Effect of reaction components on the hydrolytic stability of tetrabutoxytitanium as the catalyst of benzanilide synthesis

Tetrabutoxytitanium reacts with vebzoic acid and benzanilide in o-xylene under reflux to form complexes resistant to water. Indirect evidence for the composition of such complexes was obtained by IR spectral analysis of their hydrolysis products. Under comparable conditions, tetrabutoxytitanium and its complexes with aniline, butanol, and butyl benzoate undergo fast hydrolysis yielding hydrated titanium oxide that precipitates. In the reaction of benzoic acid with aniline, catalyzed by tetrabutoxytitaniumom, the latter, forming complexes with benzoic acid and benzanilide, is not prone to hydrolysis and changing its catalytic activity due to reaction with the liberated water.     

Synthesis,characterization and biological studies of some Co(II), Ni(II) and Cu(II) complexes derived from indole-3-carboxaldehyde and glycylglycine as Schiff base ligand

The Schiff base ligand derived from indole-3-carboxaldehyde(indal) and glycylglycine(glygly) were synthesized and characterized by elemental analysis, IR, electronic spectrum, ¹H NMR and mass spectrum. Co(II), Ni(II) and Cu(II)–indal-glygly Schiff base complexes were synthesized and characterized by elemental analysis, molar conductance, IR, electronic spectra, magnetic measurements, ESR, electrochemical studies, TGA, DSC analysis, XRD and SEM. Conductance measurements indicate that the above complexes are 1:1 electrolytes. IR spectral data show that the ligand is tridentate and the binding sites are azomethine nitrogen, peptide nitrogen and carboxylato oxygen atoms. Electronic spectral measurements indicate tetrahedral geometry for Co(II) and Ni(II) complexes and square planar geometry for Cu(II) complex. Magnetic measurements show weak ferromagnetic behaviour for Co(II) and Ni(II) complexes and paramagnetic behaviour for Cu(II) complex. ESR spectral data shows the ionic link between metal and the Schiff base ligand. The metal complexes are found to be stabilized in the unusual oxidation states of the metal ion during electrolysis. Thermal analysis of the complex indicates that the decomposition takes place in three steps. IR and thermal studies indicate that the fourth position would be occupied by a water molecule in complexes. XRD shows that the complexes have the crystallite size of 31, 40 and 67 nm, respectively. The surface morphology of the complexes was studied by SEM. The antimicrobial activity of the ligand and its complexes were screened by Kirby Bayer Disc Diffusion method. DNA cleavage studies were performed for metal–Schiff base complexes in presence of hydrogen peroxide as oxidant.     

MCM-48掺杂铬对催化活性的影响

中介孔分子筛MCM-48因其具有三维螺旋孔道结构,且孔径均匀,长程周期性良好及骨架结构稳定等特征而有可能成为有应用前景的工业催化剂^[1～11].纯硅MCM-48分子筛因无酸性,催化活性极低.     

Preparation and catalytic properties of chitosan bound Schiff base copper complexes

Chitosan, a natural polymer, bound Schiff base copper complexes CT‐She‐Cu, CT‐o‐Bel‐Cu, CT‐m‐Bel‐Cu were prepared and characterize by inductively coupled plasma (ICP), FT‐IR and X‐ray photoelectron spectroscopy (XPS). Their catalytic activity in the oxidation of cyclohexene with molecular oxygen was studied. All the complexes have catalytic activity and the main oxidation products are 2‐cyclohexene‐ol, 2‐cyclohexene‐one and cyclohexene hydroperoxide, which were measured by gas chromatography/mass spectroscopy (GC/MS) and GC/IR. CT‐m‐Bel‐Cu was selected to study the influence of reaction temperature, amount of catalyst and additives such as acid and base on the oxidation of cyclohexene systematically. Copyright © 2004 John Wiley & Sons, Ltd.     

M（phen）3／Y分子筛复合催化材料的制备与表征

采用沸石合成法,制备了封装Ｍ（ｐｈｅｎ）３（Ｍ＝Ｆｅ,Ｃｏ,Ｃｒ）配合物于Ｙ型分子筛超笼中的复合催化材料,并利用ＸＲＤ,ＦＴＩＲ,ＵＶ－ｖｉｓ,ＩＣＰ的环己烷氧化反应等手段对其进行了表征。ＦＴ ＩＲ和ＵＶ－ｖｉｓ测试,有力地证明了合成产物中封装有Ｍ（ｐｈｅｎ）３配合物;ＸＲＤ和ＩＣＰ测试结果表明,在合成体系中引入不同的Ｍ（ｐｈｅｎ）３配合物,对Ｙ型分子筛的晶化有不同的影响     

Fe (III) complexes of a bis-benzimidazolyl diamide ligand: spectral and catalytic studies

A new tetradentate bis benzimidaozlyl diamide ligand N,N'-Bis (benzimidazol-2-yl-methyl)-hexane-1,6-dicarboxamide (GBSA) has been synthesized and utilized to prepare new Fe(III) complexes with exogenous anionic ligand X=Cl(-) and NO(3)(-). Isomer shift values are in the range found for Iron in the +3 oxidation state while Quadrupole Splitting indicates large distortion from a six coordinate geometry, a finding supported by low temperature EPR work. The E(1/2) values are found to be quite cathodic indicating stability of the Iron (III) complexes. The oxidation of alcohols was investigated using [Fe(GBSA)Cl(3)] as the catalyst with TBHP as an alternate source of oxygen. The respective carbonyl products have been isolated and characterized by (1)H NMR, electronic spectroscopy, mass and IR spectral studies.     

One pot synthesis of alpha-aminophosphonates containing bromo and 3,4,5-trimethoxybenzyl groups under solvent-free conditions

New alpha-aminophosphonates were synthesized by the Kabachnik-Fields reaction of 3,4,5-trimethoxybenzaldehyde (TMB) with p- or m-bromoaniline and a dialkyl phosphite under solvent-free conditions. TMB was prepared from gallic acid via a four step synthetic sequence involving etherification, esterification, hydrazidation and potassium ferricyanide oxidation. The structures of all synthesized compounds were confirmed by elemental analysis, IR, 1H-, 13C- and 31P-NMR spectral data. Compound 7g was also characterized by X-ray crystallography. A half-leaf method was used to determine the in vivo curative efficacy of the eight title products against tobacco mosaic virus (TMV). It was found that compounds 7g and 7h possess good in vivo curative effects against TMV.     

Mixed-valence state of a pyrazine-bridged dimer of oxocarboxylatotriruthenium complexes with a nitrosyl ligand

Three new pyrazine-bridged dimers of oxoacetatotriruthenium with an NO ligand are synthesized. These complexes show two types of stable mixed-valence states. The ν(NO) stretches for five oxidation states were obtained, and the intramolecular electron-transfer rate within the mixed-valence state is evaluated from the IR spectral line-shape simulation based on Bloch-type analysis, which is the first application of this method to a spectator ligand of NO.     

Synthesis,crystal structures,and thermal properties of rhodium(<Emphasis Type="SmallCaps">iii</Emphasis>) complexes with γ-picoline and isonicotinic acid

The complex salts [Rh(γ-Pic)₄Cl₂]X, where X = Cl, ReO₄, or ClO₄, were synthesized and characterized by IR spectroscopy, elemental analysis, X-ray powder diffraction, and single-crystal X-ray diffraction. The salts containing the ReO₄ ⁻ and ClO₄ ⁻ ions are isostructural. The oxidation of the γ-picoline complexes afforded a complex with isonicotinic acid. The crystalline product of the oxidation reaction was isolated and characterized by X-ray diffraction. The crystal structure contains two types of rhodium complex cations, which differ in the number of oxidized γ-picoline molecules. Thermal transformations of the complexes were studied by DTA, as well as by DTA coupled with evolved gas analysis. The thermolysis products were isolated and studied by IR and NMR spectroscopy. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1607–1613, August, 2008.     

铀的萃取剂——二(苯基亚磺酰)烷烃的合成

双亚砜;硫醚;铀的萃取剂——二(苯基亚磺酰)烷烃的合成     

2-异丙基-1,3-二氢-4(1H)异喹啉酮及其衍生物的合成

报道了异喹啉酮与格氏试剂反应合成四氢-4-羟基异喹啉酮化合物,NBS和混酸(HNO~3/HAc)与异喹啉酮反应合成异喹啉酮衍生物。6个新化合物的结构,通过元素分析,红外光谱和核磁共振氢谱,质谱给予证实。     

Oxovanadium(IV) and copper(II) complexes of 1,2-diaminocyclohexane based ligand encapsulated in zeolite-Y for the catalytic oxidation of styrene, cyclohexene and cyclohexane

N,N′-Bis(salicylidene)cyclohexane-1,2-diamine (H₂sal-dach) reacts with oxovanadium(IV) and copper(II) exchanged zeolite-Y in refluxing methanol to yield the corresponding zeolite-Y encapsulated metal complexes, abbreviated herein as [VO(sal-dach)]-Y and [Cu(sal-dach)]-Y. Spectroscopic studies (IR, electronic and ¹H NMR), thermal analysis, scanning electron micrographs (SEM) and X-ray diffraction patterns have been used to characterise these complexes. These encapsulated complexes catalyse the oxidation, by H₂O₂, of styrene, cyclohexene and cyclohexane efficiently in good yield. Under the optimized conditions, the oxidation of styrene catalysed by [VO(sal-dach)]-Y and [Cu(sal-dach)]-Y gave 94.6 and 21.7% conversion, respectively, where styreneoxide, benzaldehyde, benzoic acid, 1-phenylethane-1,2-diol and phenylacetaldehyde being the major products. Oxidation of cyclohexene catalysed by these complexes gave cyclohexeneoxide, 2-cyclohexene-1-ol, cyclohexane-1,2-diol and 2-cyclohexene-1-one as major products. Conversion of cyclohexene achieved was 86.6% with [VO(sal-dach)]-Y and 18.1% with [Cu(sal-dach)]-Y. A maximum of 78.1% conversion of cyclohexane catalysed by [Cu(sal-dach)]-Y and only 21.0% conversion by [VO(sal-dach)]-Y with major reaction products of cyclohexanone, cyclohexanol and cyclohexane-1,2-diol have been obtained.     

Spectroscopic, cyclic voltammetric and biological studies of transition metal complexes with mixed nitrogen-sulphur (NS) donor macrocyclic ligand derived from thiosemicarbazide

The complexation of new mixed thia-aza-oxa macrocycle viz., 2,12-dithio-5,9,14,18-tetraoxo-7,16-dithia-1,3,4,10,11,13-hexaazacyclooctadecane containing thiosemicarba-zone unit with a series of transition metals Co(II), Ni(II) and Cu(II) has been investigated, by different spectroscopic techniques. The structural features of the ligand have been studied by EI-mass, (1)H NMR and IR spectral techniques. Elemental analyses, magnetic moment susceptibility, molar conductance, IR, electronic, and EPR spectral studies characterized the complexes. Electronic absorption and IR spectra of the complexes indicate octahedral geometry for chloro, nitrato, thiocyanato or acetato complexes. The dimeric and neutral nature of the sulphato complexes are confirmed from magnetic susceptibility and low conductance values. Electronic spectra suggests square-planar geometry for all sulphato complexes. The redox behaviour was studied by cyclic voltammetry, show metal-centered reduction processes for all complexes. The complexes of copper show both oxidation and reduction process. The redox potentials depend on the conformation of central atom in the macrocyclic complexes. Newly synthesized macrocyclic ligand and its transition metal complexes show markedly growth inhibitory activity against pathogenic bacterias and plant pathogenic fungi under study. Most of the complexes have higher activity than that of the metal free ligand.     

Synthesis and spectroscopic studies of Mn(II), Co(II), and Cu(II) complexes of novel 2-[2,4-Dioxo-4-(thiophen-2-yl)butanamido]benzoic acid ligands

Mn(II), Co(II), and Cu(II) complexes with novel heterocyclic ligands derived from anthranilic acid and its 5-bromo derivative with ethyl-2-thionylpyruvate were synthesized and characterized by means of elemental analysis, molar conductivity, spectral methods (IR, ¹H NMR, and UV-Vis spectra) and simultaneous thermal analysis (TG and DTG) techniques. The IR spectra of the two ligands and their complexes were used to identify the type of bonding. The kinetic thermodynamic parameters such as: E*, ΔH*, ΔS*, and ΔG* were estimated from the DTG curves. New ligands and their complexes have been tested for their possible antibacterial and antifungal activity.     

水相法合成水杨酸类二茂钛衍生物与取代基效应及酸度影响的研 究

用二氯二茂钛-乙酰丙酮的水溶液与取代水杨酸钠在不同pH条件下合成了两种类型的配合物。所有配合物经元素分析、IR和^1HNMR进行了结构表征,并通过Hammett方程,描述了取代基效应与二茂钛水杨酸类配合物的合成和性质之间的联系。结果表明:Hammettσ值对反应有较大影响,取代基的σ值越大,越有利于合成产物由A型向B型配合物过渡;产物的颜色、分解温度、IR及^1HNMR亦与取代基有一定关系。     

Induced crystal G phase through intermolecular hydrogen bonding II. Influence of alkyl chain length of n-alkyl p-hydroxybenzoates on thermal and phase behaviour

A new series of intermolecular hydrogen-bonded complexes have been synthesized using p-n-alkoxybenzoic acid (alkyl chain length varies from propyl- to decyl- and dodecyl-) and methyl p-hydroxybenzoate moieties. The thermal and phase behaviour of these complexes were studied by thermal microscopy and differential scanning calorimetry. Further, the stabilization of intermolecular hydrogen bonding in solution was studied by IR spectroscopy. A detailed IR spectral investigation in the solid and dissolved states suggests that the acid and phenol groups act as proton donor and proton acceptor, respectively. The thermal studies also reveal the inducement of a crystal G phase in the complexes.     

Induced crystal G phase through intermolecular hydrogen bonding II. Influence of alkyl chain length of n-alkyl p-hydroxybenzoates on thermal and phase behaviour

A new series of intermolecular hydrogen-bonded complexes have been synthesized using p-n-alkoxybenzoic acid (alkyl chain length varies from propyl- to decyl- and dodecyl-) and methyl p-hydroxybenzoate moieties. The thermal and phase behaviour of these complexes were studied by thermal microscopy and differential scanning calorimetry. Further, the stabilization of intermolecular hydrogen bonding in solution was studied by IR spectroscopy. A detailed IR spectral investigation in the solid and dissolved states suggests that the acid and phenol groups act as proton donor and proton acceptor, respectively. The thermal studies also reveal the inducement of a crystal G phase in the complexes.     

Syntheses, characterization and study of the use of cobalt (II) Schiff-base complexes as catalysts for the oxidation of styrene by molecular oxygen

Schiff-Base complexes of bis-5-phenylazosalicylaldehyde ethylenediimine and bis-5-phenylazosalicylaldehyde-O-phenylenediimine ligands with Co(II) (I and II) have been synthesized and characterized by their IR spectra and elemental analyses. These complexes catalyze the oxidation of styrene in the presence of dioxygen and excess pyridine. The effect of the reaction conditions on the oxidation of styrene was studied by varying solvent, nature and amount of the catalyst and substrate. The catalytic behavior of the studied complexes was shown to be dependent on the conditions applied. In all reactions, acetophenone and 1- phenylethanol were the only observed products.     

Spectroscopic, redox and biological activities of transition metal complexes with ons donor macrocyclic ligand derived from semicarbazide and thiodiglycolic acid

A novel macrocyclic Schiff base ligand (2,5,9,12,14,18-hexaoxo-7,16-dithia-1,3,4,10,11,13-hexaazacycloocta-decane (H6L) with N4S2 coordinating sites was prepared by the reaction of the semicarbazide and thiodiglycolic acid. The transition metal complexes with macrocyclic ligand were synthesized and characterized by elemental analyses, magnetic susceptibility measurements, molar conductance, IR, electronic, and EPR spectral studies. Mass, 1H NMR and IR spectral techniques suggest the structural features of macrocyclic ligand. Magnetic and electronic spectral studies suggest an octahedral geometry of complexes. Electrochemical behaviour of cobalt, nickel and copper complexes were determined by cyclic voltammetry. The cyclic voltammogram of the copper complex at room temperature shows a quasi-reversible peaks for Cu(III)-->Cu(II) and Cu(II)-->Cu(I) couples. The macrocyclic ligand and its complexes show growth inhibitory activity against pathogenic bacteria and plant pathogenic fungi A. niger, A. alternata and P. variotii. Most of the complexes have higher activities than that of free ligand.