1-Hetaryltriazenes in the synthesis of condensed mesoionic 1,2,3-triazolio-5-olates

Condensed mesoionic 1,2,3-triazoles containing an aryl or hetaryl substituent at N₍₂₎ in the ring have been synthesized by intramolecular condensation. Dedicated to Academician M. G. Voronkov on his Eighty-Fifth Birthday. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1714–1719, November, 2006.     

Studies on the synthesis and thermal decomposition mechanisms of rare-earth metal (Pr,Nd, Sm) salt hydrates of 3-nitro-1,2,4-triazol-5-one

Three new rare-earth metal (Pr, Nd and Sm) salt hydrates of 3-nitro-1,2,4-triazol-5-one (NTO) were prepared and characterized. The thermal behaviour of the three salt hydrates, M(NTO)₃·nH₂O (M=Pr and Nd,n=9;M=Sm,n=8) were studied by means of TG and DSC under conditions of linear temperature increase. The thermal decomposition intermediates were determined by means of IR, MS and X-ray diffraction spectrometry. The thermal decomposition mechanisms of these hydrates were proposed as follows: We express our thanks to Professor Zhu Chunhua, Associate Professor Fu Xiayun, and Lecturers Fan Tao and Liang Yanjun for their help in this work.     

吡咯基金属络合物的制备及其在有机合成中的应用

本文综述了近年来吡咯基金属络合物的研究进展, 详细讨论了σ~N-、σ~C-、π-型吡咯基金属络合物的制备方法, 以及各类吡咯基金属络合物在有机合成中的应用。     

One-pot sequential diprop-2-ynylation and cycloaddition: An efficient synthesis of novel N,N-bis(1,2,3-triazol-4-yl) methylarylamines starting from primary amines

Abstract

A facile, one-pot synthesis strategy for the tertiary arylamines bearing N,N-bis(1,2,3-triazol-4-yl)methyl structure has been developed by sequential diprop-2-ynylation of primary amines with propargyl bromide in the presence of calcium hydride in DMF and [3?+?2] “click” cycloaddition with organic azides promoted by cupric acetate in the mixed DMF-H₂O media. This protocol provides some features, such as high efficiency and regioselectivity, easy operation, and moderate to good product yield (56–84%) with a wide substrate scope under mild conditions.     

Transition metal complexes of a Schiff base: synthesis,characterization, and antibacterial studies

Synthesis of a new Schiff base derived from 2-hydroxy-5-methylacetophenone and glycine and its coordination with compounds Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and UO₂(VI) are described. The ligand and complexes have been characterized on the basis of analytical, electrical conductance, infrared, ESR and electronic spectra, magnetic susceptibility measurements, and thermogravimetric analysis. The ligand is a dibasic tridentate (ONO) donor in all the complexes except Zn(II), where it is a monobasic bidentate (OO) donor. The solid state DC electrical conductivity of ligand and its complexes have been measured over 313–398 K, and the complexes were semiconducting. Antibacterial activities of ligand and its metal complexes have been determined by screening the compounds against various Gram (+) and Gram (?) bacterial strains.     

The first metal complexes of bis(diisopropylamino)carbene: synthesis, structure and ligand properties

The synthesis of rhodium(I) and iridium(I) complexes of the bis(diisopropylamino)carbene is described for the first time. The formamidinium chloride and the free bis(diisopropylamino)carbene (L) were used as consecutive precursor compounds to form the metal complexes. Spectroscopic and, for LRh(cod)Cl, crystallographic data are presented for the complexes LRh(cod)Cl and LIr(cod)Cl (L=bis(diisopropylamino)carbene). The ligand properties of the acyclic bis(diisopropylamino)carbene are compared with imidazolin-2-ylidenes and imidazolidin-2-ylidenes as ligands in related rhodium(I) carbonyl complexes. Bis(diisopropylamino)carbene is the most basic known carbene ligand to date.     

The effect of short alkane bridges in stability of bisbenzimidazole-2-ylidene silver(I) complexes: synthesis,crystal structure and antibacterial activity

Three bisbenzimidazolium salts, 3,3-(alkane-1,n-diyl)bisbenzylbenzimidazolium dibromide/dihexafluorophosphate (1a/b–3a/b) (where alkane?=?ethane, propane or butane and n?=?2, 3, or 4), were synthesized. The bromide salts were subsequently used as precursors to prepare their respective Ag(I)-NHC complexes via in situ deprotonation method. The successful formation of all bisbenzimidazolium salts and complexes were proved by elemental analysis, ¹H-NMR, ¹³C-NMR and FT-IR analyses. From single-crystal X-ray diffraction analyses, 4 has been established as a binuclear complex with the molecule arranged as in trans-conformation. Salts 1b–3b and Ag(I)-NHC complexes 4–6 were then screened for their antibacterial potential against E. coli (ATCC 25922) and S. aureus (ATCC 12600). All the bisbenzimidazolium salts do not show any activity against both bacteria while 4 exhibits the highest activity against both bacteria in all methods followed by 5 and 6.     

Nucleophilic substitution in the series of (1,2,3-triazol-1-yl)-1,2,5-oxadiazoles. Reactions with N-, O-, and S-nucleophiles

Methods for the synthesis of amino(1,2,3-triazol-1-yl)-1,2,5-oxadiazoles (amino-triazolylfurazans) with CH₂Cl and COCH₂Br substituents in the triazole ring were developed and nucleophilic substitution for their halogen atom in reactions with N-, O-, and S-nucleophiles were studied. The possibility of displacing the NO₂ group from the furazan and triazole rings in triazolylfurazans by an azido group was investigated. Novel compounds of this series were synthesized; the reaction rate and pathway were found to depend on the nature of the substrate and the reagent and the position of the substituent in isomers. __________ Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1866–1876, August, 2005.     

Four 1,3-bis(1,2,4-triazol-1-yl)propane-based metal complexes tuned by competitive coordination of mixed ligands: synthesis,solid structure,and fluorescence

Four 1,3-bis(1,2,4-triazol-1-yl)propane (btp)-based transition metal complexes, {[Zn(btp)₃] ?(ClO₄)₂} _n (1), [Zn(btp)₂(dca)₂] _n (2), [Zn(btp)(NCS)₂] (3), and [Mn(btp)₂(NCS)₂] _n (4), have been obtained by introducing small anionic coligands and structurally characterized by single crystal X-ray diffraction, elemental analysis, IR spectra, thermogravimetric curves, and solid luminescence spectra. Structural determinations reveal that the polymeric triple-stranded chain for 1 without coligand is changed into 1-D double-stranded chains for 2 and 4, and discrete binuclear structure for 3. Compared with 1, the mixed-ligand complexes are moderately destabilized for 2 and 4, and slightly enhanced for 3. Additionally, the four solid complexes exhibit strong emissions, suggesting their potential applications as luminescent materials.     

Syntheses,crystal structures and antibacterial activities of M(II) benzene-1,2,3-triyltris(oxy)triacetic acid complexes

Four metal(II) complexes with benzene-1,2,3-triyltris(oxy)triacetic acid (H₃L), {[Co_1.5(L)(H₂O)₆]·6H₂O}_n (1), {[Co_1.5(L)(4,4′-bipy)_1.5(H₂O)₄]·4H₂O}_n (2), {[Co(HL)(2,2′-bipy)(H₂O)₂]·1.5H₂O}_n (3), and {[Cu(HL)(phen)(H₂O)₂]·H₂O}_n (4) (4,4′-bipy = 4,4′-bipyridine; 2,2′-bipy = 2,2′-bipyridine; phen = phenanthroline), were prepared and structurally characterized. Complex 2 displays a 1-D structure, while 1, 3, and 4 reveal 0-D structures, which further extend to 3-D supramolecular networks by hydrogen bonding interactions, of which 1 and 4 contain double-helical chains, 2 includes meso-helices, and 3 comprises single-helices. Furthermore, the thermal stabilities and antibacterial activities of the complexes were studied.     

由4-甲基-1,2,3-噻二唑-5-甲酸构筑的过渡金属配合物的合成、晶体结构及与DNA作用

以4-甲基-1,2,3-噻二唑-5-甲酸(C_4H_4N_2O_2S,HL)分别与硫酸钴(CoSO_4·7H_2O)、氯化铜(CuCl_2·2H_2O)、硝酸银(AgNO_3)反应合成了3个配合物[Co(L)_2(H_2O)_4]·2H_2O(1)、[CuNa(L)_3]_n(2)和[AgL]_n(3),用元素分析、红外光谱、热重分析进行表征,用单晶X射线衍射测定了产物的结构。配合物1属于三斜晶系,空间群P1,Co~(2+)的配位数为6,形成一个略为拉长的CoN_2O_4八面体,与理想的正八面体非常接近。配合物2属于三斜晶系,空间群P1。Cu~(2+)离子的配位数为4,构成变形的平面四边形结构,Na~+离子的配位数为6,构成一个略微变形的八面体结构,最终形成三维网状结构。配合物3属于单斜晶系,空间群P21/c,银离子为三配位,构成变形的平面三角形构型,具有二维网状结构。用溴化乙锭荧光探针法测定了配体和配合物与DNA作用的荧光光谱。     

由4-甲基-1，2，3-噻二唑-5-甲酸构筑的过渡金属配合物的合成、晶体结构及与DNA作用

以4-甲基-1,2,3-噻二唑-5-甲酸（C₄H₄N₂O₂S, HL）分别与硫酸钴（CoSO₄·7H₂O）、氯化铜（CuCl₂·2H₂O）、硝酸银（AgNO₃）反应合成了3个配合物[Co（L）₂（H₂O）₄] ·2H₂O （1）、[CuNa（L）₃] _n （2）和[AgL] _n （3）,用元素分析、红外光谱、热重分析进行表征,用单晶X射线衍射测定了产物的结构。配合物1属于三斜晶系,空间群P1,Co²⁺的配位数为6,形成一个略为拉长的CoN₂O₄八面体,与理想的正八面体非常接近。配合物2属于三斜晶系,空间群P1。Cu²⁺离子的配位数为4,构成变形的平面四边形结构,Na⁺离子的配位数为6,构成一个略微变形的八面体结构,最终形成三维网状结构。配合物3属于单斜晶系,空间群P2₁/c,银离子为三配位,构成变形的平面三角形构型,具有二维网状结构。用溴化乙锭荧光探针法测定了配体和配合物与DNA作用的荧光光谱。     

Recent advances of lead-free metal halide perovskite single crystals and nanocrystals: synthesis,crystal structure,optical properties,and their diverse applications

Lead halide hybrid perovskites have received massive research attention because of their unique inherent photophysical properties that driven them for potential application in the fields of photovoltaics, light-emitting devices, lasing, X-ray detector, and so on. Perovskite single crystals and nanocrystals are generally synthesized via various low-cost solution-processed techniques. The emergence of simple growth approaches of perovskite structures enable to fabricate low-cost and highly efficient devices. However, toxicity of Pb atoms and instability of perovskite structures obstruct further commercialization of these technologies. Recent efforts have been shifted to discover novel, eco-friendly, and stable lead-free metal halide perovskite (LFHP) materials and exploring their different growth processes for various device applications. This review aims to provide an up-to-date analysis of recent progress report on LFHPs and will mainly focus on their growth processes in the single crystalline and nanocrystalline forms. This review also tries to understand how the perovskite crystal structure impacts on their fundamental properties. In addition, we discuss the current progress in various field of applications and their future aspects.     

Recent advances in the study of layered lithium transition metal oxides and their application as intercalation electrodes

A review is presented on the extensive work carried out during the last 30 years on layered oxides structurally related to LiCoO₂ and LiNiO₂. The studies considered here range from the structural and chemical characterization of the layered solids to the detailed evaluation of their aptitude towards lithium deintercalation-intercalation reactions, which form the basis of their successful application in rechargeable battery technology. The different challenges remaining in this area, such as the development of advanced preparation procedures and the optimization of the electrochemical performance by controlled changes in composition, structure, and particle morphology, are discussed. Received: 15 May 1998 / Accepted: 24 July 1998     

Recent advances in the synthesis and CF functionalization of gem-difluoroalkenes

The gem-difluoroalkenes and related compounds have gained much attention from the organic synthetic community due to their widespread applications as versatile fluorinated building blocks for the synthesis of pharmaceuticals, agrochemicals and functional materials. In the past two decades, significant progress has been made to the development of efficient methods for the construction of gem-difluoroalkenes and useful reactions involving the cleavage of CF bond in gem-difluoroalkenes. In this Digest review, these advances in the synthesis and reaction chemistry of gem-difluoroalkenes are summarized, with special emphasis placed on novel synthetic applications of them in recent ten years.     

Recent advances in the applications of [1.1.1]propellane in organic synthesis

As a highly strained small molecule, [1.1.1]propellane has been widely used in various synthetic transformations owing to the exceptional reactivity of the central bond between the two bridgehead carbons. Utilizing strain-release approaches, the rapid development of strategies for the construction of bicyclo[1.1.1]pentane (BCP) and cyclobutane derivatives using [1.1.1]propellane as the starting material has been witnessed in the past few years. In this review, we highlight the most recent advances in this field. Accordingly, the reactivity of [1.1.1]propellane can be divided into three pathways, including radical, anionic and transition metal-catalyzed pathways under appropriate conditions.     

Recent advances in the applications of [1.1.1]propellane in organic synthesis

As a highly strained small molecule, [1.1.1]propellane has been widely used in various synthetic transformations owing to the exceptional reactivity of the central bond between the two bridgehead carbons. Utilizing strain-release approaches, the rapid development of strategies for the construction of bicyclo[1.1.1]pentane (BCP) and cyclobutane derivatives using [1.1.1]propellane as the starting material has been witnessed in the past few years. In this review, we highlight the most recent advances in this field. Accordingly, the reactivity of [1.1.1]propellane can be divided into three pathways, including radical, anionic and transition metal-catalyzed pathways under appropriate conditions.     

Nano‐synthesis and spectral,thermal, modeling,quantitative structure–activity relationship and docking studies of novel bioactive homo‐binuclear metal complexes derived from thiazole drug for therapeutic applications

Seven novel homo‐binuclear Cr(III), Fe(III), Cu(II), ZrO(II), Sn(II), Pb(II) and Ce(III) nanosized complexes of a thiazole drug (H₂L) were synthesized for chemotherapeutic applications. H₂L was prepared via a condensation reaction between 2‐(4‐aminobenzenesulfonamido)thiazole and 2‐hydroxybenzaldehyde. The structures of H₂L and its metal complexes were investigated by various means. These included microanalysis, ¹H NMR, ¹³C NMR, Fourier transform infrared, UV–visible, electron spin resonance and mass spectroscopies, transmission electron microscopy (TEM), powder X‐ray diffraction (XRD), thermogravimetric analysis (TGA) and molar conductivity. The measurements revealed that H₂L coordinates with the metal ions through two chelating centers, indicating its behavior as a dibasic tetradentate ligand. The first center involves the nitrogen of azomethine (CH═N) and the α‐hydroxyl oxygen while the other center is the thiazole nitrogen and the sulfonamide oxygen. From spectroscopic and analytical data, the Cr(III), Fe(III) and Ce(III) complexes have octahedral geometries, whereas the Cu(II), ZrO(II), Sn(II) and Pb(II) complexes have tetrahedral geometries. TEM and XRD measurements unambiguously showed the nanometric particle sizes of the complexes. The activation thermo‐kinetic parameters, E*, ?H*, ?S* and ?G*, of the various decomposition steps of the complexes were determined mathematically from the TGA curves. Gaussian09 and quantitative structure–activity relationship modeling studies were utilized to verify the biological and structural feature relationships. Docking studies were performed to throw more light on the biological priority of the proposed drugs, using microorganism protein receptors. The antitumor and antimicrobial efficiencies of the H₂L drug and its complexes were determined to estimate their potential therapeutic utility. In general, the complexes showed greater antitumor and antimicrobial efficiencies than the H₂L drug. The Fe(III) complex exhibited efficient antimicrobial activities against Candida albicans and Staphylococcus aureus and its efficiency is equivalent to that of standard drugs. The Cu(II) complex showed the greatest cytotoxic activity towards HEPG2.     

Unexpected structural diversity in alkali metal azide-crown ether complexes: syntheses, X-ray structures, and quantum-chemical calculations

A series of alkali metal azide-crown ether complexes, [Li([12]crown-4)(N3)], [Na([15]crown-5)(N3)], [Na([15]crown-5)(H2O)2]N3, [K([18]crown-6)(N3)(H2O)], [Rb([18]crown-6)(N3)(H2O)], [Cs([18]crown-6)(N3)]2, and [Cs([18]crown-6)(N3)(H2O)(MeOH)], has been synthesised. In most cases, single crystals were obtained, which allowed X-ray crystal structures to be derived. The structures obtained have been compared with molecular structures computed by density functional theory (DFT) calculations. This has allowed the effects of the crystal lattice on the structures to be investigated. Also, a study of the M-N(terminal) metal-azide bond length and charge densities on the metal (M) and terminal nitrogen centre (N(terminal)) in these complexes has allowed the nature of the metal-azide bond to be probed in each case. The bonding in these complexes is believed to be predominantly ionic or ion-dipole in character, with the differences in geometries reflecting the balance between maximising the coordination number of the metal centre and minimising ligand-ligand repulsions. The structures of the crown ether complexes determined in this work show the subtle interplay of such factors. The significant role of hydrogen bonding is also demonstrated, most clearly in the structures of the K and Rb dimers, but also in the chain structure of the hydrated Cs complex.     

Synthesis and characterization of metal complexes of azo dye based on 5‐nitro‐8‐hydroxyquinoline and their applications in dyeing polyester fabrics

New Mn(II), Ni(II), Co(II) and Cu(II) complexes of an azo dye ligand based on p ‐phenylenediamine with 5‐nitro‐8‐hydroxyquinoline were synthesized and characterized using elemental analysis, inductive coupled plasma analysis, molar conductance, powder X‐ray diffraction, thermogravimetric analysis, magnetic moment measurements, and infrared, ¹H NMR, electron ionization mass and UV–visible spectral studies. The spectral and analytical data reveal that the azo dye ligand acts as a monobasic bidentate ligand via deprotonated OH and nitrogen atom of the quinoline ring. The data support the formulation of all complexes with a 2:1 ligand‐to‐metal ratio, except the Mn(II) complex that has a mononuclear formula. All complexes have an octahedral structure. The molar conductance data reveal that all the metal complexes are non‐electrolytic in nature. From the X‐ray data, the average particle size of the ligand and its complexes is 0.32–0.64 nm. The colour fastness to light, washing, perspiration, sublimation and rubbing of the prepared ligand and its complexes on polyester fabrics and colorimetric properties were measured. The results reveal that the ligand and its complexes have a good to moderate affinity to polyester fibres.