E-2-Benzylidenebenzocycloalkanones III. Studies on transmission of substituent effects on IR carbonyl stretching frequencies and 13C NMR chemical shifts of E-2-(X-benzylidene)-1-indanones. Comparison with the IR data of E-2-(X-benzylidene)-1-indanones, -tetralones, and -benzosuberones

Abstract

Single substituent parameter and dual substituent parameter analysis was applied to study transmission of substituent effects on IR carbonyl stretching frequencies of E-2-(X-benzylidene)-1-indanones ( 3), -tetralones ( 4), and -benzosuberones ( 5). Similar analyses were performed for selected 13C NMR chemical shifts of some E-2-(X-benzylidene)-1-indanones ( 3). For a better understanding of the results semiempirical and ab initio quantum chemical calculations were performed to determine the preferred geometry and to calculate the theoretical 13C NMR chemical shifts of the selected compounds ( 3). The differences among the regression coefficients were discussed in terms of the relative importance of the field and resonance effects for the analogous enones with different geometries.