Title: 4,4-p-Biphenyl bis-phosphinidene: generation of a bis-W(CO)(5) complex and ab initio calculation of its electronic structure
Authors: Tran-Huy, NH ×
Le, HT
Mathey, F
Nguyen, Minh Tho #
Issue Date: 2002
Series Title: Perkin 2 issue:12 pages:2140-2145
Conference: date:Univ Louvain, Dept Chem, B-3001 Louvain, Belgium; Ecole Polytech, DCPH, CNRS,URA 7653, Lab Heteroelements & Coordinat, F-91128 Palaiseau, France; Ho Chi Minh City Univ, Fac Chem Engn, Grp Computat Chem, Thanh Pho Ho Chi Minh, Vietnam
Abstract: The (bis-7-phosphanorbornadiene-7-yl)-biphenyl was prepared from the reaction of the 4,4'-biphenyl dianion with the readily available 1-cyano-3,4-dimethylphosphole. The resulting complex was then used as a precursor of the 4,4'-p-biphenyl bisphosphinidene (P-C6H4-C6H4-P), which is trapped either by insertion reaction with MeOH leading to the bisphosphine complex or by [1+2] cycloaddition with diphenylacetylene, leading to the 4,4'-p-biphenyl bisphosphirene complex. Ab initio calculations on biphosphinidene were carried out using the CASSCF/CASPT2 method in conjunction with the 6-31G(d) basis set and both (12 electron-12 orbital) and (14 electron-14 orbital) active spaces that include all four lone pair orbitals of phosphorus atoms and the higher-lying phenyl p-orbitals. The calculated results pointed out that, in the ligand-free form, the parent 4,4'-p-biphenyl bis-phosphinidene (BPBP) exhibits a quintet ground electronic state ((5)A) having a twisted geometry, but with small quintet-singlet and quintet-triplet ((5)A less-than (1)A(g) less-than B-3(1u)) energy gaps of only 6 and 16 kJ mol(-1), respectively. While the singlet and triplet states need to be treated by multi-reference wavefunctions, the lowest-lying quintet state (5)A can essentially be described by HF-based single reference methods. In this high-spin state, BPBP is formed by a loose connection between two phenyl phosphinidenes in keeping the spin state of the P-atoms intact, leading to a weak coupling between phosphorus non-bonding electrons through the biphenyl moiety.
ISSN: 1472-779X
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Quantum Chemistry and Physical Chemistry Section
× corresponding author
# (joint) last author

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