Photochemistry and photophysics of bis(terpyridyl) complexes of ruthenium(II) in fluid solution. Evidence for the formation of an .eta.2-diphenylterpyridine complex

Electron transfer triggered sulfoxide isomerization in ruthenium and osmium complexes

“…Naturally, this prompted the determination of the quantum yields of isomerization (Φ S→O ) for these complexes ( Table 1). The work of Ford, McMillin and others suggest that the quantum yield should be similar to those found for photosubstitution, reflecting the presumed role of the LF states in this process [34][35][36][37]47]. For [Ru(tpy)(bpy)(dmso)] 2+ , Φ S→O = 0.024(±0.02) in propylene carbonate.…”

“…For [Ru(tpy)(bpy)(dmso)] 2+ , Φ S→O = 0.024(±0.02) in propylene carbonate. This value is an order of magnitude increase over the value determined for photosubstitution of CH 3 CN by pyridine in [Ru(tpy)(bpy)(CH 3 CN)] 2+ [35,36]. This value increases another order of magnitude to Φ S→O = 0.25(±0.01) for [Ru(tpy)(pic)(dmso)] + .…”

“…In the 1980s, the work from a number of laboratories demonstrated that photosubstitution of CH 3 CN on [Ru(tpy)(bpy)(CN 3 CN)] 2+ by pyridine in acetonitrile solution occurred with a quantum yield of 0.0014 (±0.02) [34][35][36][37]. Mechanistic studies suggested a dissociative mechanism involving population of the ligand field (LF) states.…”

On the Possible Coordination on a 3MC State Itself? Mechanistic Investigation Using DFT-Based Methods

“…The aim of this work was to envisage direct NCMe coordination on the 3 considered to be involved in such mechanisms via intersystem crossing (ISC) through a neighboring minimum energy crossing point (MECP), allowing the system to populate an electrophilic, coordinatively unsaturated, and closed-shell species. The final coordination of a molecule of incoming ligand is thought to be an efficient process [43][44][45][46][47] and yields a κ 1 -bound intermediate product that requires the absorption of a second photon to fully release the departing bidentate ligand [48,49]. However an alternative pathway can also be envisaged, overall requiring only one photon, namely the direct reaction between the incoming ligand and the complex in its distorted 3 MC state, to form a new complex with triplet spin multiplicity according to Wigner rules.…”

Excited state isomerization in photochromic ruthenium complexes

“…O ) for these complexes. The work of Ford, McMillin and others suggest that the quantum yield should be similar to those found for photosubstitution, reflecting the presumed role of the LF states in this process [30][31][32][33][34][35] Ligand field vs. charge-transfer Importantly, during McMillin's detailed study of photosubstitution on ruthenium polypyridine complexes, they found that photosubstitution did not occur on osmium(II). Presumably this is due to the much larger Ligand Field (LF) exhibited by osmium relative to ruthenium.…”