高分辨NMR研究金属盐对水溶性铑膦配合物分子结构的影响

用高分辨NMR研究了NaCl、NiSO₄、CuSO₄、Fe₂(SO₄)₃和Cr₂(SO₄)₃对水溶性铑膦配合物HRh(CO)(TPPTS)₃[TPPTS;P(m-C₆H₄SO₃Na)₃]分子结构的影响.³¹P(¹H)和¹HNMR谱显示,于室温下在HRh(CO)(TPPTS)₃中加入的NaCl或NiSO₄对配合物的特征³¹P(¹H)和¹HNMR谱峰无明显影响;当加入CuSO₄后,配合物的Rh-H质子峰强度弱化明显,进而消失,且原配合物的特征磷谱峰强度减弱,新生成的磷物种谱峰逐渐成为磷谱的主要物种.当加入Fe₂(SO₄)₃或Cr₂(SO₄)₃后,三价金属离子的强顺磁性使NMR灵敏度下降,谱峰宽化,该2种盐均易与水溶性铑膦配合物产生强烈的相互作用,易使配合物特征谱峰消失.实验结果表明,上述金属盐对配合物结构破坏性大小的顺序为;Fe₂(SO₄)₃>Cr₂(SO₄)₃>CuSO₄》NiSO₄～NaCl.

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, 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.