Premium
Reactions of Thorium Atoms with Polyhalomethanes: Infrared Spectra of the CH 2 =ThX 2 , HC÷ThX 3 , and XC÷ThX 3 Molecules
Author(s) -
Lyon Jonathan T.,
Andrews Lester
Publication year - 2008
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200701048
Subject(s) - chemistry , agostic interaction , delocalized electron , crystallography , molecule , photochemistry , metal , organic chemistry
Laser‐ablated thorium atoms react with methylene fluoride to form singlet CH 2 =ThF 2 , with fluoroform to give triplet HC÷ThF 3 , and with CF 4 to produce triplet FC÷ThF 3 molecules as the major products trapped in solid argon. Infrared spectroscopy, isotopic substitution, and density functional theoretical calculations confirm the identity of these methylidene and methylidyne complexes. Parallels with the analogous chloromethane and Group 4 metal reaction products are discussed. Structure calculations show that the C=Th bond lengths decrease and the agostic distortion increases from CH 2 =ThF 2 to CH 2 =ThFCl to CH 2 =ThCl 2 for the methylidene complexes. The triplet‐state HC÷ThF 3 and FC÷ThF 3 electron‐deficient methylidyne complexes exhibit delocalized ‐bonding as evidenced by spin densities comparable to those calculated for the analogous zirconium complexes. Chlorine substitution for fluorine supports stronger C÷Th bonds. Thus, thorium appears to react as the early transition‐metal atoms with fluoro‐ and chloromethanes. However, there is a substantial contribution from Th 5f orbitals in addition to 6d in the SOMO forming the weak π‐bonds in these electron‐deficient methylidyne complexes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)