FOLDED CONFORMATIONS .10. CRYSTAL AND MOLECULAR-STRUCTURE OF PARA-DIMETHYLAMINOPHENYL N-METHYL-N-(PARA-NITROPHENYLSULPHONYLMETHYL)-CARBAMATE - NON-BONDED ENERGY CALCULATIONS ON MOLECULAR-CONFORMATIONS

The crystal and molecular structure at –160°C of the title compound (2) has been determined from diffractometer data by direct methods. The structure of (2) was refined to R 0.095 for 3 462 independent reflections. The molecule resides in a folded conformation in which the carbonyl oxygen lies above the p-nitrophenyl ring. Non-bonded energy calculations reveal that a folded conformation is energetically favourable for one separated molecule. A similar conformation has previously been proposed on the basis of n.m.r. isotropic solution spectra. The intramolecular charge-transfer band in the visible spectrum of (2) cannot be explained in terms of ‘through-space’ overlap between the donor and acceptor aromatic rings.