Hydrogen-Atom Noninnocence of a Tridentate [SNS] Pincer Ligand.
Hydrogen-Atom Noninnocence of a Tridentate [SNS] Pincer Ligand.
复制标题
三齿[SNS]钳形配体的氢原子非纯真。
作者：
Kyle E Rosenkoetter;M. K. Wojnar;Bronte J Charette;J. Ziller;A. F. Heyduk
双（2-巯基-4-甲基苯基）胺（[SNS] H3）在无空气条件下双去质子化，然后与NiCl2（PR3）2加成，得到[SN（H）S] Ni（PR3）（1a，R = Cy; 1b，R = Ph）配合物，其特征为抗磁性的正方形平面镍（II）配合物。当用3当量KH进行相同反应时，得到抗磁性阴离子K {[SNS] Ni（PR 3）}（K [2a]，R = Cy; K [2b]，R = Ph）。在空气存在下，反应伴随着单电子氧化进行。当R = Cy时，得到了一个正方形平面的S = 1/2配合物[SNS] Ni（PCy 3）（3a）。当R = Ph时，得到了三元配合物{[SNS] Ni（PPh3）} 2（{3b} 2）。这种双金属离子是抗磁性的，但是在溶液中它会解离，得到类似于3a的S = 1/2单体。配合物1 - 3代表氢原子转移系列。用相应的p Ka和E ° '值计算出1a和1b的键离解自由能（BDFE）分别为63.9 ± 0.1和62.4 ± 0.2 kcal mol-1。与这些BDFE值一致，TEMPO·与1a和1b反应，导致夺取氢原子，分别得到3a和3b。
Double deprotonation of bis(2-mercapto-4-methylphenyl)amine ([SNS]H3) followed by addition to NiCl2(PR3)2 in air-free conditions afforded [SN(H)S]Ni(PR3) (1a, R = Cy; 1b, R = Ph) complexes, characterized as diamagnetic, square-planar nickel(II) complexes. When the same reaction was conducted with 3 equiv of KH, the diamagnetic anions K{[SNS]Ni(PR3)} were obtained (K[2a], R = Cy; K[2b], R = Ph). In the presence of air, the reaction proceeds with a concomitant one-electron oxidation. When R = Cy, a square-planar, S = 1/2 complex, [SNS]Ni(PCy3) (3a), was isolated. When R = Ph, the bimetallic complex {[SNS]Ni(PPh3)}2 ({3b}2) was obtained. This bimetallic species is diamagnetic; however, in solution it dissociates to give S = 1/2 monomers analogous to 3a. Complexes 1-3 represent a hydrogen-atom-transfer series. The bond dissociation free energies (BDFEs) for 1a and 1b were calculated to be 63.9 ± 0.1 and 62.4 ± 0.2 kcal mol-1, respectively, using the corresponding p Ka and E°' values. Consistent with these BDFE values, TEMPO• reacted with 1a and 1b, resulting in the abstraction of a hydrogen atom to afford 3a and 3b, respectively.
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影响因子：
15
作者：
Saouma, Caroline T.;Kaminsky, Werner;Mayer, James M.
通讯作者：
Mayer, James M.
影响因子：
18.3
作者：
Cook, Sarah A.;Borovik, A. S.
通讯作者：
Borovik, A. S.
影响因子：
15
作者：
P. Mondal;P. Pirovano;Ankita Das;E. Farquhar;A. McDonald
通讯作者：
P. Mondal;P. Pirovano;Ankita Das;E. Farquhar;A. McDonald
影响因子：
--
作者：
Tim Storr;E. Wasinger;R. Pratt;T. Stack
通讯作者：
Tim Storr;E. Wasinger;R. Pratt;T. Stack
影响因子：
62.1
作者：
Warren, Jeffrey J.;Tronic, Tristan A.;Mayer, James M.
通讯作者：
Mayer, James M.