SYNTHESIS AND CRYSTAL-STRUCTURE OF A NEW ANTITUMOR AGENT - DIAMINOCYCLOHEXANE)(1,1-CYCLOBUTANEDICARBOXYLATE)]

The crystal structure of [Pt(cis-1,4-diaminocyclohexane) (1,1-cyclobut anedicarboxylate)].1 1/2H2O has been determined by X-ray diffraction. The crystal is monoclinic with space group P2(1)/c, a = 10.358(5), b = 21.887(6), c = 13.920(7) angstrom, beta = 107.26(3)-degrees and Z = 8 . The platinum atom has slightly distorted square planar geometry, wit h two adjacent corners being occupied by two amino nitrogens of cis-1, 4-diaminocyclohexane (1,4-DACH) and the remaining two positions occupi ed with two oxygens of 1,1-cyclobutanedicarboxylate. The DACH moiety i s in a twist-boat conformation and makes a seven-membered chelating ri ng with platinum. The strain in bidentate 1,4-DACH binding with platin um is evidenced by the expansion of average N-Pt-N and Pt-N-C angles t o 98.2-degrees and 123.4-degrees, respectively. The cyclobutane ring i s nonplanar. There are two crystallographically independent molecules in the asymmetric unit surrounding the three water molecules. The equa torial planes of the two molecules are titled at 32-degrees to each ot her. The near edges are directly hydrogen-bonded, while the open side is hydrogen bonded through the water molecules.