Introducing the Dihydro-1,3-azaboroles: Convenient Entry by a Three-Component Reaction, Synthetic and Photophysical Application

Abstract

The (Fmes)BH 2 •SMe 2 reagent (7) reacts sequentially with an acetylene and, e.g., xylylisonitrile in a convenient three-component reaction to give a series of unprecedented dihydro-1,3-azaborole derivatives 16. The tolane-derived example 16a was deprotonated and used as a ligand in organometallic chemistry. Compounds 16 served as the starting materials for the straightforward synthesis of various dihydro-1,3-azaborinine derivatives by treatment with an isonitrile. Several diaryldihydro-1,3azaboroles showed interesting photophysical properties such as aggregation-induced emission and high fluorescence quantum yields.

BN-Embedded Perylenes

“…Perylenes, as an example of two-dimensional graphene planar segments, demonstrate unique structure-dependent properties and perylene diimides (PDI) with n-type semiconductor characteristics have been successfully commercialized in organic solar-cell devices (Figure 1) [8][9][10][11][12][13][14][15]. At the required level of practical verisimilitude, structural tuning with heteroatom substitution of sp 2 -hybridized carbons becomes particularly attractive with an aim to exquisitely control the electronic properties of carbon-rich conjugate systems [16][17][18][19][20]. In this respect, the isosteric substitution of C=C bond with B-N bond is used to influence the electronic density and energy levels of corresponding frontier molecular orbitals (e.g., HOMOs and LUMOs) and hence to modulate molecular properties such as band gap, optoelectronic and catalytic properties [21][22][23].…”

Recent trends in molecular aggregates: An exploration of biomedicine

“…Erker et al introduced dihydro-1,3-azaboroles, produced via a convenient three-component reaction, as a novel AIE organoboron class. [41] Here, the (Fmes)BH 2 ⋅SMe 2 reagent reacts with acetylene and xylylisonitrile sequentially to give a series of unprecedented dihydro-1,3-azaborole derivatives. When the photophysical properties were checked, they found high quantum yields and AIE properties.…”

A Benzodiphosphaborolediide

“…In an extension of this concept, the incorporation of multiple (different) heteroatoms has also been explored, typified by the pnicta‐indenyl analogues [C 6 H 4 P 2 E] − of Russell (E=P, As) [9] and Wright (E=Sb) [10] and the dianionic stannylene [C 6 H 4 P 2 Sn] 2− , [11] albeit that the bulk of work with multi‐heteroatom systems has focused on neutral π‐conjugates relevant to molecular electronics [12] . In this latter context, the incorporation of neutral boroles into heteroaromatic π‐conjugates is an active field, [13] within which dihydro‐1,2‐azaboroles have been explored, [14] while their monoanions (Figure 1) are also known; [15] very recently, the 1,3‐azaborolyl anion has also been described [16] …”

“… Diphosphaindenyl based anions (left), [9–11] dihydro‐1,2 [15] and 1,3‐ azaborolides (middle), [16] which have been prepared previously and the hypothetical diphosphaborolediides 2 2− (right), which were studied computationally [17] …”