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Cp*Ir( iii ) complexes have been shown to be effective for the halogenation of N , N -diisopropylbenzamides with N -halosuccinimide as a suitable halogen source. The optimized conditions for the iodination reaction consist of 0.5 mol% [Cp*IrCl 2 ] 2 in 1,2-dichloroethane at 60 °C for 1 h to form a variety of iodinated benzamides in high yields. Increasing the catalyst loading to 6 mol% and the time to 4 h enabled the bromination reaction of the same substrates. Reactivity was not observed for the chlorination of these substrates. A variety of functional groups on the para -position of the benzamide were well tolerated. Kinetic studies showed the reaction dependence is first order in iridium, positive order in benzamide, and zero order in N -iodosuccinimide. A KIE of 2.5 was obtained from an independent H/D kinetic isotope effect study. Computational studies (DFT-BP3PW91) indicate that a CMD mechanism is more likely than an oxidative addition pathway for the C–H bond activation step. The calculated functionalization step involves an Ir( v ) species that is the result of oxidative addition of acetate hypoiodite that is generated in situ from N -iodosuccinimide and acetic acid.
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Synthesis, characterization, and structure determination of Cp*Ir(dpms)Cl
Bipyridyl ligands are commonplace in catalysis. Structurally similar to this ligand class with unique properties is the novel di-(2-pyridyl)methanesulfonate (dpms) ligand, which is prepared and reacted with [Cp*IrCl2]2 to afford Cp*Ir(dpms)Cl (1) in high yield. Its single-crystal X-ray structure indicates an exo–(kappa2) conformation of the ligand, with the sulfonate group directed away from the iridium center. Halogen exchange by treatment of 1 with NaI gives the iodide derivative, Cp*Ir(dpms)I (2). Abstraction of the halogen from 1 using AgPF6 generates [Cp*Ir(dpms)]PF6 (3), which was not found to activate the C-H bonds of benzene.
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- Award ID(s):
- 1762350
- PAR ID:
- 10356571
- Date Published:
- Journal Name:
- Inorganica Chimica Acta
- ISSN:
- 0020-1693
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1016/j.ica.2022.121210
