Luminescent blue emissive bis(alkynyl) borane compounds with a N,O-coordinated ligand

Five bis(alkynyl)boranes with a (imidazo[1,5-a]pyridin-3-yl)phenolate ligand have been synthesized and characterized both in solution (1H, 13C, 11B, 19F NMR) and in the solid state (X-ray). All derivatives, differing for the substituent R (H, Me, OMe, CF3, NMe2) in the para position of the phenylacetylene moieties, displayed blue fluorescence emission in solution, linearly correlated to the electronic properties of the substituent R (i.e., its σp Hammett constant). High Stokes shifts and good quantum yields were recorded. Time-Dependent Density Functional Theory (TD-DFT) calculations were performed to describe the percentage contribution of each fragment of the molecule to the frontier orbitals. Electron Density Difference Maps (EDDMs) calculated for all derivatives allowed to explain the emissive properties of the studied compounds

Mixed‐Ligand Mandelato‐Phosphine Copper(I) Complexes as Active Catalysts in Carbene Transfer Reactions

Two mixed ligand copper(I) complexes, [Cu(PPh3)3(k-O-mand)] (CuP3M) and [Cu(PPh3)2(k2-O,O’-mand)] (CuP2M) (mand=dlmandelate) 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 νC=O stretching being observed at 1626 (CuP3M) and 1593 (CuP2M) cm 1, respectively. Solution NMR studies (1H, 31P{1H}), elemental and X-ray structure analyses confirmed the nature of the synthesized compounds. Complexes CuP2M and CuP3M were in carbene transfer reactions towards unsaturated bonds, using ethyl diazoacetate (N2CHCOOEt, 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)

Long-Alkyl Chain Functionalized Imidazo[1,5-<i>a</i>]pyridine Derivatives as Blue Emissive Dyes

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