Jet-cooled laser spectroscopy and solid-state vibrational circular dichroism of the cyclo-(Tyr-Phe) diketopiperazine dipeptide

Dupont, Jennifer; Guillot, Régis; Lepère, V.; Zehnacker‐Rentien, Anne

doi:10.1016/j.molstruc.2022.133059

Cited by 8 publications

(15 citation statements)

References 64 publications

(100 reference statements)

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“…In recent years, vibrational circular dichroism (VCD) has come into focus, which is a ground‐state property relying on a wealth of absorption bands (in the infrared region), many more than its electronic counterpart. [11] Being a very sensitive probe of molecular conformation and environment, VCD has been applied to a wide range of molecules including natural products, host‐guest systems, peptides and proteins, nanoparticles or catalysts,[ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ] supramolecular organisation in the condensed phase,[ 8 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ] and the formation of chiral phases from achiral subunits. [ 5 , 33 , 34 ] In particular, the utility of solid‐state VCD for the resolution of molecular chirality and supramolecular chirality has been noted by Sato and co‐workers.…”

Section: Introductionmentioning

confidence: 99%

How Crystal Symmetry Dictates Non‐Local Vibrational Circular Dichroism in the Solid State

et al. 2022

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Solid‐State Vibrational Circular Dichroism (VCD) can be used to determine the absolute structure of chiral crystals, but its interpretation remains a challenge in modern spectroscopy. In this work, we investigate the effect of a twofold screw axis on the solid‐state VCD spectrum in a combined experimental and theoretical analysis of P21 crystals of (S)‐(+)‐1‐indanol. Even though the space group is achiral, a single proper symmetry operation has an important impact on the VCD spectrum, which reflects the supramolecular chirality of the crystal. Distinguishing between contributions originating from molecular chirality and from chiral crystal packing, we find that while IR absorption hardly depends on the symmetry of the space group, the situation is different for VCD, where completely new non‐local patterns emerge. Understanding the two underlying mechanisms, namely gauge transport and direct coupling, will help to use VCD to distinguish polymorphic forms.

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Section: Introductionmentioning

confidence: 99%

How Crystal Symmetry Dictates Non‐Local Vibrational Circular Dichroism in the Solid State

et al. 2022

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“…The potential energy surface was manually explored by building two types of initial structures in a systematic way. The first structures were built from the stable forms of protonated cyclo(Phe-Phe) modified by adding a hydroxyl substituent to the benzene ring, as it was successfully done before for finding the geometries of jet-cooled cyclo(Tyr-Phe) by removing the hydroxyl from neutral cyclo(Tyr-Tyr). , To ensure that the exploration of the photoelectron spectroscopy (PES) was complete, additional structures were obtained by adding a proton to the amide nitrogen or oxygen atom of the stable calculated structures of neutral cyclo(Tyr-Tyr) . The structures whose vibrational spectrum shows the best match with the experiment were re-optimized at the B3LYP-D3(BJ) level.…”

Section: Methodsmentioning

confidence: 99%

Do Stereochemical Effects Overcome a Charge-Induced Perturbation in Isolated Protonated Cyclo(Tyr-Tyr)?

et al. 2022

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Two diastereomers of the protonated diketopiperazine (DKP) dipeptide cyclo(Tyr-Tyr), namely, cyclo(LTyr-LTyr)H + and cyclo(LTyr-DTyr)H + , are studied in a cryogenic ion trap by means of IR photodissociation spectroscopy combined with quantum chemical calculations. The two diastereomers have similar structures in which one of the rings is folded over the DKP ring and the other one is extended in a trans geometry, allowing a strong OH + •••π interaction to take place. This contrasts to the observation of a stacked geometry for neutral cyclo(LTyr-LTyr) only under supersonic expansion conditions that do not exist for cyclo(LTyr-DTyr). In the protonated form, the strength of the OH + •••π interaction is different for the two diastereomers, resulting in a ∼110 cm −1 difference in the ν(OH + ) frequency and a smaller but clearly identifiable difference in the protonated amide ν(NH) frequency. Stereochemical effects are therefore still evidenced despite the strong perturbation due to the excess charge.

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“…We have undertaken a study of DKP dipeptides containing at least one aromatic amino acid under jet-cooled or ion trap conditions. [7][8][9][10][11][12][13][14][15][16] Among the studied systems, those containing two aromatic amino-acids are of special interest as they raise the question of the localisation of the electronic transition and the coupling between the two aromatic chromophores (see Figure 1). The most stable structures of neutral bi-chromophore DKP dipeptides, like cyclo(phenylalanyl-phenylalanyl) (c-Phe-Phe) or cyclo(phenylalanyl-tyrosyl) (c-Phe-Tyr), [10,14,15] are very similar, although spectroscopically discernible, whether the two residues have identical or opposite absolute configurations.…”

Section: Introductionmentioning

confidence: 99%

Does Chiral Sensitivity of a Structure Depend on the Metal Core? Alkali Ion Complexes of Cyclo(Tyr‐Tyr)

et al. 2023

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Alkali metal complexes of cyclic dipeptide cyclo Tyr‐Tyr have been studied under cryogenic ion trap conditions. Their structure was obtained by combining Infra‐Red Photo‐Dissociation (IRPD) and quantum chemical calculations. The structural motif strongly depends on the relative chirality of the tyrosine residues. For residues of identical chirality, the cation interacts with one amide oxygen and one of the aromatic rings only; the distance between the aromatic rings does not change with the nature of the metal. In contrast, for residues of opposite chirality, the metal cation is located in between the two aromatic rings and interacts with both of them. The distance between the two aromatic rings strongly depends on the metal. Electronic spectra obtained by Ultra Violet Photodissociation (UVPD) spectroscopy and analysis of the UV photo‐fragments shed light on the excited state deactivation processes, which depend on both the chirality of the residue and that of the metal ion core. Na+ stands out by the presence of low‐lying charge transfer states resulting in the broadening of the electronic spectrum.

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Jet-cooled laser spectroscopy and solid-state vibrational circular dichroism of the cyclo-(Tyr-Phe) diketopiperazine dipeptide

Cited by 8 publications

References 64 publications

How Crystal Symmetry Dictates Non‐Local Vibrational Circular Dichroism in the Solid State

How Crystal Symmetry Dictates Non‐Local Vibrational Circular Dichroism in the Solid State

Do Stereochemical Effects Overcome a Charge-Induced Perturbation in Isolated Protonated Cyclo(Tyr-Tyr)?

Does Chiral Sensitivity of a Structure Depend on the Metal Core? Alkali Ion Complexes of Cyclo(Tyr‐Tyr)

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