Structures of 1,3-bis(diphenylphosphino)propane platinum(II) alditolate complexes

Single-crystal X-ray diffraction studies have been carried out on three cry stalline (dppp)Pt(II)(alditolate) complexes derived from reactions of the s ugar alcohols glycerol, erythritol, and galactitol with (dppp)Ft(CO3). The alditols bind to the platinum via adjacent, deprotonated hydroxyl groups to form a 2,5-dioxaplatinacyclopentane ring system having hydroxyalkyl substi tuent side-chains. The hydroxyl groups in these side-chains all engage in e ither intra- or intermolecular hydrogen bonds, the former preferentially in volving hydrogen bond donation from a hydroxyl group on the beta-carbon of the metallacycle dihydroxyethyl or trihydroxypropyl substituent to either t he near or far metallacycle oxygen atoms to give a six- or seven-membered h ydrogen-bonded ring system, respectively. Five-membered hydrogen-bonded rin g systems to the adjacent metallacycle oxygen are observed for hydroxymethy l side-chains. These hydrogen-bonded interactions are believed to play a si gnificant role in the complexation regioselectivity observed in these aldit olate complexes. Conformations of the 2,5-dioxaplatinacyclopentane ring and dppp chelate ring are also discussed, as are comparisons with other aldito late and diolate structural determinations. (C) Published by Elsevier Scien ce S.A.