X-ray crystal structure of tetrachloro(trans-d,l-1,2-diaminocyclohexane) platinum(IV) complex: a potential anticancer agent.

Tetrachloro(trans-d,l-1,2-diaminocyclohexane)platinum(IV) complex (tetraplatin or ormaplatin) has been recognized as a potential anticancer agent. We have determined the crystal structure of this compound by x-ray single crystal diffraction. It has a unique space group and rare molecular packing. Parameters are as follows: space group R3c (rhombohedral), a = 26.425(4) A, alpha = 54.50(1) degrees; V = 11375A3, Z = 36. The coordination about Pt atoms is a slightly distorted octahedron owing to the presence of the geometrically strained five-membered ring (avg. N-Pt-N angle = 82.9 degrees). An intricate network of intermolecular hydrogen bonds holds the crystal lattice together. Three independent ormaplatin molecules surround each water molecule, forming the three shortest A...B contacts and thus the three strongest hydrogen bonds.