METAL HURDLING IN TRANSITION-METAL COMPLEXES OF 2,4,6-TRIS(2-PYRIDYL)-1,3,5-TRIAZINE (TPT) AND 2,4,6-TRIS-(2-PYRIDYL)PYRIMIDINE (TPP)

H-1 NMR two-dimensional exchange spectroscopy (EXSY) reveals that in p alladium(II) and platinum(II) complexes of the ligands 2,4,6-tris(2-py ridyl)-1,3,5-triazine (tpt) and 2,4,6-tris(2-pyridyl)pyrimidine (tpp), a highly novel type of fluxion occurs in which the metal moiety hurdl es a C-C bond and moves from one edge of the central ligand ring to an adjacent edge; this process is accompanied by 1,4 metallotropic shift s analogous to those found in complexes of 2,2':6',2 '' N-terpyridine.