The reaction of cobalt dibromide hexahydrate with 2,2'-bipyridine (bpy) and mesitylphosphinic acid MesP(O)(OH)H (Mes = = 2,4,6-trimethylphenyl) under solvothermal synthesis conditions leads to a new dinuclear cobalt(ii) complex {Co2[µ-O2P(H)Mes]2- (bpy)4}Br2 formed by two bridging...