Abstract: When NaOH was added into D₂O-solution of HRh(CO)(TPPTS)₃[TPPTS: P(m-C₆H₄SO₃Na)₃, trisodium salt of tri-(m-sulfophenyl)-phosphine], there were no changes in the characteristic peaks for the w ater-soluble com plex although a sm allpeak at δ35.1 for OTPPTS[OTPPTS: O=P(m-C₆H₄SO₃Na)₃, trisodium salt of tri-(m-sulfophenyl)-phos-phine oxide] was formed undera high concentration of NaOH, as evidenced by the spectra of ³¹P(¹H)NMR and ¹HNMR, indicating thatthe influence on the m olecular structure ofthe com plex by NaOH may be limited. Severalnew signals at δ29_ 34 accom panied by the ap-pearance of free ligand TPPTSat δ-5.0_-5.3 appeared in the ³¹P(¹H)NMR spectra w hen pyridine w as introduced into HRh(CO)(TPPTS)₃, probably due to the reaction of lig-and exchange am ong the coordinated ligands(such as TPPTS, hydrogen, and CO) in the com plex HRh (CO)(TPPTS)₃and pyridine m olecule. The w ater-soluble com plex can be readily decom posed, how ever, w hen inorganic acids such as HCl, H₂SO₄, HNO₃and H₃PO₄w ere introduced into the D₂O-solution of HRh(CO)(TPPTS)₃, as show n in ³¹P(¹H)NMR spectroscopic data. The decom position of the com plex was com pleted by the form ation of OTPPTS atδ35.1 and som e new phosphate species atδ27_ 29 in the ³¹P(¹H)NMR spectra in the presence ofabove inorganic acids. Analogous results to those by addition ofinorganic acid w ere obtained w hen acetate acid w as exceeded in m ole ratio to HRh(CO)(TPPTS)₃An increm entin n/iratio ofheptylaldehydes and a depression in TOF were obtained in case of the addition ofbase, in contrary, a low er n/iratio ofaldehydesin yellow ish productw as ob-tained in case of the addition of acid in 1-hexene hydroform ylation catalyzed by HRh(CO)(TPPTS)_3.The results obtained show ed thatthe m olecularstructure and catalytic perform ance of HRh·(CO)(TPPTS)₃may be affected by acid more disserviceably than by base.

Key words: ³¹P(¹H)NMR, ¹HNMR, HRh(CO)(TPPTS)₃, Acidity and basicity, Hydro-form ylation