交联聚苯乙烯微球固载的双齿席夫碱型氧钒(Ⅳ)配合物催化分子氧氧化苯甲醇

利用水杨醛(SA)和氨甲基(MA)交联聚苯乙烯(CPS)微球反应,制得键合有双齿席夫碱配体SAAM的交联聚苯乙烯SAAM-CPS微球,再与硫酸氧钒发生螯合配位反应,制备了固载有席夫碱型氧钒(Ⅳ)配合物催化剂,采用红外光谱、扫描电镜及热失重等手段对催化剂进行了表征,并用于催化分子氧氧化苯甲醇反应,考察了催化剂用量、反应温...     

Application in the cyclohexane oxidation of a scorpionate oxovanadium(IV) complex: synthesis,structure, and properties of VO(C5H7O2)(BC9H7N6I3)

An oxovanadium(IV) complex, VO(C₅H₇O₂)(BC₉H₇N₆I₃), derived from hydrotris(4-iodinpyrazolyl)borate was designed and synthesized at room temperature in methanol. The complex was characterized by elemental analysis, IR spectra, UV-Vis spectroscopy, and single-crystal X-ray diffraction. The structural analysis shows that the vanadium(IV) center possesses a distorted-octahedral geometry with a N₃O₃ core, containing a tridentate hydrotris(4-iodinpyrazolyl)borate with nitrogen as three donors. The complex is the first structurally characterized example of a vanadium(IV) complex with hydrotris(4-iodinpyrazolyl)borate. It was used as a catalyst for cyclohexane oxidation under mild conditions and the effects of a variety of factors such as amount of acid and H₂O₂, the kind of solvent, as well as temperatures were evaluated; the maximum turnover number value reaches 321.     

Mixed-valent dodecanuclear vanadium cluster encapsulating chloride anions and its reaction to form a "bowl"-shaped cluster

Two oxovanadium phosphonate cage compounds have been synthesized in an organic solvent, and their characterization has been done by single-crystal X-ray analysis, IR spectroscopy, and bond valence sum calculations. The simple reaction of a mixed-valent closed V12 cage system produced another quasi-closed system composed of two V6 bowl-type cages.     

Epoxidation of styrene with molecular oxygen catalyzed by a novel oxovanadium(IV) catalyst containing two different kinds of ligands

A novel type of oxovanadium(IV) 8‐hydroxyquinoline (8‐Q) complex and oxovanadium(IV) acetylacetonate (acac) complex were synchronously anchored on to amino‐modified SBA‐15 (named VO(acac:8‐Q)‐SBA‐15) and examined as a catalyst for styrene oxidation. The structure of the synthesized catalyst was characterized by means of X‐ray diffraction (XRD), FT‐IR, diffusion reflection UV–visible, inductively coupled plasma atomic emission spectroscopy (ICP‐AES), scanning electron microscopy (SEM), and thermogravimetric analysis (TG). Characterizations with FT‐IR, diffusion reflection UV‐visible, ICP‐AES and TG suggested the incorporation of oxovanadium(IV) complex in amino‐modified SBA‐15. XRD and SEM results indicated that SBA‐15 remained intact throughout the grafting procedure. It was found that VO(acac:8‐Q)‐SBA‐15 catalyst was more active than single‐ligand catalysts VO(acac)₂‐SBA‐15 and VO(8‐Q)₂‐SBA‐15 and that the product selectivity varied in cases of different oxidants. The catalyst VO(acac:8‐Q)‐SBA‐15 with two different ligands showed high yield of styrene oxide (45.8%) and good recoverability when using air as oxidant. Copyright © 2012 John Wiley & Sons, Ltd.     

An oxovanadium(IV) complex with o-vanillin-valine Schiff base and 1,10-phenanthroline ligands: synthesis,crystal structure and DNA interactions

A new mixed-ligand V(IV) complex, [VO(o-Van-Val)(phen)]·CH₃CN (o-Van-val = Schiff base derived from o-vanillin and l-valine, phen = 1,10-phenanthroline), was synthesized and characterized by physico-chemical methods and single-crystal X-ray diffraction. In the crystal, the V(IV) atom is six-coordinated by one oxo ligand, two oxygen atoms and one nitrogen atom from a valine Schiff base ligand, and two nitrogen atoms from 1,10-phenanthroline, giving a distorted octahedral arrangement. The DNA-binding properties of the complex were investigated by spectroscopic methods and viscosity measurements. The results suggest that the oxovanadium(IV) complex binds to DNA in an intercalation mode.     

新型氧钒(IV)席夫碱配合物［VO(dtbsal-met)(phen)和VO(naph-met)(phen)］的合成及其抗肿瘤活性

以L-蛋氨酸（met）, 1,10-邻菲啰啉（phen）和3,5-二叔丁基水杨醛（dbsal）［或2-羟基-1-萘醛（naph）］为原料,经胺醛缩合反应合成了两个新型的氧钒(IV)席夫碱配合物［VO(dtbsal-met)(phen)（1）和VO(naph-met)(phen)（2）］,其结构经IR, HR-ESI-MS,摩尔电导和X-射线单晶衍射表征。1（CCDC：1 429 158）和2（CCDC：1 429 159）分别属单斜晶系和三斜晶系。用MTT法研究了1和2对人肺腺癌细胞（A549）和人源肝癌细胞（HepG2）的体外抗肿瘤活性。结果表明：1和2对A549和HepG2均表现出一定的抑制活性。     

Synthesis of aziridines from alkenes and aryl azides with a reusable macrocyclic tetracarbene iron catalyst

A new iron aziridination catalyst supported by a macrocyclic tetracarbene ligand has been synthesized. The catalyst, [((Me,Et)TC(Ph))Fe(NCCH(3))(2)](PF(6))(2), was synthesized from the tetraimidazolium precursor ((Me,Et)TC(Ph))(I)(4) and characterized by NMR spectroscopy, electrospray ionization mass spectrometry, and single-crystal X-ray diffraction. This iron complex catalyzes the aziridination of electron-donating aryl azides and a wide variety of substituted aliphatic alkenes, including tetrasubstituted ones, in a "C(2) + N(1)" addition reaction. Finally, the catalyst can be recovered and reused up to three additional times without significant reduction in yield.     

Structural determination of ruthenium-porphyrin complexes relevant to catalytic epoxidation of olefins

A reproducible synthesis of a competent epoxidation catalyst, [Ru(VI)(TPP)(O)2)] (TPP = tetraphenylporphyrin dianion), starting from [Ru(II)(TPP)(CO)L] (L = none or CH3OH), is described. The molecular structure of the complex was determined by using ab initio X-ray powder diffraction (XRPD) methods, and its solution behavior was in detail investigated by NMR techniques such as PGSE (pulsed field gradient spin-echo) measurements. [Ru(IV)(TPP)(OH)]2O, a reported byproduct in the synthesis of [Ru(VI)(TPP)(O)2], was synthesized in a pure form by oxidation of [Ru(II)(TPP)(CO)L] or by a coproportionation reaction of [Ru(VI)(TPP)(O)2] and [Ru(II)(TPP)(CO)L], and its molecular structure was then determined by XRPD analysis. [Ru(VI)(TPP)(O)2] can be reduced by dimethyl sulfoxide or by carbon monoxide to yield [Ru(II)(TPP)(S-DMSO)2] or [Ru(II)(TPP)(CO)(H2O)], respectively. These two species were characterized by conventional single-crystal X-ray diffraction analysis.     

Preparation and characterization of copper/polysulfonamide complex immobilized on geraphene oxide as a novel catalyst for the synthesis of pyrimido[1,2-a]benzimidazoles

Copper–polysulfonamide complex immobilized on geraphene oxide as a novel heterogeneous catalyst (GO@PSA-Cu) was synthesized and the structure and morphology of catalyst were characterized with various analytical techniques such as Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive X-ray, N₂ isotherms, elemental mapping, inductively coupled plasma–MS, and thermogravimetric analysis. The GO@PSA-Cu catalyst demonstrated good to excellent yields for the synthesis new derivatives of pyrimido[1,2-a]benzimidazoles via one-pot three-component condensation reaction of various aromatic aldehydes, 2-aminobenzimidazole, and ethyl acetoacetate in ethanol. The method presented herein has several prominent advantages such as cost-effectiveness, operational simplicity, short reaction times, high yields, and reusability of the catalyst even after six consecutive runs.     

Mild and chemoselective synthesis of lactones from diols using a novel metal-ligand bifunctional catalyst

[reaction: see text] A novel amino alcohol-based Ir bifunctional complex acts as an efficient catalyst for oxidative lactonization of 1,4- or 1,5-diols with a substrate-to-catalyst molar ratio of 200-1000 in acetone or butanone. The reaction proceeds with broad functional group tolerance to give lactone in high yield at room temperature. The catalyst precursor Cp*IrCl[OCH(2)C(C(6)H(5))(2)NH(2)] is isolated and characterized by a single-crystal X-ray analysis.     

新型钒卤代过氧化物酶模型化合物的合成结构及仿生催化活性

模拟卤代过氧化物酶活性中心钒的配位环境设计合成了新的蝎型聚吡唑硼酸盐钒氧化合物VO(HB(3,5-Me<,2> pz)<,3>)(3,5-Me<,2>pz)(HOOCCH<,2>CH<,2>COO)(1)和VO(HB(3,5-Me<,2>pz)<,3>)(3,5-Me<,2> pz)(C<,5>H<,4>NCOO)(2...     

Synthesis,characterization and crystal structure of a manganese(III) Schiff base complex and investigation of its catalytic activity in the oxidation of benzylic alcohols

A new Mn(III) Schiff base complex was prepared by the reaction of 6,6′-diethoxy-2,2′-[2,2-dimethylpropane-1,3-diylbis(nitrilomethylidyne)]diphenol with Mn(OAc)₂·4H₂O. The complex was characterized by physicochemical and spectroscopic methods. Also, its molecular structure was determined by single-crystal X-ray diffraction. The complex was used as a catalyst for the efficient oxidation of benzylic alcohols with tetrabutylammonium periodate. Various reaction parameters were optimized for the reaction of benzyl alcohol.     

Synthesis and structures of 3-chloro-N′-(2-hydroxy-benzylidene)benzohydrazide and its oxovanadium(V) complex

A new Schiff-base 3-chloro-N ′ -(2-hydroxybenzylidene)benzohydrazide (H₂BBH) and its oxovanadium(V) complex [VO(BBH)(OCH₃)]₂ have been synthesized and characterized by elemental analysis, infrared (IR) spectra, and single-crystal X-ray determination. Both the ligand and the complex crystallized in the monoclinic space group P2₁ /c. The Schiff-base coordinates to V through the phenolate O, the imine N, and the enolic O. In the centrosymmetric dimeric oxovanadium(V) complex, the V atom is six-coordinate in an octahedral geometry. The bond lengths related to the donor atoms in the complex are different from those in the ligand. The coordination of the ligand to V is also supported by IR spectra.     

Synthesis, Characterization and the Effect of Glucose-lowering of Guanidino Acid Oxovanadium（Ⅳ） Complexes

Two guanidino acid oxovanadium(Ⅳ) complexes have been synthesized. Preliminary tests in vivo have shown that the two title complexes all display lowering glucose activity in vivo to STZ-rats. The effect of glucose-lowering of guanidino acetic acid oxovanadium(Ⅳ) complex in vivo is higher than that of guanidino propanoic acid oxovanadium(Ⅳ) complex.     

Synthesis,characterization, crystal structure,catalytic activity in oxidative bromination,and thermal study of a new oxidovanadium Schiff base complex containing O,N-bidentate Schiff base ligand

A new oxidovanadium(IV) Schiff base complex, VOL₂ (1), HL = 2-{(E)-[2- (bromoethyl)imino]methyl}-6-methoxy phenol, containing ethyl bromide pendant group was synthesized by direct reaction of HL and VO(acac)₂ in the ratio of 2 : 1 in methanol at reflux. The Schiff base ligand and its vanadyl complex were characterized by FT-IR spectra and CHN analysis. Additionally, the Schiff base ligand has been characterized by ¹H NMR spectroscopy. The crystal structure of 1 was also determined by single-crystal X-ray analysis, showing the distorted square-pyramidal N₂O₃ coordination around vanadium(IV). The catalytic activity of 1 was studied in the oxidative bromination of 2-nitrophenol as a model substrate, and different reaction parameters were investigated. The oxidative bromination of some organic compounds in the presence of 1 in optimal conditions showed that it was an effective and selective catalyst in those optimal conditions. Thermogravimetric analysis of 1 showed that it decomposed in two stages. 1 was thermally decomposed in air at 660 °C, and the XRD pattern of the obtained solid showed the formation of the V₂O₅ nanoparticles with average size of 34 nm .     

Oxo‐vanadium(IV) Schiff base complex supported on modified MCM‐41: a reusable and efficient catalyst for the oxidation of sulfides and oxidative S–S coupling of thiols

Oxo‐vanadium(IV) Schiff base complex supported on MCM‐41 as an organic–inorganic hybrid heterogeneous catalyst was synthesized with post‐grafting of MCM‐41 with 3‐aminoropropyltrimethoxysilane and subsequent reaction with 3,4‐dihydroxybenzaldehyde and then complexation with oxo‐vanadium acetylacetonate salt. The catalyst was analysed using a series of characterization techniques such as Fourier transform infrared spectroscopy, small‐angle X‐ray diffraction, nitrogen absorption isotherm, transmission electron microscopy and thermogravimetric analysis. The data collected provided evidence that the vanadium complex was anchored onto MCM‐41. High catalytic activity of this catalyst was observed in the oxidation of various sulfides and thiols (into sulfoxides and disulfides, respectively) with urea hydrogen peroxide as oxidant in high to excellent yields and selectivity under mild conditions. The heterogeneous catalyst could be recovered easily and reused several times without significant loss in catalytic activity and selectivity. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis,structural characterization and alcohol oxidation activity of a new mononuclear manganese(II) complex

A manganese(II) complex of 2,4,6-tris(2-pyridyl)-1,3,5-triazine (tptz) has been synthesized and characterized by single-crystal X-ray diffraction, elemental analyses, IR, and UV–Vis spectroscopic techniques. Oxidation of alcohols to their corresponding aldehydes and ketones was conducted by this catalyst using oxone (2KHSO₅·KHSO₄·K₂SO₄) as an oxidant under biphasic reaction conditions (CH₂Cl₂/H₂O) and tetra-n-butylammonium bromide as phase transfer agent under air at room temperature. Easy preparation, mild reaction conditions, high yields of the products, short reaction times, no further oxidation to the corresponding carboxylic acids, high selectivity and inexpensive reagents make this catalytic system a useful oxidation method for aliphatic and benzylic alcohols.     

Synthesis, ab initio calculations, thermal, thermodynamic and antioxidant properties of some oxovanadium(IV) complexes containing N2O2 set of donor atoms

The formation constants of some oxovanadium(IV) binary complexes containing Schiff bases resulting from condensation of salicylaldehyde with aniline and with its derivatives were determined spectophotometrically. The synthesized compounds were characterized by analytical and different physico-chemical techniques like ¹H NMR, IR, elemental analysis, mass and UV-Vis spectral studies. The IR spectra affirm that coordination takes place through azomethine nitrogen and phenolate oxygen. Three of the VO(IV) Schiff base complexes i.e. bis(salicylideneaniline)oxovanadium(IV), [VO(L¹)₂], bis(salicylidene-4-methoxyaniline) oxovanadium (IV), [VO(L²)₂] and bis(salicylidene-4-cyanoaniline)oxovanadium(IV), [VO(L¹⁰)₂], were studied by thermogravimetry in order to evaluate their thermal stability and thermal decomposition pathways. The number of steps and, in particular, the starting temperature of decomposition of these complexes depends on the equatorial ligand. The complexes screened for antioxidant activity and the ab initio calculations were carried out to determine the structural and the geometrical properties of a typical vanadyl salicylideneaniline complex, [VO(L¹)₂].     

Synthesis and structure of an air-stable organobismuth triflate complex and its use as a high-efficiency catalyst for the ring opening of epoxides in aqueous media with aromatic amines

An air-stable organobismuth triflate complex with a novel 5,6,7,12-tetrahydrodibenzo[c,f]-[1,5]oxabismocine framework was synthesized and characterized by spectroscopic and single-crystal X-ray diffraction techniques. The organobismuth framework is cationic, and the complex shows relatively strong Lewis acidity (0.8 < H_o ≤ 3.3). It was found to exhibit high catalytic activity towards the ring-opening reaction of epoxides in aqueous media with aromatic amines at room temperature. This catalyst shows good stability, recyclability and reusability. The catalytic system affords a simple and efficient method for the synthesis of β-amino alcohols.     

Nafion®‐supported oxovanadium‐catalyzed hydrophosphonylation of aldehydes under solventless conditions

A Nafion® resin‐supported oxovanadium(IV) catalyst was readily prepared via ion‐exchange method. This solid vanadyl perfluorinated sulfonate catalyst was used as an efficient and recoverable catalyst for the hydrophosphonylation of various aldehydes under solventless conditions at room temperature. The catalyst could be recovered by simple filtration and reused without a significant loss of activity. Copyright © 2012 John Wiley & Sons, Ltd.