title: Structure, stability, and NMR properties of lower fullerenes C38-C50 and azafullerene C44N6.
abstract: A systematic survey of the complete set of isomers of fullerenes C(38), C(40), C(42), C(44), C(46), C(48), C(50) and azafullerene C(44)N(6) is reported. All isomeric structures were optimized using first-principle density functional theory at the B3LYP/6-31G level. The isomeric structures with the lowest energies are C(38):17, C(40):38, C(42):45, C(44):75, C(44):89, C(46):109, C(48):171, and C(50):270. The ground-state structure of the azafullerene C(44)N(6) in the framework of C(50):270 has D(3) symmetry. The (13)C NMR chemical shifts and nucleus-independent chemical shifts (NICS) for the stable isomers of each fullerene are presented.
authors.affiliation: Laboratory of Medicinal Chemistry, NCI-Frederick, CCR, NCI, NIH, DHHS, 376 Boyles St., Frederick, Maryland 21702, USA.
authors.forename: Guangyu
authors.initials: G
authors.lastname: Sun
authors.forename: Marc C
authors.initials: MC
authors.lastname: Nicklaus
authors.forename: Rui-Hua
authors.initials: RH
authors.lastname: Xie
mesh_terms: D002244:Carbon / Q000737:chemistry; D002627:Chemistry, Physical / Q000379:methods*; D004583:Electrons; D037741:Fullerenes / Q000737:chemistry*; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D009584:Nitrogen / Q000737:chemistry; D012984:Software
chemical_list: D037741:Fullerenes; D002244:Carbon; D009584:Nitrogen