VIBRATIONAL ANALYSIS OF THE VAN-DER-WAALS COMPLEX BETWEEN CYCLOPROPANE AND BORON-TRIFLUORIDE IN LIQUEFIED INERT-GASES

The mid-infrared (4000-400 cm(-1)) spectra of mixtures of cyclopropane and boron trifluoride, dissolved in liquid argon (93-125 K) or in liq uid nitrogen (80-118 K), are discussed. In all the spectra, the format ion of a 1:1 van der Waals complex, c-C3H6 . BF3, was observed. From s pectra recorded between 95 and 125 K, the complexation enthalpy in liq uid argon was determined to be -7.8(6) kJ mol(-1). Using an SCRF/SCIPC M scheme to correct for the solvent influences and applying statistica l thermodynamics to account for the zero-point vibrational and thermal influences, we calculated the gas-phase complexation energy Delta E-c (exp) from the liquid-phase Delta H-0 to be -12.0(6) kJ mol(-1). The a nalysis was completed by carrying out ab initio calculations at the MP 2/6-31+G(d) level.