Synthetic routes to new polypyridyl complexes of osmium(II)

New luminescent complexes of Os(II) that contain either 2,2{prime}-bipyridine (bpy) or 1,10-phenanthroline (phen) as the chromophorib acceptor ligand have been prepared by a combination of established and new synthetic methods. Extensive use of Os(IV) and Os(III) precursors, e.g., Os{sup IV}(bpy)Cl{sub 4} and mer-Os{sup III}(PMe{sub 2}Ph){sub 3}Cl{sub 3} has led to the preparation of materials with ancillary ligands such as tertiary phosphines as preparative intermediates, including Os{sup III}(bpy)(PMe{sub 2}Ph)Cl{sub 3} and cis-Os{sup II}(phen)(diphosphine)Cl{sub 2}. Further substitution of chloro ligands into complexes such as these results in the formation of emissive complexes of Os(II). Another new synthetic route utilizes the versatile Os(II) precursor Os(bpy){sub 2}CO{sub 3}, which allows the facile preparation of dicationic, disubstituted species such as (Os(bpy){sub 2}(norbornadiene)){sup 2+}. Another general procedure, based on the control of solvent and temperature in the substitution chemistry of cis-Os(bpy){sub 2}Cl{sub 2}, has been further developed to produce a variety of new complexes of the types cis-(Os(bpy){sub 2}(L)Cl){sup +} and cis(Os(bpy){sub 2}(L){sub 2}){sup 2+}, where L is a phosphine, arsine, nitrogen, or olefin donor ligand. In a few cases, phosphine entering groups cause the cis geometry to be unfavorable and new trans-(Os(bpy){sub 2}(L){sub 2}){sup 2+} complexes have also been isolated. The resultant complexes comprise the largest family of transition-metal-based excited-state reagents with tunable photophysical and redox properties available. When possible, the new complexes have been characterized by UV-visible spectroscopy, emission spectroscopy, cyclic voltammetry, and {sup 31}P and/or {sup 1}H NMR spectroscopy.