Boron–nitrogen doped carbon scaffolding: organic chemistry, self-assembly and materials applications of borazine and its derivatives

Abstract

Discovered by Stock and Pohland in 1926, borazine is the isoelectronic and isostructural inorganic analogue of benzene, where the C[double bond, length as m-dash]C bonds are substituted by B-N bonds. The strong polarity of such heteroatomic bonds widens the HOMO-LUMO gap of the molecule, imparting strong UV-emitting/absorption and electrical insulating properties. These properties make borazine and its derivatives valuable molecular scaffolds to be inserted as doping units in graphitic-based carbon materials to tailor their optoelectronic characteristics, and specifically their semiconducting properties. By guiding the reader through the most significant examples in the field, in this feature paper we describe the past and recent developments in the organic synthesis and functionalisation of borazine and its derivatives. These boosted the production of a large variety of tailored derivatives, broadening their use in optoelectronics, H2 storage and supramolecular functional architectures, to name a few.

Layered Boron–Nitrogen–Carbon–Oxygen Materials with Tunable Composition as Lithium‐Ion Battery Anodes

“…[31] In close agreement with XPS analysis, 11 BM AS NMR spectra show three main signals at all condensation temperatures:as ignal at d iso = 17.6 ppm (C Q = 2.49 MHz, h = 0.2), corresponding to trigonal sp 2 -BO 3 ; [34] a signal at d iso = 0.2 ppm (no quadrupolar shape) duet ot etragonal BO 4 ; [35] and as ignal at d iso = 28.2 ppm (C Q = 3.0 MHz, h = 0.2), indicating the presence of planarB N 3 , [36] whichs uggests domainso fs ix-membered BN rings. [31] In close agreement with XPS analysis, 11 BM AS NMR spectra show three main signals at all condensation temperatures:as ignal at d iso = 17.6 ppm (C Q = 2.49 MHz, h = 0.2), corresponding to trigonal sp 2 -BO 3 ; [34] a signal at d iso = 0.2 ppm (no quadrupolar shape) duet ot etragonal BO 4 ; [35] and as ignal at d iso = 28.2 ppm (C Q = 3.0 MHz, h = 0.2), indicating the presence of planarB N 3 , [36] whichs uggests domainso fs ix-membered BN rings.…”

“…[3][4][5][6][7][8] Therefore, boron-carbon-nitrogen-oxygen (BNCO)m aterials are considered to be very promising materials for various applications, such as electronic, optical, and electrochemical devices,o wing to their tunable opticala nd electronic properties, which depend only on the amount and spatialo rganization of heteroatoms. [11] Although an impressively wide range of materials were synthesized by these methods, there are still some drawbacks that limit furtherp rogress in this field. [11] Although an impressively wide range of materials were synthesized by these methods, there are still some drawbacks that limit furtherp rogress in this field.…”

“…Traditional BNCO synthetic methodsi nclude solid-state reactions, [9] chemical vapor deposition (CVD), [10] and organic addition reactions of BN to polycyclic aromatic hydrocarbons (PAHs). [11] Although an impressively wide range of materials were synthesized by these methods, there are still some drawbacks that limit furtherp rogress in this field. The CVD methodo ffers low scalability,w hereas the solid-state reactionp rovides moderate control over the composition and positionofheteroatoms within the carbon network and usually includes templating, [12] externalm edia, [13] and condensation of different solid powders.…”

“…a)11 BM AS NMRs pectra of AB and BNPyr 300, 500, 700 .Asimulationi s proposed as an illustration for BNPyr 300 ;b )13 CC PMAS NMRs pectra of Pyr and BNPyr 300, 500, 700 .ChemSusChem 2018ChemSusChem , 11,2912ChemSusChem -2920 www.chemsuschem.org2018 Wiley-VCH Verlag GmbH &Co. KGaA, Weinheim state reaction, the liquid phase allows the facile organicchemistry-like reaction of the two monomers up to 400 8C.…”

Inorganic Triphenylphosphine

“…NICS values for benzene and borazine are À11.5 and À2.1 respectively), [23][24][25] and the dominant mechanisms by which they undergo substitution are fundamentally different:e lectrophilic aromatic substitution for benzene,a ddition-elimination for borazine. [26,27] B-trisubstituted borazines ( Figure 2) are readily prepared and their chemistry has been well studied [28][29][30][31][32][33] but the chemistry of the less accessible B-monosubstituted borazines (XBaz, Figure 2) has been little developed; [34][35][36] for example, 2-hydroxyborazine (HOBaz), the borazine analogue of phenol, has only been partially characterised in situ as part of am ixture of products formed in the photochemical oxidation of borazine. [37] In addition, no borazines that contain PÀBb onds have been reported which may be due to the anticipated high reactivity of the PÀBb ond.…”