Optical and thermal electron transfer in rigid difunctional molecules of fixed distance and orientation

Journal Article · Wed Aug 19 00:00:00 EDT 1987 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00251a001· OSTI ID:6089560

Penfield, K W; Miller, J R; Paddon-Row, M N; Cotsaris, E; Oliver, A M; Hush, N S

Pulse radiolysis has been used to investigate intramolecular electron transfer in a series of molecules in which dimethoxynapththalene (M/sub 2/N) and dicyanovinyl (DCV) groups are held at fixed distance and orientation by rigid saturated hydrocarbon bridges. Electron transfer from M/sub 2/N/sup -/ to DCV is faster than 1 x 10/sup 9/ s/sup -1/ for compounds in which the two groups are separated by 4, 6, 8, 10, or 12 saturated carbon-carbon bonds. For the 4-, 6-, and 8-bond compounds, optical electron transfer bands are present in the visible - near-infrared absorption spectra of the anions. The positions shift to higher energies with increasing solvent polarity. Their intensities are large (epsilon approx. = 2000 M/sup -1/ cm/sup -1/ for the 4-bond compound) and decrease rapidly as the length of the bridge increases. It is clear that exceptionally large, long-distance electronic coupling of the two ..pi.. systems occurs through the saturated bonds of the bridge. These electronic couplings are 0.16, 0.06, and 0.03 eV across 4-, 6-, and 8-bond bridges. Even larger couplings have been observed previously by photoelectron spectroscopy, but not for such large ..pi.. systems. With these large electronic couplings, long-distance electron transfer in the 4- and 6-bond compounds is expected to be adiabatic. Even for the 8-bond compound with a center-to-center distance of approx.12 A the electron-transfer rate reduced from the optical electron-transfer absorption band is > 10/sup 12/ s/sup -1/.

• Research Organization: Argonne National Lab., IL
• DOE Contract Number: W-31-109-ENG-38
• OSTI ID: 6089560
• Journal Information: J. Am. Chem. Soc.; (United States), Vol. 109:17
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
CONDENSED AROMATICS
ELECTRON TRANSFER
RADIOLYSIS
CYANIDES
ORGANIC OXYGEN COMPOUNDS
VINYL MONOMERS
CHEMICAL BONDS
EXPERIMENTAL DATA
AROMATICS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
DATA
DECOMPOSITION
INFORMATION
MONOMERS
NUMERICAL DATA
ORGANIC COMPOUNDS
RADIATION CHEMISTRY
RADIATION EFFECTS
400600* - Radiation Chemistry