Department of Chemistry and Biochemistry , University of California, San Diego , 9500 Gilman Drive, Mail Code 0358 , La Jolla , California 92093-0358 , United States.
J Am Chem Soc. 2018 Jul 5;140(26):8100-8104. doi: 10.1021/jacs.8b05019. Epub 2018 Jun 22.
Reported here is the isolation of a dianionic cobalt terminal carbyne derived from chemical reduction of an encumbering isocyanide ligand. Crystallographic, spectroscopic and computational data reveal that this carbyne possesses a low-valent cobalt center with an extensively filled d-orbital manifold. This electronic character renders the cobalt center the primary site of nucleophilicity upon reaction with protic substrates and silyl electrophiles. However, reactions with internal alkynes result in [2+2] cycloaddition with the carbyne carbon to form a new C-C bond.
本文报道了一种二价钴末端卡宾的分离，该卡宾是通过化学还原受阻异氰化物配体得到的。晶体学、光谱和计算数据表明，该卡宾具有低价钴中心和广泛填充的 d 轨道。这种电子特性使得钴中心在与亲核底物和硅基亲电试剂反应时成为亲核性的主要位点。然而，与内部炔烃的反应导致卡宾碳与[2+2]环加成，形成新的 C-C 键。
