Abstract:
The computational analysis was performed by using density functional theory method to find
the effect of temperature and solvent on geometrically different Cu(II)-trimethoprim
complexes experimentally synthesized at two different temperatures. The initial geometries
of three complexes r1403 (C36H48Cu2N8O14), r1444 (C36H48Cu2N8O14) and r1435
(C36H50Cu3N8O16) were obtained from the crystallographic data. All these geometries along
with reactants were optimized at B3LYP/6-31g, B3LYP/LANL2DZ, BLYP/6-31g and
BLYP/LANL2DZ level of DFT theories at 298K and 352K. Single point energies were
calculated in the gas as well as in the solvent phase. SDD basis set was used to calculate
single point energy values in the gas phase whereas SCRF (self-consistent reaction filed)
calculations were performed using default (water) and ethanol solvents. The results obtained
from computational analysis were compared with the experimental data and it was concluded
that r1435 is an intermediate geometry which can be converted into a stable geometry after
recrystallization process. Also, more stable and reactive copper (II) trimethoprim complexes
can be obtained at 352K temperature with ethanol as a solvent. Moreover, computational
analysis also shows that LANL2DZ is more accurate basis set and gives more reliable results
as compared to 6-31g basis set with respect to validation of experimental results.
