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We developed two synthetic strategies towards triptycene-derived bulky boranes, boronates, and boron ate-complexes. Starting from borylated or brominated anthracenes and using a Br/Li exchange and [4+2] cycloaddition reaction with in-situ generated benzyne, we produced a series of triptycene boronates and borates with various boron substituents in positions 1 and 9, such as BPin, Bneo, BF3K and B(Mes)2. Single-crystal X-ray diffraction analysis and UV-Vis/photoluminescence measurements provided quantitative information on the effect of the triptycene scaffold on the photophysical and electronic properties of the obtained compounds.

A highly bent triarylborane, 9-boratriptycene, was generated in solution by selective protodeboronation of the corresponding tetra-aryl boron ate complex with the strong Brønsted acid HNTf2. The iptycene core confers enhanced Lewis acidity to 9-boratriptycene, making it unique in terms of structure and reactivity. We studied the stereoelectronic properties of 9-boratriptycene by quantifying its association with small N- and O-centered Lewis bases, as well as with sterically hindered phosphines. The resultant Lewis adducts exhibited unique structural, spectroscopic, and photophysical properties. Beyond the high pyramidalization of the 9-boratriptycene scaffold and its low reorganization energy upon Lewis base coordination, quantum chemical calculations revealed that the absence of π donation from the triptycene aryl rings to the boron vacant pz orbital is one of the main reasons for its high Lewis acidity.

International audience; 2-N-aminoquinazolines were prepared through consecutive SNAr functionalization. X-ray structures display the nitrogen lone pair of the 2-N-morphilino group in conjugation with the electron deficient quinazoline core and thus representing electronic push-pull systems. 2-N-aminoquinazolines show a positive solvatochromism and are fluorescent in solution and in solid state with quantum yields up to 0.73. Increase in electron donor strength of the 2-amino substituent causes a red-shift of the intramolecular charge transfer (ICT) band (300-400 nm); whereas the photoluminescence emission maxima (350-450 nm) is also red-shifted significantly along with an enhancement in photoluminescence efficiency. HOMO-LUMO energies were estimated by a combination of electrochemical and photophysical methods and correlate well to those obtained by computational methods. ICT properties are theoretically attributed to an excitation to Rydberg-MO in SAC-CI method, which can be interpreted as n-pi* excitation. 7-Amino-2-N-morpholino-4-methoxyquinazoline responds to acidic conditions with significant increases in photoluminescence intensity revealing a new turn-on/off fluorescence probe.

Two straightforward synthetic methods towards semi‐planar triarylboranes with two aryl rings connected by a methylene bridge have been developed. The fine‐tuning of their stereoelectronic properties and Lewis acidities was achieved by introducing fluorine, methyl or methoxy groups either at their exocyclic or their bridged aryl rings. X‐ray diffraction analysis and quantum‐chemical calculations provided quantitative information on the structural distortion experienced by the near planar hydro‐boraanthracene skeleton during the association with Lewis bases such as NH3 and F–. Though the methylene bridge between the ortho‐positions of two aryl rings of triarylboranes decreased the Gibbs free energies of complexation with small Lewis bases by less than 5 kJ mol‐1 relative to the classical Lewis acid BAr3, the steric shielding of the CH2 bridge is sufficient to avoid the formation of Lewis adducts with larger Lewis bases such as triarylphosphines. A newly synthesized spirocyclic amino‐borane with a long intramolecular B‐N bond that could be dissociated under thermal process, UV‐irradiation, or acidic conditions might be a potential candidate in Lewis pairs catalysis.

International audience; A set of methoxy-substituted diindolo[3,2-b:2 0 ,3 0-h]carbazoles has been synthesized by twofold Suzuki– Miyaura, Cadogan and N-alkylation reactions starting from N-hexyl-2,7-dibromo-3,6-dinitro carbazole. Microwave accelerated reactions ensure a rapid straightforward and step-ecomomic assembly of the diindolo[3,2-b:2 0 ,3 0-h]carbazole framework. Besides the parent diindolo[3,2-b:2 0 ,3 0-h]carbazole four new methoxy-group bearing derivatives were obtained and their molecular properties were investigated by thermal, photophysical and electrochemical means. Dichloromethane solutions of the diindolocarbazoles display with respect to the methoxy-group substitution pattern bright photoluminescences covering the blue to green spectra with quantum yields of f F = 0.20–0.27. Notably, the N,N,N-tri-n-hexyl-1,4,9,12-tetramethoxy diindolo[3,2-b:2 0 ,3 0-h]carbazole exhibits a remarkable aggregate induced excimer-type luminescence (em l max = 562 nm, solid f F = 0.14) in the solid state resulting in bright yellow light emission, whereas the parent non-substituted compound and the other methoxy-substituted derivatives show poor photoluminescence from the solid state. HOMO/LUMO energy levels were determined by means of electrochemical and photophysical methods and were compared to those obtained by computational methods using B3LYP/6-31G(d) DFT calculations with a Polarisable Continuum Model (CPCM) for the solvent CH 2 Cl 2. Good linear correlation was observed between calculated and experimentally measured values, and the correlations were used to estimate experimental HOMO/LUMO energy values of still non-synthesized heteroatom extended heteroacenes.

International audience; The novel ynamide compound, bis-(N-4-methylbenzenesulfonyl, N-n-butyl)-1,3-butadiyne-1,4-diamide (3), was synthesized and characterized by single crystal X-ray diffraction, 1H and 13C NMR, UV-fluorescence spectroscopy, cyclic voltammetry, TGA and DSC techniques. This first reported X-ray structure of a 1,3-butadiyne-1,4-diamide revealed that the amido substituents of 3 adopt a twisted conformation in the crystal with a torsion angle of 76.6° resulting in a molecule with axial chirality. The crystal structure of compound 3 is stabilized by intermolecular CH-π interactions that give pairs of stacked bis-alkyne-3 units. HOMO/LUMO energy levels of 3 were experimentally determined by means of electrochemical and optical methods to be −5.87/−1.98 eV respectively. The solid state polymerization of the title compound was investigated by differential scanning calorimetry (DSC) revealing that polymerization proceeded simultaneously to the phase transition assigned to the melting of 3. The solid state polymerization of 3 is discussed of being a topochemically initiated polymer chain reaction that proceeds with a non-topochemical chain growth.