Böhme M, Termühlen S, Dutschke PD, Hepp A, Hahn FE. Formation of C
NHC∧C
alkyl and C
NHC∧C
aryl κ
2-Chelate Complexes through Competitive sp
3- and sp
2-CH Activations: An Experimental and Computational Study.
ACS OMEGA 2023;
8:48515-48521. [PMID:
38144098 PMCID:
PMC10733921 DOI:
10.1021/acsomega.3c08427]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 11/10/2023] [Indexed: 12/26/2023]
Abstract
Depending on the chelate ring present, cyclometalated complexes are useful catalysts for various reactions. The reactivity of IrIII and RhIII NHC complexes bearing aliphatic or aromatic N,N'-substituents and thus featuring various metalation sites toward cyclometalation has been investigated. The RhIII complex bearing an N-mesityl-N'-benzyl-NHC does not participate in any cyclometalation, while the IrIII complex reacts under metalation of an ortho-methyl group of the Mes substituent to give complex [3] with a six-membered chelate ring. The RhIII and IrIII complexes bearing an N-o-tolyl,N-benzyl-NHC undergo sp2-CH activation to yield the cyclometalated complexes [4] and [5] featuring a five-membered CNHC∧C chelate ring. Density functional theory (DFT) studies corroborated the experimental findings.
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