Solution, and solid investigations on the charge–transfer complexation between seproxetine as a selective serotonin reuptake inhibitor drug with six kinds of π–electron acceptors

Abstract The study in this article deals with the donor–acceptor interaction between seproxetine (SRX) donor and π–electron acceptors such as picric acid, dinitrobenzene, p-nitro benzoic acid, 2,6-dichloroquinone-4-chloroimide, 2,6-dibromoquinone-4-chloroimide, and 7,7′,8,8′-tetracyanoquinodi methane which can be referred to by the following chemical abbreviations “PA, DNB, p-NBA, DCQ, DBQ, and TCNQ” respectively, in a liquid medium, and the associated complexes in the solid form were also isolated and characterized. A spectrophotometric titration method was employed to the quantitative analyses of seproxetine HCl in pure form. The stoichiometric analysis based on the molar ratio technique was found to be 1:1 (SRX: π–acceptor) regarding the charge–transfer interactions between the electrons of donor and acceptors. The different physical spectroscopic parameters “formation constant (KCT), molar extinction coefficient (eCT), standard free energy (∆Go), oscillator strength (ƒ), transition dipole moment (μ), resonance energy (RN) and ionization potential (ID)” were calculated according to the spectroscopic data. The charge–transfer complexes which isolated in solid form were well characterized using some of analytical tools “microanalytical, molar conductance, FTIR, 1H-NMR and X-ray powder diffraction”. Thermal stability of solid charge transfer complexes was investigated using TG/DTG thermogravimetric technique. The kinetic thermodynamic values were calculated upon the thermal decomposition diagrams. The surface morphology, particle size and the elementary percentages of the solid SRX charge–transfer complexes were investigated with the help of scanning (SEM) and transmission (TEM) electron microscopies as well as energy-dispersive X-ray spectroscopy (EDX)