Extended π‐Conjugated Pyrene Derivatives: Structural, Photophysical and Electrochemical Properties

Abstract

This article presents a set of extended π‐conjugated pyrene derivatives, namely 1,3‐di(arylethynyl)‐7‐tert‐butylpyrenes, which were synthesized by a Pd‐catalyzed Sonogashira coupling reaction of 1,3‐dibromo‐7‐tert‐butylpyrenes with the corresponding arylethynyl group in good yields. Despite the presence of the tert‐butyl group located at the 7‐position of pyrene, X‐ray crystallographic analyses show that the planarity of the Y‐shaped molecules still exhibits strong face‐to‐face π‐π stacking in the solid state; all of the compounds exhibit blue or green emission with high quantum yields (QYs) in dichloromethane. DFT calculations and electrochemistry revealed that this category of compound possesses hole‐transporting characteristics. In addition, with strong electron‐donating (‐N(CH3)2) or electron‐withdrawing (‐CHO) groups in 2 d or 2 f, these molecules displayed efficient intramolecular charge‐transfer (ICT) emissions with solvatochromic shifts from blue to yellow (green) on increasing the solvent polarity. Furthermore, the compounds 2 d and 2 f possess strong CT characteristics.

Effects of the bridge unit in D‐π‐A architecture to improve light harvesting efficiency at DSSCs: A first principle theoretical study

“…The metal-based dyes have difficult synthesis and purification processes [9][10][11][12][13][14][15]. However, organic sensitizers have benign ecofriendly, molar extinction coefficients very high and practically very easy to preparation techniques [16][17][18][19]. The metal free sensitizer's D-p-A based dyes conversion efficiency achieved at 12.8% [20] and co-sensitized metal-free organic dyes have achieved efficiencies up to 14% [21].…”

A substituent-dependent deep-blue pyrene-based chemosensor for trace nitroaniline sensing

“…During our attempts to synthesize K-region tetrasubstituted pyrene-based derivatives as extended aromatic systems, we unexpectedly obtained another tribromo-substituted intermediate through a “one-pot” process. As depicted in Scheme S1 (ESI†), the intermediates TriBrPy and TetraBrPy were synthesized starting from 2,7-di- tert -butylpyrene 39 by a regular bromination reaction. The ratio of 1 : 9 of both intermediates was clearly calculated by 1 H NMR spectroscopic results (a consistent ratio was obtained by integration based on the pyrene moiety and tert -butyl groups, as shown in Fig.…”