Mononuclear transition metal complexes of 7-nitro-1,3,5-triazaadamantane

Complexes of the type [MCl2(7-nitro-1,3,5-triaza-adamantane)2] (M = Zn(II), Pd(II), Pt(II)) and [MCl2(H2O)2(7-nitro-1,3,5-triazaadamantane)2] (M = Mn (II), Co(II), Ni(II)) have been prepared and their structures have been analysed by X-ray crystallography, elemental analysis, IR and solid state 13C and 15N NMR spectroscopy, supported by density functional theory/gauge independent atomic orbital (DFT/GIAO) calculations. In each case, 7-nitro-1,3,5-triazaadamantane acts as a mono-dentate ligand and binds to one metal centre only, in spite of the presence of three equivalent amino nitrogens. In the Co(II) and Ni(II) complexes, a two-dimensional intermolecular hydrogen bonding network between the aqua- and the chloro ligands is established. The uncoordinated amines of the 7-nitro-1,3,5-triaza-adamantane are not involved in any H-bonding, as a result of the exceptionally low basicity of this compound