Facile Synthesis of Highly Fluorescent Boranil Complexes

Abstract

Complexation of a large variety of Anils (aniline-imines) with boron(III) precursors provides stable Boranils, some of which have been structurally characterized. Analysis of their optical properties reveals that the fluorescence stems from an intraligand charge transfer (ILCT) state with the best quantum yields reaching 90%. Chemistry on the Boranils allows grafting of photoactive modules acting as energy antennae for borondipyrromethene (Bodipy) and subphtalocyanine (SubPc) fluorophores.

Synthesis and Optical Properties of Salicylaldimine‐Based Diboron Complexes

“…The B-N and B-O bond lengths in 1 and 3 are similar to those of the other reported Schiff base-BF 2 complexes. [21,47] In both structures, the boron atom deviates from the nine-atom plane defined by the six biphenyl carbon atoms and the imino carbon, nitrogen, and oxygen atoms ( Figures 4 and S6); the deviation is more pronounced in 1 (0.39 Å for B1 and 0.37 Å for B2) than in 3 (0.30 Å for B1 and 0.18 Å for B2). The dihedral angles between the two planes (planes A and B, Figure S6) are 73.45 and 123.21°i n 1 and 3, respectively (Figures 4 and S6).…”

“…[43][44][45][46] Schiff base boron compounds ( Figure 1, C) are yet another type of four-coordinate boron complex that has gained interest owing to their greater stability than tricoordinate boron compounds. [15,18,24,[47][48][49][50] For example, Ziessel, Ulrich, and co-workers reported the synthesis and optical properties of Boranil complexes. [47] Ziessel and Ulrich are also credited for expanding the scope of the Boranil complexes in a model labeling experiment with bovine serum albumin.…”

Strongly Emissive and Photostable Four‐Coordinate Organoboron N,C Chelates and Their Use in Fluorescence Microscopy

“…[1][2][3][4] The structural scope includes N,O-and N,Nchelates with five-and six-membered rings as most common binding motifs [3,5] as well as bi-nuclear boron complexes. [6] Prominent examples are boron 8-hydroxyquinolinate complexes, [7,8] boron dipyrromethene (Bodipy) dyes, [9][10][11] boranils, [12,13] and boron iminocoumarins (Boricos). [14] To a lesser extent organoboron complexes with N,C-chelate systems were reported, [15][16][17][18][19] B(ppy)Mes2 compounds (ppy = 2-phenylpyridyl, Mes = mesityl) being an example.…”

Influence of Substituent and Benzoannulation on Photophysical Properties of 1-Benzoylmethyleneisoquinoline Difluoroborates

“…[15][16][17][18][19][20][21] In literature there exist reports on compounds where BF 2 -group is chelated also symmetrically in especially imines based on a hydroxyl-containing Schiff bases, are known. [30][31][32][33] Tailoring molecular properties by relatively simple synthetic procedures is highly desirable. Systematic change of a substituent may be a successful route in 3 many instances.…”