Preparation, spectral behaviour and oxidation of some new zinc(II) salicylaldimines containing sterically hindered phenol.
A series of new bis[N-(2,6-di-tert-butyl-1-hyxyphenyl)salicylideneminato]zinc(II) complexes bearing one or two HO- and CH3O-substituents on the salicylaldehyde moiety were prepared, and their spectroscopic properties (IR, electronic, 1H NMR) as well as the ESR spectra of the one-electron oxidation products were examined. The 1H NMR examination of Zn(Lx)2 indicates that, contrary to expectations, the proton resonances of the complexes are shifted to the high-field side compared with those of the free ligands. Oxidation of these compounds with PbO2 results in the formation of mono- and biradical types Zn(II)-stabilized phenoxyls in which there are both anisotropic and alternating line-width trends. Some spectral patterns are typical for weak interacting (J << A) or the case of J approximately A biradicals, in which ESR signal appeared as superimposition of two non-interacting monoradical centers with S = 1/2. ESR studies on biradicals type of Zn(L*x)2 at 300 and 77 K did not show any evidence of strong exchange coupling in these systems. All radical species were characterized by the ESR parameters.
Kasumov
V T
VT
Chemistry Department, Faculty of Arts and Sciences, Harran University, Sanliurfa, Turkey. vkasumov@harran.edu.tr
D000447:Aldehydes / Q000737:chemistry*; D000814:Aniline Compounds / Q000737:chemistry; D016880:Anisotropy; D004578:Electron Spin Resonance Spectroscopy; D004583:Electrons; D007854:Lead / Q000737:chemistry; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D009942:Organometallic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry; D019800:Phenol / Q000737:chemistry*; D011522:Protons; D012545:Schiff Bases / Q000737:chemistry; D013055:Spectrophotometry, Infrared; D015032:Zinc / Q000737:chemistry*
D000447:Aldehydes; D000814:Aniline Compounds; D008024:Ligands; D009942:Organometallic Compounds; D010087:Oxides; D011522:Protons; D012545:Schiff Bases; C013243:salicylaldehyde; D007854:Lead; D019800:Phenol; C047365:lead oxide; D015032:Zinc