Normal and abnormal NHC coordination in cationic hydride iodide complexes of aluminium.

Author(s) Trose, M.; Burnett, S.; Bonyhady, S.J.; Jones, C.; Cordes, D.B.; Slawin, A.M.Z.; Stasch, A.
Journal Dalton Trans
Date Published 2018 Jul 31
Abstract

The mixed N-heterocyclic carbene (NHC) complexes NHCAlHxI3-x, where NHC is IDip or IMes ((HCNAr)2C:, Ar = 2,6-iPr2C6H3 = Dip (IDip); or 2,4,6-Me3C6H2 = Mes (IMes)), x = 1 or 2, were either prepared from NHCAlH3 and NHCAlI3 or by halogenation of NHCAlH3 with MeI. Reaction of [(IDip)AlHxI3-x], with x = 0-3, with another equivalent of IDip afforded either fluxional equilibria in benzene solution for x = 0, no reaction for x = 3, or the new mixed normal-abnormal NHC-coordinated ionic complexes [(IDip)AlH2(aIDip)]I (9) and [(IDip)AlHI(aIDip)]I (10), where aIDip is the abnormal IDip carbene tautomer bonded through its 4-position. The molecular structures of 9 and 10 were determined and show slightly shorter Al-C(aIDip) than Al-C(IDip) distances. In addition, a complex containing [(IDip)AlI2(aIDip)]I (11) was structurally characterized though could not intentionally be synthesised. Possible formation mechanisms for 9-11 are discussed and the normal and abnormal IDip coordination to the aluminium(iii) centre is believed to occur for steric reasons.

DOI 10.1039/c8dt01798k
ISSN 1477-9234
Citation Trose M, Burnett S, Bonyhady SJ, Jones C, Cordes DB, Slawin AM, et al. Normal and abnormal NHC coordination in cationic hydride iodide complexes of aluminium. Dalton Trans. 2018;47(30):10281-10287.

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