A computational study of SbnF(5n) (n=1-4) - Implications for the fluoride ion affinity of nSbF(5)

作者：Jenkins HDB; Krossing I^*; Passmore J; Raabe I

来源：Journal of Fluorine Chemistry, 2004, 125(11): 1585-1592.

DOI：10.1016/j.jfluchem.2004.09.016

• fluoride ion affinity
• antimony
• ab initio
• compound methods
• thermodynamics

This contributions shows with a series of ab initio MP2 and DFT (BP86 and B3-LYP) computations with large basis sets up to cc-pVQZ quality that the literature value of the standard enthalpy of depolymerization of 1/4 Sb4F20(g) to give SbF5(g) (+18.5 kJ mol(-1)) [J. Fawcett, J.H. Holloway, R.D. Peacock, D.R. Russell, J. Fluorine Chem. 20 (1982) 9] is by about 50 kJ mol(-1) in error and that the correct value of Delta(r)Hdegrees(depoly). (1/4 Sb4F20(g)) is +68 +/- 10 kJ mol(-1). We assign Delta(r)Hdegrees(depoly), Delta(r)Hdegrees, Delta(r)Gdegrees and Delta(r)Gdegrees values for SbnF5n with n = 2-4 and compare the results to available experimental gas phase data. Especially the MP2/TZVPP values obtained in an indirect procedure that rely on isodesmic reactions or the highly accurate compound methods G2 and CBS-Q are in excellent agreement with the experimental data, and reproduce also the fine experimental details at temperatures of 423 and 498 K. With these data and the additional calculation of [SbnF5n+1](-) (n = 1-4), we then assessed the fluoride ion affinities (FIAs) of SbnF5n(g), nSbF(5(g)), nSbF(5(l)) and the standard enthalpies of formation of SbnF5n(g) and [SbnF5n+1]((g))(-): FIA(SbnF5n(g)) = 514 (n = 1), 559 (n = 2), 572 (n = 3) and 580 (n = 4) kJ mol(-1); FIA(nSbF(5(g))) = 667 (n = 2), 767 (n = 3) and 855 (n = 4) kJ mol(-1); FIA(nSbF(5(l))) = 434 (n = 1), 506 (n = 2), 528 (n = 3) and 534 (n = 4) kJ mol(-1). Error bars are approximately +/-10 kJ mol(-1). Also the related Gibbs energies were derived. Delta(f)Hdegrees([SbnF5n+1]((g))(-)) = -2064 +/- 18 (n = 1), -3516 +/- 25 (n = 2), -4919 +/- 31 (n = 3) and -6305 +/- 36 (n = 4) kJ mol(-1).

• 出版日期2004-11