The first copper complexes bearing the 1,3,5-triaza-7-phosph tadamantane (PTA) ligand

The Cu-1 compound [Cu(PTAH)(4)](NO3). (1) (PTAH = N-protonated form of 1,3,5-triaza-7-phosphaadamantane (PTA)} was easily prepared by reacting hydrated Cu(NO3)(2) and PTA in aqueous acidic solution at room temperature. Further treatment of 1 with sodium hydroxide in water led to an unprotonated PTA derivative [Cu(PTA)(4)](NO3) (2). Both compounds are water-soluble and air-stable, and were characterized by IR, H-1-, C-13 {H-1}-, P-31(H-1)- and 63 Cu NMR spectroscopy, FAB-MS(+), elemental and single-crystal X-ray diffraction structural analyses. They exhibit a nearly regular tetrahedral coordination environment about each copper centre filled by the phosphorus atoms of the four PTAH/PTA moieties, which show distinct and unusual geometrical arrangements if viewed along the P-Cu bonds. The P-31{H-1}- and Cu-63 NMR spectra of 2 in D2O solution show spin coupling between the P-31 and Cu-63 nuclei at room temperature. These compounds represent the first examples of Cu complexes bearing PTA or any derived ligand with a cagelike PTA core and expand the restricted family of aqua-soluble copper phosphane complexes. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)