Boosting Low‐Valent Aluminum(I) Reactivity with a Potassium Reagent |
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Authors: | Samuel Grams Jonathan Eyselein Jens Langer Christian Frber Sjoerd Harder |
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Institution: | Samuel Grams,Jonathan Eyselein,Jens Langer,Christian Färber,Sjoerd Harder |
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Abstract: | The reagent RK R=CH(SiMe3)2 or N(SiMe3)2] was expected to react with the low‐valent (DIPPBDI)Al (DIPPBDI=HCC(Me)N(DIPP)]2, DIPP=2,6‐iPr‐phenyl) to give (DIPPBDI)AlR]?K+. However, deprotonation of the Me group in the ligand backbone was observed and H2C=C(N‐DIPP)?C(H)=C(Me)?N?DIPP]Al?K+ ( 1 ) crystallized as a bright‐yellow product (73 %). Like most anionic AlI complexes, 1 forms a dimer in which formally negatively charged Al centers are bridged by K+ ions, showing strong K+???DIPP interactions. The rather short Al–K bonds 3.499(1)–3.588(1) Å] indicate tight bonding of the dimer. According to DOSY NMR analysis, 1 is dimeric in C6H6 and monomeric in THF, but slowly reacts with both solvents. In reaction with C6H6, two C?H bond activations are observed and a product with a para‐phenylene moiety was exclusively isolated. DFT calculations confirm that the Al center in 1 is more reactive than that in (DIPPBDI)Al. Calculations show that both AlI and K+ work in concert and determines the reactivity of 1 . |
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Keywords: | aluminum C− H activation density-functional calculations low-valent complexes potassium |
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