Heteronuclear Nucleobase Complexes as Tools for the Isolation of the Minor Rotamer of the Parent Compound: Synthesis and Crystal Structure Determination of Head-Head and Head-Tail Forms of trans-[(CH3NH2)2Pt(1-MeC-N3)2]2+ (1-MeC = 1-methylcytosine)

Abstract

The two rotamers (head-tail, 1, and head-head, 2) of the bis(1-methylcytosine)complex of trans-(CH3NH2)2Pt(II), have been crystallized as ClO4- (1, 2a) and PF6- (2b) salts and characterized by X-ray crystal structure analysis and 1H and 195Pt NMR spectroscopy. In aqueous solution, 1 is preferred over 2 by 70:30. Upon slow crystallization from H2O, 1 is obtained as the only product. Isolation of 2a and 2b has now been accomplished via formation …