80502-54-1Relevant academic research and scientific papers
Synthetic routes to new polypyridyl complexes of osmium(II)
Kober, Edward M.,Caspar, Jonathan V.,Sullivan, B. Patrick,Meyer, Thomas J.
, p. 4587 - 4598 (2008/10/08)
New luminescent complexes of Os(II) that contain either 2,2′-bipyridine (bpy) or 1,10-phenanthroline (phen) as the chromophoric 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., OsIV(bpy)Cl4 and mer-OsIII(PMe2Ph)3Cl3, has led to the preparation of materials with ancillary ligands such as tertiary phosphines as preparative intermediates, including OsIII(bpy)(PMe2Ph)Cl3 and cis-OsII(phen)(diphosphine)Cl2. 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)2CO3, which allows the facile preparation of dicationic, disubstituted species such as [Os(bpy)2(norbornadiene)]2+. Another general procedure, based on the control of solvent and temperature in the substitution chemistry of cis-Os(bpy)2Cl2, has been further developed to produce a variety of new complexes of the types cis-[Os(bpy)2(L)Cl]+ and cis-[Os(bpy)2(L)2]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)2(L)2]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 31P and/or 1H NMR spectroscopy.
Hydrido carbonyl complexes of osmium(II) and ruthenium(II) containing polypyridyl ligands
Sullivan, B. Patrick,Caspar, Jonathan V.,Johnson, Susan R.,Meyer, Thomas J.
, p. 1241 - 1251 (2008/10/08)
Several different synthetic routes have been explored to produce hydrido complexes of Os(II) and Ru(II) containing polypyridyl ligands. The resulting complexes, the majority of which contain coordinated CO, are of three types: cis-[M(chelate)2(CO)H]+, trans-[Os(chelate)(PPh3)2(CO)H]+, and [Os(chelate)(diphos)(PR3)H]+ (where M = Ru or Os and chelate is, for example, 2,2′-bipyridine or 1,10-phenanthroline or a related ligand). The electronic, infrared, and NMR spectral properties of the complexes are discussed along with the redox properties of their ground and excited states. An important observation is that the hydride ligand endows the metal to ligand charge-transfer (MLCT) excited states of some of the complexes with strong reducing properties. The ground-state chemistry of the complexes is discussed especially with regard to their use as synthetic precursors to new, highly oxidizing, long-lived MLCT excited states of Os(II), e.g., [OsIII(bpy-.)(bpy)(CO)(CH3CH)]2+.
