Carbazole-BODIPY conjugates: design, synthesis, structure and properties

Abstract

A set of carbazole substituted BODIPYs 2a-2c were designed and synthesized by the Pd-catalysed Sonogashira cross-coupling reaction. The effects of variation in the donor strength of various carbazoles were investigated by photophysical, electrochemical and computational studies. The electronic absorption spectra of BODIPYs 2a and 2c show charge transfer bands, which show red shift in polar solvents. The BODIPYs 2a-2c are highly fluorescent in nonpolar solvents (emission from the localized state) and poorly fluorescent in polar solvents (emission from the charge transfer state). The photophysical and electrochemical studies reveal strong donor-acceptor interaction between carbazole and BODIPY and follows the order 2a > 2c > 2b. The computational calculations show good agreement with the experimental results. The single crystal structures of BODIPYs 2a-2c are reported, which exhibit interesting supramolecular interactions. The packing diagrams of 2a show a zigzag 3D structural arrangement, whereas 2b and 2c show complex 3D structural motifs.

Triphenylamine Functionalized Unsymmetrical Quinoxalines

“…The results reveal that the absorption spectra of quinoxaline molecules 11 – 18 exhibits a bathochromic shift as the solvent polarity increases from non‐polar to polar solvents. The emission spectra of quinoxaline molecules 11 – 17 exhibits vibronic fine structures assigned as the locally‐excited (LE) state in low‐polarity solvents whereas the vibronic structures disappears with increasing polarity, which corresponds to the transformation in the excited state character from LE to Charge Transfer (CT) state ,. The quinoxaline 17 shows vibronic structures in the low energy region which might be resulted due to the incorporation of TCNE moiety .…”

NIR fluorescent small molecules for intraoperative imaging

“…These fluorophores have been successful in vivo due to their NIR emission, high quantum yield and ability to be synthetically tailored to several applications. 23,[37][38][39][40][41] Currently, however, high background during intravenous injection limits the scope for this molecular class. 23 Cyanine fluorophores are broadly defined as two heterocyclic nitrogen atoms that are connected via an electron deficient polymethine bridge.…”

Novel Cyclometalated Fe(II) Complex with NCN Pincer and BODIPY‐Appended 4'‐Ethynyl‐2,2':6',2”‐terpyridine as Mitochondria‐Targeted Photodynamic Anticancer Agents

“…Tetracyanobutadiene (TCBD) derivatives of ferrocenyl BODIPYs were synthesized for studying of the photonic and electrochemical properties that the TCBD and BODIPY units were connected directly through a single bond, through a phenylacetylene linkage and through a vinyl linkage. The donor‐acceptor (D‐A) carbazole‐BODIPY conjugates have been synthesized and studied for the thermal stability, the electronic absorption, fluorescence, and photophysical properties, and discussed the donor strength of different donors in designing strong D‐A materials …”