Assembly of One-, Two-, and Three-Dimensional Cu(I)-Based Coordination Frameworks for Tunable White Light Emission and Effective Fluorescence Sensing

Abstract

By assembling a tetradentate N-donor ligand tetra­(pyridine-4-yl)­benzene-1,4-diamine (TBD) with a copper ion, three novel Cu­(I)-based coordination frameworks, bearing one-, two-, and three-dimensional (3D) architectures, namely, [Cu2Br2(TBD)·H2O] (1), [Cu2Br2(TBD)] (2), and [CuI­(TBD)] (3), have been synthesized and characterized. Owing to the different coordination modes of [Cu2Br2] dinuclear units, compounds 1 and 2 display distinct structures with double-stranded chains for 1 and 4-connected layers for 2. Compound 3 presents a (3,4)-connected 3D network, which is fabricated from neutral Cu-TBD layers with the bridging organic ligands. Solid-state photoluminescence test implies that the three compounds exhibit bright yellow emissions with the luminescence lifetime at a microsecond scale. Interestingly, through the alternation of the ratios with compound 3 and blue phosphor, tunable luminescence emissions from yellow to white light have been achieved. Moreover, the luminescence sensing ability toward various metal cations was examined on 1. The compound could be competent to serve as a selective fluorescent probe for the recognition of Fe3+ despite the existence of other interferences.