Chloride anation reaction of aqua (diethylenetriamine) platinum (II): Density functional studies “Dedicated to Prof. H. B. Gray”

Partha Sarathi Sengupta^1*, Snehasis Banerjee² and Ashish  Kumar Ghosh³

¹Chemistry department, Vivekananda Mahavidyalaya, Burdwan, India, 713103.

²Darjeeling Government College India, Darjeeling, 734101, India.

³Central Institute of Mining and Fuel Research Institute, Dhanbad, India 828108.

*Corresponding author. E-mail: anapspsmo@yahoo.co.in.

Accepted 2 October, 2009

   Abstract

The nucleophilic and solvolytic path for the chloride anation reaction of aqua(diethylenetriamine)platinum (II) is computationally investigated at the Hartee-Fock (HF) and Density functional theory (B3LYP and mPW1PW91) of levels of calculation in gas phase and on the self- consistent reaction field (SCRF) model. All the stationary points are fully optimized and characterized.  The kinetic and thermodynamic properties of all the species involved are investigated and compared with the available experimental data. The transition state is described by local reactivity descriptors. A point of inflection of Fukui function and local softness of the incoming nucleophile for both the solvolytic and nucleophilic path at the transition state (Saddle point), corresponds to both bond breaking and bond making processes. The existence of the solvolytic path (k₁) along with nucleophilic path (k₂) has been supported by DFT studies. From the enthalpy of activation (ΔH^¹), entropy of activation (ΔS^¹) and the structures of the transition states, an inter change associative mechanism (I_a) is established for both nucleophilic and solvolytic path for the chloride anation reaction.

Key words: Anation reactions, aqua (diethylenetriamine) platinum (II), DFT, self consistent reaction field, Fukui function.