Synthesis, characterication and reactivity of a series of dinuclear copper commplexes bearing the lignad bis[3-(2-hydroxybenzylideneamino)phenyl] sulfone and derivatives

摘要

The ligands bis[3-(X-2-hydroxybenzylideneamino)phenyl] sulfones(X=none: BHBAPS, X=3-tert-butryl: BH(t-Bu)BAPS and X=3,5-dichloro: BHCl_2BAPS) were prepared. These, together with Cu(OAc)_2 were used in the syntheses of the dinuclear copper complexes Cu_2(BBAPS)(#mu#-OMe)_2 (1), Cu_2[B(t-Bu)BAPS](#mu#-OMe)_2(3). Complex 1 was crystallographically characterized. The structures of 2 and3 are similar to 1 by comparison of IR, UV-Vis, FAB-MS and elemental analyses results. Complexes 1-3(1 mol%) were used in the oxidation of 2,4-and 2,6-di-tutylphenol(dtbp)at -50 deg C with H_2O_2 The results show that (1) the coupling products are preferred when CH_2Cl_2 is used; and (2) the quinone yield increases when THFD is utilized. In CH_2Cl_2 with 2,4-dtbp, the yield of the coupling product ased on the complex amount, is in the order 2,1 , and 3 with yields of 6300 ,4700 and 200% , . Low temperature UV-Vi results of the reaction of 1 with H_2H_2 showed the growth of peaks at 390 and 580 nm indicative of a #mu#-#eta#~2:#eta#~2-peroxo or #mu#-#eta#~1:#eta#~1 -hydroperoxo intermediate. At -50 deg C. this spectrum does not change. But when warmed to 0 deg C , a spectrum similar to the original spectrum was obtained. This probably indicates hydrogen radical abstractions of the peroxo intermediate from solvents, and if excess H_2O_2 is present, the peroxo intermediate may again be formed . This of the complex explains the high yield using 1 and 2.