Cocrystallization of a dinuclear platinum complex as a monomer and a one-dimensional polymer

The reaction of Pt(DMB)Cl-2 (DMB=3,3'-dihydroxymethyl-2,2'-bipyridine) with AgF3CSO3 in H2O yielded a dimeric platinum complex, [{Pt(DMB)(mu-OH)}(2)](2)(F3CSO3)(4).2H(2)O. X-ray structure reveals that two conformational isomers are self-assembled by different hydrogen bonding motifs in one crystal, resulting in a new type of co-crystal of monomer and its polymer. One conformer is self-assembled into the one-dimensional polymeric chain by strong hydrogen bonds, while the other conformer of which possible hydrogen bond donors/acceptors are blocked by two triflate anions exists as an isolated molecule itself. DFT calculations show that the strong hydrogen bonds and crystal packing force might compensate for the energy gap of similar to14 kcal mol(-1) between two conformers and the conformational energetics are dominated by the energies of the coordinated ligands rather than those of hydroxo-bridged platinum cores. (C) 2002 Published by Elsevier Science Ltd.