CONFORMATIONS AND RELATIVE STABILITIES OF THE CIS AND TRANS ISOMERS IN A SERIES OF ISOLATED N-PHENYLAMIDES

摘要: The gas-phase conformations of a series isolated N-phenylamides have been determined from vibrationally resolved electronic spectra obtained by resonant two-photon ionization in supersonic jet expansion. Both the cis and trans isomers formanilide were identified, with isomer 6.5% abundance. spectral features displayed this are consistent nonplanar geometry which undergoes large change phenyl torsional angle following excitation. more abundant adopts planar structure is stabilized 2.5 kcal/mol respect to isomer. In excited state relative stabilities two reversed. Acetanilide, contrast, found exclusively as isomer, also having structure. N-Methyl substitution causes reversal leads an distribution consisting approximately 90% E 10% Z N-methylformanilide....