Aggregation‐Induced Emission of Platinum(II) Metallacycles and Their Ability to Detect Nitroaromatics

Abstract

Abstract Two new acceptors containing platinum–carbazole ( 1 ) and platinum–triphenylamine ( 2 ) backbones with bite angles of 90° and 120°, respectively, have been synthesised and characterised. Reactions of the rigid acceptor 1 with linear dipyridyl‐based donors ( 3 and 4 ) generated [4+4] self‐assembled molecular squares ( 5 and 6 ), and similar treatments with acceptor 2 instead of 1 yielded [6+6] self‐assembled molecular hexagons ( 7 and 8 ). The metallacycles were characterised by multinuclear NMR spectroscopy ( 1 H and 31 P) and ESI‐MS. The geometries of the metallacycles were optimised by using the PM6 method. When aggregates of the metallacycles were formed by adding hexane solutions in dichloromethane, aggregation‐induced emission was observed for metallacycles 5 and 7 , and aggregation‐caused quenching was observed for metallacycles 6 and 8 . The formation of aggregates was verified by dynamic light scattering and TEM analyses. Macrocycles 5 and 7 are white‐light emitters in THF. Moreover, their high luminescence in both solution and the solid state was utilised for the recognition of nitroaromatic explosives.