Synthesis and spectroscopic studies of some novel tetra-nuclear metal complexes derived from the reaction of 8,8'-dihydroxy-1,1'-binaphthyl-7,7'-dicarboxylic acid and CoIII and NiII ions

The tetra-nuclear novel solid complexeswith the general formulae, [M4(H2L- 2H)Clx(H2O)y].zH2O(M=NiII,CoIII; x= 6; y= 8; z = 10 in case ofNiII ; x = 10; y = 8; z = 4 in case of the CoIII complex) and [Co2Ni2(H2L-2H)Cl8(H2O)10], were isolated and characterized by conventional chemical, spectral (IR, UV-Vis., 1H-NMR,Mass), thermal and magnetic measurements. The existence of inter- and intra-molecular hydrogen bonding is confirmed fromthe results of IR and 1H-NMR spectra. Spectral and magnetic data suggest an octahedral geometry around themetal ions in all isolated metal complexes. The low values of magnetic moments suggest the existence of metal-metal interactions. The amounts of solvents inside and/or outside the coordination sphere were determined by gravimetric analysis.