Water-soluble organometallic compounds. 7. Further studies of 1,3,5-triaza-7-phosphaadamantane derivatives of group 10 metals, including metal carbonyls and hydrides
Water-soluble organometallic compounds. 7. Further studies of 1,3,5-triaza-7-phosphaadamantane derivatives of group 10 metals, including metal carbonyls and hydrides
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DOI：
10.1021/ic981243j
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发表时间：
1999-05-17
影响因子：
4.6
通讯作者：
Reibenspies, JH
中科院分区：
文献类型：
--
作者：
Darensbourg, DJ;Robertson, JB;Reibenspies, JH
Ni（PTA）（4）（5）、Pd（PTA）（4）（6）和Pt（PTA）（4）（8）的合成是通过在水中用过量的1，3，5-三氮杂-7-磷杂金刚烷（PTA）还原（MCl 2）-Cl-II盐来完成的。产物作为部分质子化的衍生物获得，其中质子化发生在结合的PTA配体的氮原子处。报道了8的单质子化和双质子化衍生物[Pt（PTA）（3）（PTAH）][Cl]（1 S）和[Pt（PTA）（2）]（PTA）（3）[BF_4]（2）（2S）的晶体结构。还提供了沿着还原途径的中间体[PdCl（PTA）（3）][Cl]（7）的晶体结构，显示出反式影响，由此反式到Cl-配体的Pd-P键长2.238（3）埃比顺式到Cl-配体的平均Pd-P键长2.334（2）埃短。配合物8还通过加入弱酸如CO2/H2O、NH 4Cl、PTAH（+）Cl（-）、HPy+ BF 4-和巴豆酸在金属中心质子化形成[（H）Pt（PTA）（4）][X]，其中X = Cl-、BF 4-、HCO 3-和C3 H5 CO2-。强酸如HCl或HBF 4的加入导致PTA配体处的质子化。由此，Pt金属中心显示具有7.44至9.25之间的pK（a）。复合物8上结合的PTA配体具有低于4.69但高于2.12的pK（a）。Ni（CO）（4-n）（PTA）（n）衍生物也被报道为n = 3（9）、2（10）和1（11）。使用LR数据11，确定PTA具有Tolman定义的电子参数（chi）为15.3 cm（-1），表明PTA的贡献略低于PPh 3，其中chi = 12.8 cm（-1）。络合物10从保持在-15 ℃的MeOH/醚溶液中结晶出来，并通过X射线晶体学表征。它是一个扭曲的四面体，并具有晶体学确定的托尔曼锥角PTA为103度。通过原位IR技术，Ni（PTA）（4）与CO在水中的连续反应表明，在20 ℃下，观察到的PTA解离为Ni（CO）（PTA）（3）的速率为7.92 × 10（-4）s（-1）。该速率，沿着P-31 NMR结果，表明M-0（TA）（4）络合物表现出很少的解离和结合的PTA配体的缓慢交换。
The syntheses of Ni(PTA)(4) (5), Pd(PTA)(4) (6), and Pt(PTA)(4) (8) are accomplished through the reduction of the (MCl2)-Cl-II salts in water with excess 1,3,5-triaza-7-phosphaadamantane (PTA). The products are obtained as partially protonated derivatives with protonation occurring at the nitrogen atoms of the bound PTA ligands. Crystal structures illustrating the monoprotonated and bis-protonated derivatives of 8, [Pt(PTA)(3)(PTAH)][Cl] (1S) and [Pt(PTA)(2)](PTA)(3)[BF4](2) (2S), are reported. The crystal structure of an intermediate along the reduction pathway, [PdCl(PTA)(3)][Cl] (7), is also presented, showing a trans influence whereby the Pd-P bond length trans to the Cl- ligand is shorter, 2.238(3) Angstrom, than the average Pd-P bond length cis to the Cl- ligand, 2.334(2) Angstrom. Complex 8 is also protonated at the metal center to form [(H)Pt(PTA)(4)][X], where X = Cl-, BF4-, HCO3-, and C3H5CO2-, through the addition of weak acids such as CO2/H2O, NH4Cl, PTAH(+)Cl(-), HPy+BF4-, and crotonic acid. Addition of strong acids such as HCl or HBF4 results in protonation at the PTA ligands. Thereby, the Pt metal center is shown to have a pK(a) between 7.44 and 9.25. The bound PTA ligands on complex 8 have a pK(a) below 4.69 but above 2.12. Ni(CO)(4-n)(PTA)(n) derivatives are also reported for n = 3 (9), 2 (10), and 1 (11). Using LR data of 11, PTA is determined to have an electronic parameter (chi) as defined by Tolman to be 15.3 cm(-1), indicating PTA to be slightly less donating than PPh3, where chi = 12.8 cm(-1). Complex 10 is crystallized out of a MeOH/ether solution maintained at -15 degrees C and characterized by X-ray crystallography. It is a distorted tetrahedron and has a crystallographically determined Tolman cone angle of PTA of 103 degrees. Monitored reactions of Ni(PTA)(4) with CO in water via in situ IR techniques show that the rate observed for the dissociation of PTA to provide Ni(CO)(PTA)(3) is 7.92 x 10(-4) s(-1) at 20 degrees C. This rate, along with P-31 NMR results, indicates that the M-0(TA)(4) complexes exhibit little dissociation and slow exchange of the bound PTA ligands.