A series of tetraphenylethene-based benzimidazoles: syntheses, structures, aggregation-induced emission and reversible mechanochromism. Issue 83 (23rd August 2016)

• Record Type: Journal Article
• Authors: Zhang, Tengfei; Zhang, Ran; Zhang, Zhaoming; Ni, Zhonghai
• Is Part Of: RSC advances. Volume 6:Issue 83(2016)
• Page Start: 79871
• Page End: 79878
• Publication Date: 2016-08-23
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c6ra16514a
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : A new series of tetraphenylethene-based benzimidazoles (2a–2d ) were designed and synthesized. These compounds exhibit bifunctional AIE and reversible mechanochromic properties. Abstract : Four tetraphenylethene-based benzimidazoles 5, 6-R-2-(4-tetraphenyletheneyl)-1 H -benzo[ d ]imidazoles (R = H (2a ), Cl (2b ), Br (2c ) and CH3 (2d )) were conveniently synthesized in high yields by the cyclization reaction of 4-tetraphenylenthenealdehyde with phenylenediamines. These compounds were structurally characterized and their properties were analyzed by spectroscopy, electrochemistry, X-ray diffraction, thermal stability and theoretical studies. Single crystal X-ray diffraction analyses indicate that their molecular structures in the aggregated state are highly twisted conformations and there exist obvious cavities and/or interface gaps in their crystal packing structures. These four compounds exhibit typical aggregation-induced emission (AIE) properties with relatively high absolute fluorescence quantum yields (30.6–67.5%). These compounds also exhibit reversible mechanochromism behaviors with emission changes between light blue and yellow-green, which are due to the reversible morphological transformation between unconsolidated crystalline state and amorphous state. They are thermally stable with decomposition temperatures above 340 °C.