17- Density Functional and Molecular Orbital Studies on the Activation of Donor-Acceptor Sub-systems, Charge Transfer and Binding in the H3BNCH and H3BNCCH3 Complexes. Part-I Density Functional Study

Jibanananda Jana

Department of Chemistry, Krishnagar Govt. College, Krishnagar, Nadia, W.B., INDIA

E-mail: jiban_jana@yahoo.co.in

Abstract

In this study, the nature of geometry reorganization of the acceptor (BH3) and the donors (HCN and CH3CN), i.e., the nature of change in bond lengths and /or bond angles as an effect of complex formation is justified and also may be prior predicted in terms of global and local density functional parameters. Due to reorganization of geometrical parameters from equilibrium values to that corresponding to the complexes, the activation of the acceptor and the donors to the better ones is well reflected under density functional study. Under local density functional study it is identified that N is the reactive center of CH3CN in both the donation and back-donation processes but N is the reactive center of HCN in case of donation whereas for back-donation process C is the reactive center. The greater donating capability and lower accepting capability of CH3CN are shown in terms of global and local density functional parameters. It is further furnished that though f+ and + are faithful parameters for correlating the capability of relative power of -acidity, – is the powerful and faithful parameter for correlating the relative donating ability, i.e., the order of f+ and + is the order of -acidity power and the order of  – dictates the order of donating power. Thus  – is identified as more fundamental than f– in correlating the relative donating ability of the donors.

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