R3N+N-: a substituent with extreme electronic effects

Basicity, infrared and x-ray results are reported which show the uniquely h igh electron-donor effect of R3N+N- substituents. An explanation is offered in terms of theoretically calculated resonance, field and electronegativit y sigma substituent constants. Large values of the calculated first-order h yperpolarizabilities in the R3N+N-(CH=CH)(n)NO2 series suggest the introduc tion of the R3N+N- substituents in the synthesis of push-pull conjugated st ructures for second-order non-linear optics. Copyright (C) 2000 John Wiley & Sons, Ltd.