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Jangid AK, Kim K. Phenylboronic acid-functionalized biomaterials for improved cancer immunotherapy via sialic acid targeting. Adv Colloid Interface Sci 2024; 333:103301. [PMID: 39260104 DOI: 10.1016/j.cis.2024.103301] [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: 03/16/2024] [Revised: 06/16/2024] [Accepted: 09/02/2024] [Indexed: 09/13/2024]
Abstract
Phenylboronic acid (PBA) is recognized as one of the most promising cancer cell binding modules attributed to its potential to form reversible and dynamic boronic ester covalent bonds. Exploring the advanced chemical versatility of PBA is crucial for developing new anticancer therapeutics. The presence of a specific Lewis acidic boron atom-based functional group and a Π-ring-connected ring has garnered increasing interest in the field of cancer immunotherapy. PBA-derivatized functional biomaterials can form reversible bonds with diols containing cell surface markers and proteins. This review primarily focuses on the following topics: (1) the importance and versatility of PBA, (2) different PBA derivatives with pKa values, (3) specific key features of PBA-mediated biomaterials, and (4) cell surface activity for cancer immunotherapy applications. Specific key features of PBA-mediated materials, including sensing, bioadhesion, and gelation, along with important synthesis strategies, are highlighted. The utilization of PBA-mediated biomaterials for cancer immunotherapy, especially the role of PBA-based nanoparticles and PBA-mediated cell-based therapeutics, is also discussed. Finally, a perspective on future research based on PBA-biomaterials for immunotherapy applications is presented.
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Affiliation(s)
- Ashok Kumar Jangid
- Department of Chemical & Biochemical Engineering, College of Engineering, Dongguk University, Seoul, South Korea
| | - Kyobum Kim
- Department of Chemical & Biochemical Engineering, College of Engineering, Dongguk University, Seoul, South Korea.
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2
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Doraghi F, Taherkhani AM, Hosseinifar T, Rashidi Ranjbar P, Larijani B, Mahdavi M. Transition metal-catalyzed transformations of 2-formylarylboronic acids. Org Biomol Chem 2024; 22:6905-6921. [PMID: 39140460 DOI: 10.1039/d4ob01024h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/15/2024]
Abstract
2-Formylarylboronic acids are easily available precursors in organic chemistry. Different types of transition metal catalysts, such as Pd(0), Pd(II), Rh(I), Ir(I), Ni(II), Cu(I), Cu(II), and Co(II), can efficiently catalyze coupling reactions of 2-formylarylboronic acids with other organic reactants. In this review, we describe the synthesis of a diverse range of carbocyclic and heterocyclic compounds, as well as acyclic compounds, via transition metal-catalyzed reactions of 2-formylarylboronic acids over the past two decades.
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Affiliation(s)
- Fatemeh Doraghi
- Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.
| | - Amir Mohammad Taherkhani
- Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.
| | - Tolou Hosseinifar
- School of Chemistry, College of Science, University of Tehran, Tehran, Iran
| | | | - Bagher Larijani
- Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.
| | - Mohammad Mahdavi
- Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.
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3
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Adamczyk-Woźniak A, Tarkowska M, Lazar Z, Kaczorowska E, Madura ID, Maria Dąbrowska A, Lipok J, Wieczorek D. Synthesis, structure, properties and antimicrobial activity of para trifluoromethyl phenylboronic derivatives. Bioorg Chem 2021; 119:105560. [PMID: 34942467 DOI: 10.1016/j.bioorg.2021.105560] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/15/2021] [Accepted: 12/11/2021] [Indexed: 01/16/2023]
Abstract
The [2-formyl-4-(trifluoromethyl)phenyl]boronic acid as well as its benzoxaborole and bis(benzoxaborole) derivatives were obtained and their properties studied. The 2-formyl compound displays an unusual structure in the crystalline state, with a significant twist of the boronic group, whereas in DMSO solution it tautomerizes with formation of a cyclic isomer. All the studied compounds exhibit relatively high acidity as well as a reasonable antimicrobial activity. Docking studies showed interactions of all the investigated compounds with the binding pocket of Candida albicans LeuRS. High activity against Bacillus cereus was determined for the 2-formyl compound as well as for the novel bis(benzoxaborole), whereas the studied benzoxaborole shows high antifungal action with MIC values equal to 7.8and 3.9 μg/mL against C. albicans and A. niger respectively. None of the studied compounds exhibits reasonable activity against E. coli.
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Affiliation(s)
| | - Magdalena Tarkowska
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664 , Poland
| | - Zofia Lazar
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664 , Poland
| | - Ewa Kaczorowska
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664 , Poland
| | - Izabela D Madura
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664 , Poland
| | - Anna Maria Dąbrowska
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664 , Poland
| | - Jacek Lipok
- Faculty of Chemistry, University of Opole, Oleska 48, Opole 45-052 , Poland
| | - Dorota Wieczorek
- Faculty of Chemistry, University of Opole, Oleska 48, Opole 45-052 , Poland
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4
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Vibrational Properties of Benzoxaboroles and Their Interactions with Candida albicans’ LeuRS. Symmetry (Basel) 2021. [DOI: 10.3390/sym13101845] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Benzoxaboroles have emerged over the past decade mainly due to their growing medicinal importance. Regarding the wide application of IR spectroscopy in the pharmaceutical industry, the vibrational properties of over a dozen of benzoxaboroles were described, based on results of DFT calculations as well as IR and Raman spectra measurements. Investigated series of compounds included the currently available antifungal drug (Tavaborole, AN2690) as well as its derivatives. An intense and well-isolated band corresponding to the B-OH group stretching vibrations was present in all experimental IR spectra in the range of 1446–1414 cm−1 and can be considered as characteristic for benzoxaboroles. The vibrational properties of benzoxaboroles are shown to be affected by the formation of intramolecular as well as intermolecular hydrogen bonds, which should also influence the interactions of benzoxaboroles with biomolecules and impact on their biological functions. Docking studies of the benzoxaboroles’ adenosine monophosphate (AMP) spiroboronates into the Candida albicans leucyl-RS synthetase binding pocket showed that the introduction of an amine substituent has a strong influence on their binding. The determined values of inhibition constants manifest high potential of some of the investigated molecules as possible inhibitors of that enzyme.
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5
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Borys KM, Wieczorek D, Tarkowska M, Jankowska A, Lipok J, Adamczyk-Woźniak A. Mechanochemical synthesis of antifungal bis(benzoxaboroles). RSC Adv 2020; 10:37187-37193. [PMID: 35521242 PMCID: PMC9057134 DOI: 10.1039/d0ra07767d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/15/2020] [Indexed: 11/21/2022] Open
Abstract
Several piperazine bis(benzoxaboroles) have been obtained both in solution as well as in the solid state. The environmentally friendly mechanochemical approach – hitherto not applied for the preparation of benzoxaboroles – was particularly beneficial in the case of two products afforded in low yields in solution. The in vitro studies showed high potential of the studied bis(fluorobenzoxaboroles) as antifungal agents, highlighting also the influence of the fluorine substituent position on their microbiological activity. The highest activity against A. niger, A. terreus, P. ochrochloron, C. tenuis and C. albicans was displayed by the analogue of the known benzoxaborole antifungal drug Kerydin® (Tavaborole). Several piperazine bis(benzoxaboroles) have been obtained mechanochemically – two of them have been shown to display high antifungal activity.![]()
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Affiliation(s)
- Krzysztof M Borys
- Faculty of Chemistry, Warsaw University of Technology Noakowskiego 3 00-664 Warsaw Poland
| | - Dorota Wieczorek
- Faculty of Chemistry, University of Opole Oleska 48 45-052 Opole Poland
| | - Magdalena Tarkowska
- Faculty of Chemistry, Warsaw University of Technology Noakowskiego 3 00-664 Warsaw Poland
| | - Agnieszka Jankowska
- Faculty of Chemistry, Warsaw University of Technology Noakowskiego 3 00-664 Warsaw Poland
| | - Jacek Lipok
- Faculty of Chemistry, University of Opole Oleska 48 45-052 Opole Poland
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6
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Adamczyk-Woźniak A, Sporzyński A. The influence of ortho-substituents on the properties of phenylboronic acids. J Organomet Chem 2020. [DOI: 10.1016/j.jorganchem.2020.121202] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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5-Trifluoromethyl-2-formylphenylboronic Acid. Molecules 2020; 25:molecules25040799. [PMID: 32059517 PMCID: PMC7070739 DOI: 10.3390/molecules25040799] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/05/2020] [Accepted: 02/06/2020] [Indexed: 02/05/2023] Open
Abstract
2-Formylphenylboronic acids display many interesting features, not only from synthetic but also from an application as well as structural points of view. 5-Trifluoromethyl-2-formyl phenylboronic acid has been synthesized and characterized in terms of its structure and properties. The presence of an electron-withdrawing substituent results in a considerable rise in the acidity in comparison with its analogues. In some solutions, the title compound isomerizes with formation of the corresponding 3-hydroxybenzoxaborole. Taking into account the probable mechanism of antifungal action of benzoxaboroles, which blocks the cytoplasmic leucyl-tRNA synthetase (LeuRS) of the microorganism, docking studies with the active site of the enzymes have been carried out. It showed possible binding of the cyclic isomer into the binding pocket of Candida albicans LeuRS, similar to that of the recently approved benzoxaborole antifungal drug (AN2690, Tavaborole, Kerydin). In case of Escherichia coli LeuRS, the opened isomer displays a much higher inhibition constant in comparison with the cyclic one. The antimicrobial activity of the title compound was also investigated in vitro, showing moderate action against Candida albicans. The compound reveals higher activity against Aspergillus niger as well as bacteria such as Escherichia coli and Bacillus cereus. In case of Bacillus cereus, the determined Minimum Inhibitory Concentration (MIC) value is lower than that of AN2690 (Tavaborole). The results confirm potential of 2-formylphenylboronic acids as antibacterial agents and give a hint of their possible mechanism of action.
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Larcher A, Nocentini A, Supuran CT, Winum JY, van der Lee A, Vasseur JJ, Laurencin D, Smietana M. Bis-benzoxaboroles: Design, Synthesis, and Biological Evaluation as Carbonic Anhydrase Inhibitors. ACS Med Chem Lett 2019; 10:1205-1210. [PMID: 31413806 DOI: 10.1021/acsmedchemlett.9b00252] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 07/11/2019] [Indexed: 12/25/2022] Open
Abstract
The synthesis, characterization, and biological evaluation of a series of compounds incorporating two or three benzoxaborole moieties is reported. Three different synthetic strategies were used to explore within this series as much chemical space as possible, all starting from the 6-aminobenzoxaborole reagent: amide coupling, imine bond formation, and squarate coupling. Eleven new compounds were isolated in pure form, and single crystals were obtained for two of them. These compounds were then evaluated as carbonic anhydrase inhibitors against the cytosolic hCA I and II and the transmembrane hCA IV, IX, and XII isoforms. While the benzoxaborole scaffold has been recently introduced as a new chemotype for carbonic anhydrase inhibition, these new multivalent derivatives exhibited superior inhibitory activity against the tumor-associated isoform hCA IX. In particular, compared to monovalent 6-aminobenzoxaborole (K I = 813 nM) and 6-carboxybenzoxaborole (K I = 400 nM), derivative 2h characterized by a glutamic acid structural core and two benzoxaborole moieties was found to be more potent (K I = 64 nM) and more selective over human hCA II.
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Affiliation(s)
- Adèle Larcher
- Institut Charles Gerhardt de Montpellier (ICGM), Université de Montpellier, UMR 5253, CNRS, ENSCM, Place E. Bataillon, CC1701, 34095 Montpellier Cedex 05, France
- Institut des Biomolécules Max Mousseron (IBMM), Université de Montpellier, UMR
5247, CNRS, ENSCM, Place E. Bataillon, CC 1704, 34095 Montpellier Cedex 05, France
| | - Alessio Nocentini
- NEUROFARBA Dept., University of Florence, Sezione di Scienze Farmaceutiche, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Claudiu T. Supuran
- NEUROFARBA Dept., University of Florence, Sezione di Scienze Farmaceutiche, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Jean-Yves Winum
- Institut des Biomolécules Max Mousseron (IBMM), Université de Montpellier, UMR
5247, CNRS, ENSCM, Place E. Bataillon, CC 1704, 34095 Montpellier Cedex 05, France
| | - Arie van der Lee
- Institut Européen des Membranes, Université
de Montpellier, UMR 5632 CNRS ENSCM, 34095 Montpellier, Cedex 05, France
| | - Jean-Jacques Vasseur
- Institut des Biomolécules Max Mousseron (IBMM), Université de Montpellier, UMR
5247, CNRS, ENSCM, Place E. Bataillon, CC 1704, 34095 Montpellier Cedex 05, France
| | - Danielle Laurencin
- Institut Charles Gerhardt de Montpellier (ICGM), Université de Montpellier, UMR 5253, CNRS, ENSCM, Place E. Bataillon, CC1701, 34095 Montpellier Cedex 05, France
| | - Michael Smietana
- Institut des Biomolécules Max Mousseron (IBMM), Université de Montpellier, UMR
5247, CNRS, ENSCM, Place E. Bataillon, CC 1704, 34095 Montpellier Cedex 05, France
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9
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Borys KM, Wieczorek D, Pecura K, Lipok J, Adamczyk-Woźniak A. Antifungal activity and tautomeric cyclization equilibria of formylphenylboronic acids. Bioorg Chem 2019; 91:103081. [PMID: 31445482 DOI: 10.1016/j.bioorg.2019.103081] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 05/30/2019] [Accepted: 06/19/2019] [Indexed: 12/20/2022]
Abstract
2-Formylphenylboronic acid and four isomeric fluoro-2-formylphenylboronic acids have been found active against a series of fungal strains: Aspergillus, Fusarium, Penicillium and Candida. The level of antifungal activity was evaluated by agar diffusion tests as well as the determination of minimum inhibitory concentrations (MICs) by serial dilution method. Among the tested compounds, 4-fluoro-2-formylphenylboronic acid - an analogue of the known antifungal drug Tavaborole (AN2690) - proved to be the most potent antifungal agent. The tautomeric equilibrium leading to the formation of 3-hydroxybenzoxaboroles as well as the position of the fluorine substituent were revealed to play a crucial role in the observed activity.
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Affiliation(s)
- Krzysztof M Borys
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Dorota Wieczorek
- Faculty of Chemistry, Opole University, Oleska 48, 45-052 Opole, Poland
| | - Kamila Pecura
- Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland
| | - Jacek Lipok
- Faculty of Chemistry, Opole University, Oleska 48, 45-052 Opole, Poland
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11
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Psurski M, Łupicka-Słowik A, Adamczyk-Woźniak A, Wietrzyk J, Sporzyński A. Discovering simple phenylboronic acid and benzoxaborole derivatives for experimental oncology - phase cycle-specific inducers of apoptosis in A2780 ovarian cancer cells. Invest New Drugs 2018; 37:35-46. [PMID: 29779163 PMCID: PMC6510839 DOI: 10.1007/s10637-018-0611-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 05/11/2018] [Indexed: 12/13/2022]
Abstract
Objective The aim of the study was to evaluate the antiproliferative potential of simple phenylboronic acid and benzoxaborole derivatives as well as to provide preliminary insight into their mode of action in cancer cells in vitro. Methods The antiproliferative activity was assessed in five diverse cancer cell lines via the SRB method (sulforhodamine B) or MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) method after 72 h of treatment. Further studies of the mechanism of action consisted of the influence of the compounds on cell cycle progression and apoptosis induction, which was assessed by flow cytometry, caspase-3 enzymatic activity, fluorescence microscopy and western blot analysis. Results A clear structure-activity relationship was observed for both groups of compounds with several representatives evaluated as highly active antiproliferative agents with low micromolar [Formula: see text] values. 2-Fluoro-6-formylphenylboronic acid (18) and 3-morpholino-5-fluorobenzoxaborole (27) exhibited strong cell cycle arrest induction in G2/M associated with caspase-3 activation in an A2780 ovarian cancer cell line. These events were accompanied by a mitotic catastrophe cell morphology and an increased percentage of aneuploid and tetraploid cells. Further experiments indicated that the compounds were phase cycle-specific agents since cells co-treated with hydroxyurea were less sensitive. The observed cell cycle arrest resulted from significant p21 accumulation and was associated neither with cyclin B1 nor β-tubulin degradation. Conclusion Phenylboronic acid and benzoxaborole derivatives were found to be highly promising antiproliferative and proapoptotic compounds with a cell cycle-specific mode of action. The presented data support their candidacy for further studies as a novel class of potential anticancer agents.
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Affiliation(s)
- Mateusz Psurski
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 12 Weigla St, 53114, Wrocław, Poland.
| | - Agnieszka Łupicka-Słowik
- Department of Medicinal Chemistry and Microbiology, Wrocław University of Science and Technology, 29 Wybrzeże Wyspiańskiego St, 50370, Wrocław, Poland
| | | | - Joanna Wietrzyk
- Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, 12 Weigla St, 53114, Wrocław, Poland
| | - Andrzej Sporzyński
- Faculty of Chemistry, Warsaw University of Technology, 3 Noakowskiego St, 00664, Warsaw, Poland
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12
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Larcher A, Lebrun A, Smietana M, Laurencin D. A multinuclear NMR perspective on the complexation between bisboronic acids and bisbenzoxaboroles with cis-diols. NEW J CHEM 2018. [DOI: 10.1039/c7nj04143h] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A new way of using solution NMR (especially 19F NMR) to study organoboron molecule/cis-diol equilibria is presented.
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Affiliation(s)
- Adèle Larcher
- Institut Charles Gerhardt de Montpellier (ICGM)
- UMR 5253
- CNRS
- Université de Montpellier
- ENSCM
| | - Aurélien Lebrun
- Institut des Biomolécules Max Mousseron (IBMM)
- UMR 5247
- CNRS
- Université de Montpellier
- ENSCM
| | - Michael Smietana
- Institut des Biomolécules Max Mousseron (IBMM)
- UMR 5247
- CNRS
- Université de Montpellier
- ENSCM
| | - Danielle Laurencin
- Institut Charles Gerhardt de Montpellier (ICGM)
- UMR 5253
- CNRS
- Université de Montpellier
- ENSCM
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13
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Kowalska K, Adamczyk-Woźniak A, Gajowiec P, Gierczyk B, Kaczorowska E, Popenda Ł, Schroeder G, Sikorski A, Sporzyński A. Fluoro-substituted 2-formylphenylboronic acids: Structures, properties and tautomeric equilibria. J Fluor Chem 2016. [DOI: 10.1016/j.jfluchem.2016.05.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Czerwińska K, Madura ID, Zachara J. Geometry of trigonal boron coordination sphere in boronic acids derivatives - a bond-valence vector model approach. ACTA CRYSTALLOGRAPHICA SECTION B, STRUCTURAL SCIENCE, CRYSTAL ENGINEERING AND MATERIALS 2016; 72:241-248. [PMID: 27048726 DOI: 10.1107/s2052520616002262] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/05/2016] [Indexed: 06/05/2023]
Abstract
The systematic analysis of the geometry of three-coordinate boron in boronic acid derivatives with a common [CBO2] skeleton is presented. The study is based on the bond-valence vector (BVV) model [Zachara (2007). Inorg. Chem. 46, 9760-9767], a simple tool for the identification and quantitative estimation of both steric and electronic factors causing deformations of the coordination sphere. The empirical bond-valence (BV) parameters in the exponential equation [Brown & Altermatt (1985). Acta Cryst. B41, 244-247] rij and b, for B-O and B-C bonds were determined using data deposited in the Cambridge Structural Database. The values obtained amount to rBO = 1.364 Å, bBO = 0.37 Å, rBC = 1.569 Å, bBC = 0.28 Å, and they were further used in the calculation of BVV lengths. The values of the resultant BVV were less than 0.10 v.u. for 95% of the set comprising 897 [CBO2] fragments. Analysis of the distribution of BVV components allowed for the description of subtle in- and out-of plane deviations from the `ideal' (sp(2)) geometry of boron coordination sphere. The distortions specific for distinct groups of compounds such as boronic acids, cyclic and acyclic esters, benzoxaboroles and hemiesters were revealed. In cyclic esters the direction of strains was found to be controlled by the ring size effect. It was shown that the syn or anti location of substituents on O atoms is decisive for the deformations direction for both acids and acyclic esters. The greatest strains were observed in the case of benzoxaboroles which showed the highest deviation from the zero value of the resultant BVV. The out-of-plane distortions, described by the vz component of the resultant BVV, were ascertained to be useful in the identification of weak secondary interactions on the fourth coordination site of the boron centre.
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Affiliation(s)
- Karolina Czerwińska
- Department of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664, Poland
| | - Izabela D Madura
- Department of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664, Poland
| | - Janusz Zachara
- Department of Chemistry, Warsaw University of Technology, Noakowskiego 3, Warsaw 00-664, Poland
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