Intramolecular substitutions of square planar rhodium(I) cationic complexes of cis-dicarbonyl nitrogen coordinated tridentate

Four kinds of square planar cis-dicarbonyl-N, N-bis(2-pyridylethy1)-p-substituted-phenylarnino rhodium(I) are reported. The changes of their structures were analyzed by XPS, IR and NMR spectroscopy. The results show that the weak N→Rh coordinated bond can replace very soon the strong Rh-Cπ back donation bond to form tris-nitrogen coordinated complexes due to the steric effect when the temperature is over 50°C. This reaction is reversible. The bis-nitrogen coordinated structure of the complex recovered when put under the atmosphere of CO.