Synthesis of the hydrophilic phosphine complex Cu(DHMPE)2+ from Cu(I) chloride (DHMPE = 1,2-bis[(dihydroxymethyl)phosphino]ethane, a water-soluble bidentate phosphine)

The biomedically useful Cu(DHMPE)2+ complex (DHMPE = 1,2-bis[(dihydroxymethyl)phosphino]ethane, a water-soluble bidentate phosphine) is normally synthesized from expensive Cu(I) sources because the use of cheaper CuCl can lead to a variety of unwanted coordination complex by-products. A method is reported for the synthesis of Cu(DHMPE)2+ from CuCl. Reaction of CuCl with DHMPE in methanol gave [Cu(DHMPE)2]Cl, which is soluble in water and moderately soluble in methanol. The complex crystallized as a phosphine-bridged dimer, [Cu2(DHMPE)4]Cl2, but 1H NMR DOSY experiments indicated the complex is mononuclear in solution. Reaction of CuCl with DHMPE in THF did not yield Cu(DHMPE)2+, except when a halide abstractor such as NaPF6 was added.

Graphical abstractA method is reported for the synthesis of the biomedically useful Cu(DHMPE)2+ from CuCl instead of from more expensive Cu(I) salts.Figure optionsDownload full-size imageDownload as PowerPoint slide