Theoretical description of electromagnetic nonbonded interactions of radical, cationic, and anionic NH2BHNBHNH2 inside of the B18N18 nanoring

The electromagnetic nonbounded interactions of the NH 2BHNBHNH2 molecule inside of the B18N 18 ring have been investigated with hybrid density functional theory (B3LYP) using the EPR-III and EPR-II basis sets for a physicochemical explanation of electromagnetic nonbounded interactions within these nanosystems. Optimized structures and hyperfine spectroscopic parameters such as total atomic charges, spin densities, electrical potential, and isotropic Fermi coupling constants of radical, cationic, and anionic forms of the NH 2BHNBHNH2 molecule in different loops and bonds of the B18N18-NH2BHNBHNH2 systems have been calculated. The correlations between structural, electronic, and spectral properties have been contributed to identify the characteristics of hyperfine electronic structure. Besides structural characteristics, the lowest unoccupied molecular orbital and the highest occupied molecular orbital for the lowest energy have been derived to examine the structural stability of the B 18N18-NH2BHNBHNH2 systems. We have also carried out the calculation for the alanine-glycine amino acids coupled with the NH2BHNBHNH2 molecule inside of the B 18N18 ring (ALA-NH2BHNBHNH2-GLY) and obtained quantized transitional frequencies among the forms of radical, anionic, and cationic. In a similar way, in B18N18-NH 2BHNBHNH2, the three frequencies have been yielded as vr-c = 486948.498 GHz, va-c = 1792900.812 GHz, and v r-a = 2507076.816 GHz. It can be seen that all observed frequencies appeared in the IR and macrowave regions. It seems that the B18N 18-NH2BHNBHNH2 nonbonded system can be used for the measurement of rotational spectra related to electrical voltage differences existing in a part of biomacromolecules. The radial coordinate of the dipole moment vector (r) as well as the voltage differences (ΔV) and relative energies (ΔE) of the radical, anionic and cationic forms of the NH 2BHNBHNH2 in the B18N18-NH 2BHNBHNH2 system exhibited Gaussian distribution. The expectations of the ΔE and ΔV and r have been calculated from the Gaussian curves, which have been fitted by various eigenvalues. In addition, the natural bond orbital (NBO) analysis has been performed, which was informative to reveal some important atomic and structural features. Also, analysis of the NQR hyperfine structure of the B18N18-NH 2BHNBHNH2 system has been performed in terms of the electric field gradient at each nitrogen nucleus, and the changes in the extent of electric charge distribution that accompanies complex formation have been explored. © 2010 American Chemical Society.