(hydrotris(3-tert-butyl-5-methylpyrazolyl)borato)(p-nitrophenolato)zinc | 193075-60-4

• 英文名称: (hydrotris(3-tert-butyl-5-methylpyrazolyl)borato)(p-nitrophenolato)zinc
• CAS: 193075-60-4
• 化学式: C₃₀H₄₄BN₇O₃Zn
• 分子量: 626.925
• InChiKey: XMHLGTUTHKJCQE-UHFFFAOYSA-M

计算性质

• 辛醇/水分配系数(LogP)：
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• 重原子数：
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• 可旋转键数：
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• 环数：
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• sp3杂化的碳原子比例：
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• 拓扑面积：
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• 氢给体数：
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• 氢受体数：
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反应信息

• 作为产物：
  描述：

  对硝基苯酚 、 tris(3-tert-butyl-5-methylpyrazolyl)hydroborato zinc hydroxide 生成 (hydrotris(3-tert-butyl-5-methylpyrazolyl)borato)(p-nitrophenolato)zinc
  参考文献：
  名称：

  Factors Influencing the Thermodynamics of Zinc Alkoxide Formation by Alcoholysis of the Terminal Hydroxide Complex, [Tp^But,Me]ZnOH:  An Experimental and Theoretical Study Relevant to the Mechanism of Action of Liver Alcohol Dehydrogenase

  摘要：

  The factors that influence the formation of a tetrahedral alkoxide complex related to a critical intermediate of the catalytic cycle of liver alcohol dehydrogenase have been probed by a combined experimental and computational investigation of the reactions of the tris(pyrazolyl)hydroborato zinc hydroxide complexes [Tp(RR')]ZnOH with alcohols. The study demonstrates that zinc alkoxide formation is electronically favored by incorporation of electron-withdrawing substituents in the alcohol but is sterically disfavored for bulky alkoxides. A computational analysis indicates that these trends are a result of homolytic Zn-OR and Zn-OAr BDEs being more sensitive to the nature of R and Ar than are the corresponding H-OR and H-OAr BDEs. Thus, electron-withdrawing substituents increase Zn-OAr bond energies to a greater extent than H-OAr bond energies, while bulky substituents decrease Zn-OR bond energies to a greater extent than H-OR bond energies. With the exception of derivatives of acidic alcohols (e.g., nitrophenol), the zinc alkoxide complexes [TpRR'] ZnOR are very unstable toward hydrolysis, This hydrolytic instability of simple zinc alkoxide complexes suggests that the active site environment of LADH plays an important role in stabilizing the alkoxide intermediate, possibly via hydrogen-bonding interactions.

  DOI：

  10.1021/ja002286d

文献信息

• Zinc complexes of TtzR,Me with O and S donors reveal differences between Tp and Ttz ligands: acid stability and binding to H or an additional metal (TtzR,Me = tris(3-R-5-methyl-1,2,4-triazolyl)borate; R = Ph, tBu)
  作者：Mukesh Kumar、Elizabeth T. Papish、Matthias Zeller、Allen D. Hunter

  DOI：10.1039/c1dt10429b

  日期：——

  Alkylzinc complexes, (TtzR,Me)ZnR′ (R = tBu, Ph; R′ = Me, Et), show interesting reactivity with acids, bases and water. With acids (e.g. fluorinated alcohols, phenols, thiophenol, acetylacetone, acetic acid, HCl and triflic acid) zinc complexes of the conjugate base (CB), (TtzR,Me)ZnCB, are generated. Thus the B–N bonds in Ttz ligands are acid stable. (TtzR,Me)ZnCB complexes were characterized by 1H, 13C-NMR, IR, MS, elemental analysis, and, in most cases, single crystal X-ray diffraction. The four coordinate crystal structures included (TtzR,Me)Zn(CB) [where R = Ph, CB (conjugate base) = OCH2CF3 (2), OPh (6), SPh (8), p-OC6H4(NO2) (10); R = tBu, CB = OCH(CF3)2 (3), OPh (5), SPh (7)*, p-OC6H4(NO2) (9) (* indicates a rearranged Ttz ligand)]. The use of bidentate ligands resulted in structures [(TtzPh,Me)Zn(CB) (CB = acac (12), OAc (14))] in which the coordination geometries are five, and intermediate between four and five, respectively. Interestingly, three forms of (TtzPh,Me)Zn(p-OC6H4(NO2)) (10) were analyzed crystallographically including a Zn coordinated water molecule in 10H2O, a coordination polymer in 10CP, and a p-nitrophenol molecule hydrogen bonded to a triazole ring in 10Nit. Ttz ligands are flexible since they are capable of providing κ3 or κ2metal binding and intermolecular interactions with either a metal center or H through the four position nitrogen (e.g. in 10CP and HTtztBu,Me·H2O, respectively). Preliminary kinetic studies on the protonolysis of LZnEt (L = TtztBu,Me, TptBu,Me) with p-nitrophenol in toluene at 95 °C show that these reactions are zero order in acid and first order in the LZnEt.

  烷基锌络合物 (TtzR,Me)ZnR′ (R = tBu, Ph; R′ = Me, Et) 显示出与酸、碱和水的有趣反应性。与酸（例如氟化醇、酚、硫酚、乙酰乙酮、醋酸、HCl和三氟甲磺酸）反应后，生成了共轭碱（CB）的锌络合物 (TtzR,Me)ZnCB。因此，Ttz配体中的B-N键对酸是稳定的。 (TtzR,Me)ZnCB络合物通过1H、13C-NMR、红外光谱、质谱、元素分析以及在大多数情况下通过单晶X射线衍射进行了表征。这些四配位晶体结构包括 (TtzR,Me)Zn(CB) [其中R = Ph，CB（共轭碱）= OCH2 (2)、OPh (6)、SPh (8)、p-OC6H4(NO2) (10)；R = tBu，CB = OCH(CF3)2 (3)、OPh (5)、SPh (7)*，p-OC6H4( ) (9) (* 表示重排的Ttz配体)]。使用双齿配体导致结构 [(TtzPh,Me)Zn(CB) (CB = acac (12), OAc (14))] 中的配位几何形状分别为五配位和介于四配位与五配位之间的中间状态。有趣的是，三种形式的 (TtzPh,Me)Zn(p-OC6H4( )) (10) 通过晶体学分析，其中包括一个配位有水分子的10 、一个配位聚合物10CP，以及一个与三氮唑环氢键结合的对硝基苯酚分子10Nit。Ttz配体是灵活的，因为它们能够提供κ3或κ2的金属配位以及通过四位氮与金属中心或氢的相互作用（例如在10CP和HTtztBu,Me·H2O中）。关于LZnEt (L = TtztBu,Me, TptBu,Me) 与对硝基苯酚在95 °C的甲苯中质子解离的初步动力学研究表明，这些反应在酸中为零阶，在LZnEt中为一阶。