酸碱存在下水溶性铑膦配合物的NMR表征及氢甲酰化性能研究

NMR Characterization and Catalytic Hydroform ylation of Water-Soluble Rhodium -Phosphine Com plex in the Presence of Acid and Base

３１Ｐ（１Ｈ） ＮＭＲ 和１Ｈ ＮＭＲ研究表明， 当ＮａＯＨ 加入到水溶性铑膦配合物ＨＲｈ（ＣＯ）·（ＴＰＰＴＳ）３［ＴＰＰＴＳ： Ｐ（ｍ －Ｃ６Ｈ４ＳＯ３Ｎａ）３］后， 可观察到有少量的ＯＴＰＰＴＳ［ＯＴＰＰＴＳ： Ｏ＝ Ｐ（ｍ －Ｃ６Ｈ４ＳＯ３Ｎａ）３］出现， 但配合物的特征谱峰即使在高浓度的ＮａＯＨ 存在下也基本保持不变， 表明ＮａＯＨ 对配合物分子结构的影响较小； 当吡啶加入到ＨＲｈ（ＣＯ）（ＴＰＰＴＳ）３ 中， ３１Ｐ（１Ｈ） ＮＭＲ谱图中出现游离配体ＴＰＰＴＳ的３１Ｐ谱峰及若干结构未知的新水溶性配合物的３１Ｐ谱峰， 表明吡啶分子将与配合物分子中的配体ＴＰＰＴＳ发生配体交换反应． 在ＨＲｈ（ＣＯ）（ＴＰＰＴＳ）３ 中分别加入一定量的ＨＣｌ， ＨＮＯ３， Ｈ２ＳＯ４ 和Ｈ３ＰＯ４ 等无机酸时， 随着酸量的增加， 配合物的３１Ｐ物种含量逐渐下降， 而ＯＴＰＰＴＳ量明显上升， 直至配合物３１Ｐ物种完全消失； 高浓度乙酸对配合物结构的影响与上述无机酸类似． ＨＲｈ（ＣＯ）（ＴＰＰＴＳ）３ 的１－己烯氢甲酰化催化反应结果表明， 碱存在下可获得较高的正异构醛比值， 但催化活性降低； 酸存在下所得产物正异构醛比值相对较低且呈淡黄色． 可见， 酸对Ｈ?

When NaOH w as added into D2O-solution ofHRh(CO)(TPPTS)3[TPPTS: P(m - C6H4SO3Na)3, trisodium salt of tri-(m -sulfophenyl)-phosphine], there w ere 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] w asform ed undera high concentration ofNaOH, as evidenced by the spectra of 31P(1H) NMRand 1H NMR, indicating thatthe influence on the m olecular structure ofthe com plex by NaOH m ay be lim ited. 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 oflig- and exchange am ong the coordinated ligands(such as TPPTS, hydrogen, and CO) in the com plex HRh (CO)(TPPTS)3 and pyridine m olecule. The w ater-soluble com plex can be readily decom posed, how ever, w hen inorganic acids such as HCl, H2SO4, HNO3 and H3PO4 w 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 w as com pleted by the form ation of OTPPTSatδ35.1 and som e new phosphate species atδ27_ 29 in the 31P(1H) NMRspectra 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)3. An increm entin n/iratio ofheptylaldehydes and a depression in TOFw ere 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)3 m ay be affected by acid m ore disserviceably than by base.