Electronic Spectrum of Fluorenone

The electronic spectrum of fluorenone in various solvents has been measured; from these results and from the results obtained with the simple MO method for the π-electronic system of fluorenone, the nature of each absorption band of fluorenone has been studied. It has been concluded that fluorenone has four π→π* absorption bands (near 380 mμ, 310 mμ, 290 mμ, and 250 mμ respectively) in the near-ultraviolet region. The assignments of the 380 mμ and 310 mμ bands to the transition (A1→B2) and the 290 mμ and 250 mμ bands to the transition (A1→A1) are favorable in view of the obtained results.