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Radical Reactions in an X‐Irradiated Phosphaalkene: A single‐crystal ESR study
Author(s) -
Bhat Shrinivasa N.,
Berclaz Théo,
Jouaiti Abdelaziz,
Geoffroy Michel
Publication year - 1994
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19940770135
Subject(s) - chemistry , radical , molecule , hyperfine structure , crystallography , atom (system on chip) , hyperfine coupling , ab initio , crystal (programming language) , photochemistry , atomic physics , organic chemistry , physics , computer science , programming language , embedded system
Single crystals of 1‐[2,4,6‐tri( tert ‐butyl)phenyl]‐2‐phenylphosphaethene ( PPPE ) and of 2 D‐ and 13 C‐enriched PPPE were studied by ESR after X‐ray irradiation. Two phosphorus‐centered radicals were trapped in the crystals. The first one was characterized by its 31 P, 1 H‐, and 13 C‐hyperfine tensors, the second one exhibited coupling with 31 P only. Comparison of these parameters with those predicted by ab initio calculations on some phosphinyl species indicates that these two radicals probably result, on the one hand, from an addition of a H‐atom to the C‐atom of the PC bond and, on the other, from a cyclization of the parent molecule. The proposed mechanisms are consistent with the mutual orientations of the hyperfine eigenvectors and bond directions in the undamaged molecule. A C‐centered radical which results from an addition of a H‐atom to the P‐atom of the phosphaethylene bond is also detected.