Author(s)

Iraj Parchamazad^*, Debra Hornyak, Melvin Miles

Chemistry Department, University of La Verne, La Verne, CA, USA.

In this paper the results of dynamic NMR studies on ethylmethylamino-tertiary-butyl-phenylborane (EMABPB) with or without light are reported. The NMR data were recorded on a Bruker 400 MHz NMR equipped with our custom-made optical probe and with our custom-made 450 watts (W) monochromatic light sources. The molecular photochemistry including twisted intramolecular charge-transfer-excited-state (TICT) of the EMABPB in several solvents has been investigated. These results indicate that the aminoborane demonstrates multiple configurations in CD₃Cl and CD₂Cl₂ resulting in the shifts of the signals of the alkyl groups on the nitrogen and boron. This indicates that there are some time-dependent changes at constant temperature over the irradiation interval. At ﹣60°C and the presence of light (λ = 265 nm), we observed a large change in the populations of the two sites, and this by itself indicates a modification in the rotation around the boron nitrogen bond in the excited state. By considering the existence of the TICT state, many important energy technologies may be developed with higher efficiency by controlling the back-electron transfer processes.

Twisted Intramolecular Charge Transfer State, Back Electron Transfer, Twisted Excited State, Dynamic NMR, Rotation around B-N Bond, Molecular Photochemistry inside NMR Probe, Customized Optical Probe, Solvent Effect, Low Temperature Spectra

Parchamazad, I. , Hornyak, D. and Miles, M. (2015) Dynamic NMR and Twisted Intramolecular Charge Transfer Excited States. American Journal of Analytical Chemistry, 6, 402-410. doi: 10.4236/ajac.2015.65039.