Synthesis, Characterization and Luminescence Sensitivity with Variance in pH, DNA and BSA Binding Studies of Ru(II) Polypyridyl Complexes

Abstract

Three ruthenium(II) polypyridyl complexes, [Ru(phen)(mip)](ClO) (1) (phen =1,10-Phenanthroline), [Ru(bpy)(mip)](ClO) (2) (bpy = 2,2'bipyridyl) and [Ru(dmb)(mip)](ClO) (3) (dmb = 4, 4'-dimethyl 2, 2'-bipyridine), were synthesized with an intercalative ligand mip (2-morpholino-1H-imidazo[4,5-f][1, 10]phenanthroline) and characterized by H,C-NMR, IR, UV-vis, mass spectra and elemental analysis. pH effect, ion selectivity (cations, anions) and solvent sensitivity of complexes were studied. The interaction of these complexes with DNA was performed using absorption, emission spectroscopy and viscosity measurements. The experimental results indicated that the two complexes interacted with calf thymus DNA (CT-DNA) by intercalative mode. BSA (Bovine Serum Albumin) protein binding of these complexes was studied by UV-visible and fluorescence techniques. The binding capacity of these complexes was explained theoretically by molecular docking method.

Synthesis, characterization, DNA binding/cleavage, cytotoxic, apoptotic, and antibacterial activities of V(IV), Mo(VI), and Ru(II) complexes containing a bioactive ONS‐donor chelating agent

“…The intrinsic binding constant (K b ) of the compounds were in the order 10 5 as shown in Table 6. The K b values for the complexes are of the order 5 > 2 > 1 > 4 > 3 > H 2 dhasm, which are comparable and similar with those reported DNA intercalators of ruthenium(II) complexes (K b = 1.3-3.2 × 10 5 M −1 ) [36,77] and of EB (K b = 1.4 × 10 6 M −1 ). [78] This is suggesting that there is a strong stacking interaction between the aromatic chromophore or the organic molecules and DNA base pairs.…”

“…[ 33 ] where r is the binding ratio C b /[DNA], C f is the concentration of the free complex, and C b is given using equation : where C t is the total complex concentration, F max is the fluorescence intensity of the max complex bound to DNA, F o and F are the intensities in absence and presence of a given DNA concentration, respectively. [ 36 ] The binding constant ( K b ) can be determined from the slope of Scatchard plot r / C f versus r . [ 33 ]…”

“…[ 33 ] Nonlinear least square fitting of the data yield the binding emission constant ( K b ) values (Table 6) which are in agreement with those obtained from the absorption titration experiments. [ 36,81 ]…”

“…where C t is the total complex concentration, F max is the fluorescence intensity of the max complex bound to DNA, F o and F are the intensities in absence and presence of a given DNA concentration, respectively. [36] The binding constant (K b ) can be determined from the slope of Scatchard plot r/C f versus r. [33] EB-competitive DNA binding study. Fluorescence quenching titration is another technique used to evaluate the binding of the ligand and its complexes, based on ethidium bromide (EB) displacement reaction.…”

“…The change in fluorescence intensity was recorded after each addition in 520-650 nm region using an excitation wavelength of 465 nm. [36] 2.3.2 | DNA cleavage study…”