Metal-to-ligand charge transfer excited

Copper-catalyzed [2 + 2] photocycloadditions are related to the latter reactions. These transformations have been extensively studied, frequently in the context of application to organic synthesis [21], When irradiated in the presence of copper(I) triflate, norbomene 12 was effidently transformed into its dimer 13 (Scheme 5.3, reaction 4) [22]. Although complexes such as III are involved in the reaction mechanism [22, 23], it is unclear whether MLCT (metal to ligand charge transfer) or LMCT (ligand to metal charge transfer) excitation induces the transformation. 

Kraft, B. J., Coalter, N. L., Nath, M., Clark, A. E., Siedle, A. R., Huffman, J. C., Zaleski, J. M. Photothermally Induced Bergman Cyclization of Metalloenediynes via Near-Infrared Ligand-to-Metal Charge-Transfer Excitation. Inorg. Chem. 2003,42, 1663-1672. 

Ligand-to-metal Charge-transfer Excited States... 

Kunkely, H. Vogler, A. Photoreactivity of (HBpyrazolyl(3)) TiCl3 and (C5H5)TiCl3 initiated by ligand-to-metal charge-transfer excitation. J. Photochem. Photobiol. A-Chem. 1998, 119, 187-190. 

Bergkamp, M. A. Gutlich, P. Netzel, T. L. Sutin, N. Lifetimes of the ligand-to-metal charge-transfer excited states of iron(III) and osmium(III) polypyridine complexes. Effects of isotopic substitution and temperature. J. Phys. Chem. 1983, 87, 3877-3883. 

The photoreactivity of CpTiCl3 initiated by ligand-to-metal charge transfer excitation has been studied.425... 

Ligand-to-Metal Charge Transfer Excited States.160... 

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