Janus-faced coordination chemistry of pyridyl-functionalized phosphinines with Cu(i) and Au(i)

The novel 2,6-trimethylsilyl-3,5-(2′-pyridyl)phosphinine has been synthesized and its coordination chemistry with Cu(I) and Au(I) was investigated. Selective binding through either the phosphorus atom or the pendant pyridyl groups was achieved, yielding monomeric, dimeric, and polymeric complexes. The use of copper halides produced rather structurally diverse coordination compounds, with architectures dependent on the type of halide, copper loading, and solvent, whereas Au(I) exclusively formed monomeric species. Quaternization of the ligand with alkylating agents suppressed N-coordination, enabling further study of the resulting cationic derivative with the same metals. These results highlight strongly tuneable coordination behaviour of this new phosphinine scaffold.