Synthesis,characterization and catalytic activity of Fe(III) complexes containing Schiff base and triphenylphosphine ligands

The oxidation of alcohols to carbonyls was investigated by an efficient catalyst system comprising of Fe(III)–Schiff base–triphenylphosphine complex. The complex chloroN-(2-mercaptophenyl)salicylideneiminebis(triphenylphosphine)iron(III) showed higher activity for oxidation of various alcohols under relatively mild conditions.     

Synthesis,X-ray structure and study of a mixed ligand iron(III) complex with tridentate Schiff base as a homogeneous catalyst in the efficient oxidation of sulfides

A mononuclear mixed ligand complex of iron, [Fe^III(N-OPh-sal)(acac)EtOH], where Hacac and N-HOPh-Hsal denote acetylacetone and N-hydroxyphenyl-salicylideneamine, respectively, has been synthesized and characterized by elemental analysis, spectral studies and X-ray crystallography. The catalytic system containing this complex and urea hydrogen peroxide as oxidizing agent was used to selectively oxidize a range of sulfides to the corresponding sulfoxides in good yields under mild conditions. The electronic spectra of the catalytic system were applied to explore reactivity and stability of the catalyst during sulfide oxidation reactions and to examine the nature of active species, as well.     

Synthesis,characterization and sulfide oxidation activity of vanadyl Schiff base complexes anchored on MCM-41

Vanadyl Schiff base complexes covalently attached on the surface of MCM-41 have been synthesized by anchoring Schiff base and subsequent reaction with VO(acac)₂. XRD, nitrogen adsorption and desorption, UV-visible spectroscopy and FT-IR show that vanadyl Schiff base complexes were successfully anchored on the surface of MCM-41 and the mesopore ordering decreased after the anchoring. The so-prepared heterogeneous catalysts have showed high activity for sulfide oxidation.     

Synthesis and characterization of a novel iron (III) silsesquioxane compound

A new iron (III) containing silsesquioxane compound, [Bu₄N][((CH₃)₂CHCH₂)₇Si₇O₁₂FeCl] (4) was prepared by reacting [Bu₄N][FeCl₄] (3) with the isobutyl substituted silsesquioxane trisilanol, ((CH₃)₂CHCH₂)₇Si₇O₁₂H₃, (1) in the presence of three equivalents of triethylamine, Et₃N (2). The magnetic susceptibility of 4 was measured by Evans method, and the effective magnetic moment, μ_eff, is consistent with a high spin Fe (III) center. The composition and molecular structure of 4 was fully determined by IR, elemental analysis, APCI mass spec, and X-ray crystal analyses, and its potential as a precursor to a model of the structure and chemistry of the Fe-ZSM-5 catalyst is discussed.     

Synthesis,characterisation and cryomagnetic studies of a novel homonuclear Nd(III) Schiff base dimer

A novel homodinuclear complex [Nd^III(L)(NO₃)]₂ (1) has been synthesised [H₂L = N¹,N³- bis(salicylideneimino)diethylenetriamine, a pentadentate Schiff base with N₃O₂ donor set] and characterised with spectroscopic and micro-analytical techniques. Single crystal X-ray diffraction study reveals a centrosymmetric binuclear neutral entity [space group, P2₁/n; a = 12.911(5); b = 11.938(5); c = 13.960(5) Å; Z = 4] where Nd(III) metal centers are bridged together by two phenoxo oxygen atoms each coming from the two ligands. The most interesting fact is that two similar “salen” moieties of each ligand are behaving completely different in their coordination. In the doubly deprotonated ligand (L²⁻), one phenoxo oxygen is mono coordinated to the metal, whereas its immediate neighbour on the other end bridges the two Nd(III) centers. The distance between the Nd(III) centers is found to be 3.884(3) Å. Temperature dependence (2–300 K) magnetic susceptibility study suggests the presence of an antiferromagnetic interaction operating via two phenoxo bridges.     

含硫Schiff碱铜(Ⅱ)配合物的合成与表征

合成由水杨醛和1，3－二氨基硫脲缩合的含硫希夫碱配体及其铜（Ⅱ）配合物。化合物用元素分析、红外光谱、磁化率、摩尔电导等方法进行了表征。确定了它们的组成和可能的空间构型。     

Synthesis and characterization of novel Schiff base polyurethanes

Eight different types of novel polyurethanes (PUs) were synthesized through the polyaddition reaction of 4,4′‐(ethane‐1,2‐diylidenedinitrilo)diphenol and 4,4′‐(pentane‐1,5‐diylidenedinitrilo)diphenol with four different diisocyanates: 4,4′‐diphenylmethane diisocyanate, toluene 2,4‐diisocyanate, isophorone diisocyanate, and hexamethylene diisocyanate. The resulting PUs were soluble in polar, aprotic solvents. Structures of the diols and PUs were established with ultraviolet–visible, fluorescence, Fourier transform infrared (FTIR), ¹H‐NMR, and ¹³C‐NMR spectroscopy data. FTIR and NMR spectral data indicated the disappearance of both hydroxyl and isocyanate groups in the PUs. The thermal properties were investigated with thermogravimetry and differential scanning calorimetry. The weight losses, glass transitions, onset temperatures, and crystalline melting temperatures were measured. All the PUs exhibited semicrystalline and amorphous morphologies, as indicated by X‐ray diffraction. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009.     

一种新型共轭Schiff碱聚合物的合成与表征

以对苯二甲醛和水合肼为原料,无水乙醇作溶剂合成了一种共轭Schiff碱聚合物,并通过GPC、IR、1 H NMR、紫外-可见吸收光谱和荧光光谱对其分子量和组成结构进行表征。结果表明,该物质为一种分子量较大的共轭Schiff碱聚合物,具有良好的荧光性。     

Synthesis and characterization of palladium (II) complex of Schiff base ligand: CS bond cleavage and catalytic activity

Reaction of ligand, L-CH₂Ph with Pd(CH₃CN)₂Cl₂ in acetonitrile in presence of PPh₃ and subsequent addition of NaClO₄ yielded Pd(II) complex, [Pd(L)(PPh₃)](ClO₄) 1 due to the SC (CH₂Ph) bond cleavage during complexation. Complex 1 was characterized by spectral analysis and the structure was authenticated by single crystal X-ray diffraction. The diffraction analysis revealed that the monoanionic ligand binds with palladium (II) in (N, N, S) fashion in a distorted square planar geometry where the fourth position is occupied by one tri phenyl phosphine group. One ClO₄⁻ ion satisfies the charge of the former aggregate, [Pd(L)(PPh₃)]⁺. The complex [Pd(L)(PPh₃)](ClO₄), 1 exhibits a very good catalytic activity towards CC bond formation.     

Synthesis,characterization and immobilization of iron (III) pyridoxinato complex within Al-MCM-41 as catalyst for cycloalkanes oxidation

Biomimetic [Fe(pyridoxinato)₂OH·(H₂O)₃] non-hem complex designated as [Fe(L)₂OH·(H₂O)₃] was synthesized with basic solution of pyridoxine (Vitamin B₆) and FeCl₃ in methanol under reflux condition. It was then immobilized within the Al-MCM-41. Characterizations were carried out by powder X-ray diffraction, nitrogen adsorption desorption, FTIR and UV–Vis spectroscopy. It was found that pore volume, surface area, and pore diameter of Al-MCM-41 decreases after immobilization of iron complex. Density functional theory studies confirmed the experimental results of [Fe(L)₂OH·(H₂O)₃] complex. Fe-complex/Al-MCM-41 was found to successfully catalyze the oxidation of cyclohexane, cyclooctane and adamantane using H₂O₂ as oxidant with 45–90 % conversion toward the corresponding alcohols and ketones is considerable.     

Synthesis and catalytic activity of a novel ruthenium(III) complex containing a sugar-based ligand

The novel mixed-ligand complex [Ru^III(TDL)(bipy)(H₂O)]⁺ (1) (TDL = N-3,5-ditertiarybutylsalicylidine-d-glucosamine; bipy = 2,2′-bipyridine) has been synthesized and characterized. Complex 1 found to catalyze the epoxidation of styrene and oxidize 1-indanol to 1-indanone in dichloromethane using t-BuOOH as a terminal oxidant. Enanantiomeric induction was observed in case of styrene epoxidation. Formation of a high valent Ru(V)-oxo species is proposed to be the catalytic oxidative species.     

Synthesis and characterization of iron (III) complexes of N4 schiff base macrocycles

Iron(III) complexes of the diprotic N₄ Schiff base macrocycles, 7,8,15,16,17,18-hexahydro-dibenzo[e,m] [1,4,8,11]tetraazacyclotetradecine (H₂(2,2mac)) and 8,9,16,17,18,19-hexahydro-7H-dibenzo[e,n][1,4,8,12]tetraazacyclopentaadecine(H₂(3,2mac)), were prepared by the metathesis reaction of anhydrous iron (III) bromide with the disodium or magnesium complexes of the dianionic ligands in THF under an inert atmosphere. The complexes exhibit the intermediate spin state as evidenced by magnetic susceptibility and Mössbauer spectroscopy. Fe(3,2 mac)Br is structurally characterized as a distorted square pyramid with the four nitrogen atoms in the basal positions and the bromide occupying the axial site. The average iron to nitrogen bond distance is 1.921 Å.     

新型多溴代水杨醛及其Schiff碱配体的合成与表征

以芳基硼酸和3-溴-5-叔丁基水杨醛为原料,经Suzuki偶联反应分别得到3-苯基-5-叔丁基水杨醛和3-(4-甲基苯基)-5-叔丁基水杨醛。3-苯基-5-叔丁基水杨醛在溴化反应时,发现不同温度下反应结果不同:分别生成一溴代产物3-(4-溴苯基)-5-叔丁基水杨醛和二溴代产物3-(4-溴苯基)-5-溴水杨醛。在50℃下,3-(4-甲基苯基)-5-叔丁基水杨醛经溴化得到三溴代产物3-(4-甲基-3,5-二溴苯基)-5-溴水杨醛,再经过与(S)-缬氨醇缩合后得到手性Schiff碱配体。通过红外、高分辨质谱、核磁共振等手段对其结构进行了表征。     

Synthesis and structure of a disilver(I) complex of a thiophene-linked Schiff base azacryptand

The synthesis and crystal structure of a mixed anion disilver(I) complex of a thiophene-linked Schiff base azacryptand are reported. The crystalline species is not stable at ambient temperature and the structure reveals a possible mechanism for the breakdown of the crystals.     

Synthesis and characterization of some novel conjugated polyoxadiazoles with Schiff base structure

Some novel conjugated polyoxadiazoles with Schiff base structure were efficiently synthesized through polycondensation of 4,4′-(1,3,4-oxadiazole-2,5-diyl)dianiline with some dialdehydes. The polymers were characterized by IR, ¹H NMR, ultraviolet spectroscopy, fluorescence spectroscopy, gel permeation chromatography and thermal analyses. All polymers have high thermal stability with decomposition temperature higher than 260 °C. Some polymers have good solubility in common organic solvents. They also have strong absorptions at 294–345 nm, and strong emissions at 405–432 nm.     

对氟苯甲醛缩乙醇胺席夫碱合成、表征及抑菌活性的测试

通过对氟苯甲醛与乙醇胺的反应，合成了对氟苯甲醛缩乙醇胺席夫碱，并对其进行了元素分析、核磁共振氢谱、红外光谱、紫外光谱表征。抑菌实验表明，该席夫碱对金黄色葡萄球菌和革兰氏阴性菌均有较好的抑制作用。     

Photoinitiation of methyl methacrylate with a novel iron (III) oxalato complex

Summary The photopolymerization of methyl methacrylate (MMA) by the photoinitiator iron (III) tris (oxalato) ferrate(III) tetrahydrate, Fe[Fe(C₂O₄)₃] . 4H₂O (A) has been studied under UV radiation of 254 nm at 35°C in DMSO. The initial rate of polymerization, R_p is proportional to [MMA]^1.11±0.13. R_p also varies linearly with the square root of [A] up to 5.00 X 10^-4 mol l^-1 and above this concentration, R_p decreases with the increase of [A]. It is likely that at a higher concentration of the complex A, the termination of the polymer chain occurs through interaction between the molecules of the complex. A suitable mechanism has been proposed to explain the kinetics of the reaction.     

新型Schiff碱基液晶化合物的合成及表征

以十一烯酸、对羟基苯甲酸、4-羟基苯甲醛、4-甲氧基苯胺为原料,经酰氯化、酯化和席夫碱反应合成中间体和未见文献报道的液晶化合物.通过红外光谱、核磁共振、元素分析等对化合物的结构进行表征.最后利用偏光显微镜测试目标产物的液品性能.结果表明:两种烯酸衍生物均具有向列相液品特性,化合物液晶相宽度为18℃,而增加刚性结构的长度后,合成的液晶化合物的液晶相宽度提高了近100℃,达到115℃,具有广阔的应用前景.     

希夫碱类金属配合物催化剂催化氧化烯烃研究进展

分析了希夫碱金属配合物的结构特点及其催化氧化烯烃的研究现状,阐述了用于均相催化氧化的希夫碱、固载型希夫碱金属配合物催化剂的分类及其在氧化烯烃领域的应用研究。通过分析希夫碱类小分子金属配合物催化氧化烯烃的缺陷,得出非均相的负载型希夫碱类金属配合物催化剂是目前主要发展方向的结论。