TY - JOUR
T1 - Syntheses, structural, electrochemical and optical studies of heterobinuclear ruthenium-osmium alkynyl complexes
AU - West, Patrick J.
AU - Schwich, Torsten
AU - Cifuentes, Marie P.
AU - Humphrey, Mark G.
PY - 2011/8/15
Y1 - 2011/8/15
N2 - The complexes trans-[Os(CCC6H4-4-CCR)Cl(dppe) 2] (R = SiPri3 1, H 2), trans,trans-[(dppe) 2ClOs(CCC6H4-4-CC)RuX(dppe)2] (X = Cl 3, CCC6H4-4-CCSiPri3 4), trans-[Os(CCC6H4-4-CCC6H4-4-CCR) Cl(dppe)2] (R = SiPri3 5, H 6), and trans,trans-[(dppe)2ClOs(CCC6H4-4-CCC 6H4-4-CC)RuCl(dppe)2] (7) have been synthesized, and the identities of 1, 2, and 6 confirmed by single-crystal X-ray diffraction studies. Cyclic voltammetry shows that the mononuclear complexes 1, 2, 5, and 6 are oxidized at potentials within a narrow range (0.45-0.49 V), in processes centered on the osmium ethynyl neighbourhood and for simplicity assigned as OsII/III, while the heterobinuclear complexes 3, 4, and 7 exhibit lower oxidation potentials for OsII/III and a second oxidation process assigned in a similar fashion to RuII/III; the difference in potential between the Os- and Ru-localized processes decreases as the π-bridge is lengthened. UV-vis-NIR spectroelectrochemical studies on 1 and 5 reveal the appearance on oxidation of a low-energy band ascribed to chloro to metal-ethynyl charge transfer. Osmium-centered oxidation at the heterobinuclear complexes 4 and 7 results in appearance of a low-energy band, which blue-shifts and increases in intensity on further oxidation to 4 2+ and 72+.
AB - The complexes trans-[Os(CCC6H4-4-CCR)Cl(dppe) 2] (R = SiPri3 1, H 2), trans,trans-[(dppe) 2ClOs(CCC6H4-4-CC)RuX(dppe)2] (X = Cl 3, CCC6H4-4-CCSiPri3 4), trans-[Os(CCC6H4-4-CCC6H4-4-CCR) Cl(dppe)2] (R = SiPri3 5, H 6), and trans,trans-[(dppe)2ClOs(CCC6H4-4-CCC 6H4-4-CC)RuCl(dppe)2] (7) have been synthesized, and the identities of 1, 2, and 6 confirmed by single-crystal X-ray diffraction studies. Cyclic voltammetry shows that the mononuclear complexes 1, 2, 5, and 6 are oxidized at potentials within a narrow range (0.45-0.49 V), in processes centered on the osmium ethynyl neighbourhood and for simplicity assigned as OsII/III, while the heterobinuclear complexes 3, 4, and 7 exhibit lower oxidation potentials for OsII/III and a second oxidation process assigned in a similar fashion to RuII/III; the difference in potential between the Os- and Ru-localized processes decreases as the π-bridge is lengthened. UV-vis-NIR spectroelectrochemical studies on 1 and 5 reveal the appearance on oxidation of a low-energy band ascribed to chloro to metal-ethynyl charge transfer. Osmium-centered oxidation at the heterobinuclear complexes 4 and 7 results in appearance of a low-energy band, which blue-shifts and increases in intensity on further oxidation to 4 2+ and 72+.
KW - Alkynyl complexes
KW - Cyclic voltammetry
KW - Redox processes
KW - Spectroelectrochemistry
KW - X-ray crystallography
UR - http://www.scopus.com/inward/record.url?scp=79960083931&partnerID=8YFLogxK
U2 - 10.1016/j.jorganchem.2011.02.013
DO - 10.1016/j.jorganchem.2011.02.013
M3 - Article
SN - 0022-328X
VL - 696
SP - 2886
EP - 2893
JO - Journal of Organometallic Chemistry
JF - Journal of Organometallic Chemistry
IS - 17
ER -