Structure of N-chloromethyllactams and features of the interaction of atoms in them as a result of ab initio calculations

Abstract

It is assumed (for example [1,2]) that in the nonlinear triatomic grouping Y-C-M the unshared pair of electrons of the heteroatom M participates in p,σ*-conjugation with the antibonding orbital of the C-Y bond, which leads to increased electron density on the indicator atom Y and to the properties of compounds containing such a grouping not corresponding to the inductive effect of M on Y. However it was shown (examples [3-5]) that the "anomalous" effect of M on Y, and the "anomalous" properties of such compounds caused by this, in reality corresponds to the polarization of the C-Y bond under the action of the charge on the M atom directly through the field.Since the charge on the heteroatom M is not a point but is general, it is quite natural that the size of this "anomalous" effect of atom M on Y must depend on the position of the C-Y bond relative to the atom M. A significant contribution to the asymmetry of the electron distribution in atom M is introduced by its unshared pair of electrons. Consequently the size of the "anomalous" effect of M on Y must also depend on the mutual orientation of the C-Y bond and the unshared electron pair of atom M.From a comparison of the experimental dipole moments and molar Kerr constants, and those calculated according to the additive scheme, the conformations of a large number of molecules containing the Cl-C-N grouping have been found, viz. N-chloromethylpyrrolidone [6], N-chloromethylcaprolactam [6], N-halomethylbenzamides PhCONHCH 2 Y where Y=Cl and Br [7], nitramine ClCH 2 NMeNO 2 [8], etc. [9][10][11]. It is assumed that all three bonds of the nitrogen atom in these molecules lie in one plane, perpendicular to which is disposed