First Heterobimetallic Seven-Membered Macrocycle Complex with a Fe(0) → Cu(I) Donor−Acceptor Bond

A new ligand, 2-(N-diphenylphosphinomethyl-N-cyclohexyl)aminopyridine (NNP), was prepared by the Mannich reaction of HPPh2 with 2-(N-cyclohexyl)aminopyridine and paraformaldehyde. The
ligand NNP reacted with Fe(CO)5 to give the monometallic complex trans-Fe(CO)3(NNP)2 (2). The reaction of
complex 2 with [Cu(CH3CN)4]+[ClO4]- gave a novel
complex 3, [(OC)3Fe(μ-NNP)2Cu]+ClO4-, which has two
seven-membered macrocycles and an Fe(0) → Cu(I)
donor−acceptor bond. The molecular structure of complex 3 was determined by X-ray single-crystal analysis.