Ultrafast broadband UV-visible transient absorption spectroscopy was used to characterize the photochemistry of a series of biological chromophores. The ability to use tunable pump wavelengths along with white-light continuum probes spanning the range from 270 nm to 800 nm provides the opportunity for precise characterization of both excited state pathways and ground state relaxation. The systems studied include the ring-opening reaction of 7-dehydrocholesterol (provitamin D3, Pro), the subsequent relaxation and secondary photochemistry of previtamin D3 formed from Pro, photoinduced excited state dynamics in cobalamin compounds including hydroxocobalamin, and the excited state relaxation pathways in iron-containing porphyrin molecules. The role of the environment in these various reactions and relaxation processes range from insignificant to determinative. The broadband probes used in these studies allow us to unravel the competing processes and study the role of the surrounding environment in detail.

Broadband UV-visible transient absorption studies of excited state and ground state dynamics in biological chromophores

247th National Meeting (2014)

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