The Crystal Structure and Absolute Configuration of the Antitumor Platinum Complex tran(OH)-Pt(OH)₂(Malonato)(1R, 2R, -Cyclohexanediamine)

Abstract

The absolute configuration of the anti-tumor complex trans(OH)-Pt(OH)₂(malonato)(1R, 2R-cyclohexanediamine) was determined by X-ray anomalous scattering technique. The final unit cell was monoclinic, space group P2₁ with a = 9.142Å, b = 7.788Å, c = 11.946Å, β = 96.48°, Z = 2. The crystal structure was determined by direct method and difference Fourier synthesis, and refined to R = 0.025 and R_w = 0.033 based on 2768 independent reflections. The platinum atom has roughly octahedral coordination. The cyclohexane ring has the expected chair configuration, with two amino groups in equatorial positions while the malonato ligand, in contrast, shows a boat conformation for six membered Pt O-C-C-C-O ring.