Interaction through space and valent bond in allyl compounds existing in π-complex and σ-structure forms

Quantum-chemical semiempirical method was used to study the effect of interaction through space and valent bond in allyl compounds (AC) with heteroatom X=Li, Be, B, Hg on AC geometrical and electron structure. It is shown that energy of configuration, conditioned by interaction of -CH3-XHn and -CH=CH2 fragments through C-C valent bond, is practically independent of X nature. Relative stability of non-planar and planar AC conformations is determined by possibilities of overlapping through the space of valent X orbitals and C atoms of allyl fragment. Decrease of diffuseness of valent X orbitals and growth of element ordinal number lead to transition from π-complex to AC gosh-conformer with successive decrease of its stability with respect to planar conformation in Li>Be>B>Hg series