2.6 Kinetic Study Of Coats-Redfern Complex

2.6 Kinetic studies of prepared complexes The integral method of Coats–Redfern equation[19,21,27,38] was used for determining the kinetic parameters of the decompositions process for the investigated metal complexes according to following equation: log[log⁡(w_∞/(w_∞-w))⁄T^2 ]⁡〖=log[AR/〖∅E〗^* (1-2RT⁄E^≠ )]〗-E^≠/2.303R 1/T (4)
Where w_∞ is the mass loss at the accomplishment of the decomposition reaction, w is the mass loss at temperature T, ∅ is the rate of heating and R is the universal gas constant. The left‐hand side of equation (3) is plotted against 1/T, since (1-2RT/E^* ) ≈ 1. E^≠ was estimated from a slope of this plot. A was calculated from the intercept of this plot. The enthalpy of activation (∆H^≠), the entropy
These investigated compounds were dissolved in DMSO at 10 and 20 mg ml-1,separately [19,21,25,27,34]. Nutrient agar was prepared, then sterilized in an autoclave and poured in sterile Petri plates. After cooling of nutrient ager in Petri plates, the studied organisms were grown on agar. After that, the sterili Paper discs of Whatman saturated with solution of investigated compounds were placed in the agar by working holes using a sterile crook borer. These Petri dishes were incubated for 24 h at 37oC [25]. The standard antibacterial drug gentamycin was screened under similar conditions for comparison. DMSO has no activity against microbial strains so it was alone used as a control. The results of Antibacterial bioassay for investigated compounds are
The CT-DNA was sufficiently free from protein contamination where CT‐DNA solution gave a ratio of UV absorption at 260/280 nm equal to 1.92. The stock solution was stored at 4 0C and used within for 4 days. The investigated complexes were dissolved in DMF solvent. Electronic spectra experiments were performed by keeping investigated complexes concentrations constant while changing the CT-DNA concentration in the interaction medium. The absorption due to free CT-DNA was eliminated by adding a proper amount of CT-DNA to both compound solution and the reference solution and the spectra data obtained were considered to result from the DNA–metal complex aggregation [13,26,27,28,29]. From the electronic spectra data, Kb (the intrinsic binding constant) was estimated from plotting [DNA] /(εa – εb) versus [DNA] according to the following relation