Non-conventional coordination of cavity-confined metal centres.

WIDEPHOS, a β-cyclodextrin cavitand bearing two introverted P(III) donor atoms, readily accommodates two converging Au-X fragments (X = Cl, Br, I). In the corresponding [(WIDEPHOS)(AuX)(2)] complexes, severe steric crowding within the cavity results in one of the P-Au-X rods deviating from linearity, as revealed by an X-ray diffraction study and unusual (31)P magnetic shielding of one of the two phosphorus signals. The cavitand ligand is also suited for hosting strained dipalladium moieties with a single chlorido bridge, thereby forming dynamic complexes in which ligand coordination to one of the metal centres occurs via an oschelating P,O-subunit.