Stefano Brenna

A series of boron difluoride compounds with 2-(imidazo[1,5-a]pyridin-3-yl)phenols bearing alkylic chains at the 1-position has been synthesized and characterized both with 1H and 13C NMR and infrared spectroscopy. This series of compounds displayed blue emission in solution and in thin polymeric films, with interesting features like large Stokes shifts and good fluorescence quantum yields. Time-Dependent Density Functional Theory (TD-DFT) calculations allowed for the identification of the main electronic transitions as intra ligand transitions (1ILT), as corroborated by the Natural Transition Orbitals (NTOs) shapes.

Two mixed ligand copper(I) complexes, [Cu(PPh 3 ) 3 ( κ ‐O‐mand)] ( CuP3M ) and [Cu(PPh 3 ) 2 ( κ 2 ‐O,O’‐mand)] ( CuP2M ) (mand= dl ‐mandelate) were synthesized and fully characterized. The different coordination modes of the α‐hydroxycarboxylate ligand in CuP2M and CuP3M are clearly demonstrated by infrared spectroscopy, with the asymmetric ν C=O stretching being observed at 1626 ( CuP3M ) and 1593 ( CuP2M ) cm −1 , respectively. Solution NMR studies ( 1 H, 31 P{ 1 H}), elemental and X‐ray structure analyses confirmed the nature of the synthesized compounds. Complexes CuP2M and CuP3M were active in carbene transfer reactions towards unsaturated bonds, using ethyl diazoacetate (N 2 CHCOOEt, EDA) as carbene source. Indeed, they promoted the trans ‐diastereoselective cyclopropanation of terminal and internal olefins under mild reaction conditions and low catalyst loading (1 % mol).