FAR-UV LASER FLASH-PHOTOLYSIS IN SOLUTION - A STUDY OF THE CHEMISTRY OF 1,1-DIMETHYLSILENE IN HYDROCARBON SOLVENTS

The far-UV (193 nm) laser flash photolysis of nitrogen-saturated isooc tane solutions of 1,1-dimethylsiletane allows the direct detection of 1,1-dimethylsilene as a transient species, which (at low laser intensi ties) decays with pseudo-first-order kinetics (tau similar to 10 mu s) and exhibits a UV absorption spectrum with lambda(max)similar to 255 nm. Characteristic rapid quenching is observed for the silene with met hanol (k(MeOH) = (4.9 +/- 0.2) x 10(9) M(-1)s(-1)), tert-butanol (k(Bn OH) = (1.8 +/- 0.1) x 10(9) M(-1)s(-1)) and oxygen (k(O2) = (2.0 +/- 0 .5) x 10(8) M(-1)s(-1)).The Arrhenius activation parameters for the re action with methanol have been determined to be E-a = -2.6 +/- 0.6 kca l mol(-1) and log A = 7.7 +/- 0.3. (C) 1997 Elsevier Science S.A.