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Fabri B, Funaioli T, Frédéric L, Elsner C, Bordignon E, Zinna F, Di Bari L, Pescitelli G, Lacour J. Triple para-Functionalized Cations and Neutral Radicals of Enantiopure Diaza[4]helicenes. J Am Chem Soc 2024; 146:8308-8319. [PMID: 38483324 DOI: 10.1021/jacs.3c13487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
Modulation of absorbance and emission is key for the design of chiral chromophores. Accessing a series of compounds absorbing and emitting (circularly polarized) light over a wide spectral window and often toward near-infrared is of practical value in (chir)optical applications. Herein, by late-stage functionalization on derivatives bridging triaryl methyl and helicene domains, we have achieved the regioselective triple introduction of para electron-donating or electron-withdrawing substituents. Extended tuning of electronic (e.g., E1/2red -1.50 V → -0.68 V) and optical (e.g., emission covering from 550 to 850 nm) properties is achieved for the cations and neutral radicals; the latter compounds being easily prepared by mono electron reductions under electrochemical or chemical conditions. While luminescence quantum yields can be increased up to 70% in the cationic series, strong Cotton effects are obtained for certain radicals at low energies (λabs ∼ 700-900 nm) with gabs values above 10-3. The open-shell electronic nature of the radicals was further characterized by electron paramagnetic resonance revealing an important spin density delocalization that contributes to their persistence.
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Affiliation(s)
- Bibiana Fabri
- Department of Organic Chemistry, University of Geneva, Quai Ernest Ansermet 30, Geneva 4 1211, Switzerland
| | - Tiziana Funaioli
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 13, Pisa 56124, Italy
| | - Lucas Frédéric
- Department of Organic Chemistry, University of Geneva, Quai Ernest Ansermet 30, Geneva 4 1211, Switzerland
| | - Christina Elsner
- Department of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, Geneva 4 1211, Switzerland
| | - Enrica Bordignon
- Department of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, Geneva 4 1211, Switzerland
| | - Francesco Zinna
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 13, Pisa 56124, Italy
| | - Lorenzo Di Bari
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 13, Pisa 56124, Italy
| | - Gennaro Pescitelli
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Via G. Moruzzi 13, Pisa 56124, Italy
| | - Jérôme Lacour
- Department of Organic Chemistry, University of Geneva, Quai Ernest Ansermet 30, Geneva 4 1211, Switzerland
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Zhong Z, Besnard C, Lacour J. General Ir-Catalyzed N-H Insertions of Diazomalonates into Aliphatic and Aromatic Amines. Org Lett 2024; 26:983-987. [PMID: 38277489 PMCID: PMC10863398 DOI: 10.1021/acs.orglett.3c03929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/18/2024] [Accepted: 01/24/2024] [Indexed: 01/28/2024]
Abstract
A general N-H insertion reactivity of acceptor-acceptor diazo malonate reagents is reported using [Ir(cod)Cl]2 as catalyst. A large range of amines, primary and secondary, aliphatic and aromatic, is possible. Mild temperatures, perfect substrate/reactant stoichiometry, and good functional group compatibility render the process particularly attractive for the (late-stage) functionalization of amines.
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Affiliation(s)
- Zhuang Zhong
- Department
of Organic Chemistry, University of Geneva, Quai Ernest Ansermet 30, CH-1211 Genève 4, Switzerland
| | - Céline Besnard
- Laboratory
of Crystallography, University of Geneva, Quai Ernest Ansermet 24, CH-1211 Genève 4, Switzerland
| | - Jérôme Lacour
- Department
of Organic Chemistry, University of Geneva, Quai Ernest Ansermet 30, CH-1211 Genève 4, Switzerland
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Cei M, Di Bari L, Zinna F. Circularly polarized luminescence of helicenes: A data-informed insight. Chirality 2023; 35:192-210. [PMID: 36707940 DOI: 10.1002/chir.23535] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 01/10/2023] [Accepted: 01/11/2023] [Indexed: 01/29/2023]
Abstract
Helicenes are an interesting scaffold for chiroptical properties and in particular circularly polarized luminescence (CPL). In this short review, we collect the luminescence (glum ) and absorption (gabs ) dissymmetry factors associated to the first Cotton effect of the electronic circular dichroism (ECD) spectrum. Considering the data for 170 [n]-helicenes (n = 4-11), overall we found reasonable correlations between glum and gabs . Despite a few notable exceptions, this would confirm a similarity in the stereochemistry of the ground and emitting excited states for most helicenes. These results may be useful in rationalizing chiroptical data and help chemists in designing new helicene structures with the desired CPL properties.
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Affiliation(s)
- Matteo Cei
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Pisa, Italy
| | - Lorenzo Di Bari
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Pisa, Italy
| | - Francesco Zinna
- Dipartimento di Chimica e Chimica Industriale, University of Pisa, Pisa, Italy
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