterized using various physico‐chemical, spectroscopic and single crystal X‐ray diffraction techniques. Structural studies of [Co( LH )( LH ₂ )]·H₂O ( 4 ) revealed the presence of both amido and imidol tautomeric forms of LH ₃ , resulting in a distorted octahedral geometry around the Co(III) ion. [Ni( LH )(H₂O)]·H₂O ( 5 ) and [Cu( LH )(H₂O)]·H₂O ( 6 ) are isomorphous structures and crystallize in the monoclinic P2₁/c space group. The crystal structures of 4 , 5 and 6 are stabilized by hydrogen bonds formed by the enclathrated water molecules, C‐H···π and π···π interactions. Complexes along with the ligand ( LH ₃ ) were screened for their in vivo anti‐inflammatory activity (carrageenan‐induced rat paw edema method) and in vitro antioxidant activity (DPPH free radical scavenging assay). Metal complexes have shown significant anti‐inflammatory and antioxidant potential.