Debabrata Nandi

Kinetic Studies on Interaction of Platinum(II) Complexes with an ‘S’ Containing Ligand in Aqueous Medium

The kinetics of the substitution reactions of [Pt(dach)(H2O)2]2+ and [Pt(en)(H2O)2]2+ (where ‘dach’ and ‘en’ are cis-1,2-diaminocyclohexane and ethylenediamine, respectively) with excess N,N′-diethylthiourea have been studied in aqueous solution by UV–Vis spectrophotometry. The effect of different N–N spectator ligands on the reactivity of platinum(II) complexes was investigated by studying the water lability of the reactant complexes. The kinetic study has been substantiated by product isolation, IR, NMR and ESI-MS spectral analysis and DFT calculations. The reactions follow normal square-planar substitution mainly in an associative way. Rate parameters have been evaluated under different conditions. The substitution rates of the complexes studied can be tuned through the nature of the N–N chelates, which is important in the development of new active compounds for cancer therapy.

Kinetics and mechanism of reactions of some essential amino acids with cis-diaqua(1,3-diaminopropane)-platinum(II) ion: a potent anticancer agent

Abstract The substitution of both coordinated water molecules of cis-diaqua(1,3-diaminopropane)platinum(II) complex by a series of amino acids, viz. l-asparagine, l-glutamic acid, and glycine was investigated as a function of ligand concentration, temperature, and pH and found to occur in two consecutive reaction steps. The mechanism of the substitution reactions appears associative in nature as supported by the large and negative values of ΔS≠. The kinetic study has been substantiated by product isolation, UV, IR, and ESI-MS spectroscopic analysis and rate parameters have been evaluated under different reaction conditions.Graphical Abstract

Substitution reactions of [Pd(bipy)(malonate)] explored with a different set of ligands: Kinetic and mechanistic interpretation in aqueous medium and at pH 7.4

AbstractA brief overview of mechanistic studies of the reactions of Pd(II)-bipy-malonate complex with different set of ligands, viz., (N, S), (S, O) and (S) donor molecules is reported here. The kinetics of complex-formation reactions of three sulphur containing bio-relevant ligands thioglycolic acid[L1],thiourea[L2] and thiosemicarbazide [L3] were studied with innermetallic [Pd(bipy)(malonate)] complex at physiological condition. The effect of the nucleophilicity of the chosen nucleophiles was studied for the reactant complex under pseudo-first order conditions as a function of nucleophile concentration and temperature using stopped-flow technique. This article describes the results obtained for substitution reactions of bi-functional Pd(II) complex with different biomolecules, under varying experimental conditions. The kinetic studies showed that the malonate ring departs from the coordination zone of palladium centre via two-step mechanism. The first step depends on the concentration of the incoming ligand for all the ligands. But in the second step thiourea is ligand dependent where as other two are independent of the ligand concentration. Hence, it can be concluded that the second step is the chelation step for L1 and L3. The mechanism for the substitution of the coordinated malonate molecule is associative, as demonstrated by the negative values of ΔS≠. Such type of complexes are less toxic than chloro-, which in turn hydrolyses to aqua or aqua complexes as they are prevented from oligomer formation at physiological pH. Graphical AbstractStudies of kinetic and mechanistic pathways for the reactions of Pd(II)-bipy-malonate complex with thioglycolic acid, thiourea and thiosemicarbazide have been carried out. Innermetallic [Pd(bipy)(malonate)] complex reacts with above mentioned sulphur containing ligands at physiological condition and these substitution reactions are associative in nature.

Relative reactivity of N,N-donor ligands in substitution reactions of cis-diaqua(2-aminomethylpiperidine)platinum(II): a detailed kinetic and mechanistic study

The reactivity of cis-

Kinetic and mechanistic studies on the interaction of azide ion with cis -diaqua-bis(bipyridyl) ruthenium(II) complex and hydroxopentaaqua rhodium(III) complex in aqueous medium

[\hbox {Pt}(\hbox {pipen})(\hbox {H}_{2}\hbox {O})_{2}]^{2+}

Mechanistic Aspects of Ligand Substitution on the Hydroxopentaaquarhodium(III) Ion in Aqueous Solution by Sulfur‐Containing Bioactive Ligands

[Pt(pipen)(H2O)2]2+ (

Kinetic and mechanistic studies on the substitution of aqua ligands from diaquaethylenediamineplatinum(II) ion by vicinal dioximes

\hbox {pipen} = 2\hbox {-aminomethylpiperidine}