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Huang H, Kinziabulatova L, Manickoth A, Zhang Y, Barilla MA, Blancafort L, Kohler B, Lumb JP. An iterative synthesis of poly-substituted indole oligomers reveals a short effective conjugation length in eumelanin model compounds. Chem Sci 2025:d4sc08610d. [PMID: 39981036 PMCID: PMC11836627 DOI: 10.1039/d4sc08610d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2024] [Accepted: 02/04/2025] [Indexed: 02/22/2025] Open
Abstract
Eumelanin is a multifunctional biomaterial that colors the skin, hair and eyes of mammals. Despite years of effort, its molecular structure remains unknown, limiting our understanding of its biological function and the design of synthetic mimics. In an effort to address this challenge, we report an Iterative Chain Growth (ICG) of well-defined 5,6-dihydroxyindole (DHI) model compounds that provides direct, experimental evidence of a short effective conjugation length in the resulting oligomers. Our ICG highlights the C2-selective borylation of N-H indoles in complex settings, and the utility of Suzuki-Miyaura Coupling (SMC) to grow the chain. The resulting C2-C7' linkage is installed selectively with good yields, affording products with up to 5-indole units. Access to these oligomers allows us to probe how DHI chain extension contributes to the emergence of sun screening in eumelanin. Our oligomers guarantee the absence of oxidized by-products that may otherwise complicate analysis, without substantially altering the photophysics of the indolic-backbone. Steady-state absorption and emission spectroscopy coupled with excited-state calculations reveal pronounced vibronic structure and excited state planarization, but only a moderate red shift with increasing chain length because of poor orbital coupling between adjoined π-systems. We conclude that eumelanin's characteristic ability to absorb visible light does not derive from long chains of fully reduced DHI sub-units. Our work takes an important step towards a more systematic exploration of eumelanin's structure through iterative synthesis, with the long-term goal of explaining the molecular origins of its properties.
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Affiliation(s)
- Haiyan Huang
- Department of Chemistry, McGill University 801 Sherbrooke Street West Montreal QC H3A 0B8 Canada
| | - Lilia Kinziabulatova
- Department of Chemistry and Biochemistry, The Ohio State University 100W. 18th Avenue Columbus OH 43210 USA
| | - Anju Manickoth
- Institut de Química Computacional, Departament de Química, Universitat de Girona Girona 17003 Spain
| | - Yiming Zhang
- Department of Chemistry, McGill University 801 Sherbrooke Street West Montreal QC H3A 0B8 Canada
| | - Marisa A Barilla
- Department of Chemistry and Biochemistry, The Ohio State University 100W. 18th Avenue Columbus OH 43210 USA
| | - Lluís Blancafort
- Institut de Química Computacional, Departament de Química, Universitat de Girona Girona 17003 Spain
| | - Bern Kohler
- Department of Chemistry and Biochemistry, The Ohio State University 100W. 18th Avenue Columbus OH 43210 USA
| | - Jean-Philip Lumb
- Department of Chemistry, McGill University 801 Sherbrooke Street West Montreal QC H3A 0B8 Canada
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Yin J, Wang H, Pyle D, Choi S, Liu Y, Wen J, Guest JR, Lyding JW, Dong G. Synthesis and Self-Assembly of Monodisperse Graphene Nanoribbons: Access to Submicron Architectures with Long-Range Order and Uniform Orientation. ACS NANO 2025; 19:4366-4376. [PMID: 39852765 DOI: 10.1021/acsnano.4c12313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2025]
Abstract
Fabricating organic semiconducting materials into large-scale, well-organized architectures is critical for building high-performance molecular electronics. While graphene nanoribbons (GNRs) hold enormous promise for various device applications, their assembly into a well-structured monolayer or multilayer architecture poses a substantial challenge. Here, we report the preparation of length-defined monodisperse GNRs via the integrated iterative binomial synthesis (IIBS) strategy and their self-assembly into submicrometer architectures with long-range order, uniform orientation, as well as regular layers. The use of short alkyl side chains benefits forming stable multilayers through interlocking structures. By changing the length and backbone shapes of these monodisperse GNRs, various three-dimensional assemblies, including multilayer stripes, monolayer stripes, and nanowires, can be achieved, leading to different photophysical properties and band gaps. The discovery of these intriguing self-assembly behaviors of length-defined GNRs is expected to enable various future applications.
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Affiliation(s)
- Jiangliang Yin
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Hanfei Wang
- Department of Electrical and Computer Engineering, Holonyak Micro and Nanotechnology Laboratory, University of Illinois at Urbana─Champaign, Champaign, Illinois 61801, United States
| | - Daniel Pyle
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Shinyoung Choi
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
| | - Yuzi Liu
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Jianguo Wen
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Jeffrey R Guest
- Center for Nanoscale Materials, Argonne National Laboratory, Lemont, Illinois 60439, United States
| | - Joseph W Lyding
- Department of Electrical and Computer Engineering, Holonyak Micro and Nanotechnology Laboratory, University of Illinois at Urbana─Champaign, Champaign, Illinois 61801, United States
| | - Guangbin Dong
- Department of Chemistry, University of Chicago, Chicago, Illinois 60637, United States
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Milis W, Peeters J, Erkens R, De Winter J, Gerbaux P, Koeckelberghs G. Versatile Strategy to Develop Sequence-Defined Conjugated Macromolecules: A Powerful Tool toward Tunable Optoelectronic Properties. ACS Macro Lett 2024; 13:1293-1303. [PMID: 39284131 DOI: 10.1021/acsmacrolett.4c00526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2024]
Abstract
Conjugated sequence-defined polymers represent a cutting-edge area of polymer science, merging the precision of biological macromolecules with the versatility of synthetic polymers and the unique properties of conjugated systems. While early reports focused on activation/deactivation strategies, this Letter presents the first orthogonal approach to developing sequence-defined conjugated macromolecules (CMs), incorporating a new monomer at each reaction step. In CMs, the primary monomer sequence meticulously determines the optoelectronic properties. Step-by-step, features such as structural defects, chain length, dispersity, functional groups, topology, and monomers used in the backbone are carefully considered and controlled, with optical data provided to support the necessity of sequence-defined approaches in CMs. Additionally, a pioneering and repeatable modular approach is introduced, connecting different orthogonally developed sequences. This method enhances efficiency and accelerates the synthesis process, facilitating comprehensive structure-property analyses and paving the way for tunable materials with record-breaking properties.
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Affiliation(s)
- Wout Milis
- Laboratory for Polymer Synthesis, KU Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium
| | - Janine Peeters
- Laboratory for Polymer Synthesis, KU Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium
| | - Robin Erkens
- Laboratory for Polymer Synthesis, KU Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium
| | - Julien De Winter
- Organic Synthesis and Mass Spectrometry Laboratory, Center of Innovation and Research in Materials and Polymers (CIRMAP), University of Mons, Place du Parc 23, B-700 Mons, Belgium
| | - Pascal Gerbaux
- Organic Synthesis and Mass Spectrometry Laboratory, Center of Innovation and Research in Materials and Polymers (CIRMAP), University of Mons, Place du Parc 23, B-700 Mons, Belgium
| | - Guy Koeckelberghs
- Laboratory for Polymer Synthesis, KU Leuven, Celestijnenlaan 200F, B-3001 Heverlee, Belgium
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Zhu Q, Nicolardi S, Wang Y, Liu Y, Xu P, Wang J, Zhu D, Yu B. Expeditious chemical synthesis of xylomannans disproves the proposed antifreeze activities. Natl Sci Rev 2024; 11:nwae296. [PMID: 39315280 PMCID: PMC11418650 DOI: 10.1093/nsr/nwae296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2024] [Revised: 07/23/2024] [Accepted: 08/01/2024] [Indexed: 09/25/2024] Open
Abstract
Cold-adapted species are able to generate cryoprotective proteins and glycoproteins to prevent freezing damage. The [→4)-β-D-Manp-(1→4)-β-D-Xylp-(1→] n xylomannan from the Alaska beetle Upis ceramboides was disclosed by Walters and co-workers in 2009 as the first glycan-based antifreeze agent, which was later reported to be found in diverse taxa. Here, we report the rapid synthesis of four types of xylomannans, including the proposed antifreeze xylomannan up to a 64-mer (Type I), the regioisomeric [→3)-β-D-Manp-(1→4)-β-D-Xylp-(1→] n 16-mer (Type II), the diastereomeric [→4)-β-L-Manp-(1→4)-β-D-Xylp-(1→] n 16-mer (Type III) and the block-wise [→4)-β-D-Manp-(1→] m [→4)-β-D-Xylp-(1→] n 32-mer (Type IV), by employing a strategic iterative exponential glycan growth (IEGG) process. The nuclear magnetic resonance spectral data of the alleged natural xylomannan are in accordance only to those of the block-wise Type IV glycan and none of these synthetic xylomannans has been found to be capable of inducing thermal hysteresis. These results disprove the previous reports about the natural occurrence of antifreeze xylomannans.
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Affiliation(s)
- Qian Zhu
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Simone Nicolardi
- Center for Proteomics and Metabolomics, Leiden University Medical Center, Leiden 2333ZA, The Netherlands
| | - Yuanguang Wang
- Key Laboratory of Green Printing, Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Yasong Liu
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Peng Xu
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jianjun Wang
- Key Laboratory of Green Printing, Beijing National Laboratory for Molecular Science, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China
| | - Dapeng Zhu
- Institute of Translational Medicine, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Biao Yu
- State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200032, China
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Kim MP, Kayal S, Hwang C, Bae J, Kim H, Hwang DG, Jeon MH, Seo JK, Ahn D, Lee W, Seo S, Chun JH, Yu Y, Hong SY. Iterative SuFEx approach for sequence-regulated oligosulfates and its extension to periodic copolymers. Nat Commun 2024; 15:3381. [PMID: 38643182 PMCID: PMC11032359 DOI: 10.1038/s41467-024-47567-z] [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: 11/29/2023] [Accepted: 04/05/2024] [Indexed: 04/22/2024] Open
Abstract
The synthesis of sequence-regulated oligosulfates has not yet been established due to the difficulties in precise reactivity control. In this work, we report an example of a multi-directional divergent iterative method to furnish oligosulfates based on a chain homologation approach, in which the fluorosulfate unit is regenerated. The oligosulfate sequences are determined by high resolution mass spectrometry of the hydrolyzed fragments, and polysulfate periodic copolymers are synthesized by using oligomeric bisfluorosulfates in a bi-directional fashion. The synthetic utility of this iterative ligation is demonstrated by preparing crosslinked network polymers as synthetic adhesive materials.
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Affiliation(s)
- Min Pyeong Kim
- Department of Chemistry, Department of Chemical Engineering, and Graduate School of Carbon Neutrality, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Swatilekha Kayal
- Department of Chemistry, Department of Chemical Engineering, and Graduate School of Carbon Neutrality, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Chiwon Hwang
- Center for Advanced Specialty Chemicals, Korea Research Institute of Chemical Technology (KRICT), Ulsan, 44412, Republic of Korea
| | - Jonghoon Bae
- UNIST Central Research Facility (UCRF), UNIST, Ulsan, 44919, Republic of Korea
| | - Hyunseok Kim
- Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 790-784, Republic of Korea
| | - Dong Gyu Hwang
- Department of Chemistry, Department of Chemical Engineering, and Graduate School of Carbon Neutrality, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Min Ho Jeon
- Department of Nuclear Medicine, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea
| | - Jeong Kon Seo
- UNIST Central Research Facility (UCRF), UNIST, Ulsan, 44919, Republic of Korea
| | - Dowon Ahn
- Center for Advanced Specialty Chemicals, Korea Research Institute of Chemical Technology (KRICT), Ulsan, 44412, Republic of Korea
| | - Wonjoo Lee
- Center for Advanced Specialty Chemicals, Korea Research Institute of Chemical Technology (KRICT), Ulsan, 44412, Republic of Korea
| | - Sangwon Seo
- Department of Physics and Chemistry, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, 42988, Republic of Korea
| | - Joong-Hyun Chun
- Department of Nuclear Medicine, Yonsei University College of Medicine, Seoul, 03722, Republic of Korea.
| | - Youngchang Yu
- Center for Advanced Specialty Chemicals, Korea Research Institute of Chemical Technology (KRICT), Ulsan, 44412, Republic of Korea.
| | - Sung You Hong
- Department of Chemistry, Department of Chemical Engineering, and Graduate School of Carbon Neutrality, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
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