Polymer complexes: XLIX—Supramolecular modeling of bonding in novel rare earth polymeric rhodanine drug complexes

Novel supramolecular rare earth polymeric hydrazone complexes of 5-sulphadiazineazo-3-phenyl-2-thiaxo-4-thiazolidinone (HL) of the composition [(Ln)₂(HL)₃(NO₃)₆]_n (where Ln = La(1), Y(2), Pr(3), Nd(4), Sm(5), Gd(6) and Ho(7)) have been prepared and characterized on the basis of their chemical analyses, magnetic measurements, conductance, visible and IR spectral data. Composition, conductance and IR spectral data of complexes show that all these act as a tetradentate ligand. Electronic spectra indicate weak covalent character in the metal–ligand bond. The spectra of Nd³⁺ and Ho³⁺ show characteristic f–f transitions and the metal–ligand covalency in % has been evaluated. The spectral properties of the above polymeric complexes are also discussed.     

2[(N-乙基)-1-吩噻嗪基]腙的合成及聚集荧光增强性能

以氮-氮单键连接2个吩噻嗪环构成共轭结构, 合成了2[(N-乙基)-1-吩噻嗪基]腙, 并对其进行了结构表征. 该化合物在四氢呋喃溶剂中呈分散态时无荧光; 在四氢呋喃/水混合溶剂中呈现聚集荧光增强. 荧光增强是由于聚集态中分子内单键旋转受分子堆积效应的阻碍, 氮-氮单键连接的2个吩噻嗪环趋于平面化以及J-聚集体形成的协同作用使非辐射跃迁减少所致. 同时, 利用这种聚集荧光增强性质考察了该化合物对血红蛋白的探针识别性能.     

3,4-二甲基吡咯-2-甲酰肼缩PMBP的镧系(Ce、Pr、Nd)配合物的合成、结构及荧光性质

合成并通过单晶衍射表征了3个稀土配合物[LnL（NO₃）₃（H₂O）][LnL（NO₃）₃（CH₃CN）]·2CH₃CN（Ln=Ce （1）,Pr （2）,Nd （3）,L=3,4-二甲基吡咯-2-甲酰肼缩PMBP）。3个配合物同构,属于单斜晶系,P2₁/n空间群,晶胞参数分别为：1：a=1.758 83（9） nm,b= 1.460 61（8） nm,c=2.626 28（14） nm,β=97.800 0（10）°;2：a=1.756 39（15） nm,b=1.459 97（11） nm,c=2.623 1（2） nm,β=97.771（2）°;3：a=1.758 7（2） nm,b=1.463 87（17） nm,c=2.626 3（3） nm,β=97.760（2）°。每个配合物包含2个不同的中性配合物分子。配合物中每个十配位的Ln（Ⅲ）离子与来自酰腙配体L的2个氧原子和1个氮原子,3个双齿配位硝酸根及1个溶剂分子配位,采取双帽四方反棱柱配位构型。乙腈溶液中,配合物1~3具有与配体完全不同的荧光发射,可能由配位荧光增强效应导致。     

Novel Steroidal (6R)‐Spiro‐1,3,4‐thiadiazoline Derivatives as Anti‐bacterial Agents

Novel steroidal (6R)‐spiro‐1,3,4‐thiadiazoline derivatives have been synthesized by the cyclization of steroidal thiosemicarbazones. Thiosemicarbazones have been synthesized by the reaction of steroidal ketones with thiosemicarbazide. All the compounds have been characterized by IR, ¹H NMR, mass and elemental analyses. The antibacterial activities of these compounds have been first tested in vitro by the disk diffusion assay against two Gram‐positive and two Gram‐negative bacteria, and then the minimum inhibitory concentration (MIC) values have been determined with the reference of standard drug amoxicillin. The results showed that steroidal thiadiazoline derivatives exhibited better antibacterial activity than the steroidal thiosemicarbazone derivatives. Chloro and acetoxy substituents on the 3β‐position of the steroidal thiadiazoline ring increased the anti‐bacterial activity. Among all the compounds, compounds 7 and 8 were found better inhibitors as compared to the respective drug amoxicillin.     

The Synthesis and Characterization of Mononuclear and Binuclear Iron(II) Clathrochelate Complexes Derived from 2,3-Butanedione Oxime Hydrazone

The synthesis and characterization of a new series of iron(II) clathrochelate complexes, including the first example of a binuclear covalently linked c1athrochelate complex, is reported. The ligand system is based on the bifunctional chelate 2,3-butanedione oxime hydrazone which forms a tris-complex with iron(II). The c1athrochelate is completed by capping the complex with both a boronic acid/oxime capping reaction and a formaldehyde/hydrazone capping reaction. Electrochemical and spectroscopic characterizations of the complexes are discussed.     

Synthesis and structure of amide oxygen-bridged polymeric and monomeric copper(II) complexes with aroylhydrazones

The synthesis and structure of two Cu(II) complexes, {[Cu₂(L¹)₂]?·?DMF} _n (1) and [CuL²(phen)] (2), are described. The dinegative hydrazones are obtained by deprotonation of both phenolic and amide moieties of N′-(5-bromo-2-hydroxybenzylidene)-3,5-dimethoxybenzohydrazide (H₂L¹) and N′-(2-hydroxybenzylidene)pyrazine-2-carbohydrazide (H₂L²). In each complex the planar ligand binds the metal ion via phenolate-O, imine-N, and amide-O. Complex 1 is a polymer in which phenoxo-bridged binuclear Cu(II) units are further joined by equatorial–apical amide-O bridges. The Cu···Cu separations are 3.0306 and 3.8217?Å for the phenolate-O bridged pair and the amide-O bridged pair, respectively. Complex 2 is a monomer where chelating phen displays axial–equatorial bonding, with square-pyramidal Cu(II).     

A Sensitive Analysis for Nitrosamines

Abstract

A number of nitrosamines have been reduced to hydrazines and condensed with 9-anthraldehyde and 9-phenanthraldehyde to give highly fluorescent hydrazones which can be separated by thin layer chromatography and identified using R_f, ultroviolet and mass spectra.     

Synthesis and Characterization of Three Vanadium（Ⅴ） Complexes Incorporating Tridentate Hydrazone Ligands of Thiophene-2-carboxylic Hydrazide and 2-Furoic Acid Hydrazide

Divanadium(Ⅴ) complex [VO(aptch)(μ-OCH3)]2(1) and two monovanadium(Ⅴ) complexes [VO(apfah))(OEt)](2a and 2b,H2aptch = 2-hydroxyacetophenone thiophene-2-car-boxylic hydrazone,H2apfah = 2-hydroxyacetophenone 2-furoic acid hydrazone) have been synthesized and characterized.Single-crystal X-ray diffraction studies reveal that 1 is a cen-trosymmetric dimer bridged by two methoxido O-atoms.Complex 1 crystallizes in the monoclinic crystal system,space groups P21/c with a = 7.4825(4),b = 17.0928(11),c = 11.6961(7) ,β = 98.172(4)o,Z = 2,F(000) = 728,μ = 0.829 mm-1,the final R = 0.0457 and wR = 0.1137 for 2654 observed reflections with I > 2(I).The vanadium(V) is coordinated to the tridentate ligand,ethanol molecule to form a distorted square-pyramidal geometry,complexes 2a and 2b.Although 2a and 2b have the same asymmetric unit,they belong to different space groups.Complex 2a crystallizes in the monoclinic crystal system,space groups P21/n with a = 10.2293(2),b = 15.6660(3),c = 10.6298(2) ,β = 116.259(1)o,Z = 4,μ = 0.676 mm-1;complex 2b crystallizes in the triclinic crystal system,space groups P with a = 8.2808(4),b = 9.4704(5),c = 10.0819(5) ,α = 86.133(3),= 81.956(3),γ = 80.248(3)o,Z = 2 and μ = 0.670 mm-1.The hydrogen bonds are found to exist in 2b only.The crystal structure is stabilized by intermolecular hydrogen bonds of C-H···O.     

Thermal Analysis in Structural Characterization of Hydrazone Ligands and Their Complexes

Results of our research on synthesis and characterization of complexes with acylhydrazone derivatives are described in this review paper. Structural characterization of newly synthesized complexes by thermal analysis (TG, DTA, DSC) is particularly emphasized in this paper. Thermal analysis enabled us to study not only structural changes of substances during thermal treatment, but also the mode of coordination and degree of deprotonation of acylhydrazones, as well as geometry of the coordination sphere of complexes, the structure of which had not been determined by X-ray analysis. Topics in this paper are as follows: complexes of dioxomolybdenum(VI) with tridentate hydrazones, usnic acid derivatives and their Cu(II) complexes, as well as transition metal complexes with 2,6-diacetylpyridine bis(hydrazones). This revised version was published online in July 2006 with corrections to the Cover Date.