Novel charge transfer-hydrogen bonded complex between 2-amino-4,6-dimethoxy-pyrimidine (ADMP) with chloranilic acid (H₂CA): temperature, solvation and DFT computational studies

ABSTRACT

New charge transfer complex associated with hydrogen bonding between 2-amino-4,6-dimethoxypyrimidine (ADMP) with chloranilic acid (H₂CA) was studied in solution and solid state. The solution studies were carried out in three polar solvents ethanol (EtOH), methanol (MeOH) and acetonitrile (ACN). The formed complex exhibited new absorption maxima above 500 nm. The molecular composition was done by job and photometric titration methods where the complex proceeded through 1:1 ratio. Moreover, the stability constant was calculated by Bensie-Hildebrand equation, the highest value was in methanol and least one in ethanol. The solid complex was synthesised and characterised by elemental analysis and infrared spectra, and they confirmed the formation of 2:1 (donor: acceptor) complex and its structure included charge transfer besides hydrogen bonding. DFT computations using the hybrid method B3LYP-DFT at the basis set 6-31G(d,p) were running out in gas phase to support the mechanism of complex formation in solid state.

KEYWORDS:

• Charge transfer
• hydrogen bond
• infrared spectra and DFT computations

Disclosure statement

No potential conflict of interest was reported by the authors.