Abstract: 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, Fe₂(SO₄)₃and Cr₂(SO₄)₃was investigated in connection with the biphasic catalysis system by means of high resolution liquid NMR. No evident change in the spectra of ³¹P(¹H)NMR and ¹HNMR of the watersoluble complex was observed by addition of NaCl and NiSO_4.When CuSO₄was added into the complex, however, the peak intensity of ¹HNMR due to HRh diminished and accompanied with the gradual disappearance of the phosphorus species of the complex and the appearance of the newborn phosphorus species in the ³¹P(¹H)NMR spectra. Moreover, the characteristic twin signals of the complex at δ=44.8, 43.6 in the ³¹P(¹H)NMR were completely replaced by the new complexes at δ =28.0-33.4 when Fe₂(SO₄)₃was added. The similar result was obtained in the case of Cr₂(SO₄)₃, when higher concentration of Cr₂(SO₃)₄was used. The results obtained shown that a decreasing order of influence of salt on the molecular structure of the complex is: Fe₂(SO₄)₃>Cr₂(SO₃)₄>CuSO₄NiSO₄～NaCl.

Key words: ³¹P(¹H)NMR, ¹HNMR, Water-soluble phosphine rhodium complex, Metal salt