Remarkable Rate Enhancement of Ligand Substitution Promoted by Geometrical Arrangement of Tridentate "Spectator" Ligands K.J.T. acknowledges Arco Chemical and the National Science Foundation for support of this research. M.H.V.H. gratefully acknowledges postdoctoral fellowship support from the Director's Office of Los Alamos National Laboratory. Los Alamos National Laboratory is operated by the University of California for the U.S. Department of Energy under Contract W-7405-ENG-36. M.H.V.H. also thanks Dr. Beverly K. Hartline (Deputy Laboratory Director, Argonne National Laboratory), Dr. Donald G. Lee (Chemistry Professor, University of Regina, Saskatchewan, Canada, S4S0A2), Dr. R. Thomas Baker (Los Alamos National Laboratory), and Dr. David E. Morris (Los Alamos National Laboratory) for their suggestions and discussions.