Dipole moment acridines

Abstract Quantitative structure-activity relationship (QSAR) analysis for minimum inhibitory concentration (MIC) of phenothiazines and benzo[a]phenothiazines was investigated based on the theoretical calculations. Four different dipole moments (/jq, /xesp g, /zw, and /zesp-w) and heats of formation (AHf) of the phenothiazines [1-20], benzo [n]phenothiazines [21-29], and benz[c]acridines [30-41] were separately calculated in the gas-phase and the water-solution by the conductor-like screening model/parametric method 3 (COSMO/PM3) technique. The MIC values of phenothiazines [1-20] were well correlated to A AHf, HOMO energy and hq. QSAR may be applicable to predict the MIC of phenothiazines. 

The results of the present study suggest the applicability of theoretical calculations such as frontier molecular orbital, dipole moments and AAHf in the prediction of biological activity of phenothiazines, benzo[a]phenothiazines, and benz[c] acridines. 

Chem, 30, 881-99 (1956). Dipole moment pyridine-acids in benzene, also acids-quino-line, acridine, triethylamine. 

Among the cosolvents studied, methanol and acetone have received the greatest interest (36-38). Methanol may act as either a Lewis acid or a Lewis base while acetone is a weaker Lewis base and very slightly acidic ( ). The dipole moment of acetone is 2.88 Debeye compared to 1.7 Debeye for methanol. Based on these properties, Walsh, et al., (40), interpret the data of Van Alsten (37) and Schmitt (38) and present liquid phase IR measurements which show Lewis acid-base interactions in the systems methanol/acridine and acetone/benzoic acid. Supercritical solubility data of Dobbs, et al., ( ), exhibit trends which indicate the importance of acid-base interactions. Van Alsten and Schmitt present data which show that acid-base interactions are a secondary cosolvent effect superimposed on a primary effect determined by cosolvent concentration. 

The dipole moments wctc related to hydrogen bond strength and to the ability of the proton acceptors (compounds with phosphoryl and carbonyl groups) to associate with phenol. Hydrogen bonded complexes of pyridines, quinolines and acridine with phenol are studied, in carbon tetrachloride, by dipole moment measures . Dipole moments of the complexes were related to the ability of the acceptors to associate with phenol and with their basicity. Hydrogen bonds may either reinforce the dipole moments of the resultant of the group moments or may oppose the dipole moment direction, depending on the nature of the acceptor. 

J. J. Aaron, M. Maafi, C. Parkanyi, and C. Boniface, Spectrochimica Acta, Part A, 51(603) (1995). Quantitative Treatment of the Solvent Effects on the Electronic Absorption and Fluorescence-Spectra of Acridines and Phenazines - The Ground and First Excited Singlet-State Dipole-Moments. 

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