synthesis and magnetic characterization of the copper(i1) dimer di-p- (s ub stituted phenoxo) b is- [(2,2,6,6-tetramethy l heptane-3 ,5- dionato) copper(ii)]

a number of complexes in the series (cu ll'),, where l = [(ch,),c-co-ch-coc( ch,),]-i and l'= 3-(me) c6h,0-, 2,6-(di-me)c6h30-, 4-(oh)c6h?o-, 3- (f) c6h,0-, 4-(br)c6h40-a, nd 3,s-(dl-me)c6h30h- ave been prepared and theu magnetic and optical properties determined. in chloroform, the complexes exhibit two bands in the visible and near uv regions. all complexes show room temperature magnetic moment order of 1.0 b.m. per copper atom. the x-band esr spectrum of solution samples at room temperature shows typical hm=l transition. an electron release or withdrawing group on bridging ligand causes a great change in spin-spin interaction and is observable at am =2 transition at half-field, which is the characteristic of dimeric unit