Flash photolysis 1-hexene

The reaction of EtsSiH with [l.l.l]propellane under photolytical decomposition of di-tert-butyl peroxide afforded products 17 and 18 in 1 3 ratio (Reaction 5.15) [36]. A rate constant of 6.0 x 10 M s at 19 °C for the addition EtsSi radical to [l.l.l]propellane was determined by laser flash photolysis [37]. Thus, it would appear that [l.l.l]propellane is slightly more reactive toward attack by EtsSi radicals than is styrene, and significantly more reactive than 1-hexene (cf. Table 5.1). 

Rates of reaction of CO with (arene)Mo(CO)2 (alkane) and M(C0)5 (alkane), where M = Cr, Mo, W, have demonstrated that the reaction with Cr(CO)5 (alkane) involves an interchange mechanism while for Mo and W the mechanism is more associative. These resnlts are consistent with the known ability of the higher homologs to expand beyond a coordination number of 6. Flash photolysis and ultra high speed detection (0.4 ps, 4cm resolution) have allowed direct observation (Figure 6) of the vibrational cooling of CpCo(CO)(n-hexane), CpCo(CO)(n-hexene), and the group VI carbonyls. ... 

As noted above, one of the first indications that photogenerated "unsaturated" metal carbonyls such as Cr(CO)5 were indeed solvent coordinated was the demonstration in flash photolysis experiments that the rates of the back reactions with CO as well as reactions with other other ligands are markedly dependent on the nature of the solvent medium. For example the second order rate constant k2 for eq. 5 was reported to be 3.6 x 10 M s in cyclohexane[34] and 3 x 10 M s in perfluoro-methylcyclohexane [25]. The reaction kinetics are second order, for the large part, the substitution mechanisms of these intermediates reacting with CO or other substrates are not yet fully elucidated. However, recent kinetics studies by Dobson and coworkers [35] of the reaction of Cr(CO)5S with S = n-heptane or chlorobenzene with 1-hexene or piperidine as a trapping agent have led to the conclusion that the substitution reactions occurred via competitive dissociative and interchange pathways. Complementary studies... 

In this category appear all the alkenes having at least one (3(C-C) bond. The occurrence of the primary (3(C-C) bond rupture in acyclic olefins was first shown to be the main process by Callear and Lee. Using a flash photolytic system ( > 160 nm), they generated various allylic radicals and were thus able to measure the electronic spectrum of these radicals in the 210-250 nm region (61). The quantum yields of the rupture of this bond is 0.8 (47,49,62). For example, the 147.0 and 163.3 nm photolysis of n-l-hexene leads to the primary (3(C-C) bond rupture with a high quantum value (63) ... 

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