Thermodynamic Hydricities of Biomimetic Organic Hydride Donors
Thermodynamic Hydricities of Biomimetic Organic Hydride Donors
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DOI：
10.1021/jacs.7b13526
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发表时间：
2018-04-04
影响因子：
15
通讯作者：
Glusac, Ksenija D.
中科院分区：
文献类型：
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作者：
Ilic, Stefan;Kadel, Usha Pandey;Glusac, Ksenija D.
计算并实验测量了几种无金属氢化物供体在乙腈和二甲亚砜中的热力学水合性（AGH-）： NADH类似物（BNAH, CN-BNAH, me - mah， HER），亚甲基四氢甲烷雀呤类似物（BIMH， CAFH），吖啶衍生物（Ph-AcrH, Me2N-AcrH, T-AcrH, 4OH, 2OH, 3NH）和三芳基甲烷衍生物（6OH）。用密度泛函理论计算得到的水合度值与用“电位pK(a)”和“氢化物转移”方法得到的实验值吻合较好（在3 kcal/mol以内）。模型化合物的氢化物给体能力在48.7-85.8 kcal/mol（乙腈）和46.9-84.1 kcal/mol （DMSO）之间，与先前研究的第一排过渡金属氢化物配合物相当。为了评价熵对总水合性的贡献的相关性，本研究得到的吉布斯自由能差（AGH-）与其他人得到的焓（δ H-H()）值进行了比较。结果表明，尽管δ H-H（-）值与δ G(H)（-）值表现出相同的趋势，但室温δ G(H)（-）值与δ H-H（-）值之间的差异在3 ~ 9 kcal/mol之间。本研究还报道了一种新的无金属氢化物供体，即吖啶基化合物3NH，其水合度超过NaBH4。总的来说，这项工作为在燃料形成和其他还原过程中使用无金属氢化物催化剂提供了一个前景。
Thermodynamic hydricities (AGH-) in acetonitrile and dimethyl sulfoxide have been calculated and experimentally measured for several metal-free hydride donors: NADH analogs (BNAH, CN-BNAH, Me-MNAH, HER), methylene tetrahydromethanopterin analogs (BIMH, CAFH), acridine derivatives (Ph-AcrH, Me2N-AcrH, T-AcrH, 4OH, 2OH, 3NH), and a triarylmethane derivative (6OH). The calculated hydricity values, obtained using density functional theory, showed a reasonably good match (within 3 kcal/mol) with the experimental values, obtained using "potential pK(a)" and "hydride-transfer" methods. The hydride donor abilities of model compounds were in the 48.7-85.8 kcal/mol (acetonitrile) and 46.9-84.1 kcal/mol (DMSO) range, making them comparable to previously studied first-row transition metal hydride complexes. To evaluate the relevance of entropic contribution to the overall hydricity, Gibbs free energy differences (AGH-) obtained in this work were compared with the enthalpy (Delta H-H(-)) values obtained by others. The results indicate that, even though Delta H-H(-) values exhibit the same trends as Delta G(H)(-), the differences between room-temperature Delta G(H)(-) and Delta H-H(-) values range from 3 to 9 kcal/mol. This study also reports a new metal-free hydride donor, namely, an acridine-based compound 3NH, whose hydricity exceeds that of NaBH4. Collectively, this work gives a perspective of use metal-free hydride catalysts in fuel-forming and other reduction processes.