PREPARATION AND CRYSTAL-STRUCTURE OF NICKEL(II) COMPLEX OF RAAZACYCLO[16.4.0.(1.18).0(7.12)]DOCOSA-2,13-DIENE

The addition of ethylenediamine to an acetonitrile solution of [Ni(N-m eso-L(1))](ClO4)(2) (L(1) = hyl-2,6,13,17-tetraazacyclo[16.4.0.(1.18). 0(7.12)] docosa-2,13-diene) produced the N-racemic isomer [Ni(N-racemi c-L(1))](ClO4)(2) . H2O. The electronic absorption spectrum of the N-r acemic isomer in nitromethane solution showed that the wavelength and the molar absorption coefficient are much longer and larger, respectiv ely, than those of the N-meso isomer and other related 14-membered tet raaza macrocyclic complexes. The axial coordination of solvent molecul es such as DMF and MeCN is much easier to the N-racemic isomer than to the N-meso isomer. [Ni(N-racemic-L(1))](ClO4)(2) . H2O belongs to the space group Cc (No. 9) with a = 19.706(1), b = 11.651(1), c = 12.281( 1) Angstrom and beta = 111.98(2)degrees. The structure showed that the complex has a somewhat distorted square-planar geometry.