BF₂‐Complexes of Carbazole–Benzimidazole Conjugates: Synthesis, Structures, and Spectroscopic Properties

Abstract

A series of carbazole–benzimidazole conjugates and corresponding BF2‐complexes (BODIPYs) are synthesized and characterized. Carbazole–benzimidazole conjugates are synthesized by the condensation of 1‐formyl carbazole and phenylene diamines in good yields. Various substituents are introduced into the benzimidazole moiety and subsequent reaction with BF3•Et2O afforded the BF2‐complexes in moderate to good yield. The structural and photophysical properties of the synthesized fluorophores are investigated with various spectroscopic techniques such as UV/Vis and fluorescence spectroscopy, cyclic voltammetry and X‐ray crystallography.

π-Extended Boron Difluoride [NՈNBF2] Complex, Crystal Structure, Liquid NMR, Spectral, XRD/HSA Interactions: A DFT and TD-DFT Study

“…Formally, the boron center is coordinated to one of the N atoms via an ionic bond and to the other via a coordination covalent bond to form a slightly strained-six membered ring that is perpendicular to the plane of the F-B-F group. The 2B-N (1.543 Å), B-F1 (1.397 Å), and B-F2 (1.389 Å) bond lengths are consistent with the reported data for similar tetra-coordinate boron systems [32][33][34][35][36][37][38]. The DFT theoretical calculations demonstrated a high degree of congruence, as seen in Figure 2b.…”

“…The δ v -symmetry reduces the number of protons environment to 6 instead of 12; all the protons groups chemical shifts are identified directly and labeled in the spectrum in Figure 1a. Moreover, as expected, the 11 B-{ 1 H }-NMR spectrum displays a triplet (128 Mhz, δ = 1.0 ppm), as seen in Figure 1b due to coupling to two equivalent fluorine atoms, and the 19 F-{ 1 H}-NMR shows at 1:1:1:1 quartet (376.5 MHz, δ = −146.3 ppm), resulting from two equivalent fluorine atoms due the π-extended behavior coupled to the boron [33,34]. NMRDB [35] and GIAO-DFT/B3LYP/6-311G(d,p) NMR [30] were performed using same references and CDCl 3 solvent, and the results are inserted into Figure 1 together with their experimental relatives.…”

Cinnamoyl Dipyrromethenes as Fluorescence Zinc(II) Ion Sensor

“…Table 1 summarizes the absorption and emission spectra of the dipyrromethenes. Free dipyrromethenes and the corresponding zinc(II) complexes exhibit a small Stokes shift (16–21 nm), similar to BODIPY complexes [21a–b] . Cinnamoyl dipyrromethenes show a large bathochromic shift compared to their parent molecules, which indicates a good conjugated system.…”

Carbazole Substituted BODIPYs

“…The strong fluorescence of the BF 2 complexed coumarin unit in the red region was attributed to the attachment of carbazole donor group; these dyes can be potentially useful for biological applications (Rajeshirke et al, 2018). The BF 2 complexes of carbazole-benzimidazole conjugates 139 and 140 (Chart 26) were synthesized by Dutta et al (2017). Both the CHART 24 | Carbazole based BODIPY core dendrimer, G2 series.…”