On the electronic origins of barriers to methyl rotation: CNDO/2 calculations on (CH3)2XHn (X = C, Si, N, P, O, S) molecules

摘要: Abstract CNDO calculations are performed for the homogeneous series of (CH 3 ) 2 XH n compounds (X = C, Si, N, P, O, S) in order to determine molecular equilibrium configuration. In agreement with available experimental data, all investigated molecules, theoretical energy minimum is found (θ 60°, ψ 60°) conformation which one hydrogen each methyl group X heavy atoms plane but pointing outside CXC angle. A partitioning total shows that variations this quantity completely reflected by interaction between non-bonded terms. more detailed analysis reveals, only third-row compounds, essential role interactions central atom and hydrogens.