A COMPUTATIONAL INVESTIGATION ON THE NITROGEN-RICH C2N10, C6N12, AND C6N20 COMPOUNDS BY DENSITY FUNCTIONAL METHODS

The nitrogen-rich compounds of C2N10, C6N12, and C6N20 molecules are optimized at the (U)B3LYP/6-31G(d) level. Total energies, IR, NMR chemical shifts, and equilibrium geometries of C2N10, C6N12, and C6N20 molecules are calculated. The stabilities of C2N10 and C6N20 molecules are discussed. The predicted IR spectra and NMR chemical shifts as well as equilibrium geometries of C6N20 molecules are in good agreement with available experimental measurements. Particularly, the high-energy-density nitrogen-rich C6N12 molecule with nonet spin state and eight unpaired electrons is determined as the ground state with electronic state of (9)A(g), reflecting that C6N12 is a high-spin organic magnetism and molecular-spin material. Furthermore, the average N-N dissociation energy with respect to the removal of N-2 molecules from C6N20 molecules is predicted, which corresponds to single N-N bond energy (40 Kcal/mol for the N-N single bond). On the basis of the calculated natural populations and natural electron configurations, the charge-transfer is discussed and N-3 chains in C2N10 and C6N20 molecules are bound tightly with triple covalent bonds.