Inorganic Chemistry, Vol.47, No.19, 8932-8934, 2008
Linking number analysis of a pentadecanuclear metallamacrocycle: A Mobius-Craig system revealed
An analysis of the pi-electronic topology of a recently reported pentadecanuclear manganese metallacycle in terms of linking number, twist, and writhe confirms its previous assignment as a Mobius system of order six. The total degree of local torsion is reduced by a significant contribution from writhe, thus correcting the previously inferred local torsion at each metal center from 120 degrees to similar to 90 degrees. This latter value suggests a model for the cyclic pi conjugation around the metallacycle, which involves 3d(pi)-2p(pi) interactions at the metal center, of a type first suggested by Craig 50 years ago in the context of main group cyclic aromatic systems.