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Acenes are attractive as building blocks for low gap organic materials with applications, for example, in organic light emitting diodes, solar cells, bioimaging and diagnostics. Previously, we have shown that modification of dipyridylanthracene via B–N Lewis pair fusion (BDPA) strongly redshifts the emission, while facilitating self‐sensitized reactivity toward O2 to reversibly generate the corresponding endoperoxides. Herein, we report on the further expansion of the π‐system of BDPA to a vinyl‐substituted monomer, vinylene‐bridged dimer, and a polymer with an average of 20 chromophores. The extension of π‐conjugation results in largely reduced band gaps of 1.8 eV for the dimer and 1.7 eV for the polymer, the latter giving rise to NIR emission with a maximum at 731 nm and an appreciable quantum yield of 7 %. Electrochemical and computational studies reveal efficient delocalization of the lowest unoccupied molecular orbital (LUMO) along the pyridyl‐anthracene‐pyridyl axis, which results in effective electronic communication between BDPA units, selectively lowers the LUMO, and ultimately narrows the band gap. Time‐resolved emission and transient absorption (TA) measurements offer insights into the pertinent photophysical processes. Extension of π‐conjugation also slows down the self‐sensitized formation of endoperoxides, while significantly accelerating the thermal release of singlet oxygen to regenerate the parent acenes. [ABSTRACT FROM AUTHOR]

Covering an exceptionally wide range of bond strengths, the dynamic nature and facile tunability of dative B−N bonds is highly attractive when it comes to the assembly of supramolecular polymers and materials. This Minireview offers an overview of advances in the development of functional materials where Lewis pairs (LPs) play a key role in their assembly and critically influence their properties. Specifically, we describe the reversible assembly of linear polymers with interesting optical, electronic and catalytic properties, discrete macrocycles and molecular cages that take up diverse guest molecules and undergo structural changes triggered by external stimuli, covalent organic frameworks (COFs) with intriguing interlocked structures that can embed and separate gases such as CO2 and acetylene, and soft polymer networks that serve as recyclable, self‐healing, and responsive thermosets, gels and elastomeric materials. [ABSTRACT FROM AUTHOR]

Tridentate ligands that incorporate pyridyl rather than pyrazolyl groups are emerging as an attractive class of "scorpionate"-type ligands with enhanced electron donation, increased stability, and divergent geometry at the metal centre relative to tris(pyrazolyl)borates originally introduced by Trofimenko. Following our initial reports, the tris(pyridyl)borate (Tpyb) ligand architecture has been adopted by several research groups in pursuit of functional metal complexes that offer new opportunities in catalysis and materials science. While earlier work had been focused on symmetric octahedral complexes, ML2, which are advantageous as highly robust building blocks in materials sciences, recently introduced new ligand designs provide access to heteroleptic metal complexes with vacant sites that lend themselves to applications in catalysis. Signficant progress has also been made in the post-complexation functionalization of these ligands via electrophilic and nucleophilic substitution reactions at the boron centres, opening up new routes for integration of Tpyb complexes with diverse functional materials while also raising interesting mechanistic questions. [ABSTRACT FROM AUTHOR]

Main‐chain boron‐containing π‐conjugated polymers are attractive for organic electronic, sensing, and imaging applications. Alternating terthiophene‐borane polymers were prepared and the effects of regioisomeric attachment of the conjugated linker and variations in the electronic effect of the pendent aryl groups (2,4,6‐tri‐tert‐butylphenyl, Mes*; 2,4,6‐tris(trifluoromethyl)phenyl, FMes) examined. Pd2dba3/P(t‐Bu)3‐catalyzed Stille polymerization of arylbis(2‐thienyl)borane and arylbis(3‐thienylborane) with 2,5‐bis(trimethylstannyl)thiophene at 120 °C gave polymers with appreciable molecular weight but MALDI‐TOF MS analyses showed evidence of unusually prominent homocoupling. These defects could be suppressed by using brominated rather than iodinated monomers, more hindered 2,5‐bis(tri‐n‐butylstannyl)thiophene as comonomer, and Pd2dba3/P(o‐tol)3 as the catalyst at 100 °C. Under these conditions, macrocyclic species with n=3–10 repeating units formed preferentially according to MALDI‐TOF MS analyses. Photophysical studies revealed a prominent effect of the regiochemistry and the nature of the pendent aryl groups on the absorption and emission, giving rise to orange, yellow‐green, blue‐green, and blue emissive materials respectively. The electronic effects were rationalized through DFT calculations on bis(terthiophene) model systems. [ABSTRACT FROM AUTHOR]

We herein describe a new design principle to achieve B/N‐doped cyclophane where an electron‐donor block of three triarylamines (Ar3N) and an acceptor block of three triarylboranes (Ar3B) are spatially separated on opposite sides of the π‐extended ring system. DFT computations revealed the distinct electronic structure of the block‐type macrocycle MC‐b‐B3N3 with a greatly enhanced dipole moment and reduced HOMO–LUMO energy gap in comparison to its analogue with alternating B and N sites, MC‐alt‐B3N3. The unique arrangement of borane acceptor Ar3B and amine donor Ar3N components in MC‐b‐B3N3 induces exceptionally strong intramolecular charge transfer in the excited state, which is reflected in a largely red‐shifted luminescence at 612 nm in solution. The respective linear open‐chain oligomer L‐b‐B3N3 was also synthesized for comparison. Our new approach to donor–acceptor macrocycles offers important fundamental insights and opens up a new avenue to unique optoelectronic materials. [ABSTRACT FROM AUTHOR]