Synthesis and characterization of partially substituted NHC supported alane adducts using triflate or chloride salts

Use of an aldiminium-based triflate salt as group transfer reagent to an N-heterocyclic carbene (NHC) adduct with alane [(IPr)AlH3] (IPr= 1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene) led to the substitution of a hydride by triflate and subsequently to the formation of [(IPOAlH2OTf] (1), which is the first structurally characterized aluminum dihydride triflate compound and the first (trifluoromethanesulfonyl)oxyalane NHC adduct. The related reaction with aldiminium-based chloride salt resulted in similar substitution and formation of mixed products [(IPOAiH(2)Cl] and [(IPr)AlHCl2], which co-crystallized in the form of [(IPr)AIH(3-x)Cl(x)], x = 1, 2 (2). This proves that aldiminium-based salts are suitable reagents in alane chemistry. In addition, the adduct [(IPr)AlCl3] (4) was also prepared from AlCl3 and IPr carbene. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

The use of aldiminium-based triflate and chloride salts as group transfer reagents with N-heterocyclic carbene and alane led to the formation of novel compounds, demonstrating their suitability in alane chemistry. The results included the first structurally characterized aluminum dihydride triflate compound and the first (trifluoromethanesulfonyl)oxyalane NHC adduct, as well as mixed products co-crystallized in a specific form.