title: Theoretical studies on NMR chemical shifts in azacubanes.
abstract: Successive substitution of CH groups of cubane (CH)(8), by isoelectronic nitrogen atoms leads to a class of energy-rich azacubanes (CH)(8-alpha)N(alpha) (with alpha=1-8). In the present work, we systematically investigate how substitution of nitrogen in a cubanoid influence deshielding of carbon and manifest in the chemical shift in NMR spectra calculated using the second order Møller-Plesset (MP2) perturbation level of theory. PMR spectra predict a large downshift of delta(H)=7.9 ppm in heptaazacubane owing to the more number of nitrogen and the stronger C-H...N interactions. These chemical shifts are explained by the net atomic charges derived from the population analysis based on Hirshfeld partitioning scheme.
authors.affiliation: Department of Chemistry, University of Pune, Pune 411007, India.
authors.forename: Rahul V
authors.initials: RV
authors.lastname: Pinjari
authors.forename: Nilesh R
authors.initials: NR
authors.lastname: Dhumal
authors.forename: Shridhar P
authors.initials: SP
authors.lastname: Gejji
mesh_terms: D001372:Aza Compounds / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D006859:Hydrogen / Q000737:chemistry; D006860:Hydrogen Bonding; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D008962:Models, Theoretical; D009584:Nitrogen / Q000737:chemistry; D055672:Static Electricity
chemical_list: D001372:Aza Compounds; D002244:Carbon; D006859:Hydrogen; D009584:Nitrogen