The complex [Ru(bpy)2(dbneil)][PF6]2 forms discrete dimers in solution held by strong pi-pi stacking interactions via its distorted dibenzoeilatin ligand, indicating that planarity is not an obligatory requirement for achieving strong pi-stacking, as long as complementarity between the stacking moieties can be achieved.

The C(1)-symmetrical complex [Ru(bpy)(2)(ieil)][PF(6)](2) exhibits unique electrochemical and photophysical properties, and forms discrete dimers in solution and in the solid state held by weak pi-pi stacking interactions via its isoeilatin ligand, preferentially from one of its faces and in a specific orientation.

The polymerization of propylene employing the recently developed amine bis(phenolate) zirconium catalysts is reported for the first time. The polymerizations were conducted in liquid propylene employing two different experimental setups, and two different precatalysts, based on the same amine bis(phenolate) ligand having a dimethylamino donor on a sidearm. The first precatalyst studied was a dibenzyl zirconium complex, which was found to lead to high molecular weight atactic polypropylene. The effects of the cocatalyst, the ratio between the cocatalyst and the precatalyst, and the polymerization temperature on the nature of the resulting polymer and the activity of the catalyst were studied. Reducing the relative amount of the cocatalyst and lowering the polymerization temperature increased the molecular weight of the polymer, and a temperature of 50 °C led to the most active catalyst. A dichloro zirconium complex of the same ligand, expected to show a higher hydrolytic and thermal stability was developed, its X-ray structure was solved, and its activity in polymerization of propylene was studied and found to be similar to that of the dibenzyl precatalyst.

The reaction of [(η5-Ph4C4COHOCC4Ph4-η5)(μ-H)[(CO)4Ru2] (1) with several alkynes was studied. Two new types of Ru complexes, [(η5-Ph4C4CO)(CO)2RuC(Ph)=CPh] (6) and [(η5-Ph4C4COH)(CO)2 RuC(CO2Me)=CHCO2Me] (7), were isolated and structurally characterized by single-crystal X-ray crystallography. These complexes were found to be implicated in the hydrogenation of alkynes with 1 as a catalyst precursor. While complex 7 was found to function as a catalyst in the hydrogenation cycle, complex 6 acts as a catalysis poison by virtue of its stability and irreversible formation. A catalytic cycle has been proposed.

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