A solvatochromic study of N-[4-(9-acridinylamino)-3-methoxyphenyl]methanesulfonamide hydrochloride: An experimental and theoretical approach

• Solvatochromic shifts of electronic absorption band of m-AMSA.HCl were analyzed.
• The nature of interactions of protonated m-AMSA with polar solvents was shown.
• Experimental results were compared with theoretical results.

The effects of a solvent on the position of the long-wavelength electronic absorption band of N-[4-(9-acridinylamino)-3-methoxyphenyl]methanesulfonamide hydrochloride [m-AMSA.HCl], an antitumor drug, were investigated. To assess the nature of molecular interactions of protonated m-AMSA (1) with various organic solvents the solvatochromic shifts of absorption maxima (ν‾A) with (i) traditionally used bulk solvent polarity functions (Δf and F(ε, n)) and (ii) empirical scales of solvent polarity (Z, χB   and ETN) were analyzed. Additionally, in order to investigate the influence of non-specific and specific solute–solvent interactions on absorption band shifts in protic solvents the multicomponent linear regression with two Kamlet–Taft’s solvatochromic parameters (π* and α  ) was used. The ν‾A in solvents were also obtained using theoretical calculations with the AM1-SM5.4 method and compared with experimental values. Finally, all the results show that in aprotic solvents there are general dipolarity/polarizability effects, while in protic solvents specific interactions connected with the formation of hydrogen bonds are additionally observed.

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