Employing Dianionic Macrocyclic Tetracarbenes To Synthesize Neutral Divalent Metal Complexes

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• 作者：Heather M. Bass ; S. Alan Cramer ; Alexander S. McCullough ; Karl J. Bernstein ; Christopher R. Murdock ; David M. Jenkins
• 刊名：Organometallics
• 出版年：2013
• 出版时间：April 8, 2013
• 年：2013
• 卷：32
• 期：7
• 页码：2160-2167
• 全文大小：364K
• 年卷期：v.32,no.7(April 8, 2013)
• ISSN：1520-6041

文摘

Macrocyclic tetraimidazolium diborate ligand precursors with two different ring sizes have been synthesized by ring-forming reactions between diimidazoles and haloboranes. Deprotonation of the macrocyclic tetraimidazoliums with n-butyllithium followed by the addition of divalent metal salts of palladium or nickel leads to macrocyclic tetracarbene complexes with an 18-atom macrocycle, but not the 16-atom variant. These neutral palladium and nickel complexes are the first examples of macrocyclic tetracarbene diborate complexes, and unlike their cationic counterparts, they are highly soluble in nonpolar solvents. All macrocyclic tetraimidazoliums and their corresponding metal complexes were characterized by single-crystal X-ray diffraction and spectroscopic techniques.