研究室工作進展 Sep. 13th, 2013.
Alkaline-Earth Metallocenes Coordinated with Ester Pendants: Synthesis, Structural Characterization, and Application in Metathesis Reaction
Heng Li, Wen-Xiong Zhang, and Zhenfeng Xi*
Chem. Eur. J. 2013, 19, 12859-12866.
A variety of ester-substituted cyclopentadiene derivatives were synthesized in one-pot from the reaction of 1,4-dilithio-1,3-butadienes, CO and acid chlorides. Direct deprotonation of the ester-substituted cyclopentadienes with Ae[N(SiMe3)]22 (Ae = Ca, Sr, Ba) efficiently generated a new type of heavier alkaline-earth (Ca, Sr, Ba) metallocenes in good to excellent isolated yields. Single-crystal X-ray structural analysis demonstrated that these heavier alkaline-earth metallocenes were featured with two intramolecularly coordinated ester pendants and multiply substituted cyclopentadienyl ligands. Their corresponding transition metal metallocenes, such as ferrocene derivatives and half-sandwich cyclopentadienyl tricarbonylrhenium complexes, could be generated highly efficiently via metathesis reactions. The multiply substituted cyclopentadiene ligands containing an ester pendant, and their corresponding heavier alkaline-earth and transition-metal metallocenes would have further applications in coordination chemistry, organometallic chemistry and organic synthesis.
背景介紹
近年來重堿土金屬（heavier alkaline-earth，包括鈣，锶，鋇）配合物的合成、結構與催化應用研究受到重視。但是，這些配合物的高活性（不穩定性）和很差的溶解性阻礙了其進一步研究。 尋找合适的配體以生成穩定的配合物并增加其溶解度成為重要研究方向。本工作利用我們自己發展的反應（Angew. Chem. Int. Ed. 2009, 48, 8111; Chem. Eur. J. 2011, 17, 7399.），合成了一系列酯基取代的環戊二烯配體。利用這些配體合成了重堿土金屬(Ca, Sr, Ba)配合物，并初步研究了這些配合物的反應性。預期這些配體及其金屬配合物将有更多獨特的應用。