Zatsepin Pavel, Lee Eunji, Gu Jun, Gau Michael R, Carroll Patrick J, Baik Mu-Hyun, Mindiola Daniel J
Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), and Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
J Am Chem Soc. 2020 Jun 3;142(22):10143-10152. doi: 10.1021/jacs.0c02742. Epub 2020 May 22.
The bonding between scandium and carbon in a series of alkylidene- and alkylidyne-like moieties is compared. The Tebbe analogue complex (PNP)Sc(μ-CHSiMe)(μ-CH)[Al(CH)(CHSiMe)] () (PNP = N[2-PPr-4-methylphenyl]) could be formed by adding AlMe to (PNP)Sc(CHSiMe) (). The fluxional behavior of is studied by a combination of 2D C-H HMQC, HMBC, and other heteronuclear NMR spectroscopic experiments. The phosphonioalkylidene complex (PNP)Sc(CHPPh)(CH) () could be prepared from by treatment with 2 equiv of the ylide HCPPh or by methane elimination from (PNP)Sc(CH) and 1 equiv of HCPPh. The reactivity of the alkylidene in was further explored with NAd, which gave insertion at the Sc-C bond, yielding (PNP)Sc(CH)[η-NAdCHSiMeAl(CH)(CHSiMe)] (), while DMAP provided C-H activation across the alkylidene with loss of the Al-C bond to form (PNP)Sc(η-NCHNMe)(CHSiMe) (). Utilizing the same approach that yielded , methane elimination in could further be promoted with Al(CH) to furnish the first example of a scandium phosphonioalkylidyne complex, (PNP)Sc(μ-CPh)(μ-CH)Al(CH) (). Experimental and theoretical studies were combined to compare the bonding in , , and , in order to understand the legitimacy of Sc-C multiple bond character.
比较了一系列类亚烷基和类亚炔基部分中钪与碳之间的键合。通过将AlMe添加到(PNP)Sc(CHSiMe)中，可以形成Tebbe类似物配合物(PNP)Sc(μ-CHSiMe)(μ-CH)[Al(CH)(CHSiMe)] () (PNP = N[2-PPr-4-甲基苯基])。通过二维C-H HMQC、HMBC和其他异核NMR光谱实验相结合的方法研究了的动态行为。膦亚烷基配合物(PNP)Sc(CHPPh)(CH) ()可以通过用2当量的叶立德HCPPh处理或通过(PNP)Sc(CH)和1当量的HCPPh消除甲烷来制备。用NAd进一步探索了中烷基的反应性，其在Sc-C键处发生插入，生成(PNP)Sc(CH)[η-NAdCHSiMeAl(CH)(CHSiMe)] ()，而DMAP则通过失去Al-C键在烷基上提供C-H活化，形成(PNP)Sc(η-NCHNMe)(CHSiMe) ()。利用产生的相同方法，Al(CH)可以进一步促进中的甲烷消除，以提供钪膦亚炔基配合物的第一个例子，(PNP)Sc(μ-CPh)(μ-CH)Al(CH) ()。结合实验和理论研究来比较、和中的键合，以了解Sc-C多重键特征的合理性。
