Synthesis of heteroleptic phosphine-copper(i) complexes: fluorescence sensing and catalytic properties

Heteroleptic copper(i)-phosphine complexes have attracted considerable attention because of their diverse structures, and photophysical and catalytic properties. In this work, a series of heteroleptic diimine-diphosphine Cu(i) complexes (C1-C10) were synthesized quantitively using the designed bipyridine (L1-L4) and bidentate polyphosphine (L5-L8) as functional ligands. These mixed ligand-copper(i) complexes were fully characterized by H-1 and C-13 NMR spectroscopy, electrospray ionization mass spectrometry (ESI-MS) and elemental analysis. The detailed structures of complexes C1, C2, C5, C6, C9 and C10 were confirmed by single-crystal X-ray diffraction analysis. Moreover, these phosphine-Cu(i) complexes exhibited intense emissions either in the solid state or in solution under UV light excitation. The emissive complexes C1-C4 displayed highly sensitive luminescence sensing towards silver ions in a quenching fashion (turn-off). Furthermore, all the phosphine-protected copper(i) complexes exhibited high catalytic activity towards azide-alkyne cycloaddition (CuAAC) in water.

Automated summary

Heteroleptic copper(I)-phosphine complexes with diverse structures and photophysical properties were synthesized and characterized, showing intense emission properties and high catalytic activity towards azide-alkyne cycloaddition in water.