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Mohan S, Rissanen K, Ward JS. Iodine(I) pnictogenate complexes as Iodination reagents. Commun Chem 2024; 7:159. [PMID: 39020074 PMCID: PMC11255316 DOI: 10.1038/s42004-024-01240-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Accepted: 07/08/2024] [Indexed: 07/19/2024] Open
Abstract
Halogen(I) complexes are widely used as halogenation reagents and traditionally feature homoleptic stabilising Lewis bases, though the recent revitalisation of iodine(I) carboxylate chemistry has provided isolable examples of heteroleptic iodine(I) complexes. This work reports iodine(I) pnictogenate complexes stabilised by a Lewis base (L), Ph2P(O)O─I─L, synthesised via cation exchange from the silver(I) precursor, (Ph2P(O)OAg)n. The complexes were characterised in both solution (1H, 1H-15N HMBC, 31P) and the solid state, and supplemented computationally by DFT studies. Interestingly, these iodine(I) pnictogenates demonstrate a range of stabilities, and have been found to excel as iodination reagents in comparison to carbonyl hypoiodites, with comparable reactivity to the eponymous Barluenga's reagent in the iodination of antipyrine.
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Affiliation(s)
- Sharath Mohan
- Department of Chemistry, University of Jyvaskyla, 40014, Jyväskylä, Finland
| | - Kari Rissanen
- Department of Chemistry, University of Jyvaskyla, 40014, Jyväskylä, Finland
| | - Jas S Ward
- Department of Chemistry, University of Jyvaskyla, 40014, Jyväskylä, Finland.
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Kolařík V, Rissanen K, Ward JS. Fluoro and Trifluoromethyl Benzoyl Hypoiodite Complexes with Substituted Pyridines. Chem Asian J 2024; 19:e202400349. [PMID: 38578048 DOI: 10.1002/asia.202400349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 04/05/2024] [Indexed: 04/06/2024]
Abstract
Based on the prior observation of the trifluoroacetate hypoiodite, CF3C(O)OI, demonstrating the largest σ-hole of a neutral halogen bond donor, a series of mono- and bis-carbonyl hypoiodites utilising trifluoromethyl or fluorine substituents at various positions of a parent benzoyl skeleton have been synthesised. The carbonyl hypoiodite complexes were prepared via cation exchange of the silver(I) cations with iodine(I) from the respective silver(I) carboxylates and dicarboxylates as the synthetic precursors. A range of pyridinic Lewis bases of varying nucleophilicities were used to stabilise the carbonyl hypoiodites to further probe their properties. The silver(I) intermediates with these Lewis bases were also isolated for silver(I) pentafluorobenzoate, providing additional insight into the cation exchange reaction. All complexes were characterised both in solution (1H, 1H-15N HMBC, 19F) and in the solid state (SCXRD), permitting insights into the formation of the elusive pyridine-iodine(I) cation.
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Affiliation(s)
- Václav Kolařík
- University of Jyvaskyla, Department of Chemistry, 40014, Jyväskylä, Finland
- Department of Chemistry, Faculty of Technology, Tomas Bata University in Zlín, Vavrečkova 5669, 760 01, Zlín, Czech Republic
| | - Kari Rissanen
- University of Jyvaskyla, Department of Chemistry, 40014, Jyväskylä, Finland
| | - Jas S Ward
- University of Jyvaskyla, Department of Chemistry, 40014, Jyväskylä, Finland
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Wieske LE, Erdelyi M. Halogen Bonds of Halogen(I) Ions─Where Are We and Where to Go? J Am Chem Soc 2024; 146:3-18. [PMID: 38117016 PMCID: PMC10785816 DOI: 10.1021/jacs.3c11449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 11/20/2023] [Accepted: 12/01/2023] [Indexed: 12/21/2023]
Abstract
Halenium ions, X+, are particularly strong halogen-bond donors that interact with two Lewis bases simultaneously to form linear [D···X···D]+-type halonium complexes. Their three-center, four-electron halogen bond is both fundamentally interesting and technologically valuable as it tames the reactivity of halogen(I) ions, opening up new horizons in a variety of fields including synthetic organic and supramolecular chemistry. Understanding this bonding situation enables the development of improved halogen(I) transfer reactions and of advanced functional materials. Following a decade of investigations of basic principles, the range of applications is now rapidly widening. In this Perspective, we assess the status of the field and identify its key advances and the main bottlenecks. Clearing common misunderstandings that may hinder future progress, we aim to inspire and direct future research efforts.
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Affiliation(s)
- Lianne
H. E. Wieske
- Department of Chemistry−BMC, Uppsala University, Box 576, SE-751 23 Uppsala, Sweden
| | - Mate Erdelyi
- Department of Chemistry−BMC, Uppsala University, Box 576, SE-751 23 Uppsala, Sweden
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Kumar P, Rautiainen JM, Novotný J, Ward JS, Marek R, Rissanen K, Puttreddy R. The Impact of ortho-substituents on Bonding in Silver(I) and Halogen(I) Complexes of 2-Mono- and 2,6-Disubstituted Pyridines: An In-Depth Experimental and Theoretical Study. Chemistry 2023:e202303643. [PMID: 38055221 DOI: 10.1002/chem.202303643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 12/01/2023] [Accepted: 12/05/2023] [Indexed: 12/07/2023]
Abstract
The coordination nature of 2-mono- and 2,6-disubstituted pyridines with electron-withdrawing halogen and electron-donating methyl groups for [N-X-N]+ (X=I, Br) complexations have been studied using 15 N NMR, X-ray crystallography, and Density Functional Theory (DFT) calculations. The 15 N NMR chemical shifts reveal iodine(I) and bromine(I) prefer to form complexes with 2-substituted pyridines and only 2,6-dimethylpyridine. The crystalline halogen(I) complexes of 2-substituted pyridines were characterized by using X-ray diffraction analysis, but 2,6-dihalopyridines were unable to form stable crystalline halogen(I) complexes due to the lower nucleophilicity of the pyridinic nitrogen. In contrast, the halogen(I) complexes of 2,6-dimethylpyridine, which has a more basic nitrogen, are characterized by X-crystallography, which complements the 15 N NMR studies. DFT calculations reveal that the bond energies for iodine(I) complexes vary between -291 and -351 kJ mol-1 and for bromine between -370 and -427 kJ mol-1 . The bond energies of halogen(I) complexes of 2-halopyridines with more nucleophilic nitrogen are 66-76 kJ mol-1 larger than those of analogous 2,6-dihalopyridines with less nucleophilic nitrogen. The experimental and DFT results show that the electronic influence of ortho-halogen substituents on pyridinic nitrogen leads to a completely different preference for the coordination bonding of halogen(I) ions, providing new insights into bonding in halogen(I) chemistry.
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Affiliation(s)
- Parveen Kumar
- Department of chemistry, University of Jyvaskyla, Jyvaskyla, P.O. BOX 35, FI-40014, Finland
| | - J Mikko Rautiainen
- Department of chemistry, University of Jyvaskyla, Jyvaskyla, P.O. BOX 35, FI-40014, Finland
| | - Jan Novotný
- Department of Chemistry, Faculty of Science, Masaryk university, Kamenice 5, 62500, Brno, Czechia
| | - Jas S Ward
- Department of chemistry, University of Jyvaskyla, Jyvaskyla, P.O. BOX 35, FI-40014, Finland
| | - Radek Marek
- Department of Chemistry, Faculty of Science, Masaryk university, Kamenice 5, 62500, Brno, Czechia
| | - Kari Rissanen
- Department of chemistry, University of Jyvaskyla, Jyvaskyla, P.O. BOX 35, FI-40014, Finland
| | - Rakesh Puttreddy
- Department of chemistry, University of Jyvaskyla, Jyvaskyla, P.O. BOX 35, FI-40014, Finland
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Rissanen K, Ward JS. Iodine(I) and Silver(I) Complexes Incorporating 3-Substituted Pyridines. ACS OMEGA 2023; 8:24064-24071. [PMID: 37426204 PMCID: PMC10324066 DOI: 10.1021/acsomega.3c03097] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 06/09/2023] [Indexed: 07/11/2023]
Abstract
Building upon the first report of a 3-acetaminopyridine-based iodine(I) complex (1b) and its unexpected reactivity toward tBuOMe, several new 3-substituted iodine(I) complexes (2b-5b) have been synthesized. The iodine(I) complexes were synthesized from their analogous silver(I) complexes (2a-5a) via a silver(I) to iodine(I) cation exchange reaction, incorporating functionally related substituents as 3-acetaminopyridine in 1b; 3-acetylpyridine (3-Acpy; 2), 3-aminopyridine (3-NH2py; 3), and 3-dimethylaminopyridine (3-NMe2py; 4), as well as the strongly electron-withdrawing 3-cyanopyridine (3-CNpy; 5), to probe the possible limitations of iodine(I) complex formation. The individual properties of these rare examples of iodine(I) complexes incorporating 3-substituted pyridines are also compared to each other and contrasted to their 4-substituted counterparts which are more prevalent in the literature. While the reactivity of 1b toward etheric solvents could not be reproduced in any of the functionally related analogues synthesized herein, the reactivity of 1b was further expanded to a second etheric solvent. Reaction of bis(3-acetaminopyridine)iodine(I) (1b) and iPr2O gave [3-acetamido-1-(3-iodo-2-methylpentan-2-yl)pyridin-1-ium]PF6 (1d), which demonstrated potentially useful C-C and C-I bond formation under ambient conditions.
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