Ab initio calculations and structure of three acyclic bis(acetyl acetone)imine derivatives

The possible tautomers of (acac)2u, (acac)2tu, and (acac)2u.meth molecules are studied theoretically at ab initio method using minimal (STO-3G) level of theory. It is found that the keto-imino tautomer is the dominated one among these possible tautomers. Total dipole moments, highest occupied and lowest unoccupied molecular orbitals energies (EHOMO and ELUMO respectively), and frontier molecular orbital energy gap (ELUMO-EHOMO) are calculated for all the tautomers, and reliable comparisons among them have been carried to conclude chemical reactivities, polarities, and then the stabilities. Four synthetic routes yielding (acac)2u.meth have been presented with calculation Gibbs free energies of formation to know tendencies of these reactions to occur. Also structural parameters of ab initio-calculated optimized structures of keto-imino tautomer for both (acac)2u and (acac)2tu molecules are calculated.