NMR characterization and catalytic hydroformylation of water-soluble rhodium-phosphine complex in the presence of acid and base

When NaOH was added into D2O-soiution of HRh(CO) (TPPTS)(3)[TPPTS: P(m-C6H4 SO3Na)(3), trisodium salt of tri-(m-sulfophenyl)-phosphine], there were no changes in the characteristic peaks for the water-soluble complex although a small peak at delta 35.1 for OTPPTS[OTPPTS: O = P(m-C6H4SO3Na)(3), trisod ium salt of tri-(nz-sulfophenyl)-phosphine oxide] was formed under a high c oncentration of NaOH, as evidenced by the spectra of P-31(H-1) NMR and H-1 NMR, indicating that the influence on the molecular structure of the comple x by NaOH may be limited. Several new signals at delta 29-34 accompanied by the appearance of free ligand TPPTS at delta - 5.0- - 5.3 appeared in the P-31(IH) NMR spectra when pyridine was introduced into HRh(CO)(TPPTS)(3), p robably due to the reaction of ligand exchange among the coordinated ligand s(such as TPPTS, hydrogen, and CO) in the complex HRh(CO) (TPPTS)(3) and py ridine molecule. The water-soluble complex can be readily decomposed, howev er, when inorganic acids such as HCl, H2SO4, HNO3 and H3PO4 were introduced into the D2O-solution of HRh(CO)(TPPTS)(3), as shown in P-31(H-1) NMR spec troscopic data. The decomposition of the complex was completed by the forma tion of OTPPTS at delta 35. 1 and some new phosphate species at delta 27-29 in the P-31(H-1) NMR spectra in the presence of above inorganic acids. Ana logous results to those by addition of inorganic acid were obtained when ac etate acid was exceeded in mole ratio to HRh(CO)(TPPTS)(3). An increment in n/i ratio of heptyl aldehydes and a depression in TOF were obtained in cas e of the addition of base, in contrary, a lower n/i ratio of aldehydes in y ellowish product was obtained in case of the addition of acid in I-hexene h ydroformylation catalyzed by HRh (CO)(TPPTS)(3). The results obtained showe d that the molecular structure and catalytic performance of HRh (CO)(TPPTS) (3) may be affected by acid more disserviceably than by base.