METAL-COMPLEXES OF FERROCENE CRYPTANDS

The reaction of 1,1'-ferrocenediyl(bismethylene-bispyridinium) with di aza-15-crown-5 exclusively yields the 2 + 2-addition product 1,1'':1', 1'''-bisferrocenediyl-bis[bis acyclopentadecane)][=Fcdiyl(N-2-15-C-5)( 2)Fcdiyl]. The large cavities formed by Fcdiyl(N-2-15-C-5)(2)Fcdiyl an d Fcdiyl(N-2-18-C-6)(2)Fcdiyl can accommodate two metal ions simultane ously, resulting in large iron-cation distances. The X-ray crystal str uctures of Fcdiyl(N-2-15-C-5)(2)Fcdiyl . 2Na(p-tosylate), Fcdiyl(N-2-1 8-C-6)(2)Fcdiyl .(RbI)(2), ne(1,4,10,13-tetraoxa-7,16-diazacyclooctade cane)]. Ca(ClO4)(2) [=Fcdiyl(N-2-18-C-6). Ca(ClO4)(2)] and Fcdiyl(N-2- 18-C-6). Ba(ClO4)(2) were determined to gain a better understanding of the metal complexation in ferrocene cryptands and to explore the poss ibility of direct iron-cation interactions. Fcdiyl(N-2-18-C-6). Ca(ClO 4)(2) displays an unusually short Fe-Ca2+ distance (365.8(6) pm) which might be viewed as an Fe-Ca2+ interaction. The ammonium salts formed upon protonation of Fcdiyl(N-2-15-C-5)(2)Fcdiyl and Fcdiyl(N-2-18-C-6) (2)Fcdiyl can be oxidized reversibly but the addition of anions gave n o significant cathodic shifts of the redox potentials.