Tuning the Donor−π–Acceptor Character of Arylborane–Arylamine Macrocycles

Abstract

Donor−π−acceptor compounds based on arylamine and arylborane moieties connected by a π-conjugated linker are attractive materials in organic electronics and imaging applications due to the strong charge transfer character that leads to low energy absorption and solvatochromic emission properties. Here we introduce a new conjugated macrocyclic system that consists of four arylborane and two arylamine units as confirmed by singlecrystal X-ray structure analysis. The acceptor character of the arylboranes is enhanced by exocyclic electron-withdrawing 2,4,6tris(trifluoromethyl)phenyl ( F Mes) substituent as well as the mutual interaction between adjacent boranes. The absorption, solventdependent emission, and electrochemical properties are studied and compared to those of other macrocyclic organoboranes. Computational studies offer additional insights into the electronic structure. Due to the enhanced acceptor character of the boranes, the LUMO orbitals are lower lying, leading to more facile reduction, red-shifted absorption and emission, and larger Stokes shifts than those found for previously studied B−N macrocycles.

Polycationic Redox‐Active Cyclophanes with Integrated Electron‐Rich Diboron Units

“…[8] Jäkle et al synthesized several boracyclophanes with interesting optical and redox properties. [9][10][11][12][13][14] One example is sketched in Figure 1. In these compounds, the B III atoms are Lewis-acidic sites and act as electron-acceptors.…”

Tuning the Optoelectronic Properties of Cross Conjugated Small Molecules Using Benzodithiophene As a Core Unit With Favorable Photovoltaic Parameters

“…The BDT-CR cross conjugated molecule exhibited the λ max values of 395, 554, 350 and 312 nm at B3LYP, PBEPBE, MPW1MP91 and WB97XD respectively. The above-mentioned values were sensibly equated with an experimentally reported λ max value of 407 nm [35]and calculated λ max of the BDT-CR molecule with B3LYP functional has close approximation with experimental value (see Fig. 2)so B3LYP was nominated as an appropriate method to intensify optoelectronic features and for further calculations of all investigated cross conjugated molecules.…”

Electrochromic Polycationic Organoboronium Macrocycles with Multiple Redox States

“…The synthetic strategy involves the macrocyclization of distannylated and dibromoborylated precursors via Sn–B exchange, followed by the replacement of the remaining Br atoms on each boron by 2,2′‐bipyridine (Scheme 1). [11c] The Sn–B exchange reaction between distannylated amine 1 and diborylated fluorene 2 under pseudo high dilution conditions produced the tetracationic macrocycle [ MC1 ]Br 4 (Scheme 1 a). [ MC1 ]Br 4 was isolated as a red solid in 11 % isolated yield by repeated recrystallization from a solvent mixture of ether and methanol.…”