Activity coefficient effects in spectral and solubility studies of molecular complex equilibriums

Abstract

^E 1 2 U Hg CH3 3The relatively low barrier for interconversion of 1 to 2 is also consistent with experimental11 and theoretical12 studies on the importance of carbon-metalconjugation in the stabilization of mercurinium ions. 13 The extent of perturbation of the double bond by HgCH3+ may be estimated by a comparison of the Mulliken overlap population for ethylene, p* = 0.503, with that of the system of the mercurinium ions 1-3.The Mulliken overlap population for the Ci-C2 tt bond in 1 has been reduced to 0.368.In the unsymmetrical ion 2 this value is slightly increased to 0.381.The overlap population between the carbon 2p tt orbital on Q and electron density on mercury is only 0.110 in 2.Thus, 78 % of the stabilization of the positive charge on Ci in 2 is due to delocalization of the polarizable car- bon-mercury bond and only 22% to neighboring group participation by mercury.With the classical ion 3 p, is 0.346 and the overlap population between the neighboring group HgCH3 and the orbital on carbon, Pci-Hg, is reduced to 0.052.Thus, in 3 both -ir con- jugad ve stabilization and neighboring group participation are reduced.The increase in energy of 3 is also reflected in an increase in positive charge on Q which is 0.114,0.123,and 0.177 for ions 1,2, and 3, respectively.Acknowledgment.Acknowledgment is made