<scp>L</scp>-Tryptophan formic acid solvate at 183 K

Hübschle, Christian B.; Dittrich, Birger; Luger, Peter

doi:10.1107/s0108270102012489

Cited by 6 publications

(4 citation statements)

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“…The crystal structure of TRP-PA ( 1 ) was found to be interesting both chemically and crystallographically due to the nature of the amino acid and the coformer. The amino acid exists in the zwitterionic form in the structure which is consistent with some examples cited earlier. − The FTIR spectrum, however, clarified that the commercial TRP used in this study is inherently zwitterionic (Figure S4). Further, careful inspection of the Fourier difference maps also revealed that there is an intramolecular proton transfer from the −COOH group of PA to the pyridine N atom, resulting in a zwitterion form of the PA.…”

Section: Resultssupporting

confidence: 88%

“…However, despite the possibilities of all these interactions, supramolecular host–guest complexes of tryptophan are limited. A recent study reported that there are 12 structures with zwitterionic tryptophan: nine of them of TRP, one of d -tryptophan with naproxen, and the remaining two are of pure dl -tryptophan. − Additionally, the number of structures with cationic TRP is also limited. − The indole ring of TRP is usually difficult to ionize, and only strong acids or bases can protonate or deprotonate the ring. Thus, the reactivity of the amino acid is mainly dependent on the −COOH and −NH 2 group.…”

Section: Introductionmentioning

confidence: 99%

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Influence of the Local Chemical Environment in the Formation of Multicomponent Crystals of L-Tryptophan with N-Heterocyclic Carboxylic Acids: Unusual Formation of Double Zwitterions

Das

Srivastava

2017

Crystal Growth & Design

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Formation of multicomponent crystals (MCCs) of L-tryptophan (TRP) with N-heterocyclic carboxylic acids such as 2-picolinic acid (PA) and its 3- or 4-substituent isomers (nicotinic acid or isonicotinic acid), pyrazinecarboxylic acid (PZCA), 2,3-pyrazinedicarboxylic acid (2,3-PZDCA), 2-quinaldic acid (QA), and its 3-subsituent isomer (3-QA) is investigated in this manuscript. The investigation results in four multicomponent solid forms of the amino acid with coformers where the electron withdrawing functional group (−COOH) is present in the ortho-substituent to N-heterocyclic rings. The isomers of PA or QA having −COOH at the meta- or para- position failed to produce new phases. These solid phases were identified by powder X-ray diffraction results, and the MCCs derived from 2-picolinic acid (1) and 2,3-pyrazinedicarboxylic acids (3) were further characterized with single crystal X-ray diffraction. The crystal structure of TRP-PA (1) reveal a rare form of cocrystal where both the amino acid and the picolinic acid are in zwitterionic form. Further, in our surprise, the amino acid appears to undergo change in absolute configuration during cocrystallization. Crystal TRP-2,3-PZDCA (3) is observed as a salt where the amino acid exists in cationic form, and the carboxylic acid exists in anionic form. It is observed that the complementary H-bonding between the py-N/ortho- −COOH of the coformers with the α-NH3 +/α-COO– group of L-tryptophan primarily drives the cocrystallization process. Density functional theory calculations support the experimental observations as lower total energy and higher interaction energy values are obtained for the successfully synthesized MCCs. The solid state fluorescence of TRP (known as intrinsic fluorescence probe) shows that 2,3-PZDCA is an effective quencher.

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Section: Resultssupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Influence of the Local Chemical Environment in the Formation of Multicomponent Crystals of L-Tryptophan with N-Heterocyclic Carboxylic Acids: Unusual Formation of Double Zwitterions

Das

Srivastava

2017

Crystal Growth & Design

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“…As the chemical and photochemical properties of tryptophan monomer were intensively investigated experimentally and theoretically in recent years 1, 4, 34, 35, we will not discuss the properties of tryptophan in the present article. The geometry of tryptophan in the complex with 4NQO has been fully optimized at the level of HFSCF/6‐31G** based on the few available crystal structural parameters 36, 37.…”

Section: Resultsmentioning

confidence: 99%

Ab initio study of hydrogen bonding interaction and photoinduced electron transfer between 4‐nitroquinoline‐1‐oxide and tryptophan

Liu

Zhu

2004

Int J of Quantum Chemistry

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ABSTRACT:In the present article, the electronic structure of 4-nitroquinoline-1-oxide (4NQO) has been theoretically investigated at the level of HFSCF/6-31G**. Conformation of monomeric 4NQO has been found to be the most stable when the nitro group twists from the quinoline plane by about 24°. The absorption spectra of the twisted 4NQO have been calculated by using complete active space self-consistent field method. The hydrogen bonded complexes of 4NQO and tryptophan have been intensively studied. The absorption spectra of the most stable complex have been calculated to investigate the photoinduced electron transfer between 4NQO and tryptophan. The first and second excited singlet states are found to be charge-separated. Population analysis shows that the low-lying triplet states are charge-separated as well, except for the lowest one that presents the characters of a locally excited state. A solvent effect on transition energies has been considered based on the Ooshika-Lippert-Martaga equation. Theoretical study shows that the optical excitation can lead to charge separation in the 4NQO-tryptophan complex.

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“…Recent reviews have also summarised the structures involving amino acids [14][15][16]. A search of the Cambridge Structural Database [17] gave twelve results when the zwitterionic form of tryptophan was entered as the search query; nine of the structures involve L-tryptophan [13,[18][19][20][21][22][23][24] one structure comprised of D-tryptophan with naproxen [25] and the remaining two structures are pure DL-tryptophan [26,27]. When the cationic form of tryptophan (tryptophanium) is entered as the search query an additional fourteen results are shown [26,[28][29][30][31][32][33][34][35][36][37][38] In this study we have employed R-camphor-10-sulphonic acid and S-camphor-10-sulphonic acid, as S-camphor-10-sulphonic acid has for example been used to resolve DL-phenylglycine [39].…”

Section: Introductionmentioning

confidence: 99%

Salts of Tryptophan with p-Toluenesulphonic Acid and Camphorsulphonic Acids

Sayed

Jacobs

2015

J Chem Crystallogr

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Co-crystallisation of DL-tryptophan with p-toluenesulphonic acid, R-camphor-10-sulphonic acid and S-camphor-10-sulphonic acid resulted in salts. For all the structures, the amino acid is in the cationic form with the proton transferred from the acidic co-former to the amino acid. R-camphor-10-sulphonic acid and S-camphor-10-sulphonic acid were unsuccessful at resolving DL-tryptophan. Dissolution of the respective camphorsulphonic acid and DL-tryptophan in methanol/water gave crystals which contained equimolar amounts of the D-and the L-tryptophan. The following salts were also obtained in aqueous acetonitrile; (2L-TRP ? )(2S-CSA -)Á(H 2 O) from a mixture of L-TRP/S-CSA and (D-TRP ? )(S-CSA -) from a mixture of D-TRP/S-CSA. The crystal structures and the thermal stability of the salts have been determined. (DL-TRP ? )(p-TSA -) solved in P2 1 /c with a = 19.422(2) Å , b = 5.5456(7) Å , c = 16.488(2) Å and b = 102.357(2)°. (D-TRP ? )(L-TRP ? )(2R-CSA -) solved in P2 1 with a = 12.780(3) Å , b = 10.411(2) Å , c = 32.574(7) Å and b = 97.60(3)°. (D-TRP ? )(L-TRP ? )(2S-CSA -) solved in P2 1 with a = 12.783(3) Å , b = 10.410(2) Å , c = 32.564(7) Å and b = 97.44(3)°. (2L-TRP ? )(2S-CSA -)-(H 2 O) solved in P2 1 with a = 13.1761(12) Å , b = 10.3092(10) Å , c = 16.6268(16) Å and b = 104.435(2)°. (D-TRP ? )(S-CSA -) solved in P2 1 2 1 2 1 with a = 6.4185(13) Å , b = 12.700(3) Å , c = 25.173(5) Å and a = b = c = 90°.Graphical Abstract DL-tryptophan forms salts with ptoluenesulphonic acid, R-camphor-10-sulphonic acid and S-camphor-10-sulphonic acid. L-tryptophan forms a salt hydrate with S-camphor-10-sulphonic acid and D-tryptophan forms a salt with S-camphor-10-sulphonic acid. The crystal structures and the thermal stability of the salts are reported.Electronic supplementary material The online version of this article (

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L-Tryptophan formic acid solvate at 183 K

Cited by 6 publications

References 2 publications

Influence of the Local Chemical Environment in the Formation of Multicomponent Crystals of L-Tryptophan with N-Heterocyclic Carboxylic Acids: Unusual Formation of Double Zwitterions

Influence of the Local Chemical Environment in the Formation of Multicomponent Crystals of L-Tryptophan with N-Heterocyclic Carboxylic Acids: Unusual Formation of Double Zwitterions

Ab initio study of hydrogen bonding interaction and photoinduced electron transfer between 4‐nitroquinoline‐1‐oxide and tryptophan

Salts of Tryptophan with p-Toluenesulphonic Acid and Camphorsulphonic Acids

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