Unprecedented Mixed-Valence Cu(I)/Cu(II) Complex Derived from N‑Methyl-1,3,5-triaza-7-phosphaadamantane: Synthesis, Structural Features, and Magnetic Properties

The unique mixed-valence tetracopper­(I/II) complex [Cu4I4(μ-N3)2(N3)4(μ-PTA-Me)2(PTA-Me)2]·2H2O (1), composed of the hexaazido dicopper­(II) core {Cu2(μ-N3)2(N3)4}2– and two copper­(I) {CuI2(μ-PTA-Me)­(PTA-Me)}+ units, has been easily generated by self-assembly in water from copper­(II) nitrate, N-methyl-1,3,5-triaza-7-phosphaadamantane iodide, [PTA-Me]­I, and sodium azide. It has been characterized by IR, 1H and 31P­{H} NMR, and EPR spectroscopies and elemental and single-crystal X-ray diffraction analyses. Apart from representing the first mixed-valence metal compound bearing PTA or any cage-like aminophosphine derivative, 1 also discloses a rare P,N-coordination mode of PTA-Me ligands, which act, for the first time, as spacers between the Cu­(I) and Cu­(II) centers. Magnetic susceptibility and EPR studies reveal a ferromagnetic interaction (2J = +17.1 cm–1) between the Cu­(II) atoms through μ-1,1-azido ligands.