Azaborinine

Abstract

ZusammenfassungDer formale Austausch zweier benachbarter Kohlenstoffatome im klassischen Aromaten Benzol durch jeweils ein Bor‐ und ein Stickstoffatom liefert ein 1,2‐Azaborinin. Dieses weist im Vergleich zum aus alternierenden Bor‐ und Stickstoffatomen bestehenden Sechsring Borazin eine deutlich gesteigerte Aromatizität auf, was experimentell etwa durch eine Untersuchung der Bindungslängen, Resonanzstabilisierungsenergien, NMR‐Verschiebungen oder Reaktivitäten gegenüber Elektrophilen nachgewiesen werden konnte. Im Labor lassen sich monozyklische Azaborinine vor allem über Olefinmetathesen offenkettiger B,N‐Allylderivate und anschließende Aromatisierung herstellen, doch auch der Einbau in größere Systeme ist möglich. Sowohl monozyklische als auch polyzyklische Azaborinine weisen ein großes Anwendungspotential etwa in den Materialwissenschaften, der Pharmakologie oder der Analytik auf, da die polare B‐N‐Einheit eine Reihe neuartiger chemischer, physikalischer und optischer Eigenschaften induziert.

Synthesis and crystal structure of 2-(anthracen-9-yl)-1-(tert-butyldimethylsilyl)-3,6-dihydro-1λ4,2λ4-azaborinine

“…The formal replacement of a C-C bond with a B-N motif (BN isosterism) in six-membered rings changes their reactivity, as well as the dipole moments and electronic and optical properties (Be ´langer- Chabot et al, 2017;Campbell et al, 2012;Appiarius et al, 2023). This allows for potential applications in functionalized polymers (Thiedemann et al, 2017), hydrogenstorage materials (Campbell et al, 2010), pharmacology (Boknevitz et al, 2019) or optoelectronics (Appiarius et al, 2021;Hoffmann et al, 2021a,b).…”

Synthesis and crystal structure of bis(9-mesityl-9,10-dihydro-10-aza-9-borabenzo[h]quinolinato-κ2 N 1,N 10)zinc(II)

“…The crystal structures of 13 compounds with 1,2-azaborinine substructures and nitrogen-metal bonds have been published, of which different lithium solvates as well as potassium, beryllium, aluminum, gallium and tin complexes are included in one publication (Lindl et al, 2023). Moreover, one study describes several complexes of a bidentate ligand with aluminum (Appiarius et al, 2023). However, there are only three reports of 1,2-azaborinines with N-transition-metal bonds, including zirconium (refcode JIZQEP; Pan et al, 2008), ruthenium (refcode DOXBEY; Pan et al, 2008) and iridium (refcode NEZXAV; Baschieri et al, 2023).…”

Boosting quantum yields and circularly polarized luminescence of penta- and hexahelicenes by doping with two BN-groups

“…Therefore, the doping with neighboring boron–nitrogen (BN) units has emerged as a popular strategy especially for planar PAHs, 35–38 as it provides isoelectronic and isostructural BN-PAHs. In such compounds, the disparities in properties are almost exclusively caused by altered electronegativities of the heteroatoms, 39 facilitating the comparison with the parent, all-carbon CC-PAHs. 40–42…”

“…33 Therefore, the doping with neighboring boron-nitrogen (BN) units has emerged as a popular strategy especially for planar PAHs, [35][36][37][38] as it provides isoelectronic and isostructural BN-PAHs. In such compounds, the disparities in properties are almost exclusively caused by altered electronegativities of the heteroatoms, 39 facilitating the comparison with the parent, allcarbon CC-PAHs. [40][41][42] Unfortunately, reports of helical BN-derivatives have remained scarce, [43][44][45][46][47] which especially applies to helicenes with B]N groups in the aromatic backbone.…”