Nanoparticles and nanocrystals of a new bidentate nickel(II) complex of N-[ethyl(propan-2-yl)carbamothioyl]-4-nitrobenzamide: synthesis,characterization, and crystal structures

The nickel(II) complex of N-[ethyl(propan-2-yl)carbamothioyl]-4-nitrobenzamide has been synthesized and characterized by Fourier transform-infrared spectroscopy, elemental analysis, nuclear magnetic resonance spectroscopy, and mass spectrometry (atmospheric pressure chemical ionization mass spectrometry). The single-crystal X-ray structures of N-[ethyl(propan-2-yl)carbamothioyl]-4-nitrobenzamide (1) and bis[N-[ethyl(propan-2-yl)carbamothioyl]-4-nitrobenzamide]nickel(II) (2) have been determined from single-crystal X-ray diffraction data. Loss of the N–H proton resonance and the N–H stretching vibration and the shift of the ν_C=O and ν_C=S stretching vibrations confirm formation of the metal complex. These studies show that the metal complex is neutral in cis-configuration. The complex has been used as a single-source precursor for the deposition of nickel sulfide nanocrystals by thermolysis. The nickel sulfide nanocrystals were characterized by X-ray powder diffraction and transmission electron microscopy.     

A new 2-D cobalt coordination polymer with the flexible 2-(1H-imidazole-1-yl)acetate: synthesis,structure, and characterization

A new cobalt coordination polymer with linking unit 2-(1H-imidazole-1-yl)acetate (ima), [Co(ima)₂] _n (1), has been synthesized and structurally characterized by elemental analysis, IR spectra, and X-ray single-crystal diffraction. The X-ray analysis indicates that a neutral 2-D coordination polymer with (3,6) topology was obtained, which shows a 3-D supramolecular network through C–H···O weak interactions. Complex 1 displays mild antimicrobial activity against Achromobacter xylosoxidans ATCC 2706, Bacillus subtilis ATCC 6633, and Candida albicans ATCC 90028, respectively. The magnetic and thermal gravimetric properties for 1 have been investigated and discussed.     

Syntheses,crystal structures,and DNA-binding properties of two nickel(II) complexes with 1,3-bis(benzimidazol-2-yl)-2-oxapropane derivatives

[Ni(obb)(DMF)₂(H₂O)]·(Pic)₂·0.5DMF (1) and [Ni(Etobb)₂]·(Pic)₂·2DMF (2) (obb = 1,3-bis(benzimidazol-2-yl)-2-oxapropane, Etobb = 1,3-bis(1-ethylbenzimidazol-2-yl)-2-oxapropane, Pic = picrate) have been synthesized and characterized by physicochemical and spectroscopic methods. The structures of both complexes have been determined by X-ray single-crystal diffraction. The coordination geometries of 1 and 2 can be described as distorted octahedra. The interaction of the nickel(II) complexes with calf thymus DNA was investigated by electronic absorption, fluorescence spectroscopy, and viscosity measurements. The experimental results suggest that 1 and 2 bind to DNA in an intercalation mode, and their binding affinity for DNA follows the order 1 > 2. DNA-binding behaviors can be attributed to the large coplanar aromatic rings in the V-shaped ligand and steric hindrance.     

Ruthenium-Assisted Tellurium Abstraction in Bis(thiophen-2-yl) Ditelluride

The reaction of [RuCl₂(CO)₃]₂ and Te₂Tpn₂ (Tpn=thiophen-2-yl, C₄H₃S) in the absence of light resulted in the formation of cct-[RuCl₂(CO)₂(TeTpn₂)₂] ( 1 ) [cis(Cl)-cis(CO)-trans(TeTpn₂)] and TeTpn₂ ( 2 ) together with the precipitation of tellurium. The complex 1 and the monotelluride 2 were characterized by NMR spectroscopy and single-crystal X-ray diffraction. The decomposition of Te₂Tpn₂ to TeTpn₂ has been monitored by ¹²⁵Te NMR spectroscopy and seemed to be faster than the ligand substitution in [RuCl₂(CO)₃]₂ by TeTpn₂. A catalytic cycle is proposed for the decomposition of Te₂Tpn₂ to TeTpn₂ based on the PBE0-D3/def2-TZVP calculations.     

A twofold interpenetrated 3-D Cu(II) coordination polymer based on 5-(pyridin-4-yl)isophthalic acid: synthesis,crystal structure,and magnetic properties

A new copper(II) coordination polymer, [Cu(PIA)·2H₂O]_n (1) [H₂PIA = 5-(pyridin-4-yl)isophthalic acid], has been synthesized and characterized by elemental analysis, IR spectroscopy, TGA, powder, and single-crystal X-ray diffraction. Structural analysis shows that each PIA^2? in 1 bridges three Cu(II) ions, and likewise each Cu(II) ion connects to three PIA^2? ligands, giving a 3-D framework with utp topology and left-/right-handed helical channels. Interestingly, two such identical frameworks interlock with each other to generate a twofold interpenetrated structure that is stabilized by hydrogen bonding and π–π interactions. In addition, the thermal stability and the magnetic properties of 1 have been investigated.     

3-(噻吩-2-基)-β-内酰胺的合成及其立体化学

Staudinger 反应是合成β-内酰胺类化合物最重要的方法之一. 3-(噻吩-2-基)-β-内酰胺是一类重要的β-内酰胺类衍生物. 发展了一种从1-(噻吩-2-基)-4,4,4-三氟-1,3-丁二酮和对甲苯磺酰叠氮方便地制备1-(噻吩-2-基)-2-重氮基乙酮的新方法, 利用1-(噻吩-2-基)-2-重氮基乙酮加热分解生成的噻吩-2-基烯酮参与的Staudinger反应合成了一系列3-(噻 吩-2-基)-β-内酰胺衍生物, 并研究了噻吩-2-基烯酮参与的Staudinger反应的立体选择性. 实验结果表明噻吩-2-基烯酮是比苯基烯酮更富电子的Moore烯酮, 其电子性质介于对甲氧基苯基烯酮和对甲基苯基烯酮之间.     

Synthesis,properties, and X-ray crystal structures of two Ag(I) complexes with 2-(pyridin-4-yl)-1H-imidazole-4,5-dicarboxylic acid

Two 1-D and 3-D Ag(I) complexes involving 2-(pyridin-4-yl)-1H-imidazole-4,5-dicarboxylic acid (H₃PIDC) have been characterized by infrared spectrum, elemental analysis, and single-crystal X-ray diffraction. [Ag₂(HPIDC)]_n (1), synthesized under hydrothermal conditions, gave a 3-D framework; [Ag₂(HPIDC)(MBI)]_n (2) (MBI?=?2-methyl-1H-benzo[d]imidazole), with MBI as the second ligand, gave a 1-D zigzag chain and further formed a 3-D supramolecular structure through π···π interactions. The most interesting structural features of these complexes are the presence of C–H···Ag hydrogen bonding interactions and Ag···C weak interactions between the Ag centers and H₃PIDC. Luminescence indicates that 2 has significantly stronger fluorescent emissions than 1 in the solid state at room temperature.     

A theoretical study on 1-(thiophen-2-yl-methyl)-2-(thiophen-2-yl)-1H-benzimidazole

The molecular geometry and vibrational frequencies of 1-(thiophen-2-yl-methyl)-2-(thiophen-2-yl)-1H-benzimidazole (C(16)H(12)N(2)S(2)) in the ground state has been calculated using the Hartree-Fock (HF) and density functional method (B3LYP) with 6-31G(d) basis set. The optimized geometric bond lengths and bond angles obtained by using HF and DFT (B3LYP) show the best agreement with the experimental data. Comparison of the observed fundamental vibrational frequencies of 1-(thiophen-2-yl-methyl)-2-(thiophen-2-yl)-1H-benzimidazole (C(16)H(12)N(2)S(2)) and calculated results by density functional B3LYP and Hartree-Fock methods indicate that B3LYP is superior to the scaled Hartree-Fock approach for molecular vibrational problems.     

Crystal structure and characterization of two cadmium(II) coordination polymers with a multidentate N-donor tecton 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole

Two new cadmium(II) complexes [Cd_1.5(L)Cl₂(H₂O)]_{2 n} (1) and [CdL₂] _n (2) with a multidentate N-donor building block 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole (HL) have been prepared and characterized by elemental analysis, infra-red spectra, powder X-ray diffraction (XRD), and single-crystal XRD. 1 is a 2-D layered coordination polymer constructed from linkage of [Cd₃(μ-Cl)₄] trinuclear units with HL spacers, while 2 shows a 2-D layer structure. 3-D supramolecular architectures are further assembled in 1 and 2 via hydrogen-bonding contacts. Both 1 and 2 are thermally stable to 450?°C, and 2 showed strong fluorescent emission bands.     

Structure,DNA-binding interaction and antitumour activity of two novel complexes coordinated by tridentate 1,3-bis(benzimidazol-2-yl)-2-oxapropane ligand

Two novel DNA-intercalating complexes, [Cd(hipa)(bbiop)] _n (1) and [Ni(ada)(bbiop)] _n ·2H₂O (2) with hipa, ada and potentially tridentate ligand bbiop (bbiop, 1,3-bis(benzimidazol-2-yl)-2-oxa-propane; hipa, 5-hydroxyisophthalate; ada, aniline-N,N-diacetate), have been synthesised under hydrothermal methods and structurally characterised by single crystal X-ray diffraction analysis, elemental analysis, UV–vis spectrum and fluorescent spectrum. The bbiop ligand exists as chelating-tridentate μ₁-(η₃–N₁, N₂, O₆) coordination fashion. In addition, their in vitro cytotoxicities towards four selected tumour cell lines have been evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. Complex 1 exhibits the most dramatic inhibitory effect on MG-63, and its inhibition rate is higher than that of its free ligands, H₂bbiop and hipa, indicating significantly enhanced effect after forming complex. On the basis of the combination of UV–vis absorption and fluorescence titrations, complex 1 can interact with the base pairs of double-helical DNA via an intercalative mode with intrinsic binding constant, K _b, of 4.62 × 10⁷, presenting the high DNA-binding affinity.     

Synthesis,crystal structures,and DNA-binding studies of two silver(I) complexes with 1,3-bis(1-ethylbenzimidazol-2-yl)-2-thiapropane

Two new silver(I) complexes, [Ag(bebt)(methacrylate)] (1) and [Ag₂(bebt)₂](pic)₂ (2) (bebt = 1,3-bis(1-ethylbenzimidazol-2-yl)-2-thiapropane, pic = picrate), have been synthesized and characterized by physico-chemical and spectroscopic methods. Single-crystal X-ray diffraction revealed that the structure of 1 was four-coordinate in a distorted tetrahedral geometry, while in 2, it may be described as a 2 + 1 coordinated silver(I) compound with a nearly linear N–Ag–N backbone and a weak Ag–S interaction. Two ligands are arranged in a face-to-face syn conformation to coordinate to two Ag(I) ions from opposite directions in 2, generating a U-type double layer structure around the metal ions. Experimental studies of the DNA-binding properties indicated that free bebt and both complexes bind to DNA via intercalation, and the order of the binding affinity is 2 > 1 > bebt.     

Synthesis of novel 5-chloro-2-(thiophen-2-yl)-7,8-dihydroquinoline-6-carboxamides as potent inhibitors of Mycobacterium tuberculosis

A series of novel 5-chloro-2-(thiophen-2-yl)-7,8-dihydroquinoline-6-carboxamides was designed, synthesized, and evaluated for antitubercular activity. The required 5-chloro-2-(thiophen-2-yl)-7,8-dihydroquinoline-6-carboxylic acid intermediate was prepared by oxidizing the respective aldehyde with sodium chlorite and 30% H2O2. Further, the acid was coupled with various aryl, alkyl, and heterocyclic amines using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and hydroxybenzotriazole to give the desired 5-chloro-2-(thiophen-2-yl)-7,8-dihydroquinoline-6-carboxamides in excellent yields. All the new compounds were characterized by their NMR and mass spectral analysis. Screening of all new compounds for in vitro antimycobacterial activity against M. tuberculosis H37Rv (Mtb) resulted in five analogs with MIC 3.12 µg/cm3 as promising antitubercular agents with lower cytotoxicity profiles.     

Hydrothermal syntheses and structures of transition metal 2-(4,5-diphenyl-1H-imidazol-2-yl)benzoic acid complexes

Two new transition metal complexes, [Zn(Hdiba)₂(H₂O)]?·?H₂O (1) and [Cu(Hdiba)₂] (2) (H₂diba?=?2-(4,5-diphenyl-1H-imidazol-2-yl)benzoic acid), were synthesized and characterized by IR, elemental analysis, and single-crystal X-ray diffraction. Complex 1 exhibits a monomeric structure, while 2 displays a dimeric structure. Both structures extend to 2-D supramolecular networks via hydrogen bonds. Thermal stabilities of 1 and 2 and photophysical properties of 1 are also discussed.     

Ethynylation of 2-(furan-2-yl)- and 2-(thiophen-2-yl)pyrroles with acylbromoacetylenes in the Al2O3 medium: relative reactivity of heterocycles

2-(Furan-2-yl)- and 2-(thiophen-2-yl)pyrroles are readily ethynylated with acylbromoacetylenes in the solid Al₂O₃ medium (no solvent, room temperature, 1 h) to afford 5-(furan-2-yl)- and 5-(thiophen-2-yl)-2-acylethynylpyrroles in 39–74% yields. In the case of 2-(furan-2-yl)pyrroles, an alternative ethynylation of the furan ring takes place, the ratio of the furan and pyrrole ring ethynylation products being 1:5–7. No ethynylation of the thiophene ring as well as ethynylation of both heterocycles in a one molecule has been detected. Thus the reactivity of the heterocycles towards the ethynylation system (acylbromoacetylenes/Al₂O₃) falls in the order: pyrrole>furan>thiophene.     

Synthesis,crystal structure,and antibacterial activity of two new mononuclear nickel(II) complexes of a NNS Schiff base

Two new mononuclear nickel(II) complexes, [Ni(L)(N₃)] (1) and [Ni(L)₂(NCS)₂] (2), where HL = 2-{[phenyl(pyridin-2-yl)methylidene]amino}benzenethiol, a tridentate Schiff base derived from 2-aminothiophenol and 2-benzoylpyridine, have been prepared and characterized. The syntheses of 1 and 2 have been achieved by the reaction of equimolar amounts of nickel perchlorate and HL in the presence of azide and thiocyanate, respectively. The complexes have been characterized by microanalytical, spectroscopic, single-crystal X-ray diffraction, and other physicochemical studies. Structural studies reveal that 1 and 2 adopt two different geometries, distorted square planar in 1 and octahedral in 2. The two mononuclear complex units are held together by π…π or C–H…π weak intermolecular interactions to develop supramolecular networks in their solid states. The antibacterial activity of 1, 2 and their constituent Schiff base has been tested against some gram(+) and gram(?) bacteria.     

Synthesis, Crystal Structure and Bioactivities of 1-（4-Chlorophenyl）-3- [ 5-（pyrid-4-yl）- 1,3,4-thiadiazol-2-yl] urea

The title compound 1-(4-chlorophenyl)-3-[5-(pyrid-4-yl)-1,3,4-thiadiazol-2-yl]urea (C14H10ClN5OS, Mr = 331.79) has been synthesized by the reaction of 2-amino-5-(pyrid-4-yl)- 1,3,4-thiadiazole with 4-chlorobenzoyl azide, and its crystal structure was determined by single-crystal X-ray diffraction. The crystal belongs to triclinic system, space group P with a = 5.8550(8), b = 7.5668(10), c = 16.416(2) , α = 78.364(2), β = 81.204(2), γ = 84.749(2)°, V = 702.58(16) 3, Z = 2, Dc = 1.568 g/cm3, μ = 0.429 mm-1, F(000) = 340, the final R = 0.0442 and wR = 0.1092 for 2001 observed reflections (I > 2σ(I)). X-ray diffraction analysis reveals that the title molecule is nearly planar. In the crystal structure, the molecules are linked by strong intermolecular N-H…N hydrogen bonds together with weak nonclassical intermolecular (C-H…Y, Y = N, O and Cl) hydrogen bonds and stacked through π-π interactions. The preliminary bioassay shows that the title compound exhibits good fungicidal activities against Rhizoctonia solani, Botrytis cinerea and Dothiorella gregaria.     

Cyclometallated iridium(III) complex with 2-(benzo[<Emphasis Type="Italic">b</Emphasis>]thiophen-2-yl)pyridyl and norbornene-substituted pyrazolonate ligands and related electroluminescent red light-emitting polymers

New cyclometallated iridium(III) complex, (NBEpz)Ir(Btp)2 (I) (NBEpzH is 1-phenyl-3-methyl-4-(5-bicyclo[2.2.1]hept-5-en-2-yl)-5-pyrazolone, and BtpH is 2-(benzo[b]thiophen-2-yl)pyridine), is synthesized. The structure of the compound is determined by X-ray diffraction analysis (CIF file CCDC no. 1406737). Copolymers with the carbazole and iridium-containing fragments in the side chains (P1–P3) are prepared from monomer I using the ROMP method (ROMP is Ring-Opening Metathesis Polymerization). Their photoluminescence and electroluminescence properties are studied. Copolymers P1–P3 exhibit an intense photoluminescence and electroluminescence of red color. The maximum current efficiency (17.9 cd/A) and power efficiency (9.1 lm/W) are reached using emitter P2.     

A copper(II) complex of 6-(pyrazin-2-yl)-1,3,5-triazine-2,4-diamine and L-serinate: synthesis,crystal structure,DNA-binding and molecular docking studies

A water-soluble Cu(II) complex, [Cu(pzta)(L-Ser)(ClO₄)]·1.5H₂O (pzta = 6-(pyrazin-2-yl)-1,3,5-triazine-2,4-diamine; L-Ser = L-serinate), was synthesized and characterized by analytical and spectral techniques. In addition, the molecular structure of the complex was confirmed by single-crystal X-ray diffraction, revealing that the central Cu(II) atom was located in a six-coordinate distorted octahedral geometry. Multi-spectroscopic methods, viscosity measurements and thermal denaturation experiments revealed that the complex binds to DNA with apparent binding constant of 2.93 × 10³ M^?1 through a groove binding mode. The positive values of ΔH and ΔS obtained from isothermal titration calorimetry experiments indicated that hydrophobic interactions play an important role in the formation of the complex–DNA adduct. Molecular docking studies were carried out to better understand the binding mode of the complex with DNA.     

New tetrathiafulvalenes containing a 2,5-bis(thiophen-2-yl)pyrrole fragment: Synthesis, optical properties, and electrochemical behavior

The reaction of 1-(3-bromopropyl)-2,5-bis(thiophen-2-yl)-1H-pyrrole with cesium 5-methylsulfanyl-2-thioxo-1,3-dithiole-4-thiolate generated in situ gave previously unknown 4-{3-[2,5-bis(thiophen-2-yl)-1H-pyrrol-1-yl]propylsulfanyl}-5-methylsulfanyl-1,3-dithiole-2-thione, and cross-coupling of the latter with 4,5-disubstituted 1,3-dithiole-2-thiones in the presence of triethyl phosphite afforded new substituted tetrathiafulvalenes containing a 2,5-bis(thiophen-2-yl)pyrrole fragment. Optical properties and electrochemical behavior of the synthesized compounds were studied, and their ability to undergo electropolymerization was confirmed.