Collect. Czech. Chem. Commun. 1993, 58, 105-112

Configuration and Conformation of N,N'-Diarylamidines: A Dipole Moment Study

Václav Všetečkaa, Janusz Oszczapowiczb and Otto Exnerc

a Department of Organic Chemistry, Charles University, 128 40 Prague 2, Czech Republic
b Chemistry Department, University of Warszaw, 01093, Warszaw, Poland
c Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6, Czech Republic


Dipole moments of N,N'-diphenylformamidine and its para-halogen derivatives were measured in benzene solution. Since the prototropic rearrangement is degenerate, the dipole moments can be simply interpreted in terms of the E configuration on C=N and a conformational equilibrium on C-N. The two forms, Eap and Esp are populated approximately in the 1 : 1 ratio: the former is the conformation found in the crystal. The dipole moments anticipated for individual conformations were calculated by vectoraddition of bond moments: the previously determined correction for conjugation was found unnecessary.