1761-44-0Relevant academic research and scientific papers
Synthesis, spectroscopic, antibacterial and antioxidant activities of Pd(Ii) mixed-ligand complexes containing tridentate schiff bases
Demehin,Oladipo,Semire
, p. 413 - 426 (2020/11/13)
Pd(II) complexes of the form [PdLNH3] (where L = N-salicylidene-o-aminophenol (L1), N-(5-methoxysalicylidene-o-aminophenol) (L2) and N-(2-hydroxy-1-naphthalidene)-o-aminophenol) (L3) containing ammonia and ONO tridentate Schiff bases were synthesized. These complexes were characterized by elemental analysis, infrared, ultraviolet-visible, proton and carbon-13 spectroscopies. The NMR spectra showed that the Schiff bases coordinated to the palladium(II) ion through the two deprotonated phenolic oxygen and azomethine nitrogen atoms. The presence of ammonia molecules in these complexes were indicated by the IR and 1H NMR spectra. The spectral data suggested a square planar geometry for the complexes. The biological studies revealed that the complexes displayed better antibacterial and antioxidant activities than the parent Schiff bases.
Mechanistic Features of the Oxidation-Reductive Coupling of Alcohols Catalyzed by Oxo-Vanadium Complexes
Steffensmeier, Eric,Swann, Matthew T.,Nicholas, Kenneth M.
, p. 844 - 854 (2019/01/04)
The oxo-vanadium-catalyzed redox disproportionation of activated alcohols (oxidation-reductive coupling, Ox-RC) produces carbonyl compounds and hydrocarbon dimers. A mechanistic study of this novel reaction is reported herein. Following our initial disclosure, new findings include the following: (1) The [(salimin)VO2]--catalyzed Ox-RC of Ph2CHOH in the presence of fluorene affords the products of H-atom abstraction and all possible hydrocarbon dimers. (2) Electronic substituent effects on the relative rates of Ox-RC with respect to 4-X-BnOH reactants and Bu4N[(Y-salimin)VO2] catalysts (1a-c) reveal (a) a correlation of the oxidation rate of X-BnOH reactants with the radical σ parameter and (b) correlation of the oxidation rate for (Y-salimin)VO2- with the standard Hammett σ parameter. (3) The ease of electrochemical reduction of 1a-c is Y = NO2 > OMe > H. (4) Ambient 1H NMR studies of the interaction of 1 with alcohols suggest only a weak equilibrium association. (5) Density functional theory computational modeling of the Ox-RC reaction supports a ping-pong-type catalytic pathway, beginning with alcohol oxidation by (salimin)VO2-, preferably by stepwise-H-atom transfer from the alcohol to 1, affording the carbonyl product and the reduced (salimin)V(III)(OH)2-. The reduction half-reaction likely begins with condensation of the latter species with R2CHOH to give the alkoxide complex (salimin)V(OR)OH- homolysis of the R···OV(III)(salimin) bond affords (salimin)V(IV)OH(O)- and the R-radical; the latter dimerizes and the former can disproportionate via H-transfer to reform catalyst (salimin)VO2- (1) and (salimin)V(OH)2-.
