Phosphorus As a Simultaneous Electron-Pair Acceptor in Intermolecular P center dot center dot center dot N Pnicogen Bonds and Electron-Pair Donor to Lewis Acids

0393029 - ÚOCHB 2014 RIV US eng J - Journal Article
Del Bene, J. E. - Alkorta, I. - Sanchez-Sanz, Goar - Elguero, J.
Phosphorus As a Simultaneous Electron-Pair Acceptor in Intermolecular P center dot center dot center dot N Pnicogen Bonds and Electron-Pair Donor to Lewis Acids.
Journal of Physical Chemistry A. Roč. 117, č. 14 (2013), s. 3133-3141. ISSN 1089-5639. E-ISSN 1520-5215
Institutional support: RVO:61388963
Keywords : spin coupling-constants * Gaussian-basis sets * correlated molecular calculations * noncovalent interaction
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 2.775, year: 2013

Ab initio MP2/aug'-cc-pVTZ calculations have been performed to investigate the structures and energies of binary complexes LA:PH2F and LA:PH3 and of ternary complexes LA:H2FP:NFH2 and LA:H3P:NH3 in which the pnicogen-bonded P atom also acts as an electron-pair donor to a Lewis acid (LA), for LA = BH3, NCH, ClH, FH, FCl, and HLi. Hydrogen bonds, halogen bonds, and dative covalent bonds are found at P in some cases, depending on the nature of the Lewis acid. HLi forms a lithium bond with P only in the binary complex HLi:PH3. The binding energies of ternary complexes exhibit a classical synergistic effect, although the computed cooperativity may be overestimated due to neglect of the interaction of the Lewis acid with NH2F or NH3 in some cases. The hydrogen-bonding Lewis acids appear to have little effect on the strength of the P center dot center dot center dot N bond, while the remaining Lewis acids strengthen the pnicogen bond. P-31 absolute chemical shieldings increase in LA:H2FP:NFH2 complexes relative to the corresponding LA:PH2F complexes as the positive charge on P decreases, while chemical shieldings decrease in LA:H3P:NH3 relative to the corresponding LA:PH3 complexes as the positive charge increases. Absolute values of (1P)J(P-N) spin-spin coupling constants in complexes LA:H2FP:NFH2 decrease as the P-N distance decreases. It appears that this behavior is associated with the presence of a second intermolecular interaction, whether electron-donation by P or hydrogen bond formation at P-F.
Permanent Link: http://hdl.handle.net/11104/0221783