Electron localization in liquid acetonitrile.

Journal Article · Thu Oct 03 04:00:00 EDT 2002 · J. Phys. Chem. A

DOI:https://doi.org/10.1021/jp0207580· OSTI ID:949613

Shkrob, I A; Sauer, M C

Time-resolved one- and two-pulse laser dc photoconductivity has been used to observe two kinds of reducing species, anion-1 and anion-2, in liquid acetonitrile. At 25 C, the standard enthalpy of conversion from anion-1 to anion-2 is -44.3 {+-} 3.6 kJ/mol and the conversion time is 3 ns. The high-temperature form, anion-1, absorbs in the IR and migrates >3.3 times faster than any other ion in acetonitrile. This rapid migration has a low activation energy of 3.2 kJ/mol (vs 7.6 kJ/mol for other ions). Anion-1 rapidly transfers the electron to acceptors with high electron affinity, with rate constant up to 10{sup 11} M{sup -1} s{sup -1}. The low-temperature form, anion-2, absorbs in the visible and exhibits normal mobility and electron-transfer rates, ca. 1.5 x 10{sup 10} M{sup -1} s{sup -1}. It reacts, by proton transfer, with two hydrogen-bonded molecules of water and/or aliphatic alcohols. Laser photoexcitation of these two solvent anions in their respective absorption bands leads to the formation of CH{sub 3} and CN{sup -}. We present arguments indicating that anion-2 is a dimer radical anion of acetonitrile, whereas anion-1 is a multimer radical anion that may be regarded as a 'solvated electron'.

• Research Organization: Argonne National Laboratory (ANL)
• Sponsoring Organization: SC
• DOE Contract Number: AC02-06CH11357
• OSTI ID: 949613
• Report Number(s): ANL/CHM/JA-42536
• Journal Information: J. Phys. Chem. A, Journal Name: J. Phys. Chem. A Journal Issue: 39 ; Oct. 3, 2002 Vol. 106; ISSN 1089-5639; ISSN JPCAFH
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ACETONITRILE
ACTIVATION ENERGY
ELECTRON TRANSFER
ELECTRONS
PHOTOCONDUCTIVITY