1. (c) Structure8was characterized as a minimum by frequency calculations at the B3LYP/3-21G level (we are aware of the issues associated with using B3LYP/3-21G calculations to characterize the nature of this stationary point, but all attempts to perform frequency calculations on8with the larger 6-31G(d) basis set proved computationally unfeasible; we believe, on the basis of our experience with related systems, that B3LYP/6-31G(d) frequency calculations would also show8to be a true minimum).
2. Helicoid Shiftamers