Expansion of the scope of alkylboryl-bridged N → B-ladder boranes: new substituents and alternative substrates

Abstract

A series of new boranes capable of forming intramolecular N → B-heterocycles has been prepared and their properties have been studied by electrochemical methods and UV-vis-spectroscopy complemented by DFT calculations.

Recent advances in the synthesis of luminescent tetra-coordinated boron compounds

“…The photophysical and DFT experiments showed that the electronic properties of the synthesized boranes can be tuned by varying the substituents on boron. The same methodology was further extended to 104,105 prepare a series of conjugated ladder type B-N coordinated boranes (86,87) by the two-fold hydroboration reaction of quarterpyridine, pyrimidine, and 1,5-naphthyridine precursors with 9H-BBN and Piers' boranes ((C 6 H 5 ) 2 BH). Photophysical and electrochemical experiments showed that the optical band gaps of these boranes are reduced and their electron affinities are increased to between −3.4 and −4 eV, which make them suitable candidates for use as n-type organic semiconductors.…”

“…The emission of complexes showed a red shifted band with respect to their respective ligands. A similar methodology was also adopted to make 118 phenanthroimidazole based boron compounds (105). All the compounds showed moderate to good quantum yields in the solution state and moderate solid state quantum yields.…”

Tetrazole‐Functionalized Organoboranes Exhibiting Dynamic Intramolecular N→B‐Coordination and Cyanide‐Selective Anion Binding

“…[57,58] Hydroboration of suitable substrates can also yield a broad range of N!B-heterocycles. [59][60][61][62][63][64][65][66] Recently we developed strategies for the synthesis of N!Bheterocycles by building-up the N-heterocyclic component through cycloaddition-reactions. We found that both 1,3-dipolar [3 + 2] azide-alkyne cycloaddition [67,68] and cobalt-mediated [2 + 2 + 2] cycloaddition between nitriles and alkynes [69] are highly efficient tools for the preparation of electronically and structurally diverse N!B-ladder boranes.…”

“…and electrophilic C−H‐borylation [57,58] . Hydroboration of suitable substrates can also yield a broad range of N→B‐heterocycles [59–66] …”

Synthesis and stereochemistry of chiral aza-boraspirobifluorenes with tetrahedral boron-stereogenic centers

“…13 Due to the high stability of the B-C bonds, BC 4 boranes exhibit high stereochemical stability. 14 To date, chiral tetrahedral boranes with B-N, [15][16][17][18][19][20][21][22][23][24][25][26][27] B-O, [28][29][30][31] B-H, 32,33 and boron-heteroatom [34][35][36][37] bonds have been synthesized and the stereochemistry of the compounds has been studied extensively. For example, Toyota has reported stable chiral tetrahedral boranes with three B-C bonds and one B-N bond (BC 3 N), and examined the racemization process (Fig.…”