Synthesis, Structure, and Reactivity of a Superbulky Low-Valent β-Diketiminate Al(I) Complex

Abstract

Low-valent β-diketiminate Al­(I) complexes are generally synthesized in low yields (<20%). This is due to an intermolecular decomposition reaction. A new β-diketiminate Al­(I) complex with a very bulky β-diketiminate ligand DIPePBDI was obtained in a high yield (81%) and the raw product was found to be essentially pure (DIPePBDI = HC­[C­(Me)­N­(DIPeP)]2; DIPeP = 2,6-C­(H)­Et2-phenyl). The crystal structure of (DIPePBDI)­Al shows a monomeric complex. The reaction of (DIPePBDI)­Al with AlBr3 gave (DIPePBDI)­AlBr2 and Al(0). The reaction of (DIPePBDI)Al with KCH­(SiMe3)2 led to deprotonation of a backbone Me group and formation of a K aluminyl complex. A minor side-product in which the BDI ligand was cleaved is also described. The very high yield of (DIPePBDI)Al makes it a welcome addition to the family of β-diketiminate Al­(I) complexes.

Alkaline‐Earth Metal Mediated Benzene‐to‐Biphenyl Coupling

“…However, after performing the reaction just above the melting point of the solvent (10 °C) and removal of benzene by freeze‐drying at −15 °C, [( DIPeP BDI)Sr] 2 (C 6 H 6 ) ( 4 ) could be extracted with cold pentane in form of an essentially pure pitch‐black powder (61 % yield). We anticipate that this recently introduced benzene freeze‐drying method [25] could generally become a key to the isolation of thermally labile complexes. Crystallization from pentane gave black crystals of 4 which are even at −20 °C only of limited stability.…”

The emerging chemistry of the aluminyl anion

“…An analogous reaction of the NDipep substituted precursor Al(BDI Dipep ) ( VII ) with K[R] was shown to be solvent dependant. 12 In hexane the reaction forms exclusively the potassium aluminyl [K{Al(BDI Dipep -H)}] 2 4 Dipep , whereas in benzene a mixture of 4 Dipep and a ligand C–H activation product was formed.…”

“…X-Ray crystallography has shown that the potassium aluminyls 1 , 28 2 , 29 3 Ar (Ar = Dipp, 30 Mes 31 ) and 4 Ar (Ar = Dipp, 32 Dipep 12 ) exist as contacted dimeric pairs (CDPs) in the solid-state, in which the two aluminyl anions are linked by flanking K⋯π(arene) interactions (Fig. 3).…”

“…Al( tBu BDI Dipp ) VI incorporates tBu groups into the ligand framework, 11 whereas the new ''superbulky'' derivative Al(BDI Dipep ) (VII) replaces the nitrogen substituents with 2,6-diisopentylphenyl (Dipep) groups. 12 The rich chemistry of both Cp-and BDI-derived Al(I) systems have been the subject of several detailed review articles. 13 A noteworthy addition to the family of Al(I) compounds consists of a one coordinate Al-centre in an aluminylene complex.…”

High-Level Coupled-Cluster Study on Substituent Effects in H2Activation by Low-Valent Aluminyl Anions

“…Albeit the seminal work of Aldridge and Goicoechea first reported the activation of the H–H bond in benzene, the dual activation of C–H bonds in para positions was first reported by Harder et al using catalyst VI bearing an N,N ligand . Other seminal examples and reactivity regarding aluminyl anions can be found in the literature − and references therein.…”