The reactivity and ligand dynamics of the
3-
2-imidoyl clustersRu
3(CO)
9(
3-
2-RC=NR')(
-H) (R = CH
3, R' = Et
2; RR' =(CH
2)
3,
3; RR' =(CH
2)
2C(H)CH
2OCH
34, R = R' = CH
3,
5)are compared with the previously reported osmium analogs. Thelowest energy dynamicalprocess in these clusters is the "windshield wiper" motion over theface of the cluster whereastripodal rotation of the carbonyl groups on the unbridged metal atom isthe fastest processin the analogous osmium compounds. Although the structures of thephosphine andisocyanide substitution products reported,Ru
3(CO)
8(
3-
2-RC=NR')(
-H)L(R = CH
3, R' =CH
2CH
3, L = PPh
3(
8a), L = CNMe (
12); R = R' =(CH
2)
3, L = PPh
3 (
9),L = CNMe (
13); R= R' = CH
3, L = PPh
3 (
10), areidentical to their osmium analogs, the pathway to theirformation reflects the lower CO dissociation energies for rutheniumclusters and a greatersensitivity to the substituents on the imidoyl group. The solidstate structures of
9 and
12are reported as well as that ofOs
3(CO)
8(
-
2-C=N(CH
2)
3(
-H)(PPh
3)(MeNC)(
15). The latterillustrates the hemilabile nature of the
3-imidoylligand even in phosphine-substitutedderivatives and the structural preferences of phosphine and isocyanideligands in this classof clusters.