Quantum and chemical calculation of methylcyclobutane and ethylcyclobutane molecules by AM1 method

For the first time methylcyclobutan and ethylcyclobutan are polymerized in the presence of AlCl3/HBr, AlCl3/HCl and Al(OH)Cl2 catalysts to room temperature in 1953. Other systematic researches on polymerization of these monomers are practically absent. Still quantum and chemical calculations of these monomers, and, in particular, are not executed by the AM1 method, and mechanisms of elementary acts at electronic level are not studied and the nature of the active centers is not investigated. In this regard, the purpose of the real work is quantum and chemical calculation methylcyclobutan and ethylcyclobutan AM1 method with geometry optimization in all respects the standard gradient method which has been built in PC GAMESS, in approach of the isolated molecule in a gas phase and a theoretical assessment of its acid force. For visual representation of models of molecules the known MacMolPlt program was used. The optimized geometrical and electronic structure, the general energy and electronic energy methylcyclobutan and ethylcyclobutan are received by the AM1 method and shown in fig. 1-2 and in tab. 1-2. Applying a formula rKa = 47.74 - 154.949 (= +0.09 and +0.10 - the maximum charges on atoms of hydrogen, rKa - a universal indicator of acidity), we find values of acid force equal a rKa = 34 and 32. For the first time it is executed quantum chemical calculation of the molecules of methylcyclobutane and ethylcyclobutane by AM1 method with optimization of geometry on all parameters. The optimized geometrical and electronic structures of these connections are received. Acid forces of methylcyclobutane and ethylcyclobutane are theoretically appreciated. It is established, than it relates to the class of very weak H-acids.