Metal(II) template assisted syntheses of two P―C―O―P chelating ligands incorporating a bulky 1,3,5,7-tetramethyl-2,4,8-trioxa-6-phosphaadamantyl cage

Facile condensation of one equiv. of the caged hydroxymethylphosphine Ad`PCH2OH (Ad` = C10H16O3) with ClPR2 (R = Ph, iPr), in the presence of one equiv. of MCl2(cod) (M = Pt, Pd; cod = cycloocta-1,5-diene), afforded the five-membered chelate complexes cis-MCl2(Ad`PCH2OPR2) (1a, M = Pt, R = Ph; 1b, M = Pd, R = Ph; 2a, M = Pt, R = iPr) in reasonable to excellent yields. The X-ray structures of 1a and 2a have been determined, the latter using diffraction data collected at a synchrotron source. The M―P―C―O―P metallacycle remains intact even after stirring in CD3OD for 24 h at room temperature.

Metal-assisted template condensation of Ad`PCH2OH and R2PCl (R = Ph, iPr) with MCl2(cod) (M = Pt, Pd) affords the square planar nonsymmetric complexes MCl2(Ad`PCH2OPR2) in reasonable to high yields.Figure optionsDownload as PowerPoint slideResearch highlights
► Metal-assisted condensation for new nonsymmetric phosphorus ligands.
► Structures verified in solution using NMR spectroscopy.
► Single crystal X-ray crystallography confirmed solid state structures in two cases.
► The M–P–C–O–P metallacycle is stable at room temperature in methanol.