An Aluminum Telluride with a Terminal Al=Te Bond and its Conversion to an Aluminum Tellurocarbonate by CO₂ Reduction

Abstract

Facile access to dimeric heavier aluminum chalcogenides [(NHC)Al(Tipp)‐μ‐Ch]2 (NHC=IiPr (1,3‐diisopropyl‐4,5‐dimethylimidazol‐2‐ylidene, IMe4 (1,3,4,5‐tetramethylimidazol‐2‐ylidene); Tipp=2,4,6‐iPr3C6H2; Ch=Se, Te) by treatment of NHC‐stabilized aluminum dihydrides with elemental Se and Te is reported. The higher affinity of IMe4 in comparison with IiPr toward the Al center in [(NHC)Al(Tipp)‐μ‐Ch]2 can be used for ligand exchange. Additionally, the presence of excess IMe4 allows for cleavage of the dimers to form a rare example of a neutral multiply bonded heavier aluminum chalcogenide in the form of a tetracoordinate aluminum complex, (IMe4)2(Tipp)Al=Te. This species reacts with three equivalents of CO2 across two Al−CNHC and the Al=Te bond affording a pentacoordinate aluminum complex containing a dianionic tellurocarbonate ligand [CO2Te]2−, which is the first example of tellurium analogue of a carbonate [CO3]2−.

Small molecule activation by well-defined compounds of heavy p-block elements

“…91 tellurocarbonate moiety (a tellurium analog of carbonate) as well as a penta-coordinate aluminum center. 92…”

Donor‐Acceptor Activation of Carbon Dioxide

“…Besides phosphorus and nitrogen, group 16 elements have been employed as Lewis basic centres in combination with aluminium for CO 2 activation (compounds 49-51, Figure 6). [44][45][46] Thus, the reaction of sulfido and selenido complexes K[Al-(NON Dipp )(E)] (E = S, Se) with CO 2 afforded compounds 49 and 50 via a [2 + 2]-cycloaddition pathway with Al=E bond reduction. Interestingly, while the reaction with the sulphur compound took two days at room temperature for completion, the selenium analogue 50 was formed in only fifteen minutes under the same conditions.…”

Reductive Coupling of a Diazoalkane Derivative Promoted by a Potassium Aluminyl and Elimination of Dinitrogen to Generate a Reactive Aluminium Ketimide

“…One such area is the isolation of compounds containing Al=E multiple bonds, which although previously noted for neutral Al(I) systems, [5] were at the time largely derived from unanticipated reactions. [6] Taking the low valent aluminyl anion as a precursor to Al=E bond formation using an oxidative addition approach, our group and others have reported examples of Al=O, [7] Al=S, [8] Al=Se, [9] Al=Te, [10] and Al=NR [11] bonds. In this context, Kinjo and co-workers examined the reaction of the lithium salt of a cyclic (alkyl)(amino)aluminyl anion, Li[Al(bo2e-C Ar N Dipp )] ([bo2e-C Ar N Dipp ] 2À = [(bicyclo[2.2.2]oct-2-ene)C(Ar) 2 N-(Dipp)] 2À , Ar = 3,5-tBu 2 C 6 H 3 ) with the bulky diaryldiazoalkane, Ar 2 CN 2 as a route to Al=CR 2 systems (Figure 1a).…”