Chalcones, dipole moments

The UV spectra, electric dipole moments, and IR carbonylstretching vibrations of the heterocyclic chalcone analogs (6) have been studied.100 In the electronic spectra, the heterocyclic radicals appear to display a significant electron-donating effect in the excited state (compared with phenyl), giving rise to a bathochromic shift of 31 to 44 m/x. The heterocycles affect the UV spectrum in the order a-selenienyl > a-thienyl > a-furyl > phenyl, and the bathochromic... 

Dipole moments of the chalcones containing heterocyclic radicals confirm the electron-donor properties of the five-membered heterocycles in their ground states. The moments in these compounds are dominated by the carbonyl polarization which is stronger the more electron-donating is the radical bonded to the carbonyl. Thus, all the physical data on the chalcone analogs suggest that the electron-donating effect of the heteroaromatic radicals decreases in the order a-selenienyl > a-thienyl > a-furyl.100... 

The n.m.r. spectra of a number of mono- and di-substituted selenophens have been analysed and the chemical shifts discussed in additivity terms. An A%ray analysis of racemic 4,4 -dicarboxy-2,2, 5,5 -tetramethyl-3-3, -biselenienyl has been carried out. Dipole moments and u.v. spectra of chalcone analogues containing a selenophen ring have been studied. 

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