168775-31-3

Relevant academic research and scientific papers

Redox-induced conversion pathways in rhodium and iridium complexes containing C-S bond cleaved benzo[b]thiophene

The thermally generated 16-electron fragments [(triphos)MH] (M = Rh, Ir) react with benzo[b]thiophene by C-S bond scission to yield the 2-vinylthiophenolate derivatives (triphos)M[η3-S(C6H4)CH=CH2] (M = Rh, 1; Ir, 2) which display a rich redox-induced reactivity [triphos = MeC(CH2PPh2)3]. Removal of one electron from 1 or 2 leads to the corresponding paramagnetic cations I+ and 2+, respectively; these compounds undergo a radical reaction with H? in solution to form the diamagnetic 2-ethylidenecyclohexadienethione complexes anti-[(triphos)M{η4-S(C6H4)CH(CH 3)}]+ (M = Rh, anti-3+; Ir, anti-6+) which isomerize to syn-3+ and syn-6+, respectively. Addition of one electron to syn-3+ and syn-6+ gives the neutral paramagnetic derivatives syn-[(triphos)M{η4-S(C6H4)CH(CH 3)}] (M = Rh, syn-3; Ir, syn-6) which convert back to the starting complexes 1 and 2 by homolytic C-H bond cleavage liberating H?, and thus completing a full electrochemical cycle by addition/ elimination of one electron and one H atom. The related 2-(3,3,3-triphenylpropylidene)-cyclohexadienethione complex [(triphos)Rh{η4-S(C6H4)CH(CH 2CPh3)}]PF6 (4PF6) undergoes similar reactions including loss of a trityl radical by a C-C bond cleavage reaction in the neutral derivative (triphos)Rh{η4-S(C6H4)CH(CH 2CPh3)} (4). Removal of a second electron from I+ or 2+ leads to the dicationic species I2+ and 22+, which spontaneously lose a proton and produce the cationic metallabenzothiabenzene complexes [(triphos)M(η2-C,S-C8H6S)]+ (M = Rh, 5+; Ir, 7+). Finally, addition of one elecytron to 5+ or 7+ produces the corresponding neutral paramagnetic metallabenzothiabenzene complexes [(triphos)M(η2-C,S-C8H6S)] (M = Rh, 5, Ir, 7). All the long-lived paramagnetic compounds have been characterized by X-band ESR spectroscopy.