Effect of substituents on spin density in benzimidazole nitronyl nitroxide radicals studied by electron spin resonance.
Several novel benzimidazole-3-oxide-1-oxyl radicals with substituents at 5 and/or 6 position were synthesized. The ESR analysis of nitrogen hyperfine coupling constants (hfccs) revealed that substituents at 5 and 6-position affect the spin density to greater extent than substituents on the phenyl ring at 2-position. Density functional theory calculations of nitrogen hfccs were performed using several different Pople type basis sets, as well as double and triple zeta quality individual gauge for localized orbital (IGLO-II, IGLO-III) and electron paramagnetic resonance (EPR-II, EPR-II) basis sets. Experimental and theoretical hfccs are compared.
Department of Chemistry, Fatih University, Buyukcekmece, Istanbul, Turkey. besat@fatih.edu.tr
Burak
B
Esat
Ismail
I
Fidan
Sumeyye
S
Bahceci
Yusuf
Y
Yerli
Levent
L
Sari