Borane-lewis base complexes as homolytic hydrogen atom donors.
Radical stabilization energies (RSE)s have been calculated for a variety of boryl radicals complexed to Lewis bases at the G3(MP2)-RAD level of theory. These are referenced to the B-H bond dissociation energy (BDE) in BH(3) determined at W4.3 level. High RSE values (and thus low BDE(B-H) values) have been found for borane complexes of a variety of five- and six-membered ring heterocycles. Variations of RSE values have been correlated with the strength of Lewis acid-Lewis base complex formation at the boryl radical stage. The analysis of charge- and spin-density distributions shows that spin delocalization in the boryl radical complexes constitutes one of the mechanisms of radical stabilization.
Hioe
Johnny
J
Department Chemie und Biochemie, LMU München, Butenandtstrasse 5-13, 81377 München, Germany.
Karton
Amir
A
Martin
Jan M L
JM
Zipse
Hendrik
H