Search results for "Pi bond"
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Structure, magnetizability, and nuclear magnetic shielding tensors of bis-heteropentalenes. IV. Dihydrophospholophosphole isomers
2005
The geometry of the heteropentalenes formed by two phosphole units has been determined at the DFT level. The magnetic susceptibility and the nuclear magnetic shielding at the nuclei of these systems have also been calculated using gauge-including atomic orbitals and a large Gaussian basis set to achieve near Hartree-Fock estimates. A comparative study of the various isomers, of their flattened analogs, and of the parent phosphole molecule, shows that the [3,4-c] isomer is the most aromatic system in the set considered, assuming diatropicity and degree of planarity as indicators, even if it is the less stable in terms of total molecular energy. Plots of magnetic field-induced current densiti…
Ab initio molecular orbital study of the substituent effect on phosphine–borane complexes
1998
Abstract Ab initio molecular orbital calculations have been used to study the substituent effect on H 3 BPH n Me 3− n and Me 3− n H n BPH 3 ( n =0–3) phosphine–borane complexes. The ab initio results show that successive methyl substitution on the phosphine favours complex formation, contrary to successive methyl substitution on the borane. The natural bond orbitals partitioning scheme suggests that, in general, there is no correlation between the charge transfer and the complexation energies. It also shows the shortening of the P–H and P–C bond lengths, upon complexation, is due to the increasing `s' character of these bonds.