Structural aspects of Pt complexes containing model nucleobases

Compounds of Pt(II) and Pt(IV)-containing nucleobases as ligands (also including a few related ligands) are summarized and described, according to the nuclearity of the complexes. The large amount of available crystallographic data allows geometrical parameters such as bond lengths and angles, angular distortions, torsional angles related to the nucleobase plane orientations etc., to be derived with relatively high accuracy. Simple relationships between some of these parameters are reported and discussed. On mononuclear Pt complexes containing one or more nucleobase ligands a simple descriptive statistical analysis has been performed. The structural properties of polynuclear, often heteronuclear species have also been reviewed, where the nucleobases, particularly pyrimidines, act as polydentate - often bridging - ligands. A simple MO theoretical analysis of the metal - metal interaction in homo- and heterodinuclear species allows the degree of the intermetallic bond formation to be rationalized and the correlation of the qualitative results with the experimental metal - metal distances. Cyclic polynuclear species, which appear to be a new expanding field in the chemistry of Pt - nucleobase complexes, are also described.