GEPCS – Group of Spectroscopy of Plasmas and Supersonic Jets
An investigation on matrine , a tetracyclic bis-quinolizidine alkaloid from the Sephora plants, was published in January 2021 in Journal of Organic Chemistry. The molecule showed two (trans and cis) isomers in the gas-phase, confirming conformational rearrangements in matrine alkaloids. Matrine alkaloids have four stereogenic carbon centers, producing a large family of 16 stereoisomers in 8 enantiomeric pairs.
Category : Group News Molecular Structure MW Spectroscopy New Results!
An investigation on diphenyl disulfide has been highlighted in the cover of CPC. This collaboration with Jean Demaison and Natalja Vogt uses a combination of supersonic jet experimental data and high-level ab initio calculations for the precise determination of the equilibrium molecular structure. The cover features the biologically and industrially important disulfide bridge.
Hydrogen bonds (HBs) involving sulfur are considered much weaker than those of more electronegative atoms. We recently published a comparison between the HBs in the furfuryl mercaptan – water dimer and compared the HBs with those in furfuryl alcohol. The investigation was published in Chemistry – A European Journal. and highlighted in the Journal cover.
The cover below shows a 3D map of electronegativity along the periodic table and the observed dimers.
Category : Alkaloids Molecular Structure MW Spectroscopy New Results!
An article on the methyl inversion and structure of the tropane alkaloid pseudopelletierine has been published in Chemistry: A European Journal. The article includes extensive (multi-isotopologue) rotational data, together with theoretical calculations on the equilibrium structure of the molecule, in collaboration with Jean Demaison and Natalja Vogt.
In the figure below the inversion potential of the methyl group in pseudopelletierine and the pomegranate tree, where this alkaloid can be found.
Category : Group News Molecular Structure MW Spectroscopy New Results!
The conformational landscape of enflurane was published in Chemistry – A European Journal. This report closes a series or rotational investigations on volatile and injection anesthetics, including among others sevoflurane, isoflurane and propofol. Enflurane has three distinct rotamers in the gas phase, originated by the internal rotation of the terminal chlorine atom. The presence of hyperfine interations and different isotopologues resulted in a crowded spectrum, as can be observed in the figure below.
Category : Conferences Group News MW Spectroscopy
The XXIV Colloquium on High Resolution Molecular Spectroscopy (HRMS 2015) was organized in Dijon last August 23-28, 2015. Our group presented a poster on the conformational map of enflurane. Emilio Cocinero gave a plenary talk at the meeting. Next meeting in the HRMS series will be in Helsinki in 2017.
In the picture below part of the Spanish team at the HRMS 2015, including Dionisio Bermejo and José Luis Domenech (CSIC), Alberto (UVa) and María Eugenia Sanz (UCL, London).
New cover on PCCP! A work in collaboration with the Brooks H. Pate group in Virginia was featured as cover of PCCP in the July 28th issue. We show how transient chirality in the anesthetic sevoflurane is stabilized on formation of the dimer, as two different diastereoisomers (homochiral: left/left or right/right; heterochiral: left/right or right/left) are formed and distinguished by their spectral rotational signature. The structure of the dimers were fully resolved usign isotopic information, rendering information on the weak hydrogen bonds stabilizing the cluster.
The International Symposium on Molecular Spectroscopy (ISMS), a landmark for the high-resolution Spectroscopy community, will move to Champaign-Urbana this year (June, 16-20). The meeting follows 68 succesful editions at the Ohio State University (Columbus, OH). Our group collaborates in five communications.
We show in the figure above two conformations observed for the floppy seven-membered ring of caprolactone.
A work in collaboration with the Pate group in Virginia examined the weakly-bound cluster of sevoflurane···benzene ans was published in Angewandte Chemie. The primary interaction is a relatively strong C-H···pi hydrogen bond. The presence of additional C-H···F weak interactions hinders the six-fold symmetric internal rotation of benzene around sevoflurane. This is probably the first time that such a V6 barrier has been determined in a intermolecular complex.
The VI meeting of young researchers in Atomic and Molecular Physics (J2IFAM-2014) organized in Bilbao (January 22-24) is now over. Montse gave a talk on pyridine···freon intermolecular complexes last Thursday 23rd.
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