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Jana P, Koppayithodi S, Mahato S, Molla S, Bandyopadhyay S. Stable Diradical on the Dimethyldihydropyrene Scaffold. J Phys Chem Lett 2023; 14:7433-7439. [PMID: 37578893 DOI: 10.1021/acs.jpclett.3c01808] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
The diradical character in a molecular architecture can be customized primarily in two ways: first, by employing a quinoidal pro-aromatic system with net energy gained by aromatization that compensates for the energy required to generate the diradical species and, second, by employing an antiaromatic system having easily accessible triplet states that impart a diradical character. We have chosen a 14π aromatic framework, Boekelheide's dimethyldihydropyrene, and perturbed its aromaticity through the construction of its quinoidal form. The perturbed aromaticity was evident from the bond alteration in the X-ray diffraction structure, 1H nuclear magnetic resonance chemical shifts, and quantum chemical calculations. The aromaticity was restored as the system underwent a transition to the biradical structure centered on two exocyclic carbons. In addition, upon photoexcitation and without using an external reducing reagent, the diradical could be converted to a radical anion and dianion form easily when dimethylformamide was used as a solvent.
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Affiliation(s)
- Palash Jana
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, Nadia, West Bengal 741246, India
| | - Sudeep Koppayithodi
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, Nadia, West Bengal 741246, India
| | - Samyadeb Mahato
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, Nadia, West Bengal 741246, India
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Sariful Molla
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, Nadia, West Bengal 741246, India
| | - Subhajit Bandyopadhyay
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, Nadia, West Bengal 741246, India
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Plasser F, Glöcklhofer F. Visualisation of Chemical Shielding Tensors (VIST) to Elucidate Aromaticity and Antiaromaticity. European J Org Chem 2021; 2021:2529-2539. [PMID: 34248413 PMCID: PMC8251739 DOI: 10.1002/ejoc.202100352] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/01/2021] [Indexed: 01/25/2023]
Abstract
Aromaticity is a central concept in chemistry, pervading areas from biochemistry to materials science. Recently, chemists also started to exploit intricate phenomena such as the interplay of local and global (anti)aromaticity or aromaticity in non-planar systems and three dimensions. These phenomena pose new challenges in terms of our fundamental understanding and the practical visualisation of aromaticity. To overcome these challenges, a method for the visualisation of chemical shielding tensors (VIST) is developed here that allows for a 3D visualisation with quantitative information about the local variations and anisotropy of the chemical shielding. After exemplifying the method in different planar hydrocarbons, we study two non-planar macrocycles to show the unique benefits of the VIST method for molecules with competing π-conjugated systems and conclude with a norcorrole dimer showing clear evidence of through-space aromaticity. We believe that the VIST method will be a highly valuable addition to the computational toolbox.
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Affiliation(s)
- Felix Plasser
- Department of ChemistryLoughborough UniversityLoughboroughLE11 3TUUnited Kingdom
| | - Florian Glöcklhofer
- Department of Chemistry andCentre for Processable ElectronicsImperial College LondonMolecular Sciences Research HubLondonW12 0BZUnited Kingdom
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Wang ZY, Dai YZ, Ding L, Dong BW, Jiang SD, Wang JY, Pei J. A Stable Triplet-Ground-State Conjugated Diradical Based on a Diindenopyrazine Skeleton. Angew Chem Int Ed Engl 2021; 60:4594-4598. [PMID: 33241615 DOI: 10.1002/anie.202012989] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/24/2020] [Indexed: 01/24/2023]
Abstract
High-spin conjugated radicals have great potential in magnetic materials and organic spintronics. However, to obtain high-spin conjugated radicals is still quite challenging due to their poor stability. We report the successful synthesis and isolation of a stable triplet conjugated diradical, 10,12-diaryldiindeno[1,2-b:2',1'-e]pyrazine (m-DIP). With the m-xylylene analogue skeleton containing electron-deficient sp2 -nitrogen atoms, m-DIP displays significant aromatic character within its pyrazine ring and its spin density mainly delocalizes on the meta-pyrazine unit, making it a triplet ground state conjugated diradical. Our work provides an effective "spin density tuning" strategy for stable high-spin conjugated radicals.
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Affiliation(s)
- Zi-Yuan Wang
- Beijing National Laboratory for Molecular Sciences (BNLMS), The Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Center of Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Ya-Zhong Dai
- Beijing National Laboratory for Molecular Sciences (BNLMS), The Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Center of Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Li Ding
- Beijing National Laboratory for Molecular Sciences (BNLMS), The Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Center of Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Bo-Wei Dong
- Beijing National Laboratory for Molecular Science (BNLMS), Beijing Key Laboratory for Magnetoelectric Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Shang-Da Jiang
- Beijing National Laboratory for Molecular Science (BNLMS), Beijing Key Laboratory for Magnetoelectric Materials and Devices, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Jie-Yu Wang
- Beijing National Laboratory for Molecular Sciences (BNLMS), The Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Center of Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
| | - Jian Pei
- Beijing National Laboratory for Molecular Sciences (BNLMS), The Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Center of Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing, 100871, China
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4
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Wang Z, Dai Y, Ding L, Dong B, Jiang S, Wang J, Pei J. A Stable Triplet‐Ground‐State Conjugated Diradical Based on a Diindenopyrazine Skeleton. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202012989] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Zi‐Yuan Wang
- Beijing National Laboratory for Molecular Sciences (BNLMS) The Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Center of Soft Matter Science and Engineering College of Chemistry and Molecular Engineering Peking University Beijing 100871 China
| | - Ya‐Zhong Dai
- Beijing National Laboratory for Molecular Sciences (BNLMS) The Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Center of Soft Matter Science and Engineering College of Chemistry and Molecular Engineering Peking University Beijing 100871 China
| | - Li Ding
- Beijing National Laboratory for Molecular Sciences (BNLMS) The Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Center of Soft Matter Science and Engineering College of Chemistry and Molecular Engineering Peking University Beijing 100871 China
| | - Bo‐Wei Dong
- Beijing National Laboratory for Molecular Science (BNLMS) Beijing Key Laboratory for Magnetoelectric Materials and Devices College of Chemistry and Molecular Engineering Peking University Beijing 100871 China
| | - Shang‐Da Jiang
- Beijing National Laboratory for Molecular Science (BNLMS) Beijing Key Laboratory for Magnetoelectric Materials and Devices College of Chemistry and Molecular Engineering Peking University Beijing 100871 China
| | - Jie‐Yu Wang
- Beijing National Laboratory for Molecular Sciences (BNLMS) The Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Center of Soft Matter Science and Engineering College of Chemistry and Molecular Engineering Peking University Beijing 100871 China
| | - Jian Pei
- Beijing National Laboratory for Molecular Sciences (BNLMS) The Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education Center of Soft Matter Science and Engineering College of Chemistry and Molecular Engineering Peking University Beijing 100871 China
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