The preparation and solution behavior of a series of novel, dinuclear organoplatinum(II) complexes of nicotinic acid 3 and 4, isonicotinic acid 5, and nicotinamide 6 are reported. For 3 and 4, comprehensive 1H NMR titration studies demonstrate their spontaneous self-association to afford discrete, hydrogen-bonded aggregates in CD2Cl2 solution at 298 ± 0.1 K. For 3, the titration data are consistent with the formation of a nanoscale cyclic entity (3)3 which, despite rise presence of bulky PPh3 ligands, is strongly favored in solution (K3 = 1.99 x 104 ± 7.89 x 102 mol-2 dm6). Complex 4 aggregates to form a cyclic dimer (4)2 with K2 = 98.2 ± 1.1 mol-1 dm3, and complexes 5 and 6 appear to afford oligomeric (or polymeric) aggregates. The X-ray crystal structure of 6 shows the dications associate to form corrugated chains connected by hydrogen bonds. This work demonstrates that the noncovalent assembly of multimeric cyclic arrays with nanoscale dimensions from simple diplatinum(II) complexes is feasible in nonaqueous solution.
ASJC Scopus subject areas
- Colloid and Surface Chemistry