PULSE RADIOLYTICALLY INDUCED RECOX AND ALKYLATION PROCESSES OF C70

Redox and alkylation (radical addition) reactions with C70 have been investigated by means of radiation chemical methods, particularly time-resolved pulse radiolysis measurements. All experiments were conducted in solutions (propan-2-ol, 2-methylpropan-2-ol and 1,2-dichloroethane) at room temperature. The differential spectrum obtained upon one-electron reduction Of C70 by (CH3)2C(OH). (k = 8 x 10(8) dm3 mol-1 s-1) and attributable to the formation of C70- shows a relatively weak but still distinct absorption band in the IR at 880 nm. One-electron oxidation of C70 by the cation of 1,2-dichloroethane (1,2-DCE.+) yields C70.+ radical cations (k greater-than-or-equal-to 2 x 10(10) dm3 mol-1 s-1) with an even weaker but still noticeable band at 925 nm. Compared with the IR-absorption bands of the analogue C60.- and C60.+ (which exhibit relatively strong and characteristic bands at 1080 and 980 nm, respectively) those attributable to the C70-derived species are considerably less intense but not absent as might have been deduced from earlier experimental and theoretical studies. IR absorptions (with maxima around 960 nm) have also been observed for (C70-CH2CH2Cl)' and (C70-CH2C(CH3)20H). which are formed upon addition of .CH2CH2Cl (k = 1.9 x 10(9) dm3 mol-1 s-1) and .CH2C(CH3)2OH (k = 1.8 x 10(9) dM3 mol-1 s-1), respectively, to C70. The absolute rate constants are very similar to those measured for the corresponding radical reactions with C60. In conclusion, C70 exhibits rather similar features to those of C60 with respect to radical and one-electron redox initiated reactions with, however, some noticeable differences.