An Easily Accessible Chiral Carbodiphosphorane and its Coinage Metal Complexes

Herin, the high yielding synthesis of the chiral carbodiphosphorane (3) prepared in a two-step procedure from commercially available (R)-BINAP (([1,1′-binaphthalene]-2,2′-diyl)bis(diphenylphosphane), BINAP) and dibromomethane is presented. In the first reaction step, the bis phosphonium salt 1[Br]$_2$ is obtained, which is subsequently deprotonated either with potassium hydroxide to yield the mono phosphonium salt 2[Br], or with potassium hexamethyldisilazide to produce 3. Moreover, coinage metal complexes of 3 were prepared via reaction with CuCl (4$^{Cu}$, 5$^{Cu}$, 6$^{Cu}$), Cu(OTf)⋅toluene0.5 (7$^{Cu}$) or AuCl ⋅ (tht) (5$^{Au}$, 6Au). The prepared compounds were characterised by NMR- and IR-spectroscopy, mass spectrometry, elemental analysis, single crystal X-ray diffraction and UV/Vis spectroscopy. Photoluminescence emission spectra were obtained for most of the complexes (3, 4$^{Cu}$, 5$^{Cu}$, 6$^{Cu}$ and 6$^{Au}$).