Formation and Redox Interconversion of Niobium Methylidene and Methylidyne Complexes.
The niobium methylidene [{(Ar'O)2 Nb}2 (μ2 -Cl)2 (μ2 -CH2 )] (2) can be cleanly prepared via thermolysis or photolysis of [(Ar'O)2 Nb(CH3 )2 Cl] (1) (OAr'=2,6-bis(diphenylmethyl)-4-tert-butylphenoxide). Reduction of 2 with two equivalents of KC8 results in formation of the first niobium methylidyne [K][{(Ar'O)2 Nb}2 (μ2 -CH)(μ2 -H)(μ2 -Cl)] (3) via a binuclear α-hydrogen elimination. Oxidation of 3 with two equiv of ClCPh3 reforms 2. In addition to solid state X-ray analysis, all these complexes were elucidated via multinuclear NMR experiments and isotopic labelling studies, including a crossover experiment, support the notion for a radical mechanism as well as a binuclear α-hydrogen abstraction pathway being operative in the formation of 2 from 1.
Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA.
Keith
K
Searles
Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA.
Kyle T
KT
Smith
Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA.
Takashi
T
Kurogi
Molecular Structure Center, Indiana University, Bloomington, IN, 47405, USA.
Chun-Hsing
CH
Chen
Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA.
Patrick J
PJ
Carroll
Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104, USA. mindiola@sas.upenn.edu.
Daniel J
0000-0001-8205-7868
DJ
Mindiola
aryloxide; dinuclear complexes; methylidene; methylidyne; niobium