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−.