INCLUSION OF NEUTRAL AND ANIONIC GUESTS WITHIN THE CAVITY OF PI-METALATED CYCLOTRIVERATRYLENES

Treatment of the chloride bridged species [{M(L)Cl(mu-Cl)}(2)] (M = Ru , L = 4-MeC(6)H(4)CHMe(2), C6H6, or C(6)Me(6); M = Ir, L = C(5)Me(5)) with silver salts AgX (X = BF4, CF3SO3, CF3CO2 etc.) followed by reflu x with the bowl-shaped macrocycle cyclotriveratrylene (CTV) results in the clean formation of mono-, di-, and trimetallic CTV complexes [{M( L)}(n)(CTV)]X(2n) (n = 1, 2, 3). Further salts (X = ReO4-, I-) may be generated by anion metathesis. All three types of complex display nove l host-guest properties. In the case of the monometallic hosts the dis ruption of the characteristic columnar packing mode of the CTV, a resu lt of the presence of the metal center, leads to the inclusion of neut ral and anionic guest species (NO(2)Me, Et(2)O, H{CF3CO2}(-)(2), etc.) within the CTV cavity. For complexes where n = 2 or 3 the inclusion o f anionic guests is invariably observed. The extent of anion binding h as been established by means of X-ray crystal structure determinations upon various di- and trimetallic species containing BF4-, CF3SO3-, or ReO4-, by radiotracer analysis in solution using (TCO4-)-T-99m and (R eO4-)-Re-188, and by cyclic voltammetry. The trimetallic complex [{Ir( Cp)](3)(CTV)] [BF4](6) (9a) in particular exhibits F ... C-CTV contac ts as short as 2.78(3) Angstrom. The dimetallic host )-4-MeC(6)H(4)CHM e(2))}(2)(eta(6):eta(6)-CTV)](4+) (4) is shown to have a specific affi nity for large tetrahedral anions and will selectively extract both (T CO4-)-T-99 and ReO4- from aqueous solution, even in the presence of a large excess of Cl-, CF3SO3-, NO3-, SO42-, and to some extent ClO4-.