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Summary: Radical Reactions of a Stable N-Heterocyclic Germylene: EPR Study and DFT
Calculation
Boris Tumanskii, Pauline Pine, Yitzhak Apeloig, Nicholas J. Hill, and Robert West*,
Department of Chemistry and the Lise Meitner-MinerVa Center for Computational Quantum Chemistry,
Technion-Israel Institute of Technology, Haifa 32000, Israel, and Department of Chemistry, UniVersity of
Wisconsin, Madison, Wisconsin 53706
Received February 23, 2005; E-mail: West@chem.wisc.edu
Although many reactions of stable unsaturated N-heterocyclic
divalent compounds of group 14 elements (1-4) have now been
described,1-3 the radical chemistry of these compounds is relatively
little known.4-7 Several radical adducts of silylene 2 with free
radicals of different chemical nature (TEMPO, ·P(O)(OiPr)2,
·Re(CO)5, ·MoCp(CO)2, ·WCp(CO)3, ·CH2Ph) have been studied
by EPR and DFT calculations.4 These adducts represent a new type
of neutral silyl radicals stabilized by delocalization. The first
synthetic results of free radical addition to silylenes and germylenes
have also been reported recently. The products obtained by addition
of 2,2,6,6-tetramethylpiperidine N-oxide (TEMPO) to silylenes and
germylenes differ depending upon the nature of the divalent
atoms.5,6 EPR study and DFT calculation of new radical intermedi-
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