Self-assembly of 2-aminopyrimidines in nonpolar solvents

A combined experimental and theoretical study on self-assembly of 2-aminopyrimidine (ampm), 2-amino-4-chloro-6-methyl-pyrimidine (ampm1), 2-amino-4,6-dimethyl-pyrimidine (ampm2) and 2-amino-4,6-dichloro-pyrimidine (ampm3) was performed. The effects of concentration increase in low polar solvents C6H6 and CCl4 on average molecular weight, dipole moments and IR spectra of these compounds were investigated. Strong association of all these molecules was found, through N–H⋯N hydrogen bonding. The association leads to formation of less polar species. DFT B3LYP/6-31G** calculations for monomers and dimers of these molecules were performed to model the structure of possible aggregates.