Supramolecular trapping of phosphanes by cyclodextrins: A general approach to generate phosphane coordinatively unsaturated organometallic complexes

As shown by P-31{H-1} NMR spectroscopy, addition of the native beta-cyclodextrin or randomly methylated beta-cyclodextrin to an aqueous solution of Cl[Pt{(p-tBuC(6)H(4))P(m-C6H4SO3Na)(2)}(3)Cl] or [Pd{(p-tBuC(6)H(4))P(m-C6H4SO3Na)(2)}(3)] allows us to generate the phosphane coordinatively unsaturated [Pt{(ptBuC(6)H(4))P(m-C6H4SO3Na)(2)}(2)Cl-2] or [Pd{(P-tBuC(6)H(4))P(m-C6H4SO3Na)(2)}(2)] complexes, respectively. The existence of second-sphere coordination adducts between the organometallic complex and the cyclodextrin, in which the local bulkiness around the metallic centre is high, appears to be the essential prerequisite for the dissociation of one (p-tBuC(6)H(4)) P(m-C6H4SO3Nd)(2) phosphane ligand from the metal centre. ((c) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006).