Fig. 3: Spectroscopic investigations of 2 + 2 IOPC reaction intermediates.
From: Intermolecular 2+2 imine-olefin photocycloadditions enabled by Cu(I)-alkene MLCT
a Synthesis of hydrotris(pyrazolyl)borate copper olefin compounds. b X-ray structures of the norbornene and maleic anhydride complexes TpCu-NB and TpCu-MA. c Electronic absorption spectra of reaction components (TpCu, MA = maleic anhydride, imine = 1) and transmission spectrum of reaction vessels used. Pink line = stoichiometric mixture of TpCu and maleic anhydride; orange line = stoichiometric mixture of TpCu, maleic anhydride, and 1; gold line = stoichiometric mixture of TpCu and 1; green line = TpCu; light blue line = maleic anhydride; dark blue line = 1. Gray shaded area indicates transmission spectrum of the borosilicate glass reaction vessels used. A.U. = arbitrary units.
