199683-40-4Relevant academic research and scientific papers
Crystal structures and catalytic performance of three new methoxy substituted salen type nickel(II) Schiff base complexes derived from meso-1,2-diphenyl-1,2-ethylenediamine
Ghaffari, Abolfazl,Behzad, Mahdi,Pooyan, Mahsa,Amiri Rudbari, Hadi,Bruno, Giuseppe
, p. 1 - 7 (2014)
Three new nickel(II) complexes of a series of methoxy substituted salen type Schiff base ligands were synthesized and characterized by IR, UV-Vis and 1H NMR spectroscopy and elemental analysis. The ligands were synthesized from the condensation of meso-1,2-diphenyl-1,2-ethylenediamine with n-methoxysalicylaldehyde (n = 3, 4 and 5). Crystal structures of these complexes were determined. Electrochemical behavior of the complexes was studied by means of cyclic voltammetry in DMSO solutions. Catalytic performance of the complexes was studied in the epoxidation of cyclooctene using tert-butylhydroperoxide (TBHP) as oxidant under various conditions to find the optimum operating parameters. Low catalytic activity with moderate epoxide selectivity was observed in in-solvent conditions but in the solvent-free conditions, enhanced catalytic activity with high epoxide selectivity was achieved.
Crystal structure, electrochemistry, and catalytic studies of a series of new oxidovanadium(IV) Schiff-base complexes derived from 1,2-diphenyl-1,2- ethylenediamine
Ghaffari, Abolfazl,Behzad, Mahdi,Dutkiewicz, Grzegorz,Kubicki, MacIej,Salehi, Mehdi
experimental part, p. 840 - 855 (2012/09/22)
New derivatives of N2O2 tetradentate Schiff bases, from condensation of meso-1,2-diphenyl-1,2-ethylenediamine and salicylaldehyde derivatives (X-salicylaldehyde; X=3-OMe, 4-OMe, 5-OMe, 6-OMe, 5-Cl, 5-Me), and oxidovanadium(IV) complexes were synthesized and characterized by 1H NMR, UV-Vis, IR spectroscopy, and elemental analysis. Crystal structure of 5-OMe; H2L3and two of the complexes (VOL2 and VOL3) were also obtained. In the crystals, the molecule of H 2L3 is Ci symmetrical, as it occupies the special position on the center of symmetry; its conformation is partially determined by classical intramolecular O-H ... N hydrogen bonds. The complexes have monomeric structures with a distorted square pyramid of vanadium, with the oxo ligand in the apical position. Cyclic voltammetry studies show quasi-reversible VIV/VV redox for which the presence of electron-withdrawing groups on salicylaldehyde derivatives shifts the E 0 to more positive values. The complexes were used as catalysts for selective epoxidation of cyclooctene with tert-butylhydroperoxide as oxidant, in various solvents and reaction conditions. High catalytic activities and excellent selectivity was found. The catalytic activity of the complexes increased increasing E0, a consequence of the presence of electronegative substituents. This epoxidation process with the new catalysts was also studied under solvent-free condition and excellent reactivity was observed.
