RESEARCH ARTICLE

The binary boron trifluoride-hydroxylamine molecular complex: N-bound or O-bound?^*

T. Anthony Ford^**

Centre for Theoretical and Computational Chemistry, School of Chemistry, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban 4000, South Africa

ABSTRACT

Boron trifluoride acts as a classical Lewis acid in forming molecular complexes with a variety of electron donors. Recent computational results on a number of complexes with some oxygen and nitrogen bases have indicated relationships between the properties of the adducts, such as the interaction energies and the wavenumber shifts of some of the modes of the boron trifluoride sub-molecule, and some physical properties of the bases. Hydroxylamine represents an example of a base containing two potential sites of electron donation, the nitrogen and the oxygen atoms. Predictions based on our earlier investigations of systems of this type suggest that hydroxylamine would bind to boron trifluoride preferentially through its nitrogen atom. Whether such a complex adopts an equilibrium structure in which the NO bond of hydroxylamine lies cis or trans to one of the BF bonds of boron trifluoride is more difficult to predict. This paper investigates the relative binding properties of N-bound versus O-bound complexes of boron trifluoride with hydroxylamine, and explores the conformational preferences and vibrational spectra of both types of adduct.

Keywords: Ab initio calculations, molecular complexes, boron trifluoride, hydroxylamine

Full text available only in pdf format.

Acknowledgements

This material is based upon work supported by the National Research Foundation under Grant Number 2053648. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Research Foundation. The author also acknowledges the financial assistance of the University of KwaZulu-Natal Research Fund, through its support of the Centre for Theoretical and Computational Chemistry, helpful discussions with Dr Gert Kruger and the invaluable technical assistance of Mr Kishore Singh.

References

1 T.A. Ford, Molecular complexes: perturbations of vibrational spectra, in Encyclopaedia of Computational Chemistry (online edition), (P. von R. Schleyer, H.F. Schaefer III, P.R. Scheiner, W.L. Jorgensen, W. Thiel and R.C. Glen, eds.), John Wiley and Sons, Chichester, UK. Article online posting date 15 June 2004. DOI: 10.1002/0470845015.cu0033.         [ Links ]

2 L.M. Nxumalo and T.A. Ford, S. Afr. J. Chem., 1995, 48, 30-38.         [ Links ]

3 L.M. Nxumalo, G.A. Yeo and T.A. Ford, S. Afr. J. Chem., 1998, 51, 25-34.         [ Links ]

4 G.A. Yeo and T.A. Ford, S. Afr. J. Chem., 2006, 59, 129-134.         [ Links ]

5 T.A. Ford, J. Mol. Structure, 2007, 834-836, 30-41.         [ Links ]

6 L.M. Nxumalo, M. Andrzejak and T.A. Ford, J. Chem. Inf. Comput. Sci, 1996, 36, 377-384.         [ Links ]

7 F. Gaffoor and T.A. Ford, Spectrochim. Acta, Part A, in press. Article online posting date 17 January 2008. DOI: 10.1016/j.saa.2008.01.014.         [ Links ]

8 Gaussian-98, Rev. A.7, M.J. Frisch, G.W. Trucks, H.B. Schlegel, G.E. Scuseria, M.A. Robb, J.R. Cheeseman, V.G. Zakrzewski, J.A. Montgomery, jr., R.E. Stratmann, J.C. Burant, S. Dapprich, J.M. Millam, A.D. Daniels, K.N. Kudin, M.C. Strain, O. Farkas, J. Tomasi, V. Barone, M. Cossi, R. Cammi, B. Mennucci, C. Pomelli, C. Adamo, S. Clifford, J. Ochterski, G.A. Petersson, P.Y. Ayala, Q. Cui, K. Morokuma, D.K. Malick, A.D. Rabuck, K. Raghava-chari, J.B. Foresman, J. Cioslowski, J.V. Ortiz , A.G. Baboul, B.B. Stefanov, G. Liu, A. Liashenko, P. Piskorz, I. Komaromi, R. Gomperts, R.L. Martin, D.J. Fox, T. Keith, M.A. Al-Laham, C.Y. Peng, A. Nanayakkara, C. Gonzalez, M. Challacombe, P.M.W. Gill, B. Johnson, W. Chen, M.W. Wong, J.L. Andres, M. Head- Gordon, E.S. Replogle and J.A. Pople, Gaussian, Inc., Pittsburgh, PA, USA, 1998.         [ Links ]

9 C. Moller and M.S. Plesset, Phys. Rev., 1934, 46, 618-622.         [ Links ]

10 R. Krishnan, J.S. Binkley, R. Seeger andJ.A. Pople, J. Chem. Phys., 1980, 72, 650-654.         [ Links ]

11 T. Clark, J. Chandrasekhar, G.W. Spitznagel and P. von R. Schleyer, J. Comput. Chem., 1983, 4, 294-301.         [ Links ]

12 B. Liu and A.D. McLean, J. Chem. Phys., 1973, 59, 4557-4558.         [ Links ]

13 S.F. Boys and F. Bernardi, Mol. Phys., 1970, 19, 553-556.         [ Links ]

Received 3 December 2007
Revised 7 May 2008
Accepted 29 May 2008

^*This paper was presented at the Carman National Physical Chemistry Symposium, Cape Town, 23-28 September 2007.
**E-mail: ford@ukzn.ac.za