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Núñez‐Martínez M, Arias S, Bergueiro J, Quiñoá E, Riguera R, Freire F. The Role of Polymer–AuNP Interaction in the Stimuli‐Response Properties of PPA–AuNP Nanocomposites. Macromol Rapid Commun 2022. [DOI: 10.1002/marc.202270009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Núñez-Martínez M, Arias S, Bergueiro J, Quiñoá E, Riguera R, Freire F. The Role of Polymer-AuNP Interaction in the Stimuli-Response Properties of PPA-AuNP Nanocomposites. Macromol Rapid Commun 2021; 43:e2100616. [PMID: 34761481 DOI: 10.1002/marc.202100616] [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: 10/26/2021] [Indexed: 11/10/2022]
Abstract
The helical sense control of dynamic helical polymers such as poly(phenylacetylene)s (PPAs) is greatly affected when they are conjugated to AuNPs through a strong thiol-Au connection, which restricts conformational changes at the polymer. Thus, the classical thiol-MNP bonds must be replaced by weaker ones, such as supramolecular amide-Au interactions. A straightforward preparation of the PPA-Au nanocomposite by reduction of a preformed PPA-Au3+ complex cannot be used due to a redox reaction between the two components of the complex which degrades the polymer. To avoid the interaction between the PPA and the Au3+ ions before the reduction takes place, the metal ions are added to the polymer solution capped as a TOAB complex, which keeps the PPA stable due to the lack of PPA-Au3+ interactions. Ulterior reduction of the Au3+ ions by NaBH4 affords the desired nanocomposite, where the AuNPs are stabilized by supramolecular anilide-AuNPs interactions. By using this approach, 3.7 nm gold nanoparticles are generated and aligned along the polymer chain with a regular distance between particles of 6 nm that corresponds to two helical pitches. These nanocomposites show stimuli-responsive properties and are also able to form macroscopically chiral nanospheres with tunable size.
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Rey‐Tarrío F, Rodríguez R, Quiñoá E, Riguera R, Freire F. Photochemical Electrocyclization of Poly(phenylacetylene)s: Unwinding Helices to Elucidate their 3D Structure in Solution. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202014780] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Rey-Tarrío F, Rodríguez R, Quiñoá E, Riguera R, Freire F. Photochemical Electrocyclization of Poly(phenylacetylene)s: Unwinding Helices to Elucidate their 3D Structure in Solution. Angew Chem Int Ed Engl 2021; 60:8095-8103. [PMID: 33332770 DOI: 10.1002/anie.202014780] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/03/2020] [Indexed: 12/16/2022]
Abstract
Photochemical electrocyclization of poly(phenylacetylene)s (PPAs) is used for the structural elucidation of a polyene backbone. This method not only allows classification of PPAs in cis-cisoidal (ω1 <90°) or cis-transoidal structures (ω1 >90°), but also approximating ω1 . A PPA solution is illuminated with visible light and monitoring the photochemical electrocyclization of the PPA helix by measuring the ECD spectra at different times. PPAs with a cis-cisoidal structure show a reduction of the ECD signal of at least 50 % before 30 min of irradiation, while cis-transoidal helices need much longer time because the transoidal bond must be isomerized. The different cis-cisoidal and cis-transoidal helices require different times to decrease their ECD signal by 50 % (t1/2 ), depending on the degree of compression or stretching of the helix, establishing a relationship between the secondary structure adopted by PPA (ω1 ) and the time required to lose the ECD vinylic signal by light irradiation.
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Rey‐Tarrío F, Rodríguez R, Quiñoá E, Riguera R, Freire F. Titelbild: Photochemical Electrocyclization of Poly(phenylacetylene)s: Unwinding Helices to Elucidate their 3D Structure in Solution (Angew. Chem. 15/2021). Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202102308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Rey‐Tarrío F, Rodríguez R, Quiñoá E, Riguera R, Freire F. Cover Picture: Photochemical Electrocyclization of Poly(phenylacetylene)s: Unwinding Helices to Elucidate their 3D Structure in Solution (Angew. Chem. Int. Ed. 15/2021). Angew Chem Int Ed Engl 2021. [DOI: 10.1002/anie.202102308] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Cobos K, Rodríguez R, Quiñoá E, Riguera R, Freire F. From Sergeants and Soldiers to Chiral Conflict Effects in Helical Polymers by Acting on the Conformational Composition of the Comonomers. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009215] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Cobos K, Rodríguez R, Quiñoá E, Riguera R, Freire F. From Sergeants and Soldiers to Chiral Conflict Effects in Helical Polymers by Acting on the Conformational Composition of the Comonomers. Angew Chem Int Ed Engl 2020; 59:23724-23730. [DOI: 10.1002/anie.202009215] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 09/01/2020] [Indexed: 12/17/2022]
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Fernández Z, Fernández B, Quiñoá E, Riguera R, Freire F. Chiral information harvesting in helical poly(acetylene) derivatives using oligo( p-phenyleneethynylene)s as spacers. Chem Sci 2020; 11:7182-7187. [PMID: 34123003 PMCID: PMC8159296 DOI: 10.1039/d0sc02685a] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 06/16/2020] [Indexed: 01/20/2023] Open
Abstract
A chiral harvesting transmission mechanism is described in poly(acetylene)s bearing oligo(p-phenyleneethynylene)s (OPEs) used as rigid achiral spacers and derivatized with chiral pendant groups. The chiral moieties induce a positive or negative tilting degree in the stacking of OPE units along the polymer structure, which is further harvested by the polyene backbone adopting either a P or M helix.
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Cobos K, Rodríguez R, Domarco O, Fernández B, Quiñoá E, Riguera R, Freire F. Polymeric Helical Structures à la Carte by Rational Design of Monomers. Macromolecules 2020. [DOI: 10.1021/acs.macromol.0c00085] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Rodríguez R, Suárez‐Picado E, Quiñoá E, Riguera R, Freire F. A Stimuli‐Responsive Macromolecular Gear: Interlocking Dynamic Helical Polymers with Foldamers. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201915488] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Rodríguez R, Suárez‐Picado E, Quiñoá E, Riguera R, Freire F. A Stimuli‐Responsive Macromolecular Gear: Interlocking Dynamic Helical Polymers with Foldamers. Angew Chem Int Ed Engl 2020; 59:8616-8622. [DOI: 10.1002/anie.201915488] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/07/2020] [Indexed: 01/11/2023]
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Suárez‐Picado E, Quiñoá E, Riguera R, Freire F. Chiral Overpass Induction in Dynamic Helical Polymers Bearing Pendant Groups with Two Chiral Centers. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201915213] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Suárez-Picado E, Quiñoá E, Riguera R, Freire F. Chiral Overpass Induction in Dynamic Helical Polymers Bearing Pendant Groups with Two Chiral Centers. Angew Chem Int Ed Engl 2020; 59:4537-4543. [PMID: 31880378 DOI: 10.1002/anie.201915213] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Indexed: 12/16/2022]
Abstract
The dynamic behavior of helical polymers bearing pendant groups with two chiral centers was studied. Controlled conformational changes at the chiral units placed either closer to or further away from the main chain promote different helical structures. Although the first residue is usually responsible for determining a specific helicity (P or M), we now found that the second chiral center is also able to induce a preferred helical sense when it is located closer in space to the main chain, thereby cancelling the order from the first chiral moiety. This result was achieved through proper coordination with a metal cation. As proof of concept, poly(phenylacetylene)s (PPAs) that bear one and two chiral amino acid units of different sizes and configuration combinations (l/d-alanine and l/d-phenylalanine) as pendants were evaluated. In total, ten polymers were studied. This constitutes the first report of axial control from a remote stereocenter in polymers bearing complex chiral pendants.
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Bergueiro J, Núñez-Martínez M, Arias S, Quiñoá E, Riguera R, Freire F. Chiral gold-PPA nanocomposites with tunable helical sense and morphology. NANOSCALE HORIZONS 2020; 5:495-500. [PMID: 32118234 DOI: 10.1039/c9nh00659a] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A novel type of stimuli-responsive dynamic helical polymer-metal nanoparticle nanocomposite formed by a helical poly(phenylacetylene) (PPA) combined with gold nanoparticles (AuNPs) is described. Thus, several PPA copolymers containing the ethynyl-4-benzamide of (S)-phenylglycine methyl ester (M1) to dictate the helical structure/sense of the copolymer, and the ethynyl-4-benzamide of the 11-((2-(2-(2-aminoethoxy)ethoxy)ethyl)amino)undecane-1-thiol (M2) to link the copolymer to the AuNPs are prepared. Different morphologies of these nanocomposites were obtained by considering the thiol ratio and the self-assembly properties of the PPA, which generates from dispersed AuNPs to fibre-like structures. All these nanocomposites show a dynamic chiral behaviour, it being possible to manipulate their helical sense by the action of external stimuli. Moreover, it is possible to control the aggregation of these nanocomposites into macroscopically chiral nanospheres with low polydispersity by using Ba2+ as a crosslinking agent.
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Alzubi M, Arias S, Rodríguez R, Quiñoá E, Riguera R, Freire F. Chiral Conflict as a Method to Create Stimuli‐Responsive Materials Based on Dynamic Helical Polymers. Angew Chem Int Ed Engl 2019; 58:13365-13369. [DOI: 10.1002/anie.201907069] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 07/06/2019] [Indexed: 11/05/2022]
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Alzubi M, Arias S, Rodríguez R, Quiñoá E, Riguera R, Freire F. Chiral Conflict as a Method to Create Stimuli‐Responsive Materials Based on Dynamic Helical Polymers. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201907069] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Fernández B, Rodríguez R, Quiñoá E, Riguera R, Freire F. Decoding the ECD Spectra of Poly(phenylacetylene)s: Structural Significance. ACS OMEGA 2019; 4:5233-5240. [PMID: 31459695 PMCID: PMC6648364 DOI: 10.1021/acsomega.9b00122] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 02/08/2019] [Indexed: 06/10/2023]
Abstract
The role of the main dihedral angles in the electronic circular dichroism (ECD) spectra of poly(phenylacetylene)s (PPAs) was estimated by using time-dependent density functional theory (TD-DFT) for oligo(phenylacetylene)s (n = 12). These studies reveal that in cis-transoidal arrangements, the first Cotton effect is dominated by excitations involving molecular orbitals (MOs) mainly related to the polyene backbone. Hence, for this scaffold, the ± sign of the first Cotton effect reflects the P/M helical sense of the internal helix of the polymer. However, in cis-cisoidal arrangements, contribution of MOs in the polyene and the aryl rings of the PPA backbone produce the first Cotton effect band. As a result, two different ECD signatures with three or four alternating Cotton effects can be produced depending on the sign of the ω1 and ω3 dihedral angles which determine the helical sense of the polyene (ω1) and the relative orientation of the aryl ring toward the polyene (ω3), respectively. Thus, on the one hand, if ω1 and ω3 rotate in opposite directions, a CD with three alternating Cotton effects is observed, where the sign of first Cotton correlates with the P/M helical sense of the polyene. On the other hand, if ω1 and ω3 rotate in the same direction, a CD signature with four alternating Cotton effects is produced where the information relative to the P/M helical sense of the polyene is contained in the second Cotton effect.
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Rodríguez R, Quiñoá E, Riguera R, Freire F. Stimuli-Directed Colorimetric Interconversion of Helical Polymers Accompanied by a Tunable Self-Assembly Process. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1805413. [PMID: 30786148 DOI: 10.1002/smll.201805413] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 01/23/2019] [Indexed: 06/09/2023]
Abstract
Interconversion between extended and bent structures at the pendant groups of a chiral polyene framework [poly(phenylacetylene) with (R)-(2-methoxy-2-phenylacetyl)glycine residues linked to 4-vinylanilines] allows the reversible colorimetric transformation from stretched to compressed helical cis-transoid polyenic structures through manipulation of the flexible spacer. This transformation generates either organogels (stretched helical form) or nanoparticles (compressed helical form) under the control of polar/low polar stimuli respectively and opens the way to the development of new sensors and stimuli-sensitive materials based on these concepts.
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Correa J, Pinto LF, Zhao L, Riguera R, Fernandez‐Megia E. Filtering the NMR Spectra of Complex Mixtures through Polymer‐Mediated Paramagnetic Spin Relaxation. Chemistry 2018; 24:19236-19242. [DOI: 10.1002/chem.201803519] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 10/05/2018] [Indexed: 11/10/2022]
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Cobos K, Quiñoá E, Riguera R, Freire F. Chiral-to-Chiral Communication in Polymers: A Unique Approach To Control Both Helical Sense and Chirality at the Periphery. J Am Chem Soc 2018; 140:12239-12246. [PMID: 30156414 DOI: 10.1021/jacs.8b07782] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A novel approach to the classical Sergeants and Soldiers effect, using chiral Sergeants and chiral Soldiers, allows control over both helical and external chirality in helical polymers. In the systems reported here, it is possible to induce the same helical sense ( M or P) from either of the two enantiomers of a chiral pendant group ["chiral Soldier", major component; i.e., ( R)- or ( S)-1] when it faces a single enantiomer of an appropriate "chiral Sergeant" [minor component; i.e., ( S)-2]. For instance, the copolymer series poly[( R)-1 r- co-( S)-2(1- r)], poly[( S)-1 r- co-( S)-2(1- r)], and poly[( rac)-1 r- co-( S)-2(1- r)] adopt the same P helix even though the major component shows the opposite absolute configuration. This chiral-to-chiral communication effect is transmitted by the stabilization of different conformations in each enantiomeric form of the Soldier. As a result, this groundbreaking approximation to the Sergeants and Soldiers effect allows the preparation of a single-handed helix-which depends only on the Sergeant's configuration-with different chiralities on the helix periphery. Thus, a P helix can be decorated with the R isomer, S isomer, or even a racemic mixture of the chiral Soldier. A change in the absolute configuration of the Sergeant affords the opposite M helix, which can also be decorated with the R isomer, S isomer, or racemic mixture of the chiral Soldier.
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Nieto-Ortega B, Rodríguez R, Medina S, Quiñoá E, Riguera R, Casado J, Freire F, Ramírez FJ. Sequential Induction of Chirality in Helical Polymers: From the Stereocenter to the Achiral Solvent. J Phys Chem Lett 2018; 9:2266-2270. [PMID: 29652510 DOI: 10.1021/acs.jpclett.8b00519] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Several steps of chiral induction have been detected in poly(phenylacetylene)s among their different hierarchical levels of chirality by vibrational circular dichroism, namely, (i) from the stereogenic centers to the innermost polyacetylene helical covalent backbone (helixint), (ii) from this to the external helix (helixext) formed by the side phenyl pendants that form a complementary helix or counter-helix, and (iii) from this pendant helix to the helical solvation sphere (helixsolv.), the last one being observed along this work. The pendant to polyene backbone chiral induction determines the helical structure adopted by the polymer and therefore the solvation helix. This helical structure is promoted by two mechanisms: steric effects and hydrogen bonding. An important finding concerns the demonstration by VCD of how an achiral solvent becomes chirally organized owing to the template effect of the covalent polymer helices, an effect that is silent to other structural techniques such as ECD or AFM and that hence significantly broadens the scope of these previous analyses.
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Amaral SP, Tawara MH, Fernandez-Villamarin M, Borrajo E, Martínez-Costas J, Vidal A, Riguera R, Fernandez-Megia E. Tuning the Size of Nanoassembles: A Hierarchical Transfer of Information from Dendrimers to Polyion Complexes. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201712244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Amaral SP, Tawara MH, Fernandez-Villamarin M, Borrajo E, Martínez-Costas J, Vidal A, Riguera R, Fernandez-Megia E. Tuning the Size of Nanoassembles: A Hierarchical Transfer of Information from Dendrimers to Polyion Complexes. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/anie.201712244] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Pinto LF, Correa J, Zhao L, Riguera R, Fernandez-Megia E. Fast NMR Screening of Macromolecular Complexes by a Paramagnetic Spin Relaxation Filter. ACS OMEGA 2018; 3:2974-2983. [PMID: 31458565 PMCID: PMC6641404 DOI: 10.1021/acsomega.7b02074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Accepted: 02/28/2018] [Indexed: 05/09/2023]
Abstract
The paramagnetic spin relaxation filter is described for the rapid NMR screening of intermolecular interactions between ligands and macromolecular anionic receptors with large transverse relaxation enhancements (R 2p). The addition of micromolar concentrations of Gd3+ to the mixture produces the immediate broadening/suppression of the NMR signals of interacting species while leaving unaffected those of noncompetitive binders (one-dimensional and two-dimensional experiments). The method is highly sensitive, unveiling interactions that are too weak to generate changes in chemical shifts or relaxation times. It is operationally very simple and hence, it is amenable to ready implementation by nonspecialists. Examples of application such as detecting the formation of interpolymer complexes, cyclodextrin host-guest interactions, and the screening of DNA ligands are included that demonstrate the reliability and broad applicability of the method.
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