Herein, we perform for the first time a preliminary NMR and computational study of the spiroglycol structure. Spiroglycol is a highly symmetrical molecule, but it should be chiral due to the presence of a chiral axis. The presence of two enantiomers was demonstrated performing NMR enantiodifferentiation experiments using α,α′-bis(trifluoromethyl)-9,10-anthracenedimethanol (ABTE) as a chiral solvating agent (CSA). The addition of 0.6 equiv of ABTE allows the differentiation of several spiroglycol proton signals. The lack of resolution observed in the proton spectrum can be tackled through the corresponding 13C NMR spectrum where a significant enantiodifferentiation at the spirocarbon atom was observed. In order to physically separate both enantiomers, a SPG derivatization with camphorsulfonic acid and Mosher’s acid was performed affording the corresponding diastereoisomeric ester mixtures. Computations performed with the Gaussian16 package showed that the enantiodifferentiation is mainly due to the different compound thermodynamics stability.
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Some of the SeRMN staff will present our last research works at the annual meeting of the European magnetic resonance community ISMAR EUROMAR 2019 Conference that will take place from 25th to 30th August in Berlin. Find below a summary of our contributions.
Speeding-up NMR molecular analysis is an
important research field which has been continuously advancing since NMR early
days. The relevant benefits are clear and evident: reduce the time per analysis
directly reduce its cost and gaining spectrometer time to analyze new samples. Many
interesting tools and concepts have been appearing in last decades. Concretely,
our experience focuses on the development of new NMR experiments using TS
(Time-Shared), SA (Spectral Aliasing) and MFA (Multiple Fid Acquisition). MFA
strategy is an interesting strategy that allows the acquisition of different structural
information in a single experiment. Basically, MFA experiments consist in the
design of pulse sequence experiments which accommodate several acquisition
windows per experi-ment, each registering different relevant information for
the structural molecular character-ization. The methodology brings a
corresponding important time benefit. Last year, we have reported several new
NMR experiments designed with MFA stratey and herein we would present the most
relevant achievements. The overall discussion will be mainly focused on the
sensitivity gains per time unit of the presented experiments.
The
3,9-bis(1,1-dimethyl-2-hydroxyethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane
commonly named pentaspiroglycol
(PSG) or spiroglycol (SPG) is a high molecular weight rigid alicy-clic diol widely used in the chemical
industry. SPG has no hazardous classification, it is not mutagenic and is a safe alternative to
Bisphenol A, a well-known chemical which is rising concern due to his proved endocrine
disruptor activity. Moreover, some of the SPG main applications are focused on epoxy resins,
liquid polyester resins, radiation curing resins and
in polymer film material field. However, the spiroglycol structure,
configuration and conformation
have never been deeply studied. Herein,
we perform for the first time a preliminary NMR and computational study of the spiroglycol structure. SPG is a highly
symmetrical molecule but it should be chiral due to
the presence of a chiral axis. The presence of two enantiomers was demonstrated
per-forming NMR
enantiodifferentiation experiments using α,α’-bis(trifluoromethyl)-9,10-an-thracenedimethanol (ABTE) as chiral
solvating agent (CSA). The addition of 0.6 equivalents of ABTE allows the differentiation of
several spiroglycol proton signals. The lack of resolu-tion observed in the proton spectrum can be
tackled through the corresponding 13C NMR spectrum
where a significant enantiodifferentiation at the spirocarbon atom was observed.In order to physically separate both
enantiomers, a SPG derivatization with camphor-sulphonic
acid was performed affording the corresponding diastereoisomeric ester mixture.
Some members of the SeRMN staff and relatives have run today the 6th edition of the La Cursa de la UAB. This charity race is setting up every year by the UAB with the aim to collect founds supporting the La Marató TV3.
“A New Chirally Organized Trifluoromethylanthrylmethanol Derivative and Its Application as Chiral Solvating Agent” By Eva Monteagudo, Pere de March, Ángel Álvarez‐Larena and Albert Virgili. ChemistrySelect, 2017, 2, pp. 7362-7367 DOI:10.1002/slct.201701429
The synthesis and structure of 1,1′‐(((10,10’‐(1,1′‐binaphthalene)‐2,2′‐diylbis(oxy))bis(methylene))bis(anthracene‐10,9‐diyl))bis(2,2,2‐trifluoroethanol), 4, is reported. This compound owns both axial and central chirality allowing its use as a chiral solvating agent (CSA) for the enantiomeric composition determination of several mixtures of chiral aromatic alcohols and amines using NMR. The study of the resulting diastereoisomeric complexes was carried out by determining its stoichiometry and association binding constants.
Some of the SeRMN staff presented our last research works at the annual meeting of the European magnetic resonance community EUROMAR 2017 Conference that took place from 2th to 6th July in Warsaw, Poland. Find below a summary of our contributions.
A method based on d-DNP NMR spectroscopy to study chiral recognition is described for the first time. The enantiodifferentiation of a racemic metabolite in a millimolar aqueous solution using a chiral solvating agent was performed. Hyperpolarized 13C-labeled DL-methionine enantiomers were differently observed with a single-scan 13C NMR experiment, while the chiral auxiliary at thermal equilibrium remained unobserved. The method developed entails a step forward in the chiral recognition of small molecules by NMR spectroscopy, opening new possibilities in situations where the sensitivity is limited, for example, when a low concentration of analyte is available or when the measurement of an insensitive nucleus, like 13C, is required. The advantages and current limitations of the method, as well as future perspectives, are discussed.
“Optimized polarization build-up times in dissolution DNP-NMR using a benzyl amino derivative of BDPA” by José Luis. Muñoz Gómez, Eva Monteagudo, Vega LLoveras, Teodor Parella, Jaume Veciana and José Vidal Gancedo. RSC Advances, 2016, 6, 27077. DOI: 10.1039/c6ra00635c
Some of the SeRMN staff will present our last research works at the annual meeting of the European magnetic resonance community EUROMAR 2015 Conference that will take place from 5th to 10th July in Prague, Czech Republic. Find below a summary of our contributions. Continue reading SeRMN contributions at EUROMAR 2015 Conference→
“A Benzyl Alcohol Derivative of BDPA Radical for Fast Dissolution Dynamic Nuclear Polarization NMR Spectroscopy” by José Luis Muñoz Gómez, Eva Monteagudo, Vega Lloveras, Teodor Parella, Jaume Veciana and José Vidal Gancedo. Organic & Biomolecular Chemistry, 2015, 13:2689-2693. DOI: 10.1039/C4OB02356K
The synthesis, structural characterization and the successful application of a carbon centered radical derived from 1,3-bisdiphenylene-2-phenylallyl (BDPA), its benzyl alcohol derivative (BA-BDPA), as a polarizing agent for Dynamic Nuclear Polarization (DNP) are described. Continue reading A New Polarizing Agent for Dissolution-DNP→
