Displacement Reaction Using Ibuprofen in a Mixture of Bioactive Imidazole Derivative and Bovine Serum Albumin—a Fluorescence Quenching Study

Photophysical and computational studies of novel heterocyclic imidazole derivatives containing trifluoromethyl group substituent

Phenanthrimidazole ligands with potential electron withdrawing trifluoromethyl substituent have been synthesized and characterized using IR, mass and NMR spectral studies. The effect of solvent on their absorption and emission have been analysed in detail by Kamlet-Taft Catalan approach. The introduction of trifluoromethyl substituent results in a significant blue shift in emission when compared to its parent compound. This is due to the presence of the electron withdrawing trifluoromethyl moiety which changes the π-π conjugation of the cyclometalated ligand and lowers the triplet energy level, thus lowering the lowest unoccupied molecular orbital (LUMO) level. The optimized bond lengths, bond angles and dihedral angles calculated by DFT/B3LYP/6-31G (d,p) method are found to be slightly higher than that of XRD values of its parent compound. NBO, NLO, MEP and HOMO-LUMO energy analysis have been carried out by DFT method. This shows that the synthesized imidazole derivatives possess non-linear optical (NLO) behavior. In addition to these, calculations regarding the chemical potential, hardness and electrophilicity index have also been done.

Studies on interaction between an imidazole derivative and bovine serum by spectral methods

The interaction between a trifluoromethyl substituted imidazole derivative 2-(4-(trifluoromethyl)phenyl)-1-phenyl-1H-imidazo[4,5-f] [1,10] phenanthroline (tfmppip) and bovine serum albumin (BSA) was investigated by solution spectral studies. The observed experimental result shows that the imidazole derivative has strong ability to quench the fluorescence of BSA by forming complex which is stabilized by electrostatic interactions. The effective quenching constants (k(sv)) were 2.79 × 10(4), 2.51 × 10(4), and 2.32 × 10(4) at 301, 310 and 318K respectively. The Stern-Volmer quenching constant (K(sv)), binding site number (n), apparent binding constant (K(A)) and corresponding thermodynamic parameters (ΔG, ΔH and ΔS) were calculated. The distance between the donor (BSA) and acceptor (tfmppip) was obtained according to fluorescence resonance energy transfer (FRET). Conformational changes of BSA were observed from synchronous fluorescence technique. The effect of metal ions such as Cu(2+), Zn(2+), Ca(2+), Mg(2+), Ni(2+), Co(2+) and Fe(2+) on the binding constants between the imidazole derivative and BSA were also studied.