SYNTHESIS-X-RAY STRUCTURE AND SPIN-CROSSOVER IN THE TRIPLE-DECKER COMPLEX (5)ME(5))CR(MU(2)ETA(5)-P-5)CR(ETA(5)-C(5)ME(5))]- (A=PF6, SBF6)([A])

The triple-decker chromium complexes )Me(5))Cr(mu(2):eta(5)-P-5)Cr(eta (5)C(5)Me(5))](+) [A]-(A = PF6, SbF6) can be prepared in high yield by oxidation of (5)Me(5))Cr(mu(2):eta(5)-P-5)Cr(eta(5)-C(5)Me(5))] With either [Fe(eta(5)-C5H5)(2)](+)[A](-) (A=PF(6,), SbF6); the single crys tal X-ray structure determination for (mu(2):eta(5))-P-5)Cr(eta(5)-C(5 )Me(5))](+)[SbF6]- reveals that the Cr-Cr separation is 3.185(8) Angst rom which is 0.456 Angstrom longer than the neutral complex; magnetic susceptibility studies show that these 26-electron multidecker cations in these salts undergo spin crossovers at 33 and 23 K respectively.