J. Phys. Org. Chem.23, 1202-1213 (2010).

© Wiley-Blackwell

Photochemical Generation of Thiophene Analogs of 9-Fluorenyl Cations .

Matthew Bancerz, Lawrence A. Huck, William J. Leigh, Gabriela Mladenova, Katayoun Najafian, Xiaofeng Zeng, and Edward Lee-Ruff,*

Contribution from the Department of Chemistry, York University, Toronto, Ontario, Canada, M3J 1P3
the Department of Chemistry & Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, ON Canada L8S 4M1.

The 9-fluorenyl cation is a member of the 4N Hückel antiaromatic series of intermediates, first observed by time-resolved spectroscopy on UV photo-excitation of 9-fluorenol. Thiophene analogs of 9-fluorenol in which one of the annelated benzene rings is replaced by a thiophene were prepared in three regioisomeric forms, and subjected to preparative and laser flash photolysis. Photoproduct studies in methanol indicated products derived from the corresponding fluorenyl cations and radical intermediates. Time-resolved spectroscopy showed transients which were assigned to the corresponding cations as evident from methanol quenching. The lifetimes and methanol scavenging rates of these transients were compared with those of parent fluorenyl cation. The kinetic stabilities of these ions were compared to thermodynamic parameters obtained from theoretical calculations.

Back to WJL's Publication List.