Cu(I) coordination by N,N,N',N'-tetra(di-ortho-anisylphosphanylmethyl) ethylene and propylene diamine: First example of a sandwiched CuCl-tetramer

New chelating alpha-aminophosphanes were obtained by Mannich-type reactions between formaldehyde, bis(2-methoxyphenyl)phosphane and aliphatic primary diamines bearing either a C2 or C3 carbon bridge between the amine functionalities. The reaction conditions, and in particular, the reaction sequence was found to significantly depend on the length of the carbon bridge of the diamine. Both obtained alpha-aminophosphanes (i.e. N,N,N',N'-tetra(di-ortho-anisylphosphanylmethyl)-1,2-diaminoethane (L1) and N,N,N',N'-tetra(di-ortho-anisylphosphanylmethyl)-1,3-diaminopropane (L2)) gave along with neocuproine cationic dinuclear Cu(I) complexes. The Cu(I) complex with L2 as ligand was further converted by the aid of NiCl2(DME) (DME = 1,2-dimethoxyethane) into a tetranuclear copper cluster showing a new type of CuCl-tetramer molecular structure. All synthesized compounds were characterized in solution by multinuclear NMR-, UV/Vis-spectroscopy, mass spectrometry and in the solid state by elemental analysis and some of them by single crystal structure analysis.