Free radicals in an adamantane matrix. VIII. Epr and INDO study of the benzyl, anilino, and phenoxy radicals and their fluorinated derivatives

Journal Article · Fri Feb 01 00:00:00 EDT 1974 · J. Amer. Chem. Soc., v. 96, no. 3, pp. 659-665

OSTI ID:4346184

Lloyd, R V; Wood, D E

The effect of the different exo groups (--CH/sub 2/, -NH, or -O) on the structure and EPR parameters of the radicals was studied and trends in the fluorine and proton hfs were correlated with structural changes in the series. Fully optimized geometries calculated by INDO for the parent radicals show that in going from benzyl to phenoxy the benzene ring, which is a distorted hexagon in benzyl, becomes increasingly more symmetric, due to the increasing importance of an ionic resonance form which places an electron pair on the exo atom (C, N, or O) and an unpaired electron on the positively charged ring. EPR parameters were obtained of all the monofluoro derivatives of benzyl, anilino, and phenoxy, including those previously unknown. Trends in the various hyperfine splittings show that the overall spin density in the ring increases from benzyl to phenoxy, thus supporting the prediction of increasing importance of an ionic form. The existence of the ortho'' effect in benzyl and anilino but not in phenoxy radicals was confirmed both experimentally and theoretically whereby the fluorine hfs in o-fluoro derivatives is less than would normally be expected. Results suggest that the effect is due to a bonding interaction between the ortho fluorine and a proton on the exo atom. (auth)

• Research Organization: Univ. of Connecticut, Storrs
• NSA Number: NSA-29-018173
• OSTI ID: 4346184
• Journal Information: J. Amer. Chem. Soc., v. 96, no. 3, pp. 659-665, Journal Name: J. Amer. Chem. Soc., v. 96, no. 3, pp. 659-665; ISSN JACSA
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

*ANILINE-- RADIOLYSIS
*ARYL RADICALS-- MOLECULAR STRUCTURE
*BENZYL RADICALS-- MOLECULAR STRUCTURE
*ORGANIC FLUORINE COMPOUNDS-- RADIOLYSIS
*PHENOL- - RADIOLYSIS
*PHENOXY RADICALS-- MOLECULAR STRUCTURE
ADAMANTANE
ELECTRON SPIN RESONANCE
HYPERFINE STRUCTURE
MATRIX MATERIALS
MOLECULAR ORBITAL METHOD
N40300* --Chemistry--Radiation Chemistry
PHOTON BEAMS
SPECTRA
X RADIATION ADAMANTANE