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Ribeiro FWM, Omari I, Thomas GT, Paul M, Williams PJH, McIndoe JS, Correra TC. Microstructural Analysis of Benzoxazine Cationic Ring-Opening Polymerization Pathways. Macromol Rapid Commun 2024; 45:e2300470. [PMID: 37716013 DOI: 10.1002/marc.202300470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 09/06/2023] [Indexed: 09/18/2023]
Abstract
Herein, an evaluation of the initial step of benzoxazine polymerization is presented by mass spectrometry, with a focus on differentiating the phenoxy and phenolic products formed by distinct pathways of the cationic ring opening polymerization (ROP) mechanism of polybenzoxazine formation. The use of infrared multiple photon dissociation (IRMPD) and ion mobility spectrometry (IMS) techniques allows for differentiation of the two pathways and provides valuable insights into the ROP mechanism. The results suggest that type I pathway is favored in the initial stages of the reaction yielding the phenoxy product, while type II product should be observed at later stages when the phenoxy product would interconvert to the most stable type II phenolic product. Overall, the findings presented here provide important information on the initial step of the benzoxazine polymerization, allowing the development of optimal polymerization conditions and represents a way to evaluate other multifunctional polymerization processes.
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Affiliation(s)
- Francisco W M Ribeiro
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, 05508-000, Brazil
| | - Isaac Omari
- Department of Chemistry, University of Victoria, P. O. Box 3065, Victoria, BC V8W 3V6, Canada
| | - Gilian T Thomas
- Department of Chemistry, University of Victoria, P. O. Box 3065, Victoria, BC V8W 3V6, Canada
| | - Mathias Paul
- Department of Chemistry, University of Victoria, P. O. Box 3065, Victoria, BC V8W 3V6, Canada
| | - Peter J H Williams
- Department of Chemistry, University of Victoria, P. O. Box 3065, Victoria, BC V8W 3V6, Canada
| | - J Scott McIndoe
- Department of Chemistry, University of Victoria, P. O. Box 3065, Victoria, BC V8W 3V6, Canada
| | - Thiago C Correra
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, 05508-000, Brazil
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Fernandes AS, Obeid G, Laureno TJN, Correra TC. Protonated and Sodiated Cyclophosphamide Fragmentation Pathways Evaluation by Infrared Multiple Photon Dissociation Spectroscopy. J Phys Chem A 2023. [PMID: 37285455 DOI: 10.1021/acs.jpca.3c01323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Cyclophosphamide (CP or CTX) is a widely used antineoplastic agent, and the evaluation of its efficacy and its impacts on the environment are dependent on tandem mass spectrometry (MSn) techniques. Because there is no dedicated experimental study to characterize the actual molecular nature of the CP fragments upon collision-induced dissociation, this work evaluated the chemical structure of the fragments of protonated and sodiated CP and CP protonation sites by infrared multiple photon dissociation spectroscopy supported by density functional theory calculations. This study allowed us to propose a new fragment structure and confirm the nature of multiple fragments, including those relevant for transitions used for CP quantitative and qualitative analyses. Our results also show that there is no spectroscopic evidence that can rule out the existence of aziridinium fragments, making it clear that further studies on the nature of iminium/aziridinium fragments in the gas phase are necessary.
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Affiliation(s)
- André S Fernandes
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo 05508-000, São Paulo, Brazil
| | - Guilherme Obeid
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo 05508-000, São Paulo, Brazil
| | - Tiago J N Laureno
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo 05508-000, São Paulo, Brazil
| | - Thiago C Correra
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo 05508-000, São Paulo, Brazil
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Obeid G, Moraes GO, Penna TC, Schenberg LA, Ducati LC, Correra TC. Solvation effects on glyphosate protonation and deprotonation states evaluated by mass spectrometry and explicit solvation simulations. J Chem Phys 2023; 158:054306. [PMID: 36754805 DOI: 10.1063/5.0134003] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Glyphosate is a widely used herbicide, and its protonation and deprotonation sites are fundamental to understanding its properties. In this work, the sodiated, protonated, and deprotonated glyphosate were evaluated in the gas phase by infrared multiple photon dissociation spectroscopy to determine the exact nature of these coordination, protonation, and deprotonation states in the gas phase. In this context, Natural Bond Orbital analyses were carried out to unravel interactions that govern glyphosate (de)protonation states in the gas phase. The solvent effect on the protonation/deprotonation equilibria was also investigated by implicit (Solvation Model Based on Density and polarizable continuum models) and explicit solvation models (Monte Carlo and Molecular Dynamics simulations). These results show that glyphosate is protonated in the phosphonate group in the gas phase because of the strong hydrogen bond between the carboxylic oxygen (O7) and the protonated phosphonate group (O8-H19), while the most stable species in water is protonated at the amino group because of the preferential interaction of the NH2 + group and the solvent water molecules. Similarly, deprotonated glyphosate [Glyp-H]- was shown to be deprotonated at the phosphonate group in the gas phase but not in solution, also because of the preferential solvation of the NH2 + group present in the other deprotomers. Therefore, these results show that the stabilization of the protonated amino group by the solvent molecules is the governing factor of the (de)protonation equilibrium of glyphosate in water.
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Affiliation(s)
- Guilherme Obeid
- Department of Fundamental Chemistry, Institute of Chemistry-University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil
| | - Gustavo O Moraes
- Department of Fundamental Chemistry, Institute of Chemistry-University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil
| | - Tatiana C Penna
- Department of Fundamental Chemistry, Institute of Chemistry-University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil
| | - Leonardo A Schenberg
- Department of Fundamental Chemistry, Institute of Chemistry-University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil
| | - Lucas C Ducati
- Department of Fundamental Chemistry, Institute of Chemistry-University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil
| | - Thiago C Correra
- Department of Fundamental Chemistry, Institute of Chemistry-University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil
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Batista PR, Penna TC, Ducati LC, Correra TC. p-Aminobenzoic acid protonation dynamics in an evaporating droplet by ab initio molecular dynamics. Phys Chem Chem Phys 2021; 23:19659-19672. [PMID: 34524295 DOI: 10.1039/d1cp01495a] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Protonation equilibria are known to vary from the bulk to microdroplet conditions, which could induce many chemical and physical phenomena. Protonated p-aminobenzoic acid (PABA + H+) can be considered a model for probing the protonation dynamics in an evaporating droplet, as its protonation equilibrium is highly dependent on the formation conditions from solution via atmospheric pressure ionization sources. Experiments using diverse experimental techniques have shown that protic solvents allow formation of the O-protomer (PABA protonated in the carboxylic acid group) stable in the gas phase, while aprotic solvents yield the N-protomer (protonated in the amino group) that is the most stable protomer in solution. In this work, we explore the protonation equilibrium of PABA solvated by different numbers of water molecules (n = 0 to 32) using ab initio molecular dynamics. For n = 8-32, the protonation is either at the NH2 group or in the solvent network. The solvent network interacts with the carboxylic acid group, but there is no complete proton transfer to form the O-protomer. For smaller clusters, however, solvent-mediated proton transfers to the carboxylic acid were observed, both via the Grotthuss mechanism and the vehicle or shuttle mechanism (for n = 1 and 2). Thermodynamic considerations allowed a description of the origins of the kinetic trapping effect, which explains the observation of the solution structure in the gas phase. This effect likely occurs in the final evaporation steps, which are outside the droplet size range covered by previous classical molecular dynamics simulations of charged droplets. These results may be considered relevant in determining the nature of the species observed in the ubiquitous ESI based mass spectrometry analysis, and in general for droplet chemistry, explaining how protonation equilibria are drastically changed from bulk to microdroplet conditions.
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Affiliation(s)
- Patrick R Batista
- Department of Fundamental Chemistry, Institute of Chemistry - University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil.
| | - Tatiana C Penna
- Department of Fundamental Chemistry, Institute of Chemistry - University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil.
| | - Lucas C Ducati
- Department of Fundamental Chemistry, Institute of Chemistry - University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil.
| | - Thiago C Correra
- Department of Fundamental Chemistry, Institute of Chemistry - University of São Paulo, Av. Prof. Lineu Prestes, 748, Cidade Universitária, São Paulo, SP, Brazil.
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Penna TC, Cervi G, Rodrigues-Oliveira AF, Yamada BD, Lima RZC, Menegon JJ, Bastos EL, Correra TC. Development of a photoinduced fragmentation ion trap for infrared multiple photon dissociation spectroscopy. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34 Suppl 3:e8635. [PMID: 31677291 DOI: 10.1002/rcm.8635] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/07/2019] [Accepted: 10/08/2019] [Indexed: 06/10/2023]
Abstract
RATIONALE Methods for isomer discrimination by mass spectroscopy are of increasing interest. Here we describe the development of a three-dimensional ion trap for infrared multiple photon dissociation (IRMPD) spectroscopy that enables the acquisition of the infrared spectrum of selected ions in the gas phase. This system is suitable for the study of a myriad of chemical systems, including isomer mixtures. METHODS A modified three-dimensional ion trap was coupled to a CO2 laser and an optical parametric oscillator/optical parametric amplifier (OPO/OPA) system operating in the range 2300 to 4000 cm-1 . Density functional theory vibrational frequency calculations were carried out to support spectral assignments. RESULTS Detailed descriptions of the interface between the laser and the mass spectrometer, the hardware to control the laser systems, the automated system for IRMPD spectrum acquisition and data management are presented. The optimization of the crystal position of the OPO/OPA system to maximize the spectroscopic response under low-power laser radiation is also discussed. CONCLUSIONS OPO/OPA and CO2 laser-assisted dissociation of gas-phase ions was successfully achieved. The system was validated by acquiring the IRMPD spectra of model species and comparing with literature data. Two isomeric alkaloids of high economic importance were characterized to demonstrate the potential of this technique, which is now available as an open IRMPD spectroscopy facility in Brazil.
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Affiliation(s)
- Tatiana C Penna
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000, São Paulo, SP, Brazil
| | - Gustavo Cervi
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000, São Paulo, SP, Brazil
| | - André F Rodrigues-Oliveira
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000, São Paulo, SP, Brazil
| | - Bruno D Yamada
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000, São Paulo, SP, Brazil
| | - Rafael Z C Lima
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000, São Paulo, SP, Brazil
| | - Jair J Menegon
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000, São Paulo, SP, Brazil
| | - Erick L Bastos
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000, São Paulo, SP, Brazil
| | - Thiago C Correra
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000, São Paulo, SP, Brazil
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Rodrigues-Oliveira AF, Batista PR, Ducati LC, Correra TC. Analyzing the N–H+…π interactions of protonated tryptophan and phenylalkylamines using QTAIM, NCI, and NBO. Theor Chem Acc 2020. [DOI: 10.1007/s00214-020-02643-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Batista PR, Karas LJ, Viesser RV, de Oliveira CC, Gonçalves MB, Tormena CF, Rittner R, Ducati LC, de Oliveira PR. Dealing with Hydrogen Bonding on the Conformational Preference of 1,3-Aminopropanols: Experimental and Molecular Dynamics Approaches. J Phys Chem A 2019; 123:8583-8594. [PMID: 31517493 DOI: 10.1021/acs.jpca.9b05619] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
This study expands the knowledge on the conformational preference of 1,3-amino alcohols in the gas phase and in solution. By employing Fourier transform infrared spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, density functional theory (DFT) calculations, quantum theory of atoms in molecules (QTAIM), natural bond orbital (NBO) analysis, and molecular dynamics (MD), the compounds 3-aminopropan-1-ol (1), 3-methylaminopropan-1-ol (2), and 3-dimethylaminopropan-1-ol (3) are evaluated. The results show that the most stable conformation of each compound in the gas phase and in nonpolar solvents exhibited an O-H···N intramolecular hydrogen bond (IHB). Based on the experimental and theoretical OH-stretching frequencies, the IHB becomes stronger from 1 to 3. In addition, from the experimental NMR J-couplings, the IHB conformers are predominant in nonbasic solvents, representing 70-80% of the conformational equilibrium, while in basic solvents, such conformers only represent 10%. DFT calculations and QTAIM analysis in the gas phase support the occurrence of IHBs in these compounds. The MD simulation indicates that the non-hydrogen-bonded conformers are the lowest energy conformations in the solution because of molecular interactions with the solvent, while they are absent in the implicit solvation model based on density. NBO analysis suggests that methyl groups attached on the nitrogen atom affect the charge transfer energy involved in the IHB. This effect occurs mostly because of a decrease in the s-character of the LPN orbital along with weakening of the charge transfer from LPN to σ*OH, which is caused by an increase in the C-C-N bond angle.
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Affiliation(s)
- Patrick R Batista
- Department of Fundamental Chemistry, Institute of Chemistry , University of São Paulo , Av. Prof. Lineu Prestes , P.O. Box 748, 05508-000 São Paulo , São Paulo , Brazil
| | - Lucas J Karas
- Department of Chemistry , University of Houston , Houston , Texas 77204 , United States
| | - Renan V Viesser
- Physical Organic Chemistry Laboratory, Institute of Chemistry , University of Campinas , P.O. Box 6154, 13083-970 Campinas , São Paulo , Brazil
| | - Cynthia C de Oliveira
- Academic Department of Physics , Federal Technological University of Paraná , 80230-901 Curitiba , Paraná , Brazil
| | - Marcos B Gonçalves
- Academic Department of Physics , Federal Technological University of Paraná , 80230-901 Curitiba , Paraná , Brazil
| | - Cláudio F Tormena
- Physical Organic Chemistry Laboratory, Institute of Chemistry , University of Campinas , P.O. Box 6154, 13083-970 Campinas , São Paulo , Brazil
| | - Roberto Rittner
- Physical Organic Chemistry Laboratory, Institute of Chemistry , University of Campinas , P.O. Box 6154, 13083-970 Campinas , São Paulo , Brazil
| | - Lucas C Ducati
- Department of Fundamental Chemistry, Institute of Chemistry , University of São Paulo , Av. Prof. Lineu Prestes , P.O. Box 748, 05508-000 São Paulo , São Paulo , Brazil
| | - Paulo R de Oliveira
- Conformational Analysis and Renewable Resources Laboratory, Department of Chemistry and Biology , Federal Technological University of Paraná , P.O. Box 5000, 81280-340 Curitiba , Paraná , Brazil
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M Ribeiro FW, Rodrigues-Oliveira AF, C Correra T. Benzoxazine Formation Mechanism Evaluation by Direct Observation of Reaction Intermediates. J Phys Chem A 2019; 123:8179-8187. [PMID: 31483645 DOI: 10.1021/acs.jpca.9b05065] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Benzoxazine formation is a fundamental step in the preparation of polybenzoxazine resins, and a detailed description of the mechanism governing the formation of benzoxazine and side products is vital for improving the properties and performance of these resins. Determination of the nature and properties of reaction intermediates is not trivial. Therefore, a Mannich-type condensation of aniline, formaldehyde, and phenol was evaluated as a potential method to form benzoxazine. Coupling positive mode electrospray ionization mass spectrometry (ESI(+)-MS) with infrared multiple photon dissociation (IRMPD) spectroscopy allowed unambiguous determination of an iminium-based mechanism and the direct observation of iminium intermediates. The benzoxazine formation mechanism was indirectly confirmed by the observation of side products that are relevant to the polymerization step, and directly confirmed by the identification of four distinct reaction intermediates that were completely characterized by IRMPD spectroscopy. The benzoxazine monomer was also shown to undergo isomerization under standard ESI-MS analysis conditions, suggesting the presence of a mixture of three isomers during their usual ESI-MS analysis.
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Affiliation(s)
- Francisco W M Ribeiro
- Department of Fundamental Chemistry, Institute of Chemistry , University of São Paulo Av. Prof. Lineu Prestes, 748, Cidade Universitária , São Paulo , São Paulo 05508-000 , Brazil
| | - André F Rodrigues-Oliveira
- Department of Fundamental Chemistry, Institute of Chemistry , University of São Paulo Av. Prof. Lineu Prestes, 748, Cidade Universitária , São Paulo , São Paulo 05508-000 , Brazil
| | - Thiago C Correra
- Department of Fundamental Chemistry, Institute of Chemistry , University of São Paulo Av. Prof. Lineu Prestes, 748, Cidade Universitária , São Paulo , São Paulo 05508-000 , Brazil
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Santos Fernandes A, Maître P, Carita Correra T. Evaluation of the Katsuki–Sharpless Epoxidation Precatalysts by ESI-FTMS, CID, and IRMPD Spectroscopy. J Phys Chem A 2019; 123:1022-1029. [DOI: 10.1021/acs.jpca.8b09979] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- André Santos Fernandes
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, 05508-000, São Paulo, SP, Brazil
| | - Philippe Maître
- Laboratoire de Chimie Physique, URM8000, CNRS, Université Paris-Sud, Université Paris-Saclay, 91405, Orsay, France
| | - Thiago Carita Correra
- Department of Fundamental Chemistry, Institute of Chemistry, University of São Paulo, Av. Prof. Lineu Prestes, 748, 05508-000, São Paulo, SP, Brazil
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Avilés-Moreno JR, Berden G, Oomens J, Martínez-Haya B. Intra-cavity proton bonding and anharmonicity in the anionophore cyclen. Phys Chem Chem Phys 2018; 20:8968-8975. [PMID: 29557457 DOI: 10.1039/c8cp00660a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Proton bonding drives the supramolecular chemistry of a broad range of materials with polar moieties. Proton delocalization and electronic charge redistribution have a profound impact on the structure of proton-bound molecular frameworks, and pose fundamental challenges to quantum chemical modelling. This study provides insights into the structural and spectral signatures of the intramolecular proton bond formed in a benchmark polyazamacrocycle anionophore (cyclen, 1,4,7,10-tetraazacyclododecane). Infrared action spectroscopy is employed to characterize the macrocycle, isolated in protonated form. In its most stable configuration, protonated cyclen adopts an open arrangement of Cs symmetry with a particularly strong NHδ+N bond across the cavity. The quantum chemical analysis of the infrared spectrum reveals intrinsic difficulties for the accurate description of the vibrational modes of the system. The reconciliation of the computational predictions with experiment demands a careful anharmonic treatment of the proton motion, which exposes the limitations of current methods. Best results are obtained with the incorporation of anharmonicity only to the fundamental modes directly related to motions of the proton. However, the full anharmonic treatment of the system fails to describe correctly the vibrations related to the macrocycle backbone. The results should serve as motivation for new developments in the modelling of proton bonded systems.
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Affiliation(s)
- Juan Ramón Avilés-Moreno
- Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, E-41013 Seville, Spain.
| | - Giel Berden
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525ED Nijmegen, The Netherlands
| | - Jos Oomens
- Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernooiveld 7c, 6525ED Nijmegen, The Netherlands
| | - Bruno Martínez-Haya
- Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, E-41013 Seville, Spain.
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