An experimental and theoretical study of dipole moments of N-[4-(9-acridinylamino)-3-methoxyphenyl]methanesulfonamide

The excited state (S1) dipole moment of m-AMSA (1), an acridine derivative with antitumor activity, was determined from solvatochromic shifts of the lowest energy absorption band in several organic solvents. The effect of the solute shape and the values of polarizability on the determined change of dipole moment between ground and excited state was discussed. The dipole moments in S0 and S1 state were calculated in gas phase with semiempirical quantum-chemical and DFT and CIS methods and in solvents with SM5.4A solvation model and compared with values obtained experimentally. All the results show that the dipole moment of compound 1 in the excited state is higher than that in the ground state. These methods quite well predict the values of Δμ between two states of an investigated compound.