Gas-Phase Infrared and NMR Investigation of the Conformers of Diacetone Diperoxide (DADP)
Chunlei Guo1, John Persons1, Jeffrey N Woodford2
1Department of Chemistry, University of Nebraska at Lincoln , Lincoln, Nebraska 68588-0304, United States.
Abstract:
Gas-phase infrared measurements of diacetone diperoxide (DADP) indicate a chair conformation with less than 5% of the predicted twist conformer. Vibrational frequencies are very similar to those previously measured in the solid state. Solution NMR measurements using 2D exchange spectroscopy (EXSY) also set a very low maximum limit on the equilibrium population of the twist conformer, with a room-temperature free-energy difference in excess of 14.5 kJ/mol. These experimental results are in accord with high-level quantum calculations incorporating full thermochemistry and solvation effects, which indicate a free-energy difference in the range of 14.7-17.5 kJ/mol in polar solvents.
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