Metallo-cryptophane cages from cis-linked and trans-linked strategies

Trigonal bipyramidal metallo-cage species [Pd3(dppp)3(L)2]∙6OTf (where dppp = bis(diphenylphosphino)propane, OTf = triflate and L is tris(iso-nicotinoyl)cyclotriguaiacylene (L1) or tris(fluoro-iso-nicotinoyl)cyclotriguaiacylene (FL1)) have been characterised in solution to exist predominantly as the anti-isomers. The crystal structure of [Pd3(dppp)3(FL1)2]∙6OTf, however, was found to be the achiral syn-isomer. The complex [Pd3Cl3(L2)2] (where L2 = tris(methylbenzimidazolyl)cyclotriguaiacylene) is a trans-linked M3L2 cage, observed by mass spectrometry and in the solid state as the anti-isomer. Ligand L2 also forms a 1:1 co-crystal with cyclotriguaiacylene.