Synthesis, spectroscopic characterization and reactivity studies of oxovanadium(IV) complexes with bulky N,N '-polymethylenebis(3,5-(t)Bu(2)salicylaldimine) ligands


Kasumov V. T. , Koksal F., Aslanoglu M., Yerli Y.

SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY, vol.77, no.3, pp.630-637, 2010 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 77 Issue: 3
  • Publication Date: 2010
  • Doi Number: 10.1016/j.saa.2010.06.040
  • Title of Journal : SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
  • Page Numbers: pp.630-637

Abstract

A series of new sterically hindered N,N'-polymethylenebis(3,5-(t)Bu(2)salicylaldimine) ligands (H2Lx)VO(IV) complexes, [VO{(2-O-3,5-(Bu2C6H2)-Bu-t)CH=N-R-N=CH-(3,5-Bu-t(2)-C6H2O-2)] (X), where R =-(CH2)(3)- (3), -(CH2)(4)- (4), -(CH2)(5)- (5), -(CH2)(6)- (6) and -CH2C(CH3)(2)CH2- (7) and early reported -(CH2)(2)- (1) and -CH2CH(CH3)- (2), has been synthesized and characterized by spectroscopic (IR, UV/vis, H-1 NMR, EPR), electrochemical and magnetic susceptibility measurements. Complexes 1-7 are described a trigonal distorted pyramids. All seven compounds give nearly the same parallel hyperfine coupling constant (A(z)) regardless that the geometry of VO(IV) changes from square pyramidal to trigonal distorted pyramids. Chemical oxidation of 1-7 by one equiv Ce(IV) leads to the formation of stable [VO(V)L-x](+) complexes. Cyclic voltammograms of 2-6 in DMSO along with a quasi-reversible VO(IV)/VO(V) redox couple also showed irreversible phenolate/phenoxyl responses. Each 1 and 7 shows only one reversible VO(IV) centered oxidation waves. Chemical oxidation of H2Lx forms the stable [H2Lx](+) radical species. (C) 2010 Elsevier B.V. All rights reserved.