Scandium Terminal Imido Chemistry
| Autor: | Erli Lu, Yaofeng Chen, Jiaxiang Chu |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Lanthanide
010405 organic chemistry chemistry.chemical_element General Medicine General Chemistry Actinide 010402 general chemistry 01 natural sciences 0104 chemical sciences Catalysis Metal chemistry.chemical_compound Crystallography chemistry Transition metal visual_art visual_art.visual_art_medium Reactivity (chemistry) Organic synthesis Scandium |
| Zdroj: | Accounts of Chemical Research. 51:557-566 |
| ISSN: | 1520-4898 0001-4842 |
| DOI: | 10.1021/acs.accounts.7b00605 |
| Popis: | Research into transition metal complexes bearing multiply bonded main-group ligands has developed into a thriving and fruitful field over the past half century. These complexes, featuring terminal M═E/M≡E (M = transition metal; E = main-group element) multiple bonds, exhibit unique structural properties as well as rich reactivity, which render them attractive targets for inorganic/organometallic chemists as well as indispensable tools for organic/catalytic chemists. This fact has been highlighted by their widespread applications in organic synthesis, for example, as olefin metathesis catalysts. In the ongoing renaissance of transition metal-ligand multiple-bonding chemistry, there have been reports of M═E/M≡E interactions for the majority of the metallic elements of the periodic table, even some actinide metals. In stark contrast, the largest subgroup of the periodic table, rare-earth metals (Ln = Sc, Y, and lanthanides), have been excluded from this upsurge. Indeed, the synthesis of terminal Ln═E/Ln≡E multiple-bonding species lagged behind that of the transition metal and actinide congeners for decades. Although these species had been pursued since the discovery of a rare-earth metal bridging imide in 1991, such a terminal (nonpincer/bridging hapticities) Ln═E/Ln≡E bond species was not obtained until 2010. The scarcity is mainly attributed to the energy mismatch between the frontier orbitals of the metal and the ligand atoms. This renders the putative terminal Ln═E/Ln≡E bonds extremely reactive, thus resulting in the formation of aggregates and/or reaction with the ligand/environment, quenching the multiple-bond character. In 2010, the stalemate was broken by the isolation and structural characterization of the first rare-earth metal terminal imide-a scandium terminal imide-by our group. The double-bond character of the Sc═N bond was unequivocally confirmed by single-crystal X-ray diffraction. Theoretical investigations revealed the presence of two p-d π bonds between the scandium ion and the nitrogen atom of the imido ligand and showed that the dianionic [NR] |
| Databáze: | OpenAIRE |
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