Synthesis, Characterization, and Reactivity of a Pincer-Type Aluminum(III) Complex

Abstract

Pincer-type main-group complexes have attractive properties and excellent potential as catalysts. A set of sterically hindered trianionic pincer-type phosphorus complexes have been shown to activate a series of E−H bonds, but the corresponding aluminum species has not been isolated. Herein, we report a novel pincer-type aluminum complex with a [ONO] 3− ligand. This species can react with the O−H bond in alcohol, phenol, and water, leading to the formation of a series of four-, six-, and eightmembered alumoxanes.

Reversible OH-bond activation and amphoterism by metal–ligand cooperativity of calix[4]pyrrolato aluminate

“…16 Other examples of aluminum-based cooperative OHaddition reactions were provided by Fedushkin 17 and recently by Zhu. 18 The formal oxidative addition of ROH to phosphorus(III), likely assisted by ELC, was reported for structurally constrained systems by Goicoechea 19 and Dobrovetsky. 20 However, the reversible activation of OH-bonds by p-block elements poses a more challenging task.…”

Pincer‐Type Ligand‐Assisted Catalysis and Small‐Molecule Activation by non‐VSEPR Main‐Group Compounds

“…Compound 40 reacts with alcohols and phenols under the mild condition to give alkoxide or phenoxide bridge dimers (41) (Scheme 41). [55]…”

“…Compound 40 was synthesized from the reaction between L 4 and AlBr 3 and was characterized by single crystal X‐ray diffraction and high‐resolution mass spectrometry (HRMS). Compound 40 reacts with alcohols and phenols under the mild condition to give alkoxide or phenoxide bridge dimers ( 41 ) (Scheme ) …”

Isolable Pincer-type Dianionic Dialane(6)

“…The group of Berben reported the novel octahedral aluminum­(III) complex I featuring two trianionic bis­(imino)­pyridine radical ligands and the Al-supported 1,3-dihydropyridinate II (Chart A) . Very recently, Zhu and coworkers isolated the pincer-type Al­(III) species III possessing a [ONO] 3– ligand, which exhibits interesting reactivity toward alcohol, phenol, and water to form cyclic alumoxanes . Despite these initial advances in this field, all of the Al centers in I – III are in the normal +3 oxidation state, and pincer-type species bearing low valent aluminum centers have still escaped isolation.…”

“…3 Very recently, Zhu and coworkers isolated the pincer-type Al(III) species III possessing a [ONO] 3− ligand, which exhibits interesting reactivity toward alcohol, phenol, and water to form cyclic alumoxanes. 4 Despite these initial advances in this field, all of the Al centers in I−III are in the normal +3 oxidation state, and pincer-type species bearing low valent aluminum centers have still escaped isolation.…”