Modulating the σ-Accepting Properties of an Antimony Z-type Ligand via Anion Abstraction: Remote-Controlled Reactivity of the Coordinated Platinum Atom.
Modulating the σ-Accepting Properties of an Antimony Z-type Ligand via Anion Abstraction: Remote-Controlled Reactivity of the Coordinated Platinum Atom.
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通过阴离子抽象调节锑 Z 型配体的 σ 接受性质：配位铂原子的远程控制反应性。
DOI：
10.1021/jacs.8b05520
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发表时间：
2018
影响因子：
15
通讯作者：
F. Gabbaï
中科院分区：
文献类型：
--
作者：
D. You;Haifeng Yang;S. Sen;F. Gabbaï
为了寻找可用于远程控制过渡金属催化活性的配体平台，我们研究了含有三氟二硼烷单元作为路易斯酸的两亲性L2/ z型配体的配位非无性。已知的二氯二硼烷铂配合物（(o-（Ph2P)C6H4)2SbCl2）PtCl(1)）在乙腈（MeCN）和环己基异氰酸酯（CyNC）存在下与TlF反应，分别生成三氟二硼烷铂配合物2 ((o-(Ph2P)C6H4)2SbF3)Pt-NCMe和3 (((o-(Ph2P)C6H4)2SbF3)Pt-CNCy。这些配合物的形成是由于卤化物配体在双核周围的重新分布，影响了Pt-Sb键的性质。后者从1的共价转变为2和3的极性共价（或对价），其中三氟二硼烷部分在Pt→Sb相互作用中与铂中心接合。通过B(C6F5)3提取锑结合氟配体，可以进一步调节Pt-Sb键的极性。这些反应产生阳离子络合物[(o-(Ph2P)C6H4)2SbF2)Pt-NCMe]+([5]+)和[(o-(Ph2P)C6H4)2SbF2)Pt-CNCy]+([6]+)，已分离为[BF(C6F5)3]-盐。这些配合物具有高度的路易斯酸性二氟锑基团，这对铂中心的电子密度产生强烈的吸引力。结果，后者的亲电性显著增强。对于含有不稳定乙腈配体的[5]+，这种增加的亲电性转化为增加的亲碳性，这反映在该配合物促进酶环化反应的能力上。这些结果表明，锑z配体的配位非清白性可以用来调节相邻金属中心的催化活性。
In search of ligand platforms, which can be used to remotely control the catalytic activity of a transition metal, we have investigated the coordination noninnocence of ambiphilic L2/Z-type ligands containing a trifluorostiborane unit as a Lewis acid. The known dichlorostiboranyl platinum complex (( o-(Ph2P)C6H4)2SbCl2)PtCl (1) reacts with TlF in the presence of acetonitrile (MeCN) and cyclohexyl isocyanide (CyNC) to afford the trifluorostiborane platinum complexes 2 ((( o-(Ph2P)C6H4)2SbF3)Pt-NCMe) and 3 ((( o-(Ph2P)C6H4)2SbF3)Pt-CNCy), respectively. Formation of these complexes, which results from a redistribution of the halide ligands about the dinuclear core, affects the nature of the Pt-Sb bond. The latter switches from covalent in 1 to polar covalent (or dative) in 2 and 3 where the trifluorostiborane moiety engages the platinum center in a Pt → Sb interaction. The polarity of the Pt-Sb bond can be modulated further by abstraction of an antimony-bound fluoride ligand using B(C6F5)3. These reactions afford the cationic complexes [(( o-(Ph2P)C6H4)2SbF2)Pt-NCMe]+ ([5]+) and [(( o-(Ph2P)C6H4)2SbF2)Pt-CNCy]+ ([6]+) which have been isolated as [BF(C6F5)3]- salts. These complexes possess a highly Lewis acidic difluorostibonium moiety, which exerts an intense draw on the electron density of the platinum center. As a result, the latter becomes significantly more electrophilic. In the case of [5]+, which contains a labile acetonitrile ligand, this increased electrophilicity translates into increased carbophilicity as reflected by the ability of this complex to promote enyne cyclization reactions. These results demonstrate that the coordination noninnocence of antimony Z-ligands can be used to adjust the catalytic activity of an adjoining metal center.
影响因子：
2.8
作者：
Fong H;Moret ME;Lee Y;Peters JC
通讯作者：
Peters JC