Highly covalent metal–ligand π bonding in chelated bis- and tris(iminoxolene) complexes of osmium and ruthenium
Highly covalent metal–ligand π bonding in chelated bis- and tris(iminoxolene) complexes of osmium and ruthenium
复制标题
锇和钌螯合双和三（亚胺氧烯）配合物中的高共价金属-配体-键合
DOI：
10.1039/d0dt01287d
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发表时间：
2020
影响因子：
4
通讯作者：
Brown, Seth N.
中科院分区：
文献类型：
--
作者：
Gianino, Jacqueline;Brown, Seth N.
在吡啶和三乙胺存在下，双(氨基苯酚)2，2′-biphenylbis(3，5-di-tert-butyl-2-hydroxyphenylamine)(ClipH4)与{(对伞花烃)OsCl2}2发生好氧反应生成反式-(Clip)Os(Py)2。一种氧化程度较高的物种cis-β-(Clip)Os(OCH2CH2O)是由配体与Oso(OCH2CH2O)2反应生成的，并与Me3SiCl2反应生成氯络合物cis-β-(Clip)OsCl2。以tris(2-(3′，5′-di-tert-butyl-2′-hydroxyphenyl)amino-4-methylphenyl)amine(MeClampH6)为配体，与二价金属前驱体进行有氧反应，形成了八面体的Os和Ru三亚胺基茂烯络合物。用一个简单的成键模型很好地描述了配合物的结构和电子特征，该模型强调了金属和亚胺基甲苯配体之间的π键的共价性，而不是试图将部分分解为离散的氧化态。强调了不同络合物之间成键的连续性，各种Os和Ru络合物的结构数据显示出与π键级的良好相关性，并且可以分析键内和键距对键级的响应，以说明金属与亚胺氧杂环烯上氧化还原活性轨道之间成键的极性。金属和配位体的π键合轨道各占40%和60%，金属和配位体各占65%和35%。
The bis(aminophenol) 2,2′-biphenylbis(3,5-di-tert-butyl-2-hydroxyphenylamine) (ClipH4) forms trans-(Clip)Os(py)2 upon aerobic reaction of the ligand with {(p-cymene)OsCl2}2 in the presence of pyridine and triethylamine. A more oxidized species, cis-β-(Clip)Os(OCH2CH2O), is formed from reaction of the ligand with the osmium(VI) complex OsO(OCH2CH2O)2, and reacts with Me3SiCl to give the chloro complex cis-β-(Clip)OsCl2. Octahedral osmium and ruthenium tris-iminoxolene complexes are formed from the chelating ligand tris(2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)amino-4-methylphenyl)amine (MeClampH6) on aerobic reaction with divalent metal precursors. The complexes’ structural and electronic features are well described using a simple bonding model that emphasizes the covalency of the π bonding between the metal and iminoxolene ligands rather than attempting to dissect the parts into discrete oxidation states. Emphasizing the continuity of bonding between disparate complexes, the structural data from a variety of Os and Ru complexes show good correlations to π bond order, and the response of the intraligand bond distances to the bond order can be analyzed to illuminate the polarity of the bonding between metal and the redox-active orbital on the iminoxolenes. The osmium compounds’ π bonding orbitals are about 40% metal-centered and 60% ligand-centered, with the ruthenium compounds’ orbitals about 65% metal-centered and 35% ligand-centered.