Macrocyclic tetrakis-phosphines and their copper(I) complexes

A series of mono-, di- and tetranuclear copper(I) complexes with macrocyclic 14-, 16-, 18- and 20-membered tetrakis-phosphine ligands (P4N2) was obtained and fully characterized including single crystal X-ray diffraction. The 14-membered P4N2 macrocycles form very stable cationic mononuclear tetraphospha-coordinated copper(I) complexes, whereas their higher 16-, 18- and 20-membered homologues give neutral dinuclear [Cu2I2L] complexes under the same conditions. An unusual tetranuclear complex with two three and two four-coordinated copper(I) atoms was obtained from 16-P-Mes N-4(CH2CH2Py-2) (2) and copper(I) iodide. This is the first example of N-coordination of cyclic aminomethylphosphines towards soft copper(I).