One-Atom Insertion Procedures

It now remains to consider how the various gif terms are expressed with respect to the atomic masses and the dimensions of the molecule. The procedure, although not difficult or profound, is definitely tedious it is explained in Wilson, Decius, and Cross and other specialized textbooks. Fortunately, it is possible to tabulate the most commonly used ones in the form of general expressions into which the specific parameters of any molecule may be inserted. Such a tabulation and directions for its use are given in Appendix VI. It is found that... 

The nickel ) complex of 92 cannot be prepared directly via the template method, but can be prepared by a transmetallation procedure. Synthesis of the macrocycle in the presence of one of the metal ions known to be effective as a template is followed by a metal exchange process in solution to insert the nickel ) ion. This cation exhibits a strong preference for the square planar, square pyramidal, and octahedral geometries 79). Thus the failure of the nickel ) cation to behave as a template ion in the synthesis of 92 is probably due to the disinclination of the metal to accommodate the pentagonal array of donor nitrogen atoms necessary for reaction to occur. 

Metals can also be simulated using empirical multibody potential functions developed from quantum-mechanical results. One procedure that has been successful is the embedded-atom method [30,31], which focuses on the quantum-mechanically-derived energy required to introduce an atom into the host metal. This energy is considered to be a function only of the electron density at the point of insertion, and is written as a sum of two terms A... 

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