Scandium Alkyl Complexes Supported by a Ferrocene Diamide Ligand
摘要:
Synthesis of a scandium dimethylbenzyl complex supported by a ferrocene diamide ligand was accomplished by alkane elimination from Sc(CH(2)Xy-3,5)(3)(THF)(2). The scandium dimethylbenzyl complex Sc(fc[NSi(tBu)Me-2](2))(CH(2)Xy-3,5)(THF), 2-(CH(2)Xy-3,5)(THF), was used as a starting material for the synthesis of the corresponding chloride-bridged dimer, (2-CI)(2), which, in turn, led to a scandium bis(neo-pentyl) ate salt, Li[2Np(2)]. Attempts to remove the coordinated THF molecule from 2-(CH(2)Xy-3,5)(THF) with AlMe3 led to the isolation of a scandium methyl complex with two coordinated AlMe3 molecules, 2-Me(AlMe3)(2). Compound 2-Me(AlMe3)(2) led to a scandium methyl complex, 2-Me(THF)(2), by stirring in THF. All ferrocene diamido compounds were characterized by X-ray crystallography. DFT calculations on model compounds were used to explain the stability of the compounds synthesized and to probe the existence of an iron-scandium interaction. Compounds 2-(CH(2)Xy-3,5)(THF) and 2-Me(AlMe3)(2) polymerize L-lactide.
作者:Colin T. Carver、Diego Benitez、Kevin L. Miller、Bryan N. Williams、Ekaterina Tkatchouk、William A. Goddard、Paula L. Diaconescu
DOI:10.1021/ja902794w
日期:2009.7.29
Group III alkyl complexessupported by a ferrocenediamideligand (1,1'-fc(NSi(t)BuMe(2))(2)) have been found to be reactive toward aromatic N-heterocycles such as 1-methylimidazole and pyridines. These reactions were investigated experimentally and computationally. An initial C-H activation event is followed by a coupling reaction to form biheterocyclic complexes, in which one of the rings is dearomatized
已发现由二茂铁二酰胺配体 (1,1'-fc(NSi(t)BuMe(2))(2)) 支持的第 III 组烷基配合物对芳香族 N-杂环(如 1-甲基咪唑和吡啶)具有反应性。通过实验和计算研究了这些反应。最初的 CH 活化事件之后是偶联反应以形成双杂环复合物,其中一个环被脱芳构化。在1-甲基咪唑的情况下,双杂环化合物不能被分离并进一步导致咪唑开环产物;在吡啶的情况下,它转化为具有双键扩展共轭的异构体。根据实验和计算结果提出了两种反应的机理。
Insertion reactions of scandium pyridyl complexes supported by a ferrocene diamide ligand
作者:Colin T. Carver、Paula L. Diaconescu
DOI:10.1016/j.jallcom.2008.10.007
日期:2009.12
C)-pyridyl complexes, scandium η2(N,C)-pyridyl complexes supported by a ferrocene diamide ligand react further with pyridines to give coupling products. Although most of their insertion reactions with unsaturated substrates are similar to those of previous yttrocene and zirconocene complexes, in the reaction with butadiene, higher reactivity than the one reported for the yttrocene complex was observed
Dearomatization Reactions of N-Heterocycles Mediated by Group 3 Complexes
作者:Kevin L. Miller、Bryan N. Williams、Diego Benitez、Colin T. Carver、Kevin R. Ogilby、Ekaterina Tkatchouk、William A. Goddard、Paula L. Diaconescu
DOI:10.1021/ja908489p
日期:2010.1.13
ligand are reactive toward aromatic N-heterocycles by mediating their coupling and, in a few cases, the cleavage of their C-N bonds. When these complexes reacted with 2,2'-bipyridine or isoquinoline, they facilitated the alkyl migration of the benzyl ligand onto the pyridine ring, a process accompanied by the dearomatization of the N-heterocycle. The products of the alkyl-transfer reactions act as hydrogen
Ring-Opening Reactions of Aromatic N-Heterocycles by Scandium and Yttrium Alkyl Complexes
作者:Colin T. Carver、Paula L. Diaconescu
DOI:10.1021/ja802728k
日期:2008.6.18
The C-N bond in aromatic N-heterocycles is a strong bond, its cleaving involving mostly examples of metal-element multiple bonds. We report on the C-C coupling of two molecules of an aromatic N-heterocyclemediated by scandium and yttrium benzyl complexes supported by a ferrocene 1,1'-diamide ligand. The reaction with 1-methylimidazole leads, ultimately, to the formation of a ring-opened imidazole
Group 3 Metal Complexes of Radical-Anionic 2,2′-Bipyridyl Ligands
作者:Bryan N. Williams、Wenliang Huang、Kevin L. Miller、Paula L. Diaconescu
DOI:10.1021/ic101493k
日期:2010.12.20
A new method for generating group3 metal complexes containing radical-anionic 2,2′-bipyridyl (bipy) ligands is described that relies on hydrogen-atom abstraction from dearomatized biheterocyclic complexes. This method does not involve electron transfer to neutral 2,2′-bipyridyl or salt metathesis between the lithium salt of the 2,2′-bipyridyl radical anion and group3 metal halides. The new metal