An N-Alkylated 2-(5-Bromo-4-methylthiophen-2-y)-imidazo[4,5-f]-[1,10]-phenanthroline Rhenium(I) Tricarbonyl Compound Showing Aggregation-Induced Emission Enhancement

This work probes the aggregation-induced emission enhancement (AIEE) property of a 2-(2-thienyl)imidazo [4,5-f]-[1,10]-phenanthroline (TIP) based rhenium(II) tricarbonyl compound. Herein, N-alkylation reactions between 2-(5-bromo-4-methylthiophen-2-yl)-imidazo [4,5-f]-[1,10]-phenanthroline (1) and different alkyl bromides were carried out and three N-alkylated TIP derivatives (2a-2c) have been prepared successfully. The implantation of an N-alkyl group into the imidazole ring of TIP core can obviously increase the solubility in common organic solutions and affect the dihedral angles between imidazo [4,5-f] [1,10]phenanthroline and its neighbouring thiophene ring to different extents. The AIEE active rhenium(II) tricarbonyl 3 was prepared via the reaction between 2a and Re(CO)(5)Cl. X-ray single-crystal analysis of 3 indicates that the loose packing mode and the multiple intermolecular hydrogen-bonding interactions are suggested to be responsible for the AIEE activity. CCDC: 1992191, 1; 1992192, 2a; 1992193, 2b; 1992194, 2c; 1992195, 3.