Addition of Bu(t)NC to [Ru-5(mu-C-2(p-SMe)(2)(mu-PPh(2))(2)(CO)(11)] 1
results in expansion of the Ru-5 polygon and flattening of the C2Ru5
cluster so that in the product 2 one carbon atom acquires a planar tet
racoordinate configuration; reversible loss of CO from 2 affords a CNB
u(t) derivative of 1.