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Wang M, Wang Y. Advances for Triangular and Sandwich-Shaped All-Metal Aromatics. Molecules 2024; 29:763. [PMID: 38398515 PMCID: PMC10892378 DOI: 10.3390/molecules29040763] [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: 12/26/2023] [Revised: 01/19/2024] [Accepted: 01/26/2024] [Indexed: 02/25/2024] Open
Abstract
Much experimental work has been contributed to all-metal σ, π and δ-aromaticity among transition metals, semimetallics and other metals in the past two decades. Before our focused investigations on the properties of triangular and sandwich-shaped all-metal aromatics, A. I. Boldyrev presented general discussions on the concepts of all-metal σ-aromaticity and σ-antiaromaticity for metallo-clusters. Schleyer illustrated that Nucleus-Independent Chemical Shifts (NICS) were among the most authoritative criteria for aromaticity. Ugalde discussed the earlier developments of all-metal aromatic compounds with all possible shapes. Besides the theoretical predictions, many stable all-metal aromatic trinuclear clusters have been isolated as the metallic analogues of either the σ-aromatic molecule's [H3]+ ion or the π-aromatic molecule's [C3H3]+ ion. Different from Hoffman's opinion on all-metal aromaticity, triangular all-metal aromatics were found to hold great potential in applications in coordination chemistry, catalysis, and material science. Triangular all-metal aromatics, which were theoretically proved to conform to the Hückel (4n + 2) rule and possess the smallest aromatic ring, could also play roles as stable ligands during the formation of all-metal sandwiches. The triangular and sandwich-shaped all-metal aromatics have not yet been specifically summarized despite their diversity of existence, puissant developments and various interesting applications. These findings are different from the public opinion that all-metal aromatics would be limited to further applications due to their overstated difficulties in synthesis and uncertain stabilities. Our review will specifically focus on the summarization of theoretical predictions, feasible syntheses and isolations, and multiple applications of triangular and sandwich shaped all-metal aromatics. The appropriateness and necessities of this review will emphasize and disseminate their importance and applications forcefully and in a timely manner.
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Affiliation(s)
| | - Yanlan Wang
- Department of Chemistry and Chemical Engineering, Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, Liaocheng University, Liaocheng 252059, China;
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Grewelinger P, Wiesmeier T, Präsang C, Morgenstern B, Scheschkewitz D. Diboriranide σ-Complexes of d- and p-Block Metals. Angew Chem Int Ed Engl 2023; 62:e202308678. [PMID: 37522813 DOI: 10.1002/anie.202308678] [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: 06/20/2023] [Revised: 07/28/2023] [Accepted: 07/31/2023] [Indexed: 08/01/2023]
Abstract
Diboriranides are the smallest conceivable monoanionic aromatic cycles, yet only limited examples have been reported and their reactivity and complexation behavior remain completely unexplored. We report a straightforward synthesis of the first peraryl diboriranide c-(DurB)2 CPh- as its lithium salt in three steps via the corresponding non-classical diborirane from a readily available 1,2-dichlorodiborane(4) (Dur=2,3,5,6-tetramethylphenyl). With the preparation and complete characterization of representative complexes with tin, copper, gold and zinc, we demonstrate the strong preference of the diboriranide for σ-type coordination modes towards main group and transition metal centers under unperturbed retention of the three-membered B2 C-ring's 2e- π-system.
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Affiliation(s)
- Philipp Grewelinger
- Krupp-Chair for General and Inorganic Chemistry, Saarland University, 66123, Saarbrücken, Germany
| | - Tim Wiesmeier
- Krupp-Chair for General and Inorganic Chemistry, Saarland University, 66123, Saarbrücken, Germany
| | - Carsten Präsang
- Krupp-Chair for General and Inorganic Chemistry, Saarland University, 66123, Saarbrücken, Germany
| | - Bernd Morgenstern
- Service Center X-ray diffraction, Saarland University, 66123, Saarbrücken, Germany
| | - David Scheschkewitz
- Krupp-Chair for General and Inorganic Chemistry, Saarland University, 66123, Saarbrücken, Germany
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Coburger P, Schweinzer C, Li Z, Grützmacher H. Reversible Single Electron Redox Steps Convert Polycycles with a C 3 P 3 Core to a Planar Triphosphinine. Angew Chem Int Ed Engl 2023; 62:e202214548. [PMID: 36688727 DOI: 10.1002/anie.202214548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 12/18/2022] [Accepted: 01/23/2023] [Indexed: 01/24/2023]
Abstract
Reaction of the imidazolium-stabilized diphosphete-diide IDP with trityl phosphaalkyne affords a mixture which contains the molecules 1 a and 1 b with a central C3 P3 core, which formally carries a two-fold negative charge. In order to avoid the formation of an antiaromatic 8π electron system within a conjugated dianionic six-membered [C3 P3 ]2- ring, 1 a adopts a bicyclic [3.1.0] and 1 b a tricyclic [2.2.0.0] structure which are in a dynamic equilibrium. 1 a, b can be reversibly oxidized to a triphosphinine dication [5]2+ with a central flat aromatic six-membered C3 P3 ring. This two-electron redox reaction occurs in two single-electron transfer steps via the 7π-radical cation [4]⋅+ , which could also be isolated and fully characterized. The profound reversible structural change observed for the two-electron redox couple [5]2+ /1 a, b is in sharp contrast to the C6 H6 /[C6 H6 ]2- couple, which undergoes only a modest structural deformation.
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Affiliation(s)
- Peter Coburger
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland
| | - Clara Schweinzer
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland
| | - Zhongshu Li
- Lehn Institute of Functional Materials (LIFM), School of Chemistry, Sun Yat-Sen University, 510275, Guangzhou, China.,State Key Laboratory of Elemento-Organic Chemistry, Nankai University, 30071, Tianjin, China
| | - Hansjörg Grützmacher
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 1-5/10, 8093, Zürich, Switzerland
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Huang X, Jin L, Deng H, Wu D, Shen QK, Quan ZS, Zhang CH, Guo HY. Research and Development of Natural Product Tanshinone I: Pharmacology, Total Synthesis, and Structure Modifications. Front Pharmacol 2022; 13:920411. [PMID: 35903340 PMCID: PMC9315943 DOI: 10.3389/fphar.2022.920411] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 06/08/2022] [Indexed: 11/13/2022] Open
Abstract
Salvia miltiorrhiza (S. miltiorrhiza), which has been used for thousands of years to treat cardiovascular diseases, is a well-known Chinese medicinal plant. The fat-soluble tanshinones in S. miltiorrhiza are important biologically active ingredients including tanshinone I, tanshinone IIA, dihydrotanshinone, and cryptotanshinone. Tanshinone I, a natural diterpenoid quinone compound widely used in traditional Chinese medicine, has a wide range of biological effects including anti-cancer, antioxidant, neuroprotective, and anti-inflammatory activities. To further improve its potency, water solubility, and bioavailability, tanshinone I can be used as a platform for drug discovery to generate high-quality drug candidates with unique targets and enhanced drug properties. Numerous derivatives of tanshinone I have been developed and have contributed to major advances in the identification of new drugs to treat human cancers and other diseases and in the study of related molecular mechanisms. This review focuses on the structural modification, total synthesis, and pharmacology of tanshinone I. We hope that this review will help understanding the research progress in this field and provide constructive suggestions for further research on tanshinone I.
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Affiliation(s)
| | | | | | | | | | | | | | - Hong-Yan Guo
- *Correspondence: Chang-hao Zhang, ; Hong-Yan Guo,
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Neogi I, Szpilman AM. Synthesis and Reactions of Borazines. SYNTHESIS-STUTTGART 2022. [DOI: 10.1055/a-1684-0031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
AbstractGiven the wide array of current applications of borazine-based materials, synthetic access to these compounds is of importance. This review summarizes the many ways of preparing borazines and its carbo-substituted analogues. In addition, the functionalization of borazines is covered. The synthesis of molecules incorporating more than one borazine units as well as aspects of unsymmetrically substituted borazines are not included. The literature has been covered comprehensively until the end of 2020.1 Introduction: Structure and Properties of Borazine2 Synthesis of Parent Borazine3 Synthesis of N-Substituted Borazines4 Synthesis of B-Halo/B-Halo-N-Substituted Borazines5 Synthesis of B-Substituted Borazines6 Synthesis of Polycyclic Borazines Containing One Borazine Ring7 Modifications or Hydrolysis of the Borazine Ring8 Borazine Metal Complexes9 Outlook and Conclusion
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Affiliation(s)
- Ishita Neogi
- Photoscience and Photonics Section, Chemical Science and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology (CSIR-NIIST)
- Academy of Scientific and Innovative Research (AcSIR)
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Zhu D, Guo L, Li J, Cui C. From BN-Naphthalenes to Benzoborole Dianions. Chemistry 2021; 27:9514-9518. [PMID: 33909296 DOI: 10.1002/chem.202101178] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Indexed: 01/02/2023]
Abstract
The synthesis of benzoborole dianions by alkali metal reduction of BN-naphthalene derivatives via a ring-contraction strategy has been developed. Reduction of 1-alkynyl 2,1-benzazaborine 1 a in Et2 O led to the elimination of alkynyllithium with the formation of 1-amino-1-benzoborole trilithium salt 2 a, whereas reduction of 1-phenyl 2,1-benzazaborine 1 c in THF yielded 1-phenyl-1-benzoborole dilithium salt 2 c with the elimination of ArNHLi. The trilithium and dilithium salts 2 a and 2 c have been fully characterized. Treatment of trilithium salt 2 a with Et3 NHCl led to the selective protonation of the amino lithium to afford the dilithium salt 2 aH, which could be cleanly oxidized to 1-amino-1-benzoborole 3 in an excellent yield. Reaction of 1-phenyl-1-benzoborole dilithium salt 2 c with MeI yielded the lithium borate 4 c, which is luminescent both in solution and in the solid state.
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Affiliation(s)
- Dezhao Zhu
- State Key Laboratory of Elemento-Organic Chemistry and College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Lulu Guo
- State Key Laboratory of Elemento-Organic Chemistry and College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Jianfeng Li
- State Key Laboratory of Elemento-Organic Chemistry and College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Chunming Cui
- State Key Laboratory of Elemento-Organic Chemistry and College of Chemistry, Nankai University, Tianjin, 300071, China
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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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