Distance and exoergicity controlled excited state electron transfer kinetics

Abstract

The oxidative quenching of excited state ruthenium(ll) complexes, Ru(2,2'-bipyridine)<img src='http://www.niscair.res.in/jinfo/equation52.gif' border=0> (Ru(bpy) <img src='http://www.niscair.res.in/jinfo/equation52.gif' border=0>), Ru(4,4'-dimethyl- ,2'-bipyridine) <img src='http://www.niscair.res.in/jinfo/equation52.gif' border=0> (Ru(dmbpy) <img src='http://www.niscair.res.in/jinfo/equation52.gif' border=0>) and Ru(4-methyl-4' -neophentyl- 2,2'-bipyridine) <img src='http://www.niscair.res.in/jinfo/equation52.gif' border=0> (Ru(mnbpy) <img src='http://www.niscair.res.in/jinfo/equation52.gif' border=0>) by nitroaromatics, quinones and methyl viologen have been studied in acetonitrile. The value of the quenching rate constant, <i>k_q, </i> is in the order Ru(bpy) < Ru(dmbpy) > Ru(mnbpy) . This trend has been rationalised in terms of the interplay of electron-transfer distance and exoergicity.he oxidative quenching of excited state ruthenium(ll) complexes, Ru(2,2'-bipyridine)+(Ru(bpy) +), Ru(4,4'-dimethyl- ,2'-bipyridine) (Ru(dmbpy)) and Ru(4-methyl-4' -neophentyl- 2,2'-bipyridine) (Ru(mnbpy)+) by nitroaromatics, quinones and methyl viologen have been studied in acetonitrile. The value of the quenching rate constant, <i>k_q, </i>is in the order Ru(bpy) < Ru(dmbpy) > Ru(mnbpy) . This trend has been rationalised in terms of the interplay of electron-transfer distance and exoergicity.