MOLECULAR INTERACTION BETWEEN BENZONITRILE AND HEXAMETHYLPHOSPHORIC TRIAMIDE BY 13C NMR T1 RELAXATION TIME STUDIES AND AB INITIO QM CALCULATIONS: EXTENDED INVESTIGATION

Parsaoran Siahaan (Department of Chemistry, Faculty of Mathematics and Natural Sciences, Bandung Institut of Technology. Jl. Ganesha 10 Bandung)
Cynthia L. Radiman (norganic and Physical Chemistry, Faculty of Mathematics and Natural Sciences, Bandung Institut of Technology. Jl. Ganesha 10 Bandung)
Susanto Imam Rahayu (norganic and Physical Chemistry, Faculty of Mathematics and Natural Sciences, Bandung Institut of Technology. Jl. Ganesha 10 Bandung)
Muhamad A. Martoprawiro (norganic and Physical Chemistry, Faculty of Mathematics and Natural Sciences, Bandung Institut of Technology. Jl. Ganesha 10 Bandung)
Dieter Ziessow (Stranski Laboratory for Physical and Theoretical Chemistry TU Berlin)

Indonesian Journal of Chemistry
Vol 9, No 2 (2009)

It has been obtained the anisotropy ratio a = T1(ortho-,meta-13C)/T1(para-13C) of dilute solutions of bn change from 1.7 in fa solution and 1.5 in neat bn to 1.0 in HMPT. Thus the anisotropy ratio comes out to be a = 1. In HMPT, obviously, solvent molecules cluster around Ph-CºN in such a way, that non-covalent interactions lead to isotropic reorientational motion like a spherical molecule. To conform with the T1 times, a layer arrangement with at least two HMPT molecules per Ph-CºN seems to be likely. From computational quantum calculations of non-covalent intermolecular interactions and Mie potential analysis, the solute-solvent molecular pairs in  bnּּּHMPT have almost equal interaction energies for the ortho, meta, and para configuration and the layered configurations are energetically permitted