Catalytic Property For Epoxidation Research Articles

Ethanol-Coordinated Dioxidomolybdenum(VI) Complexes with Aroylhyrazone Ligands: Synthesis, Spectroscopic Characterization, Crystal structures and Catalytic Oxidation Property

Two new dioxidomolybdenum(VI) complexes, [MoO2L1(EtOH)] (1) and [MoO2L2(EtOH)] (2), derived from the aroylhydrazone ligands N’-(2-hydroxyl-3-methoxybenzylidene)-3-methylbenzohydrazide (H2L1) and 4-fluoro-N’-(2-hydroxylbenzylidene) benzohydrazide (H2L2), respectively, were prepared in ethanol under ambient temperature. Both complexes were characterized by elemental analysis, IR and UV-Vis spectroscopy, as well as single crystal X-ray determination. The Mo atoms in the complexes are in octahedral coordination. Crystal structures of the complexes are stabilized by hydrogen bonds. The catalytic property for epoxidation of styrene by both complexes was studied.

Methyl Maltolate and Ethyl Maltolate Coordinated Oxidovanadium(V) Complexes with N'-(2-Hydroxy-5-methylbenzylidene)-4-trifluoromethylbenzohydrazide: Synthesis, Crystal Structures and Catalytic Epoxidation Property.

A mononuclear methyl maltolate (Hmm) coordinated oxidovanadium(V) complex [VOL1(mm)] (1), and a mononuclear ethyl maltolate (Hem) coordinated oxidovanadium(V) complex [VOL2(em)] (2), where L1 and L2 are the dianionic form of N'-(2-hydroxy-5-methylbenzylidene)-3-trifluoromethylbenzohydrazide (H2L1) and N'-(2-hydroxy-5-methylbenzylidene)-4-trifluoromethylbenzohydrazide (H2L2), respectively, have been prepared. The hydrazones and the complexes were characterized by elemental analysis, FT-IR and UV-Vis spectra. Structures of H2L1 and the two complexes were further characterized by single crystal X-ray diffraction. The two complexes have similar structures, with the V atoms in octahedral coordination. The hydrazones behave as ONO tridentate ligands with the V atoms. Both complexes have interesting properties on the catalytic epoxidation of cyclooctene.

Synthesis, characterization and X-ray crystal structures of oxidovanadium(V) and dioxidomolybdenum(VI) complexes derived from 2-bromo-N'-(3,5-dichloro-2-hydroxybenzylidene)benzohydrazide

A new oxidovanadium(V) complex, [VOL(OEt)(EtOH)] (1), and a new dioxidomolybdenum(VI) complex, [MoO2L(OH2)] (2), where L is the dianionic form of 2-bromo-N'-(3,5-dichloro-2-hydroxybenzylidene)benzohydrazide, have been synthesized and structurally characterized by physico-chemical methods and single crystal X-ray determination. X-ray analysis indicates that the V and Mo ions in the complexes are in octahedral coordination. Crystal structures of the complexes are stabilized by hydrogen bonds. The catalytic property for epoxidation of styrene by the complexes was evaluated. Both complexes have effective catalytic properties for the epoxidation of styrene, with conversions over 76% and selectivities over 92%.

Two Oxidovanadium(V) Complexes with Hydrazone Ligands: Synthesis, Crystal Structures and Catalytic Oxidation Property.

Two new oxidovanadium(V) complexes, [VOL1(aha)]DMF (1) and [VOL2(mat)] (2), where L1 and L2 are the dianionic form of N'-(4-bromo-2-hydroxybenzylidene)-3-methyl-4-nitrobenzohydrazide and N'-(3,5-dibromo-2-hydroxybenzylidene)pivalohydrazide, respectively, and aha and mat are the monoanionic form of acetohydroxamic acid and maltol, respectively, have been synthesized and structurally characterized by physico-chemical methods and single crystal X-ray determination. X-ray analysis indicates that the V atoms in the complexes are in octahedral coordination. Crystal structures of the complexes are stabilized by hydrogen bonds. The catalytic property for epoxidation of styrene by the complexes was evaluated.

Synthesis, Crystal Structures, Characterization and Catalytic Property of Copper(II) Complexes Derived from Hydrazone Ligands

A new bromido-coordinated mononuclear copper(II) complex [Cu(HL1)Br2] (1), and a new mononuclear copper(II) complex [CuL2(HL2)]ClO4·0.5H2O (2), with the hydrazone ligands 4-tert-butyl-N'-(1-(pyridin-2-yl)ethylidene)benzohydrazide (HL1) and 4-bromo-N'-(pyridin-2-ylmethylene)benzohydrazide (HL2), have been synthesized and structurally characterized by physico-chemical methods and single crystal X-ray determination. X-ray analysis indicates that the Cu atom in complex 1 is in distorted square pyramidal coordination, and that in complex 2 is in octahedral coordination. The catalytic property for epoxidation of styrene by the complexes was evaluated.

Two new polyoxoniobosilicate-based compounds: Syntheses, structures, characterizations and their catalytic properties for epoxidation and water oxidation

Two new polyoxoniobosilicates, Na12[Cu(en)2(H2O)2]5[H3(SiOH)2Si2Nb16O54]2·52H2O (1) and K4[Cu(en)2(H2O)2]2[Cu(en)2(H2O)]2[Cu(en)2][SiNb18O54]·16H2O (2) (en ​= ​ethylenediamine), have been successfully prepared with the combination method of hydrothermal and solvent evaporation methods. Both the two compounds were characterized by IR, PXRD, single crystal X-ray diffraction analysis, etc. Single crystal X-ray analysis shows that compounds 1 and 2 include a Dawson-like and a crescent-like cluster, respectively. The catalytic performances of compounds 1 and 2 were evaluated for the oxidation of styrene and the oxygen evolution reaction (OER). For the oxidation of styrene, under optimized conditions, compound 2 can achieve a 93.3% conversion in 8 ​h with a 71.1% selectivity toward styrene oxide, while, for the OER compound 1 exhibited the higher performance, offering a stable current density of 10 ​mA ​cm−2 at 533 ​mV in basic media.

Synthesis, Crystal Structures, Characterization and Catalytic Property of Manganese(II) Complexes Derived from Hydrazone Ligands

A new bromido-coordinated mononuclear manganese(II) complex [MnL1Br2(OH2)] (1), and a new nitrato-coordinated mononuclear manganese(II) complex [Mn(L2)2(ONO2)(OH2)]NO3 (2), with the hydrazone ligands 4-hydroxy-N’-(pyridin-2-ylmethylene)benzohydrazide (HL1) and N’-(pyridin-2-ylmethylene)isonicotinohydrazide (HL2), have been synthesized and structurally characterized by physico-chemical methods and single crystal X-ray determination. Single crystal structural analysis shows that the Mn atom in complex 1 is in octahedral coordination, and that in complex 2 is in pentagonal bipyramidal coordination. The catalytic property for epoxidation of styrene by the complexes was evaluated.

Synthesis, Crystal Structures and Catalytic Property of Dioxidomolybdenum(VI) Complexes with Tridentate Hydrazones

New dioxidomolybdenum(VI) complexes with the formula [MoO 2 L(MeOH)], derived from N' -(5-chloro-2-hydroxybenzylidene)-2-methylbenzohydrazide (H 2 L 1 ) and N' -(3,5-dichloro-2-hydroxybenzylidene)-2-methylbenzohydrazide (H 2 L 2 ) were prepared. Crystal and molecular structures of the complexes were determined by single crystal X-ray diffraction method. Both complexes were further characterized by elemental analysis and FT-IR spectra. Single crystal X-ray structural studies indicate that the hydrazones L 1 and L 2 coordinate to the MoO 2 cores through the enolate oxygen, phenolate oxygen and azomethine nitrogen. The Mo atoms in both complexes are in octahedral coordination. Catalytic properties for epoxidation of styrene by the complexes using PhIO and NaOCl as oxidant have been studied.

Synthesis, X-Ray Crystal Structure of Oxidovanadium(V) Complex Derived from 4-Bromo-N’-(2-hydroxybenzylidene) benzohydrazide with Catalytic Epoxidation Property

A new oxidovanadium(V) complex, [VOL(OCH3)(CH3OH)], where H2L = 4-bromo-N'-(2-hydroxybenzylidene)benzohydrazide, has been synthesized and fully characterized on the basis of CHN elemental analysis, FT-IR, UV-Vis, 1H and 13C NMR spectroscopy. Structures of the free hydrazone and the complex were further characterized by single crystal X-ray diffraction, which indicates that the V atom in the complex adopts octahedral coordination, and the hydrazone ligand behaves as a tridentate ligand. The catalytic epoxidation property of the complex was investigated.

Six-coordinated oxidovanadium(V) complexes derived from hydrazone and pyrone ligands: synthesis, spectroscopy, and catalytic property

Two six-coordinated oxidovanadium(V) complexes derived from N'-(2-hydroxy-5-methoxybenzylidene)pivalohydrazide with 3-hydroxy-2-methyl-4H-pyran-4-one or 2-ethyl-3-hydroxy-4H-pyran-4-one, have been prepared. The structures of the complexes have been studied using physicochemical methods. Single crystal structures have been further confirmed by X-ray crystallographic techniques. The V atoms are six-coordinated in octahedral geometry. Catalytic properties for epoxidation of styrene by the complexes using PhIO and NaOCl as oxidant have been studied.

Synthesis, X-Ray Crystal Structure, and Catalytic Epoxidation Property of an Oxovanadium(V) Complex with Hydrazone and Ethyl Maltol Ligands

A new oxovanadium(V) complex [VO(BH)(EM)], where BH = N′-(2-hydroxybenzylidene)-4-trifluoromethylbenzohydrazide, EM = ethyl maltol, is synthesized and fully characterized based on the elemental analysis, FT-IR, UV-Vis, and 1H NMR spectra. The complex is also characterized by single crystal X-ray diffraction, which indicates that the V atom adopts the octahedral coordination. The hydrazone ligand behaves as a tridentate ligand, and the ethyl maltol ligand behaves as a bidentate ligand. The catalytic epoxidation property of the complex is investigated.

Synthesis and Crystal Structure of a Dioxomolybdenum(VI) Complex Derived from 2-Bromo-N'-(3,5-dichloro-2-hydroxybenzylidene)benzohydrazide with Catalytic Epoxidation Property

A dioxomolybdenum(VI) complex [MoO2L(EtOH)] (I), derived from the hydrazone ligand 2‑bromo-N'-(3,5-dichloro-2-hydroxybenzylidene)benzohydrazide has been prepared and characterized by physico-chemical and spectroscopic methods, as well as single crystal X-ray diffraction (CIF file CCDC no. 1840671). The hydrazone ligand coordinates to the Mo atom through the phenolate oxygen, imino nitrogen, and enolic oxygen. The Mo atom is six-coordinate in an octahedral geometry. Complex I shows high catalytic activity and selectivity in the epoxidation of cyclohexene with tert-butylhydroperoxide as primary oxidant.

Synthesis and Characterization of a Novel POM-Based Compound Contained Bi-Capped Bi Keggin Anion and Organic Ligand for Multifunctional Catalytic Property

A new organic–inorganic hybrid compound contained bi-capped Bi Keggin anion, [biim][PMo 1 V Mo 11 VI Bi1.24O40]·3H2O (1) (biim = biimidazole) has been firstly synthesized and characterized by IR, UV–Vis, XRD, XPS, elemental analyses, fluorescent spectrum and TG analysis. Compound 1 exhibits a novel 2-D supramolecular network structure constructed from {PMo 1 V Mo 11 VI Bi1.24O40} anions by O···O interactions, and further extends a 3-D supramolecular framework by bridges of biimidazole with N–H···O hydrogen bonding interactions. The compound 1 performs well catalytic property for epoxidation of styrene to styrene oxide. Moreover, compound 1 displays excellent photodegradation activity for methyl orange dye.

Synthesis, X-ray crystal structure, and catalytic epoxidation property of an oxovanadium(V) complex with hydrazone and ethyl maltol ligands

A new oxovanadium(V) complex [VO(BH)(EM)], where BH = N'-(2-hydroxybenzylidene)-4-trifluoromethylbenzohydrazide, EM = ethyl maltol, is synthesized and fully characterized based on the elemental analysis, FT-IR, UV-Vis, and 1H NMR spectra. The complex is also characterized by single crystal X-ray diffraction, which indicates that the V atom adopts the octahedral coordination. The hydrazone ligand behaves as a tridentate ligand, and the ethyl maltol ligand behaves as a bidentate ligand. The catalytic epoxidation property of the complex is investigated.

Preparation and characterization of micro-spherical poly-organo-silsesquioxane immobilized ligand systems to support MoO2(acac)2 and investigation of their catalytic properties in epoxidation of alkenes

Poly(chloropropyl-methyl)silsesquioxanes (PCMSQ) were prepared using the base catalyzed sol–gel processing on methyltrimethoxysilane (MTMS) and 3-chloropropyltriethoxysilane (CPTES) with 5:5, 6:4, and 7:3 molar ratios in methanol and water. The PCMSQ with 6:4 molar ratio of MTMS:CPTES, which has the maximum yield, according to the elemental analysis, was chosen and some chlorine atoms of the chloropropyl groups were changed to different amines by refluxing it with ethylenediamine (en), diethylenetriamine (dien), ortho-phenylenediamine (opda), and 2-imidazolidinethion (imt). The amine grafted PCMSQ were then used to support MoO2(acac)2 complex and dien grafted PCMSQ with higher metal content was applied to the epoxidation of cis-cyclooctene with TBHP. The product yields were studied by gas liquid chromatography and the catalytic procedure was optimized for the parameters involved such as the solvent and oxidant. The catalytic activity of this catalyst also was investigated toward epoxidation of some other alkenes. It was also applied to check its reuse ability.

Synthesis, Crystal Structures, and Catalytic Properties of Dinuclear Manganese(III) Complexes Derived from N,N′-Bis(5-Methylsalicylidene)propane-1,2-Diamine

Two centrosymmetric dinuclear manganese(III) complexes, [Mn2L2(N3)2] (I) and [Mn2L2(NCS)2] (II), where L is the deprotonated form of N,N'-bis(5-methylsalicylidene)propane-1,2- diamine (H2L), have been prepared and structurally characterized by elemental analysis, IR and UV-Vis spectra and single crystal X-ray diffraction (СIF files CCDC nos. 1553014 (I), 1553015 (II)). The Mn atoms are in octahedral coordination. Catalytic properties for epoxidation of styrene by the complexes using PhIO and NaOCl as oxidant have been studied.

Synthesis, Crystal Structures and Catalytic Oxidation of Manganese(III) Complexes Derived from Salen-Type Schiff Base N,N'-Bis(5-nitrosalicylidene)ethane-1,2-diamine.

Two mononuclear Schiff base manganese(III) complexes, [MnL(N3)(OH2)]·CH3OH (1) and [MnL(NCS)(OH2)] · H2O (2), where L is the dianionic form of N,N'-bis(5-nitrosalicylidene)ethane-1,2-diamine, have been prepared and characterized by elemental analysis, IR and UV-Vis spectroscopy and single crystal X-ray diffraction. The Mn atom in each complex is in an octahedral coordination. Molecules of the complexes are linked through intermolecular hydrogen bonds. Catalytic properties for epoxidation of styrene by the complexes using PhIO and NaOCl as oxidant have been studied.

Synthesis, X-ray structural characterization, and catalytic property of an end-to-end azido-bridged polymeric manganese(III) complex derived from N,N′-bis(5-fluorosalicylidene)-1,2-diaminoethane

ABSTRACTA new end-to-end azido-bridged polymeric manganese(III) complex [MnL(μ1,3-N3)]n with the Schiff base ligand N,N′-bis(5-fluorosalicylidene)-1,2-diaminoethane (H2L), has been synthesized and structurally characterized by physicochemical methods and single-crystal X-ray determination. Crystal of the complex crystallizes in orthorhombic space group Pca21, with a = 10.8211(5), b = 13.4644(6), c = 11.1811(5) Å, V = 1629.08(13) Å3, Z = 4, R1 = 0.0255, wR2 = 0.0653, GOOF = 1.053. X-ray analysis indicates that the complex is an end-to-end azido-bridged polymeric manganese species. The Mn atom is coordinated in an octahedral coordination by two phenolate O and two imine N atoms from the Schiff base ligand, and two azido N atoms. The catalytic property for epoxidation of styrene by the complex was evaluated.

A mononuclear nickel(II) complex and a dinuclear manganese(III) complex derived from N,N'-bis(5-methoxysalicylidene)-1,2-ethanediamine: synthesis, crystal structures, and catalytic epoxidation property

A mononuclear nickel(II) complex and a dinuclear manganese(III) complex derived from N,N'-<i>bis</i>(5-methoxysalicylidene)-1,2-ethanediamine: synthesis, crystal structures, and catalytic epoxidation property

A mononuclear nickel(II) complex and a dinuclear manganese(III) complex derived from N,N'-bis(5-methoxysalicylidene)-1,2-ethanediamine: Synthesis, crystal structures and catalytic epoxidation property

Synthesis and characterization of a mononuclear nickel(II) complex [NiL] · CH3OH (I) and a dinuclear manganese(III) complex [Mn2L2(NCS)2] (II) derived from the bis-Schiff base N,N'-bis(5-methoxysalicylidene)-1,2-ethanediamine (H2L) are reported. The complexes were characterized by elemental analyses, IR spectra and molar conductivity. Single crystal X-ray structures of the complexes have been determined (CIF files CCDC nos. 1056778 (I) and 1056688 (II)). The Ni atom in I is in a square planar coordination, and the Mn atom in II is in an octahedral coordination. Catalytic property for epoxidation of styrene by the complexes using PhIO and NaOCl as oxidant has been studied. As a result, complex II is efficient for the styrene epoxidation.