1
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Kumawat LK, Wynne C, Cappello E, Fisher P, Brennan LE, Strofaldi A, McManus JJ, Hawes CS, Jolliffe KA, Gunnlaugsson T, Elmes RBP. Squaramide-Based Self-Associating Amphiphiles for Anion Recognition. Chempluschem 2021; 86:1058-1068. [PMID: 34351081 PMCID: PMC8456826 DOI: 10.1002/cplu.202100275] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 07/08/2021] [Indexed: 12/03/2022]
Abstract
The synthesis and characterisation of two novel self-assembled amphiphiles (SSAs) SQS-1 and SQS-2 are reported. Both compounds, based on the squaramide motif, were fully soluble in a range of solvents and were shown to undergo self-assembly through a range of physical techniques. Self-assembly was shown to favour the formation of crystalline domains on the nanoscale but also fibrillar film formation, as suggested by SEM analysis. Moreover, both SQS-1 and SQS-2 were capable of anion recognition in DMSO solution as demonstrated using 1 H NMR and UV/Vis absorption spectroscopy, but displayed lower binding affinities for various anions when compared against other squaramide based receptors. In more competitive solvent mixtures SQS-1 gave rise to a colourimetric response in the presence of HPO42- that was clearly visible to the naked eye. We anticipate that the observed response is due to the basic nature of the HPO42- anion when compared against other biologically relevant anions.
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Affiliation(s)
- Lokesh K. Kumawat
- Department of ChemistryMaynooth UniversityNational University of IrelandMaynoothCo. KildareIreland
| | - Conor Wynne
- Department of ChemistryMaynooth UniversityNational University of IrelandMaynoothCo. KildareIreland
- Synthesis and Solid State Pharmaceutical Centre (SSPC)Ireland
| | - Emanuele Cappello
- School of ChemistryTrinity Biomedical Sciences Institute (TBSI)Trinity College DublinThe University of DublinDublin 2Ireland
| | - Peter Fisher
- Department of ChemistryMaynooth UniversityNational University of IrelandMaynoothCo. KildareIreland
| | - Luke E. Brennan
- Department of ChemistryMaynooth UniversityNational University of IrelandMaynoothCo. KildareIreland
| | - Alessandro Strofaldi
- Department of ChemistryMaynooth UniversityNational University of IrelandMaynoothCo. KildareIreland
| | - Jennifer J. McManus
- Department of ChemistryMaynooth UniversityNational University of IrelandMaynoothCo. KildareIreland
- HH Wills Physics LaboratoryUniversity of BristolTyndall AvenueBristolBS8 1TLUnited Kingdom
- Synthesis and Solid State Pharmaceutical Centre (SSPC)Ireland
| | - Chris S. Hawes
- School of Chemical and Physical SciencesKeele UniversityKeeleST5 5BGUnited Kingdom
| | | | - Thorfinnur Gunnlaugsson
- School of ChemistryTrinity Biomedical Sciences Institute (TBSI)Trinity College DublinThe University of DublinDublin 2Ireland
- Synthesis and Solid State Pharmaceutical Centre (SSPC)Ireland
| | - Robert B. P. Elmes
- Department of ChemistryMaynooth UniversityNational University of IrelandMaynoothCo. KildareIreland
- Kathleen Lonsdale Institute for Human Health ResearchMaynooth UniversityMaynoothCo. KildareIreland
- Synthesis and Solid State Pharmaceutical Centre (SSPC)Ireland
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2
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Arimura M, Tanaka K, Kanda M, Urushibara K, Fujii S, Katagiri K, Azumaya I, Kagechika H, Tanatani A. Construction of Aromatic Multilayered Structures Based on the Conformational Properties of N,N'-Dimethylated Squaramide. Chempluschem 2021; 86:198-205. [PMID: 33508169 DOI: 10.1002/cplu.202000678] [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: 10/13/2020] [Revised: 01/12/2021] [Indexed: 11/10/2022]
Abstract
Squaramide is a highly rigid four-membered ring system bearing two carbonyl and two amino groups, and its derivatives have found applications in many fields. We synthesized several N,N'-dimethylated oligosquaramides linked via phenyl groups, and investigated their structures in the crystalline state and in solution. Compounds 1, 2 (bissquaramides), and 13 (trissquaramide) exist as folded structures in the crystalline state, in which the aromatic rings are located in a face-to-face position. In their multilayered structures, the benzene rings are more nearly parallel and are closer to each other, compared with those in N,N'-dimethylated oligoureas. Individual molecules of meta-connected compounds 2 and 13 show a helical structure with all-R or all-S axis chirality, but afford only racemic crystals. The NMR spectra indicated that these compounds retain well-ordered folded structures in solution. The unique steric and electronic properties of N,N'-dimethylated squaramide can provide access to novel functional aromatic multilayered and helical foldamers.
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Affiliation(s)
- Maiko Arimura
- Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo, 112-8610, Japan
| | - Kimiko Tanaka
- Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo, 112-8610, Japan
| | - Midori Kanda
- Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo, 112-8610, Japan
| | - Ko Urushibara
- Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo, 112-8610, Japan
| | - Shinya Fujii
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo, 101-0062, Japan
| | - Kosuke Katagiri
- Department of Chemistry, Faculty of Science and Engineering, Konan University, 8-9-1 Okamoto, Higashinada, Kobe, Hyogo, 658-8501, Japan
| | - Isao Azumaya
- Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba, 274-8510, Japan
| | - Hiroyuki Kagechika
- Institute of Biomaterials and Bioengineering, Tokyo Medical and Dental University (TMDU), 2-3-10 Kanda-Surugadai, Chiyoda-ku, Tokyo, 101-0062, Japan
| | - Aya Tanatani
- Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo, 112-8610, Japan
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3
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Qin L, Wright JR, Lane JDE, Berry SN, Elmes RBP, Jolliffe KA. Receptors for sulfate that function across a wide pH range in mixed aqueous-DMSO media. Chem Commun (Camb) 2019; 55:12312-12315. [PMID: 31559993 DOI: 10.1039/c9cc06812k] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Water soluble squaramide macrocycles (MSQs) display high sulfate binding affinities in aqueous DMSO mixtures. The introduction of pyridine spacers into the macrocycles resulted in increased sulfate binding affinity in comparison to compounds with benzene spacers. [3]MSQ 6 was found to be a selective ligand for SO42- in highly competitive conditions and over a wide pH range (3.2-14).
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Affiliation(s)
- Lei Qin
- School of Chemistry, The University of Sydney, NSW 2006, Australia.
| | - James R Wright
- School of Chemistry, The University of Sydney, NSW 2006, Australia.
| | - Jakob D E Lane
- School of Chemistry, The University of Sydney, NSW 2006, Australia.
| | - Stuart N Berry
- School of Chemistry, The University of Sydney, NSW 2006, Australia.
| | - Robert B P Elmes
- School of Chemistry, The University of Sydney, NSW 2006, Australia. and Department of Chemistry, Maynooth University, National University of Ireland, Maynooth, Co., Kildare, Ireland
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4
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Spontaneous chiral resolution of N,N′-diarylsquaramides: Formation of various types of one-handed helical networks during crystallization. Tetrahedron 2019. [DOI: 10.1016/j.tet.2019.03.049] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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5
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Esteves CV, Costa J, Esteban-Gómez D, Lamosa P, Bernard H, Platas-Iglesias C, Tripier R, Delgado R. Phosphate and polyphosphate anion recognition by a dinuclear copper(ii) complex of an unsymmetrical squaramide. Dalton Trans 2019; 48:10104-10115. [DOI: 10.1039/c9dt01434a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
At pH = 7.4, ATP4− is selectively removed from water containing PhPO42−, Haep−, AMP2− and ADP3− by the studied squaramide-based dicopper(ii) complex.
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Affiliation(s)
- Catarina V. Esteves
- Instituto de Tecnologia Química e Biológica António Xavier
- Universidade Nova de Lisboa
- 2780-157 Oeiras
- Portugal
| | - Judite Costa
- Research Institute for Medicines (iMed.ULisboa)
- Faculty of Pharmacy
- Universidade de Lisboa
- 1649-003 Lisboa
- Portugal
| | - David Esteban-Gómez
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química
- Universidade da Coruña
- 15008 A Coruña
- Spain
| | - Pedro Lamosa
- Instituto de Tecnologia Química e Biológica António Xavier
- Universidade Nova de Lisboa
- 2780-157 Oeiras
- Portugal
| | - Hélène Bernard
- Université de Brest
- UMR-CNRS 6521
- IBSAM
- UFR des Sciences et Techniques
- 29238 Brest Cedex 3
| | - Carlos Platas-Iglesias
- Centro de Investigacións Científicas Avanzadas (CICA) and Departamento de Química
- Universidade da Coruña
- 15008 A Coruña
- Spain
| | - Raphäel Tripier
- Université de Brest
- UMR-CNRS 6521
- IBSAM
- UFR des Sciences et Techniques
- 29238 Brest Cedex 3
| | - Rita Delgado
- Instituto de Tecnologia Química e Biológica António Xavier
- Universidade Nova de Lisboa
- 2780-157 Oeiras
- Portugal
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6
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Ullah M, Itsuno S. Cinchona Squaramide-Based Chiral Polymers as Highly Efficient Catalysts in Asymmetric Michael Addition Reaction. ACS OMEGA 2018; 3:4573-4582. [PMID: 31458680 PMCID: PMC6641636 DOI: 10.1021/acsomega.8b00398] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2018] [Accepted: 04/18/2018] [Indexed: 05/03/2023]
Abstract
We have synthesized novel chiral polymers containing a cinchona-based squaramide in the main chain. We designed a novel cinchona squaramide dimer that contains two cinchona squaramide units connected by diamines. The olefinic double bonds in the cinchona squaramide dimer were used for Mizoroki-Heck (MH) polymerization with aromatic diiodides. The MH polymerization of the cinchona squaramide dimer and aromatic diiodide proceeded well to give the corresponding chiral polymers in good yields. The catalytic activity of the chiral polymers was investigated for asymmetric Michael addition reactions. The effect of the squaramide structure of the polymeric catalyst on the catalytic performance is discussed in detail. We have surveyed the influence of the chiral polymer structure on the catalytic activity and enantioselectivity of the asymmetric reaction. The asymmetric Michael addition of β-ketoesters to nitroolefins was successfully catalyzed by polymeric cinchona squaramide organocatalysts to obtain the corresponding Michael adducts in good yields with excellent enantio- and diastereoselectivities. The polymeric catalysts were insoluble in commonly used organic solvents and easily recovered from the reaction mixture and reused several times without the loss of catalytic activity.
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7
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Niu H, Shu Q, Jin S, Li B, Zhu J, Li L, Chen S. A simple ratiometric and colorimetric chemosensor for the selective detection of fluoride in DMSO buffered solution. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2016; 153:194-198. [PMID: 26311480 DOI: 10.1016/j.saa.2015.08.030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 07/31/2015] [Accepted: 08/12/2015] [Indexed: 06/04/2023]
Abstract
A derivative of squaramide (cyclobuta[b]quinoxaline-1, 2(3H, 8H)-dione) has been synthesized for the ratiometric and colorimetric sensing of F(-) in aqueous solution in competitive fashion. With F(-), probe 1 showed a highly selective naked-eye detectable color change along with a characteristic UV-Vis absorbance over other tested ions, which probably originates from the deprotonation occurred between 1 and F(-), as proved by the (1)H NMR titration experiments and DFT calculations.
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Affiliation(s)
- Hu Niu
- School of Materials Science & Engineering, Beijing Institute of Technology, Beijing, China
| | - Qinghai Shu
- School of Materials Science & Engineering, Beijing Institute of Technology, Beijing, China.
| | - Shaohua Jin
- School of Materials Science & Engineering, Beijing Institute of Technology, Beijing, China
| | - Bingjun Li
- School of Materials Science & Engineering, Beijing Institute of Technology, Beijing, China
| | - Jiaping Zhu
- School of Materials Science & Engineering, Beijing Institute of Technology, Beijing, China
| | - Lijie Li
- School of Materials Science & Engineering, Beijing Institute of Technology, Beijing, China
| | - Shusen Chen
- School of Materials Science & Engineering, Beijing Institute of Technology, Beijing, China
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8
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Ito M, Iseki M, Itazaki M, Nakazawa H. Tetrahedral cage complex with planar vertices: selective synthesis of Pt4L6 cage complexes involving hydrogen bonds driven by halide binding. Chem Commun (Camb) 2016; 52:7205-8. [DOI: 10.1039/c6cc01448h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The first synthesis of tetrahedral cage complexes with four square-planar Pt complexes at the vertex positions was achieved.
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Affiliation(s)
- Masaki Ito
- Department of Chemistry
- Graduate School of Science Osaka City University
- Osaka 558-8585
- Japan
| | - Masato Iseki
- Department of Chemistry
- Graduate School of Science Osaka City University
- Osaka 558-8585
- Japan
| | - Masumi Itazaki
- Department of Chemistry
- Graduate School of Science Osaka City University
- Osaka 558-8585
- Japan
| | - Hiroshi Nakazawa
- Department of Chemistry
- Graduate School of Science Osaka City University
- Osaka 558-8585
- Japan
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9
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Sanna E, López C, Ballester P, Rotger C, Costa A. Unexpected Squaramide-Induced Cleavage of Benzils: Synthesis and Characterization of Mono-Aroyl Squarimides. European J Org Chem 2015. [DOI: 10.1002/ejoc.201501235] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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10
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Sampedro A, Villalonga-Planells R, Vega M, Ramis G, Fernández de Mattos S, Villalonga P, Costa A, Rotger C. Cell uptake and localization studies of squaramide based fluorescent probes. Bioconjug Chem 2014; 25:1537-46. [PMID: 25036647 DOI: 10.1021/bc500258b] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cell internalization is a major issue in drug design. Although squaramide-based compounds are receiving much attention because of their interesting bioactivity, cell uptake and trafficking within cells of this type of compounds are still unknown. In order to monitor the cell internalization process of cyclosquaramide compounds we have prepared two fluorescent probes by covalently linking a fluorescent dye (BODIPY derivative or fluorescein) to a noncytotoxic cyclosquaramide framework. These two probes (C2-BDP and C2-FITC) rapidly internalize across live cell membranes through endocytic receptor-mediated mechanisms. Due to its higher fluorescence and photochemical stability, C2-BDP is a superior dye than C2-FITC. C2-BDP remains sequestered in late endosomes allowing their fast and selective imaging in various live cell types. Cyclosquaramide-cell membrane interactions facilitate cell uptake and have been investigated by binding studies in solution as well as in live cells. Cyclosquaramide 1 (C2-BDP) can be used as a highly fluorescent probe for the rapid and selective imaging of late endosomes in live cells.
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Affiliation(s)
- Angel Sampedro
- Departament de Química, ‡Departament de Biologia Fonamental, Institut Universitari d'Investigació en Ciències de la Salut (IUNICS) and Instituto de Investigación Sanitaria de Palma (IdISPa), Illes Balears, Spain, Universitat de les Illes Balears , Ctra. Valldemossa km 7.5, 07122 Palma, Spain
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11
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Gaeta C, Talotta C, Della Sala P, Margarucci L, Casapullo A, Neri P. Anion-induced dimerization in p-squaramidocalix[4]arene derivatives. J Org Chem 2014; 79:3704-8. [PMID: 24645825 DOI: 10.1021/jo500422u] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Spherical anions induce the dimerization of calix[4]arene derivatives 3 and 4 bearing squaramide moieties at the exo rim (p-squaramidocalixarenes). (1)H NMR titration experiments showed that unlike the distal isomer 3, proximal p-squaramidocalixarene 4 is also able to form dimeric complexes with trigonal-planar anions.
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Affiliation(s)
- Carmine Gaeta
- Dipartimento di Chimica e Biologia, Università di Salerno , Via Giovanni Paolo II 132, I-84084 Fisciano (Salerno), Italy
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12
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Tsakos M, Kokotos CG. Primary and secondary amine-(thio)ureas and squaramides and their applications in asymmetric organocatalysis. Tetrahedron 2013. [DOI: 10.1016/j.tet.2013.09.080] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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13
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Rostami A, Guérin G, Taylor MS. Structure–Activity Relationships for Anion-Responsive Poly(squaramides): Support for an Analyte-Induced Noncovalent Polymer Cross-Linking Mechanism. Macromolecules 2013. [DOI: 10.1021/ma401263q] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ali Rostami
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Gérald Guérin
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
| | - Mark S. Taylor
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada
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14
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Novel calix[4]arene-based receptors with bis-squaramide moieties for colorimetric sensing of anions via two different interaction modes. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2012.11.117] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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15
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López C, Vega M, Sanna E, Rotger C, Costa A. Efficient microwave-assisted preparation of squaric acid monoamides in water. RSC Adv 2013. [DOI: 10.1039/c3ra41369a] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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16
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Soberats B, Martínez L, Sanna E, Sampedro A, Rotger C, Costa A. Janus-Like Squaramide-Based Hosts: Dual Mode of Binding and Conformational Transitions Driven by Ion-Pair Recognition. Chemistry 2012; 18:7533-42. [DOI: 10.1002/chem.201103345] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Revised: 02/09/2012] [Indexed: 11/09/2022]
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17
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A novel squaraine dye with squaramide as a scaffold and the colorimetric detection of amine. CHINESE CHEM LETT 2012. [DOI: 10.1016/j.cclet.2011.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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18
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Delgado-Pinar E, Rotger C, Costa A, Piña MN, Jiménez HR, Alarcón J, García-España E. Grafted squaramide monoamine nanoparticles as simple systems for sulfate recognition in pure water. Chem Commun (Camb) 2012; 48:2609-11. [DOI: 10.1039/c2cc17798f] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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19
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Quiñonero D, López KA, Deyà PM, Piña MN, Morey J. Synthetic Tripodal Squaramido-Based Receptors for the Complexation of Antineoplastic Folates in Water. European J Org Chem 2011. [DOI: 10.1002/ejoc.201100855] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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20
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Amendola V, Fabbrizzi L, Mosca L, Schmidtchen FP. Urea-, Squaramide-, and Sulfonamide-Based Anion Receptors: A Thermodynamic Study. Chemistry 2011; 17:5972-81. [DOI: 10.1002/chem.201003411] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Indexed: 11/09/2022]
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21
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Rostami A, Wei CJ, Guérin G, Taylor MS. Anion Detection by a Fluorescent Poly(squaramide): Self-Assembly of Anion-Binding Sites by Polymer Aggregation. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201006884] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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22
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Rostami A, Wei CJ, Guérin G, Taylor MS. Anion detection by a fluorescent poly(squaramide): self-assembly of anion-binding sites by polymer aggregation. Angew Chem Int Ed Engl 2011; 50:2059-62. [PMID: 21344551 DOI: 10.1002/anie.201006884] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Indexed: 11/07/2022]
Affiliation(s)
- Ali Rostami
- Department of Chemistry, Lash Miller Laboratories, University of Toronto, 80 St. George St., Toronto, ON M5S 3H6, Canada
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23
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Amendola V, Bergamaschi G, Boiocchi M, Fabbrizzi L, Milani M. The squaramide versus urea contest for anion recognition. Chemistry 2010; 16:4368-80. [PMID: 20222093 DOI: 10.1002/chem.200903190] [Citation(s) in RCA: 154] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The interaction of a neutral squaramide-based receptor, equipped with two 4-nitrophenyl substituents (R(sq)), with halides and oxoanions has been studied in MeCN. UV/Vis and (1)H NMR spectroscopy titration experiments clearly indicated the formation of 1:1 hydrogen bonding [R(sq)X](+) complexes with all the investigated anions. X-ray diffraction studies on the chloride and bromide complex salts confirmed the 1:1 stoichiometry and indicated the establishment of bifurcated hydrogen-bond interactions between the squaramide-based receptor and the halide anion that involved both 1) amide N-H and 2) aryl proximate C-H fragments, for a total of four bonds. Probably due to the contribution of C-H fragments, complexes of R(sq) with halides are 1 to 2 orders of magnitude more stable than the corresponding ones with the analogous urea-based receptor that contains two 4-nitrophenyl substituents (R(ur)). In the case of oxoanions, R(sq) forms complexes, the stability of which decreases with the decreasing basicity of the anion (H(2)PO(4) (-)>NO(2) (-) approximately HSO(4) (-)>NO(3) (-)), and is comparable to that of complexes of the urea-based receptor R(ur). Such a behaviour is ascribed to the predominance of different contributions: electrostatic interaction for halides, acid-to-base 'frozen' proton transfer for oxoanions. Finally, with the strongly basic anions F(-) and CH(3)COO(-), R(sq) first gives genuine hydrogen-bond complexes of 1:1 stoichiometry; then, upon addition of a second anion equivalent, it undergoes deprotonation of one N--H fragment, with the simultaneous formation of the dianion hydrogen-bond complexes, [HF(2)](-) and [CH(3)COOHCH(3)COO](-), respectively. In the case of the urea-based derivative R(ur), deprotonation takes place with fluoride but not with acetate. The apparently higher Brønsted acidity of R(sq) with respect to R(ur) reflects the capability of the squaramide receptor to delocalise the negative charge formed on N--H deprotonation over the cyclobutene-1,2-dione ring and the entire molecular framework.
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Affiliation(s)
- Valeria Amendola
- Dipartimento di Chimica Generale, Università di Pavia via Taramelli 12, 27100 Pavia, Italy
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24
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Xu DQ, Wang YF, Zhang W, Luo SP, Zhong AG, Xia AB, Xu ZY. Chiral Squaramides as Highly Enantioselective Catalysts for Michael Addition Reactions of 4-Hydroxycoumarins and 4-Hydroxypyrone to β,γ-Unsaturated α-Keto Esters. Chemistry 2010; 16:4177-80. [DOI: 10.1002/chem.201000094] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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26
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Bjelić S, Jelesarov I. A survey of the year 2007 literature on applications of isothermal titration calorimetry. J Mol Recognit 2008; 21:289-312. [PMID: 18729242 DOI: 10.1002/jmr.909] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Elucidation of the energetic principles of binding affinity and specificity is a central task in many branches of current sciences: biology, medicine, pharmacology, chemistry, material sciences, etc. In biomedical research, integral approaches combining structural information with in-solution biophysical data have proved to be a powerful way toward understanding the physical basis of vital cellular phenomena. Isothermal titration calorimetry (ITC) is a valuable experimental tool facilitating quantification of the thermodynamic parameters that characterize recognition processes involving biomacromolecules. The method provides access to all relevant thermodynamic information by performing a few experiments. In particular, ITC experiments allow to by-pass tedious and (rarely precise) procedures aimed at determining the changes in enthalpy and entropy upon binding by van't Hoff analysis. Notwithstanding limitations, ITC has now the reputation of being the "gold standard" and ITC data are widely used to validate theoretical predictions of thermodynamic parameters, as well as to benchmark the results of novel binding assays. In this paper, we discuss several publications from 2007 reporting ITC results. The focus is on applications in biologically oriented fields. We do not intend a comprehensive coverage of all newly accumulated information. Rather, we emphasize work which has captured our attention with originality and far-reaching analysis, or else has provided ideas for expanding the potential of the method.
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Affiliation(s)
- Sasa Bjelić
- Biochemisches Institut der Universität Zürich, Winterthurerstrasse 190, Zürich, Switzerland
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Rotger C, Soberats B, Quiñonero D, Frontera A, Ballester P, Benet-Buchholz J, Deyà PM, Costa A. Crystallographic and Theoretical Evidence of Anion–π and Hydrogen-Bonding Interactions in a Squaramide–Nitrate Salt. European J Org Chem 2008. [DOI: 10.1002/ejoc.200701209] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Piña MN, Soberats B, Rotger C, Ballester P, Deyà PM, Costa A. Selective sensing of competitive anions by non-selective hosts: the case of sulfate and phosphate in water. NEW J CHEM 2008. [DOI: 10.1039/b809454c] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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