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Full-Text Articles in Physical Sciences and Mathematics
Dications Of 3-Phenyl-Indenylidene Dibenzo[ A.D ]Cycloheptene: The Role Of Charge In The Antiaromaticity Of Cationic Systems, Nancy S. Mills, Francine E. Cheng, Joseph M. Baylan, Cornelia Tirla, Jennifer L. Hartmann, Kiran C. Patel, Bart J. Dahl, Sean P. Mcclintock
Dications Of 3-Phenyl-Indenylidene Dibenzo[ A.D ]Cycloheptene: The Role Of Charge In The Antiaromaticity Of Cationic Systems, Nancy S. Mills, Francine E. Cheng, Joseph M. Baylan, Cornelia Tirla, Jennifer L. Hartmann, Kiran C. Patel, Bart J. Dahl, Sean P. Mcclintock
Chemistry Faculty Research
Dications of 9-(3-phenyl-1H-inden-1-ylidene)-5H-dibenzo[a,d]cycloheptene, 52+, were prepared by oxidation with SbF5 in SO2ClF, and their magnetic behavior was compared to dications of 9-(3-phenyl-1H-inden-1-ylidene)-9H-fluorene, 22+. The good correlation between the experimental 1H NMR shifts for the dications that were oxidized cleanly and the chemical shifts calculated by the GAIO method supported the use of the nucleus independent chemical shifts, NICS, to evaluate the antiaromaticity of the indenyl systems of 22+/52+ and their unsubstituted parent compounds, 62+ and 72+, as well as the antiaromaticity of the fluorenyl system of 22+/72+ …
Reduction Of Benzylidene Dibenzo[ A, D ]Cycloheptenes: Over-Reduction Of Antiaromatic Dianions To Aromatic Tetraanions, Blakely Tresca, Macdonald Higbee, Nancy S. Mills
Reduction Of Benzylidene Dibenzo[ A, D ]Cycloheptenes: Over-Reduction Of Antiaromatic Dianions To Aromatic Tetraanions, Blakely Tresca, Macdonald Higbee, Nancy S. Mills
Chemistry Faculty Research
The antiaromaticity of a series of dianions of p-substituted benzylidene dibenzo[a,d]cycloheptenes was examined through calculated measures of antiaromaticity. The nucleus-independent chemical shifts (NICS) and magnetic susceptibility exaltation both showed substantial antiaromatic character in the benzannulated tropylium anion. When the antiaromaticity was normalized for the area of the ring, these tropylium anions were shown to be among the most antiaromatic anions in the chemical literature. Attempts to make the dianion through reduction with lithium or potassium gave the tetraanion as the only species observable in the (1)H NMR spectrum. Quench of the reaction mixture with trimethylsilyl chloride or D(2)O confirmed the …