A cyclodiphosphazane based pincer ligand, [2,6-{μ-((t)BuN)2P((t)BuHN)PO}2C6H3I]: Ni(II), Pd(II), Pt(II) and Cu(I) complexes and catalytic studies.

Synthesis and late-transition metal complexes of pincer capable cyclodiphosphazane, 2,6-{μ-((t)BuN)2P((t)BuHN)PO}2C6H3I (1) are described. The condensation of 2-iodoresorcinol with cis-{ClP(μ-N(t)Bu)2PN(H)(t)Bu} produced a difunctional derivative 1 in good yield. The treatment of Ni(COD)2, Pd2(dba)3·CHCl3 or Pt(PPh3)4 with 1 afforded pincer complexes [2,6-{μ-((t)BuN)2P((t)BuHN)PO}2C6H3MI] (2 M = Ni; 3 M = Pd and 4 M = Pt). The reaction of complex 3 with copper halides resulted in the formation of heterobimetallic complexes bridged by rhombic {Cu(μ-X)}2 units, [{{Cu(μ-X)}2}{μ-((t)BuN)2P((t)BuHN)PO}2C6H3PdI] (5 X = I and 6 X = Br). The crystal structures of 1-3, and 6 were established by single X-ray diffraction studies. The palladium complex 3 was tested for catalytic P-arylation of diphenylphosphine oxide (Ph2P(O)H) under microwave irradiation. Moderate to good catalytic activity was observed with aryl bromides.