[CP-ASTERISK-FE(ETA(5)-P-5)] AS A USEFUL SOURCE FOR THE SYNTHESIS OF COBALT COMPLEXES WITH NAKED P-N LIGANDS

The cothermolysis of the sandwich complex [CpFe(eta(5)-P-5)] (1) and [(CpCo)-Co-R(CO)(2)] (2a: Cp-R = C(5)H(4)tBu, 2b: Cp-R = C(5)H(3)tBu(2 )-1,3) gives the following series of clusters with ''naked'' P-n ligan ds: [{CpFe}{(CpCoP4)-Co-R}{FeCp*}] (4), a ''triple decker'' with a Co P4 middle deck, [{CpFe}{(CpCo)-Co-R}(2)(P-4)(P)] (5), [{(CpCo)-Co-R}( 4)P-4] (6a, b), and [{(CpCo)-Co-R}(3)(mu(3)-P)(2)] (7a, b). The therma l or photochemical reaction of [CpFe(eta(5)-P-5)] (1') (Cp*' = C5Me4E t) with [{(CpCo)-Co-R(mu-CO)}(2)] (3) (Cp-R = C(5)H(3)tBu(2)-1,3) affo rds [{Cp'Fe}(mu(4)-eta(5):eta(2):eta(2):eta(1)-P-5) {Co(CO)Cp-R}{Co2C p2R (mu-CO)}] (8) in which, in addition to the eta(5)-cyclo-P-5 coordi nation, one terminal and two eta(2) side-on binding coordination modes have been realized. In the case of the cubanelike compounds 6a and 6b the oxidation of its P atoms with S-8 or Se-(grey) gives [{(CpCo)-Co- R}(4)(P)(PX)(3)] (9: X = S, 10: X = Se; Cp-R = C(5)H(4)tBu), products of threefold oxidation, and [{(CpCo)-Co-R}(4)(P)(2)(PX)(2)] (12: X = S , 13: X = Se; Cp-R = C(5)H(3)tBu(2),-1,3) with only two PX ligands. [{ (CpCo)-Co-R}(4)(mu(3)-PS)(4)] (11), the fully sulfurized derivative of 6a, can be synthesized by oxidation of 9 with S-8 in dichloromethane. The complexes 4, 5, 6b, 7b, 8, and 10 have been characterized by X-ra y crystal structure determination.