The Crystal Structure, Absolute Configuration and Circular Dichroism of (-)CD630 - and (+ )CD630 -cis-Bis[2-(2-benzoxazolyl)phenol-N]dichloroplatinum(II) . Ethanol

Abstract

The crystals of the title complex resolve spontaneously, They are orthorhombic, space group P212121, a = 1034.6(4), b = 3120(6), c = 835.3(4) pm and Z = 4. The final R values of the enantiomers are 0.036 and 0.047 for 2873 and 3622 unique reflections, respectively. This is a square-planar complex with 2 Cl atoms in cispositions. The Iigand molecule acts as a unidentate and is coordinated to the Pt atom with its N atom. The average Pt-Cl and Pt-N distances are 228.9(3) and 200.9(8) pm, respectively. The two benzoxazolyl moieties are approximately related by a twofold rotation axis through the central Pt atom and the midpoint of the two N atoms. The optical activity arises from the dissymmetric disposition of the two ligand molecules with respect to the coordination plane. The CD spectra in the range 13,000-40,000 cm-1 were measured in KBr matrix. The CD patterns were correlated with the absolute configuration as well as the crystal habit