Reactivity of the substituted butadienes, isoprene and myrcene, with decamethylsamarocene

The interaction of the substituted diene monomers isoprene, C5H8, and myrcene, C10H16, with a lanthanide was probed by examining their chemistry with (C5Me5)(2)Sm. CH2=CHC(Me)=CH2 reacts with (C5Me5)(2)SM to form the bimetallic [(C5Me5)(2)Sm](2)[mu-eta (2):eta (4)-CH2CHC(Me)CH2], 1. Both (C5Me5)2SM components in 1 exhibit trivalent metrical parameters. One Sm is oriented toward all four of the dienyl carbon atoms at distances of 2.604(9)-2.799(8) A, and the other Sm interacts with only two carbons at distances of 2.544(9) and 2.674(9) Angstrom CH2=CHC(=CH2)CH2CH2CH=CMe2 reacts with (C5Me5)(2)Sm to form [(C5Me5)(2)Sm](2)[mu-eta (2): eta (4)-CH2CHC(CH2)CH2CH2CHCMe2], 2, which is similar in structure to 1. The double bond of the pendant olefinic substituent attached to the diene in myreene does not coordinate. The structures of 1 and 2 are compared to the (C5Me5)(2)Sm/PhC=CPh bimetallic reaction product [(C5Me5)(2)Sm](2)[mu-eta (1):eta (1)-PhCCPh], 3, which also contains two (C5Me5)(2)Sm units attached to an unsaturated hydrocarbon, but has equivalent trivalent (C5Me5)(2)Sm units. Each Sm in 3 interacts with the reduced (PhC drop CPh)(2-) primarily through a 2.52-2.54 Angstrom Sm-C bond, although an ortho phenyl carbon is oriented toward each metal at a distance of > 2.96 Angstrom.