Influence of metal salt on molecular structure of water-soluble rhdium-phosphine complex

The molecular structure of water-soluble phosphine-rhdium complex HRh(CO) . (TPPTS)(3) [TPPTS: P(m-C6H4SO3Na)(3)] affected by the metal salts, e.g., NaCl, NiSO4, CuSO4, Fe-2(SO4)(3) and Cr-2(SO4)(3) was investigated in connection with the biphasic catalysis system by means of high resolution liquid NMR. No evident change in the spectra of P-31(H-1) NMR and H-1 NMR of the water-soluble complex was observed by addition of NaCl and NiSO4. When CuSO4 was added into the complex, however, the peak intensity of H-1 NMR due to H-Rh diminished and accompanied with the gradual disappearance of the phosphorus species of the complex and the appearance of the new-born phosphorus species in the P-31(H-1) NMR spectra. More over, the characteristic twin signals of the complex at delta=44.8, 43.6 in the P-31(H-1) NMR were completely replaced by the new complexes at delta = 28.0-33.4 when Fe-2(SO4)(3) was added. The similar result was obtained in the case of Cr-2(SO4)(3), when higher concentration of Cr-2(SO3)(4) was used. The results obtained shown that a decreasing order of influence of salt on the molecular structure of the complex is: Fe-2(SO4)(3)>Cr-2 (SO3)(4)>CuSO4>>NiSO(4)similar to NaCl.