Kinetics of the interaction between [Pt(pic)(H2O)2](ClO4)2and selected thiols has been studied in aqueous medium as a function of [complex], [thiol], pH and temperature at constant ionic strength.

Cis-[Pt (TEEDA)Cl 2 ]; 1 (where TEEDA = N,N,N 0 -triethylethylenediamine) was synthesised, and its SCXRD structure was determined. Complex 1 crystallises in the monoclinic space group I2/a; (z = 8) and unit cell parameters are a = 15.1919(4) Å; b = 9.6049(3) Å; c = 16.7825 Å; α = 90.00 ; β = 94.784(3) and γ = 90.00 . Complex 1 was hydrolysed to diaqua species cis-[Pt (TEEDA)(H 2 O) 2 ] 2+ ; 2 L-cysteine (L-cys) and N-acetyl-L-cysteine (N-ac-L-cys) chelated complex cis-[Pt (TEEDA)(L-cys)] + 3 and cis-[Pt (TEEDA)(N-ac-L-cys)] 4 were synthesised and characterised by spectroscopic methods. Kinetic study of substitution reactions of Complex 2 to Complexes 3 and 4 have been explored with the thiols L-cys and N-ac-L-cys, respectively. The theoretical study with density functional theory (DFT) has been considered to optimise the structures of Complexes 1-4 for HOMO-LUMO energy calculation, TD-DFT simulation and natural bond orbital (NBO) analysis to support structural characterisation of the complexes. Various electronic properties, known as DFT-based descriptors, have been calculated from frontier molecular orbital energies to correlate with the adduct formation aptitude of the complexes with DNA and BSA. The binding aptitude and binding mode of the complexes with DNA and BSA have been performed by UV-Vis and spectrofluorometric titration methods. To observe the interaction of the complexes with CT-DNA, gel electrophoresis experiment has been carried out. A molecular docking study of the complexes was performed with DNA and BSA. The anticancer activity and ROS generation of the complexes were investigated on different cancer cell lines and fibroblast cells with DCF-DA using FITC filter. K E Y W O R D S anticancer activity, DNA and BSA binding, kinetics and mechanism, MTT assay and DFT study, Pt(II) complex Saikat Mandal and Venkata P. Reddy B. contributed equally to this research work.

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Third order kinetics of bio-relevant thiols and thio-ether with dinuclear Pd(ii) complex possessing anticancer and antibacterial properties.

Different species of L-ascorbic acid and their corresponding complex formation ability with Cu(II) and Ni(II) metal ions in aqueous medium has been studied in the pH range from 2.0-12.5. The stability constants of different complexes of Cu(II) and Ni(II) with the bidentate ligand, L-ascorbic acid were determined theoretically using MINIQUARD software. Speciation of ligand and complex of Cu(II)/Ni(II) ascorbate were experimentally investigated by the titration method in solution within this pH range. Different Cu (II) and Ni(II)-L-ascorbic acid species percentages with variation of pH were calculated within the studied pH range with the help of another computer programs SIM and SPECIES. Different species distribution diagrams and the equilibria for the formation of the species were also investigated and at higher pH, ML2 species was found to be the major species in the case of both the metal complexes. All the theoretical possible structures of Cu(II) and Ni(II) complexes with L-ascorbic acid were optimized and square pyramidal and square planer geometry have been evaluated for Cu(II) and Ni(II) respectively by Gaussian09 software. Their corresponding HOMO-LUMO energy and reactivity parameters such as chemical hardness (ç), ionization potential (I), electron affinity (A), electro negativity (÷), chemical potential (ì), electrophilicity index (ù) have been calculated in order to provide a better understanding of the electronic structure of complexes with the experimental results.