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1.
Copper(II) complex of a Schiff base ligand (H 2L) was synthesized, characterized, and encapsulated in the cavities of zeolite-Y by a fixed ligand method. The zeolite encapsulated metal complex (CuL-Y) was characterized using FT-IR, UV–Vis and atomic absorption spectroscopy, thermogravimetric analysis (TGA), X-ray powder diffraction (XRD), scanning electron microscopy images (SEM), energy-dispersive X-ray spectroscopy (EDX), and Brunauer-Emmett-Teller (BET). The catalytic activity and electrochemical behavior of the encapsulated complex has been studied in the oxidation of a wide range of sulfides and olefins using H 2O 2 in ethanol. This heterogeneous catalytic system shows a dramatic increase in total turnover number (46,500) for oxidation of styrene. It could be readily reused for at least eight successive times without discernible activity and selectivity deterioration, which displays potential for practical applications. 相似文献
2.
N, N′-Bis(salicylidene)cyclohexane-1,2-diamine (H 2sal-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 H 2O 2, 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. 相似文献
3.
A series of dioxovanadium(V) complexes of Schiff and tetrahydro-Schiff bases were encapsulated into the supercages of zeolite-Y and were characterized by X-ray diffraction, SEM, N 2 adsorption/desorption, FT-IR, UV-vis spectroscopy, ICPAES, pair distribution function (PDF) and X-ray absorption near edge structure (XANES) measurements. The encapsulation is achieved by a flexible ligand method in which the transition metal cations were first ion-exchanged into zeolite-Y and then complexed with ligands. The dioxovanadium-exchanged zeolite, dioxovanadium complexes encapsulated in zeolite-Y plus non-encapsulated homogeneous counterparts were all screened as catalysts for the aerobic oxidation of styrene under mild conditions. It was found that the encapsulated complexes showed better activity than their respective nonencapsulated counterparts in most cases. All encapsulated dioxovanadium tetrahydro-Schiff base complexes showed much higher activity in aerobic oxidation of styrene than their corresponding Schiff base complexes. 相似文献
4.
Two kinds of immobilized bidentate Schiff base oxovanadium(IV) complexes are prepared via polymer reactions and coordination reactions with chloromethylated cross-linked polystyrene (CMCPS) microspheres as matrix. Benzaldehyde (BA)-functionalized CPS microspheres, BA-CPS microspheres, were prepared through nucleophilic substitution with CMCPS microsphere as precursor and p-hydroxy benzaldehyde as reagent, and then Schiff base reactions were carried out with 3-aminopyridine (AP) and glycine (GL) as reagents, respectively, obtaining two kinds of bidentate Schiff base ligand-bonded microspheres, BAAP-CPS microspheres and BAGL-CPS microspheres. Finally, through coordination reactions with vanadyl sulfate (VOSO 4) as reagent, the two kinds of immobilized bidentate Schiff base oxovanadium(IV) complex microspheres, CPS-[VO(BAAP) 2] and CPS-[VO(BAGL) 2], were obtained. The two immobilized complexes, VO(BAAP) 2 and VO(BAGL) 2, are N,N- and N,O-type bidentate Schiff base oxovanadium(IV) complexes and their ligands have different chemical structures. The two catalyst microspheres were used in oxidation of cyclohexanol and benzyl alcohol with molecular oxygen as oxidant and their catalytic activities are compared. The experimental results show that both solid catalysts can catalyze the transformation reactions of cyclohexanol and benzyl alcohol to their corresponding carbonyl compounds under mild conditions. However, CPS-[VO(BAAP) 2] microspheres have much higher catalytic activity and better stability than CPS-[VO(BAGL) 2] microspheres. For the immobilized bidentate Schiff base oxovanadium(IV) catalysts, the catalytic property is closely related to the chemical structures of the ligands, and for this, a theoretical explanation is given. 相似文献
5.
Reactions of silicon tetraacetate with different types of Schiff bases have been investigated in anhydrous benzene. Monofunctional bidentate, C 6H 5CHN XOH and HORCHNC 6H 5 [where X=CH 2CH 2, CH 2CH(CH 3) or o-C 6H 4 and R=o-C 6H 4 or 2,1-C 10H 6], bifunctional tridentate, o-HOC 6H 4CHN YOH [where Y=CH 2CH 2 or CH 2CH(CH 3)] and bifunctional tetradentate Schiff bases, o-HOC 6H 4C(CH 3)N(CH 2)
n
NC(CH 3)C 6H 4OH-o (where n=2 or 3) have been shown to yield derivatives of the type, Si(O Ac) 4–
m
L
m, Si(O Ac) 4–2
n
L
n and Si(O Ac) 2
L (where m=1,2 or 3; n=1 or 2 and H L, H 2
L and H 2
L represent the molecules of monofunctional bidentate, bifunctional tridentate and bifunctional tetradentate Schiff bases resp.) and have been found to be monomeric in boiling benzene. Tentative structures based on IR and in a few cases PMR spectra have been indicated for the resulting derivatives.With 2 Figures 相似文献
6.
Summary Eleven oxovanadium(IV) complexes of tetradentate Schiff bases, obtained by condensating two moles of an o-hydroxycarbonyl compound with a diamine, have been prepared and characterized by elemental analysis, m.p., and i.r. and electronic spectra. The i.r. and electronic spectra of the free ligand and the complexes are compared and discussed. The Gaussian analysis of the vis. spectra of the complexes, normally C 1 or C s, in MeCN yielded four peaks at ca. 12000, 15000, 17700 and 20000–23000cm –1, assigned to the four d-d transitions. 相似文献
7.
Three new Pd(II) complexes of Schiff base ligands, namely, [Pd 4(L 1) 4] ( 1), [Pd 2(L 2) 2Cl 2] ( 2) and [Pd(L 3) 2Cl 2] ( 3) [ HL 1 ?=?N-(benzylidene)-2-aminophenol; L 2 ?=?N-(2,4-dichlorobenzylidene)-2,6-diethylbenzenamine, L 3 ?=?4-(2,4-dichlorobenzylide-neamino)phenol] have been synthesized using solvothermal methods and characterized by elemental analysis, spectroscopy and single crystal X-ray diffraction. The crystal structures of the free ligands were also determined. The ??-oxygen-bridged tetranuclear cyclometallated Pd(II) complex ( 1) contains four nearly planar units, in which Pd II is four-coordinate. Complex 2 is a ??-chloro-bridged dinuclear cyclometallated Pd(II) complex, whereas complex 3 is mononuclear. The Heck reactions of bromobenzene with acrylic acid catalyzed by complexes 1?C 3 have also been studied. 相似文献
8.
Complexes of the type [Ru(CO)(EPh 3)(B)(L)] (E = P or As; B = PPh 3, AsPh 3, py or pip; L = dianion of the Schiff bases derived from the condensation of salicyloyl hydrazide with acetone, ethyl methyl ketone and salicylaldehyde have been synthesised by the reaction of equimolar amounts of [RuHCl(CO)(EPh 3) 2(B)] and Schiff bases in benzene. The resulting complexes have been characterized by analytical and spectral (i.r., electronic, n.m.r.) data. The arrangements of Ph 3P groups around the Ru metal was determined from 31P-n.m.r. spectra. An octahedral structure has been assigned to all the new complexes. All the complexes exhibit catalytic activity for the oxidation of benzyl alcohol and cyclohexanol in the presence of N-methylmorpholine- N-oxide as co-oxidant. 相似文献
9.
Zn(II) and Mn(II) organometallic complexes I and II were first used to catalyze the cyanosilylation reaction, and good catalytic results (24–99 %) were achieved. The catalytic activity of the complexes was determined by 1H NMR. 相似文献
10.
In this study, some cobalt(II)tetraaza Schiff base complexes were used as donors in coordinating to triphenyltin(IV)chloride as acceptors; the kinetics and mechanism of the adduct formation were studied spectrophotometrically. Co(II)tetraaza Schiff base complexes used were [Co(amaen)][ N, N′‐ethylene‐bis‐( o‐amino‐α‐methylbenzylideneiminato)cobalt(II)] ( 1 ), [Co(appn)] [ N, N′‐1,2‐propylene‐bis‐( o‐amino‐α‐phenylbenzylideneiminato)cobalt(II)] ( 2 ), [Co(ampen)] [ N, N′‐ethylene‐bis‐( o‐amino‐α‐phenylbenzylideneiminato)cobalt‐(II)] ( 3 ), [Co(cappn)][ N, N′‐1,2‐proylene‐bis‐(5‐chloro‐ o‐amino‐α‐phenylbenzylideneiminato)cobalt(II)] ( 4 ), and [Co(campen)] [ N, N′‐ethylene‐bis‐(5‐chloro‐ o‐amino‐α‐phenylbenzylid‐eneiminato)cobalt(II)] ( 5 ). The reactivity trend of the complexes in interaction with triphenyltin(IV)chloride was Co(amaen) > Co(appn) > Co(ampen) > Co(cappn) > Co(campen). The linear plots of kobs versus the molar concentration of the triphenyltin(IV)chloride, a high span of the second‐order rate constant k2 values, and large negative values of Δ S≠ and low Δ H≠ values suggest an associative (A) mechanism for the acceptor–donor adduct formation. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 635–640, 2012 相似文献
11.
2-[(pyridin-2-ylmethylidene)amino]-6-aminopyridine (L1), 2-[(2-furylmethylene)]phenylenediamine (L2) and their Mn(II) and Pd(II) complexes have been synthesized as potential photoactive materials, and their structures were elucidated using a variety of physicochemical techniques. The molar conductance data reveal that all complexes are nonionic in nature. Theoretical calculations were computed using the density functional theory, where the B3LYP functional was employed. The experimental results and the calculated parameters revealed a square planar and octahedral geometry around Pd(II) and Mn(II), respectively, in which the ligands coordinate to the metal ions as a bidentate manner. The thermal decomposition of the complexes has been studied. The catalytic activity of the complexes toward hydrogen peroxide decomposition reaction was investigated at 35 and 55 °C. In addition, the synthesized ligands, in comparison with their metal complexes, were screened for their antibacterial activity. 相似文献
12.
The catalytic epoxidation of styrene using urea-hydrogen peroxide and heterotrinuclear Cu(II) complexes with general formula
(ML
n
) 2Cu(acac) 2, where n = 1–3 and M = VO 2+ or Mn 2+ is reported. Schiff base complexes ML
n
involving a 3,4-diaminopyridine bridge with free coordination site were used as the ligand, where (L n) 2− is [(5-x-Sal) 2Py] 2 and x = H, Br or NO 2. The complexes were characterized by physico-chemical and spectroscopic methods. The electrochemical properties of M were
modified upon trinuclear complex formation. The trinuclear complexes show high catalytic activity, with up to 86% conversion
and 93% selectivity, while no catalytic properties were observed for the monomeric complexes. The catalyst could be reused
with some loss of activity. 相似文献
13.
Ruthenium(II) hydrazone Schiff base complexes of the type [RuCl(CO)(B)(L)] (were B=PPh(3), AsPh(3) or Py; L=hydrazone Schiff base ligands) were synthesized from the reactions of hydrazone Schiff base ligand (obtained from isonicotinoylhydrazide and different hydroxy aldehydes) with [RuHCl(CO)(EPh(3))(2)(B)] (where E=P or As; B=PPh(3), AsPh(3) or Py) in 1:1 molar ratio. All the new complexes have been characterized by analytical and spectral (FT-IR, electronic, (1)H, (13)C and (31)P NMR) data. They have been tentatively assigned an octahedral structure. The synthesized complexes have exhibited catalytic activity for oxidation of benzyl alcohol to benzaldehyde and cyclohexanol to cyclohexanone in the presence of N-methyl morpholine N-oxide (NMO) as co-oxidant. They were also found to catalyze the transfer hydrogenation of aliphatic and aromatic ketones to alcohols in KOH/Isopropanol. 相似文献
14.
Microwave synthesis, is green chemical method, simple, sensitive, reducing solvent amount and reaction time. The attempt was made to synthesize the unsymmetrical tetradentate N(2)O(2) ligands and their VO(IV) and MoO(V) unsymmetrical tetradentate Schiff base complexes by classical and microwave techniques using domestic microwave oven. The resulting unsymmetrical Schiff base ligands L(1)-L(3) characterized by different spectral methods. Their complexes with oxocations of VO(IV) and MoO(V) have been synthesized and characterized by elemental analyses, conductometric measurements, infrared and electronic absorption, (1)H NMR spectra, mass spectrometry, ESR spectra, magnetic susceptibility measurement and thermal study. The study suggests that the oxo metal ion is bonded to the ligand through the oxygen and imino nitrogen and the geometry around metal ion is distorted octahedral. 相似文献
15.
Transition Metal Chemistry - Twenty-four oxidovanadium(IV,V) complexes with tridentate Schiff base ligands based on 5-nitrosalicylaldehyde, 5-methoxysalicylaldehyde, or 5-sulfosalicylaldehyde and... 相似文献
16.
The electrochemical properties of vanadyl(IV) derivatives, namely salen Schiff base complexes of the type [VO(Salen)] (5-BrSalen, 5-NO 2Salen, 5-MeOSalen, salpn (bis(salicylaldehyde)-1,3-propanediamine, 5-BrSalpn, 5-NO 2Salpn, 5-MeOSalpn, Me 2Salen, Salophen, 5-BrSalophen, and 5-MeOSalophen) were investigated. The equatorial Schiff base ligands affect the oxidation potentials via interaction with the d-orbitals of the vanadyl metal ion. The cathodic peak potential (E pc) becomes less negative according to the sequence MeO- < H- < Br- < NO 2?. 相似文献
17.
Summary Some thorium(IV) complexes were synthesized with the tetradentate Schiff base ligands (N 2O 2 donor set) obtained by the condensation of ethylenediamine with salicylaldehyde (H 2salen) or acetylacetone (H 2 acacen). In all cases the neutral Schiff bases and not their anions are coordinated to the central thorium(IV) atom. The complexes have the general formula: ThL 2Xa (L = H 2 salen; X = Cl, Br, 1, NCS and L = lie acacen; X = Cl, 1, NCS, ClO 4) or ThLX 4 (L = H 2 salen; X = NO 3, ClO 4 and L = H 2 acacen; X = Br, NO 3). The stoichiometry and coordination number of the complexes was determined on the basis of elemental analysis, conductivity measurements, i.r. spectra and t.g.a./d.t.a. data. The coordination number of the complexes is either 12 or 8 for the bisor monocomplexes respectively. 相似文献
18.
Two Pd(II) complexes involving Schiff base ligands, namely, [Pd(L1) 2] ( 1), [Pd 2(L 2)Cl 2] ( 2) [ HL1 = 2-((2,6-diisopropylphenylimino)methyl)-4,6-dibromophenol, L2 = N-(4-isopropylbenzylidene)-2,6-diisopropylbenzenamine] have been synthesized using solvothermal methods and characterized by elemental analysis, IR-spectroscopy, thermogravimetric analysis, powder X-ray diffraction, UV–vis absorption spectra, and single-crystal X-ray diffraction. Complex 1 is a mononuclear cyclometalated Pd(II) complex, whereas complex 2 is a μ-chloro-bridged dinuclear. Both 1 and 2 display photoluminescence in the solid state at 298 K and possess fluorescence lifetimes ( τ 1 = 86.40 ns, τ 2 = 196.21 ns, τ 3 = 1,923.31 ns at 768 nm for 1, τ 1 = 69.92 ns, τ 2 = 136.40 ns, τ 3 = 1,714.26 ns at 570 nm for 2). The Suzuki reactions of 4-bromotoluene with phenylboronic acid by complexes 1– 2 have also been studied. 相似文献
19.
A series of novel heteronuclear Ln(III)-CU(II) complexes with noncyclic polyether-amino acid Schiff base were synthesized.
The general formula is (LnCu 2(H 2TALY) (NO 3) 5] (NO 3) 2· nH 2O (Ln= La, Nd, Sm, Gd, n = 4; Ln = Yb, Y, n = 3), where H 2TALY = tetraglycol aldehyde bis-lysine Schiff base. It is the first time to report the synthetic method for this new Cu(II)
complexes and Ln(III)-Cu(II) heteronuclear complexes. The complexes were characterized by elemental analysis, IR spectra.
TG-DTA, magnetic susceptibility, and especially by a 500 MHz NMR spectrometer for 2D-COSY NMR. Coordination mechanism and
structures of complexes have been suggested as well. Of particular interest is the potential that the novel complexes obtained
may be used as a catalyst. which prompted us to investigate them. It shows 100% conversion with the viscosity-average molecular
weight 120 000 for the polymerization of methyl methacrylate (MMA) without addition of any cocatalyst. Furthermore, the complexes
with such aliphatic Schiff bases can be used as a good catalyst, which has been confirmed and discussed here. They may be
a new kind of catalyst system with the above speciality.
Project supported by the National Natural Science Foundation of China (Grant No. 29671026) and Natural Science Foundation
of Zhejiang Province (Grant No. 296062) and the Laboratory of MRAMP (Grant No. 971502). 相似文献
20.
Enantioselective catalytic trimethylsilylcyanations of aldehydes with 48% to 92% e.e. have been studied using the novel Ti-chiral Schiff base complexes. We have found that the catalyst led to high enantoselectivity when the molar ratio of the Schiff base 1 to Ti(O-i-Pr) 4 was 2:1. 相似文献
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