EVIDENCE OF DIMERIZATION THROUGH C-H-CENTER-DOT-CENTER-DOT-CENTER-DOT-O INTERACTIONS IN LIQUID 4-METHOXYBENZALDEHYDE FROM RAMAN-SPECTRA ANDAB-INITIO CALCULATIONS

The vibrational spectra of 4-methoxybenzaldehyde in the liquid phase s how pairs of bands whose temperature-and solvent-dependent behaviour c an hardly be interpreted only in terms of a cis-tuans conformational e quilibrium, In particular, the solvent and temperature-dependent inten sities of the vC=O band profile strongly suggests the presence of a di merization equilibrium with a Delta H-dim value of ca. 7.6 kJ mol(-1). Such dimerization can arise from C-W...O interations, as supported by ab initio SCF-MO calculations at the 6-31G level, (C) 1997 John Wile y & Sons, Ltd.