Geometrical characteristics of four-coordinate complexes of Ni,Pd, and Pt containing triphenylphosphine as ligand

A statistical analysis based on crystal structure results of 4-coordinated complexes of Ni, Pd, and Pt containing triphenylphosphine as ligand has been performed using the Cambridge Structural Data Base. Distorted square-planar coordination appears as the most probable one presented by these metals.

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Geometrische Charakteristika von vier-koordinierten Komplexen des Ni, Pd und Pt mit Triphenylphosphin als Ligand

Zusammenfassung Es wurde unter Verwendung der Cambridge Strukturdatenbank eine statistische Analyse von Resultaten an vier-koordinierten Komplexen des Ni, Pd und Pt mit Triphenylphosphin-Ligand durchgeführt. Dabei ergab sich eine verzerrte quadratisch-planare Koordination als die am meisten wahrscheinliche Geometrie.

     

Hydrolysis rates of alkyl and aryl sulfinamides: evidence of general acid catalysis

Sulfinamides are important in enantioselective synthesis, as rare post-translational modifications of proteins and as isosteres of the amide bond. Little is known about the rates of hydrolysis for aliphatic sulfinamides or the mechanism of hydrolysis. In this Letter, we show that sulfinamides hydrolyse by predominantly a non-specific acid/base catalysis with phosphate buffer but by varying the buffer concentration, it was possible to determine the hydrolysis rates of a range of sulfinamides with water through non-linear least squares regression.     

Novel Isatin-Schiff Base Cu (II) and Ni(II) Complexes. X-ray Crystal Structure of Bis[3-(4-hexylphenylimino)-1H-indol-2(3H)-one]-dichlorocopper(II) Complex

Schiff bases of isatin were reported to possess antibacterial, antifungal, antiviral, anti-HIV, antiprotozoal, and anthelmintic activities1. They also exhibit significantanticonvulsant activity, apart from other pharmacological properties2. Conductingsubs…     

Spectrochemical Properties of Noncubical Transition Metal Complexes in Solution. XII. Angular Overlap Studies of Salicylideneethylenediamine Cu(II) Complex in Various Solvents

As a part of our general interest in the UV-Vis spectroscopy of multidentate mixed-donor ligands, the (salicylideneethylenediamine)Cu(II) complex has been prepared and characterized by elemental analyses, solubility in common solvents, molar conductivities, and ultraviolet (UV), and visible (Vis) spectroscopy. The combined results of spectrophotometric measurements and EPR spectra, as well as known the X-ray structure for solids, were used to determine the structure of the investigated complex in solutions. The spectra of [Cu(salen)] (H₂salen = salicylideneethylenediamine), were measured in various solvents at room temperature, resolved by Gaussian analysis, and angular overlap model (AOM) treated in C _2v symmetry. Because of overparametrization problems, the bis(salicylaldehyde)Cu(II) complex has been characterized and AOM treated. The results of this have been used for AOM studies of [Cu(salen)]. The effect of the solvents upon the - and -bonding ligand abilities is discussed.     

Ln(Ⅲ)与2-羟基-1-萘醛缩蛋氨酸盐及邻菲咯啉三元配合物的合成与表征

合成了稀土硝酸盐与希夫碱盐2-羟基-1-萘醛缩蛋氨酸钾(以KL表示)及邻菲咯啉(Phen)的四种固体三元配合物。通过元素分析，IR，UV，DTA-TG及摩尔电导分析等手段确定配合物的组成为[Ln(L)(Phen)(NO3)(H2O)]NO3(Ln＝Gd，Dy，Er，Yb)，并对它们的配合方式及某些物理和化学性质进行了研究。     

铂电极上溶液酸碱性的电位溶出法响应

提出了一个广谱测定强酸、强碱溶液浓度的方法。用铂电极作工作电极，电位溶出法对溶液酸碱性产生响应。通过调节沉积时间和沉积电位，利用电位溶出法可以检测溶液酸、大致 的浓度范围为2．5mol/L H^ -1.0mol/L OH^-。详细研究了不同测定范围的实验条件，以及溶出过程的响应机理。在不同酸碱性溶液中电沉积产生的氢吸附于电极表面，溶出过程中被溶液中的氧氧化成氢离子，从而产生电位平台。该平台的出现还与随后的电极表面金属／金属氧化物电对电位值有关。     

Synthesis and Crystal Structure of an Azide Bridged Binuclear Zinc(Ⅱ) Dimer Containing Taurine Schiff Base [Zn_2(C_8H_9N_2O_3S)_2·(N_3)_2·(H_2O)_2]_2·_2H_2O

1 INTRODUCTION The investigation of Shiff base complexes con- taining sulfur and complexes of amino acid Schiff bases[1, 2] has recently aroused considerable interest due to their antiviral, anticancer and antibacterial activities. Taurine, known as 2-aminosulfonic acid, is indispensable to human beings and plays an im- portant role in physiological functions. In this con- tribution, we present the synthesis and crystal struc- ture of a new binuclear Zn(II) dimmer with a tri- dentate Sc…     

Dominant Factors Affecting the Chromatographic Behaviour of Bile Acids

With the aim of optimizing the chromatographic process by avoiding any preliminary derivatizing step, we examined the chromatographic behaviour of a selected set of unconjugated bile acids looking at the dominant factors that affect the performances of three different stationary phases: RP-8, RP-18 and RP-18 Base Deactivated (RP-18-BD). Accordingly to its structural peculiarity, the RP-18-BD column combined with a specific mobile phase has proved to be the most suitable one, in enhancing both separation factor α and resolution R _S within the selected set of analytes. Pronounced changes in the chromatographic profiles by only slightly changing the mobile phase composition (pH, buffer concentration, percentage and kind of organic modifier) prompted us to achieve satisfactory results in the separation and resolution of the selected set of bile acids.Presented at: CE in the Biotechnology & Pharmaceutical Industries: 7th symposium on the practical applications for the analysis of proteins, nucleotides and small molecules, Montreal, Canada, August 12–16, 2005.An erratum to this article can be found at     

New Cu(II) complexes with polydentate chelating Schiff base ligands: Synthesis, structures, characterisations and biochemical activity studies

We have reported herein the synthesis of three new Cu(II) complexes of tri- and tetradentate Schiff base ligands containing N₃ or N₄ donor set along with terminal NNN⁻ or SCN⁻ ligands: [L¹Cu(NCS)]ClO₄ (1), [L²Cu(NCS)₂] (2) and [L³Cu(NNN)]ClO₄ (3) [L¹ = NC₅H₄C(CH₃)=N(CH₂)₃N=C(CH₃)C₅H₄N, L²= Me₂N–(CH₂)₃–N=C(CH₃)C₅H₄N and L³ = NC₅H₄CH=N–(CH₂)₄–N=CHC₅H₄N]. The complexes have been systematically characterised by elemental, spectroscopic and electrochemical techniques. Antimicrobial activities of the Schiff base ligands and their metal complexes have been studied using the disc diffusion method on the strains of Candida tropicalis and Bacillus megaterium. Structures of all the complexes have been unequivocally established from single crystal X-ray diffraction analyses that show the monomeric units containing a five-coordinated copper center in highly distorted square pyramidal geometry with thiocyanate or azide anion coordinated as terminal ligand. The complexes 1 and 3 crystallise in monoclinic (P2₁/c) and 2 in triclinic (P-1) space group, respectively.