Kinetics of solvated electrons in reaction with hexamethylphosphoric triamide

Abstract

Solvated electrons, es-, have been generated in hexamethylphosphoric triamide (HMPA) by chemical and electrochemical means. W h e n Na metal was used to release es-, two distinct bands, already reported in the literature, appeared in t h e absorption spectrum of t h e solution, which rapidly turned red-brown and decomposed according to irreproducible complex kinetics which could not be analysed. When Li was used instead of sodium, a single broad band extending into t h e IR region developed and later decayed obeying consistently first-order kinetics in absorbance. Kinetic rate constants are reported and half-lives at ambient temperature were about 1 h duration. A systematic study of the disappearance of solvated electrons in HMPA was carried out at several temperatures (from 7 to 27°C) and an activation energy ( 8 H 9 kJ mol-') is estimated both in t h e absence and in the presence of lithium perchlorate. However, t h e overall reaction rate is markedly increased in the presence of Li' ; a mechanism is proposed to account for this lithium salt effect.

Controlled Radical Polymerization Initiated by Solvated Electrons

“…The preparation of e sol − was carried out at 10 °C, a temperature slightly larger than the melting point (7.2 °C) of HMPA, to reduce the rapid decay of e sol − at high temperatures. [ 54 ] Conductivities were measured in real‐time to monitor the states of e sol − solution. Once MMA was introduced into the Na/HMPA solution, the blue solution of e sol − turned immediately into a faint yellow of polymerization solution, together with a sharp decline in conductivities (Figure 1a), revealing the high reactivity of e sol − .…”

Unexpected electrochemical reduction of fluoranthene in the solvents DME and HMPA: new light onto the mechanism of hydrogenation to produce tetrahydrofluoranthene

“…The EPR spectrum of the oxidized species extended over a full range of 21.4 G, and was easily analysed as a set of 5 lines with 4.3 G splitting, each of which was further split into triplets with lines 1.07 G apart from each other. We have not been able to assign a structure to this paramagnetic species, but the essential fact is that it was produced at the expense of the dianionic diamagnetic blood-red X2 -; note that this paramagnetic entity eventually decomposed Production ofHMPA radical anion (7) with regeneration of the starting fluoranthene Aro. These results are fully compatible with the singlet bonding complex [Are-*-HMPA] that we propose, in which the e-are no longer readily available, e.g.…”

Spectroscopic characterization of the blue and red complexes in reduced SO2 solutions in HMPA

“…This avoids problems due to the rather weak stability of solvated electrons in HMPA at room temperature. 24 In order to minimize losses of the volume of the gas phase relative to the volume of SO 2 , the liquid phase was kept as small as possible. The value of n for each solution investigated has been calculated by taking into account the content in the gas phase.…”