Experimental and Theoretical Studies on Theobromine and Theobromine-Water Complexes

Abstract

In this study, the solvent effects on structural, spectroscopic, electronic and thermochemical properties of Theobromine (tbH) were theoretically investigated. The dichloromethane (DCM), dimethylsulfoxide (DMSO) and water (H2O) solvents have been chosen for investigations. Optimized molecular structures of tbH were obtained by using the DFT/B3LYP method with 6-311++G(d,p) basis set in vacuum and in solvent media. Calculated geometric structure parameters were compared with experimental data. In the experimental section, the mid-IR spectrum of tbH was recorded using ATR equipment and compared with calculated vibrational frequencies. tbH-H2O complexes were studied for various binding ratios. The total energies and hydrogen bond lengths of these complexes were discussed in detail. It is seen as the result of this study that N⋯H-O and O⋯H-O non-covalent bonded structures are more stable for all binding versions and hydrogen bond lengths for all tbH-H2O complexes range from 1.8-2.5 Å.

Determination of the structural, electronic, optoelectronic and thermodynamic properties of the methylxanthine molecules theophylline and theobromine

“…We noticed that the single C1–C4 bond length is shorter than the C1–C2 double bond length. The calculated C–N bond lengths were in better accord with the experimental data given in literature (Ford et al 1998 ; Bilkan 2018 ) compared to the other bond length. Similarly, the C–C–C, C–N–C O–C–N, N–C-N and C–C–O bond angles of Theobromine are approximately equal to experimental values given in literature (Ford et al 1998 ) compared to the theoretical values reported in literature (Bilkan 2018 ).…”

“…The E g values obtained from our studies eventually explains the charge transfer interactions taking place within Theophylline and Theobromine which is in line as reported in literature (Kadhum et al 2012 ). The E g value of Theobromine obtained is less than the theoretical values reported in literature (Bilkan 2018 ) which may be due to difference in basis set. The E g values obtained at the B3LYP level for both molecules are smaller than those obtained at the RHF and wB97XD.…”

“…We did not find any existing results of the bond length and bond angles for Theophylline in literature to compare our results with. From Table 1 , we observed that the calculated C–N, C–C and N–H bond lengths of Theobromine are approximately equal to the theoretical and experimental bond length given in literature with the values of wB97XD being in better accord (Ford et al 1998 ; Bilkan 2018 ). The experimental values are given in bracket.…”

“…From the values of the partition coefficients logP of the molecules documented in literature (Stanchev et al 2013 ; Bilkan 2018 ), it is clear that the molecules are highly lipophilic. The parameter evaluated in our studies such as E g , are very useful and can be used to evaluate the chemical properties and possibilities for the interaction of Theophylline and Theobromine with biological molecules (enzymes and receptor) and their transport through the blood brain barrier and cell membranes.…”

“…An overview of the molecular spectroscopic on Theobromine and it related alkaloids has been carried by Tewari et al 2012 (Tewari et al 2012 ). In 2018, Bilkan study effects of solvent on the spectroscopic and structure properties of Theobromine (Bilkan 2018 ). In 2007, Bilkan used Hatree Fock and Density functional theory to study the effect of solvent on Theobromine (Bilkan 2017 ) while Ucun et al carried out some quantum chemical calculations on the molecular structures and vibrational frequencies of Xanthine and its methyl derivatives (Ucun et al 2007 ).…”