Genesis of rare molecules using light-induced reactions of matrix-isolated tetrazoles

Frija, Luís M. T.; Cristiano, Maria Lurdes Santos; Gómez‐Zavaglia, Andrea; Reva, Igor; Fausto, Rui

doi:10.1016/j.jphotochemrev.2013.09.001

Cited by 41 publications

(19 citation statements)

References 84 publications

(147 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been shown 17,18,41,42 that the preferred reaction occurring upon subjecting tetrazoles to UV irradiation corresponds to molecular nitrogen extrusion, with formation of several different isomeric species, which include the diazirine, nitrilimine, cyanamide, and carbodiimide (Scheme 2). In general, nitrilimine and diazirine species are short lived under photolysis conditions because they quickly convert into the photostable isomeric carbodiimide or, less frequently, cyanamide.…”

Section: Uv-laser-induced Photochemistry Of Matrix-isolated 5pptmentioning

confidence: 99%

“…16 The photochemistry of tetrazoles, in solution and isolated in cryogenic matrices, has been reviewed. 17,18 Generally, irradiation of tetrazoles in the UV spectral region leads to cleavage of the tetrazole ring. The photofragmentation pattern and the structure and stability of the photoproducts obtained are determined by the chemical nature and conformational flexibility of the substituents.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Structure, vibrational spectroscopy, and photochemistry of 5-phenoxy-1-phenyltetrazole in argon and nitrogen cryomatrices

et al. 2015

Self Cite

View full text Add to dashboard Cite

The molecular structure, infrared spectra, and photochemistry of 5-phenoxy-1-phenyltetrazole (5PPT) isolated in argon and N 2 cryogenic matrices were investigated by infrared spectroscopy and theoretical calculations (DFT(B3LYP)/6-311++G(d,p)). Calculations yield two dissimilar minima on the potential energy surface of the molecule, both being eightfold degenerate by symmetry and belonging to the C 1 symmetry point group. Extensive analysis of the potential energy landscape of the molecule was performed. Upon consideration of the zero-point vibrational correction to the energy, the calculations predict that the higher energy minimum shall relax barrierlessly to the lower energy form, leading to conclude that the compound exists in a single conformer in the gas phase. Accordingly, a single conformer was observed and fully characterized spectroscopically upon isolation of the monomer of the compound in argon and nitrogen cryomatrices. UV-laser irradiation ( = 250 nm) of matrixisolated 5PPT leads to photocleavage of the tetrazole ring, with release of N 2 and formation of the corresponding carbodiimide.Résumé : La structure moléculaire, les spectres infrarouges et la photochimie de 5-phénoxy-1-phényltétrazole (5PPT) isolé dans des matrices cryogéniques de l'argon et de N 2 ont été étudiés par spectroscopie d'infrarouges et calculs théoriques (DFT(B3LYP)/ 6-311++G(d,p)). Les calculs donnent deux minima différents sur la surface d'énergie potentielle de la molécule, les deux étant de huit fois dégénéré par symétrie et appartenant au groupe de points de symétrie C 1 . Une analyse approfondie du paysage d'énergie potentielle de la molécule a été effectuée. Après examen des corrections du point zéro de vibration à l'énergie, les calculs prédisent que le minimum d'énergie plus élevée doit détendre sans barrière à la forme d'énergie plus faible, ce qui permet de conclure que le composé existe comme un seul conformère dans la phase gazeuse. En effet, un seul conformère a été observé, et caractérisé entièrement par spectroscopie, après l'isolement du monomère du composé dans des cryomatrices de l'argon et d'azote. Irradiation de 5PPT isolé en cryomatrice de l'argon avec laser UV ( = 250 nm) conduit à photoclivage de l'heterocicle tetrazole avec sortie de N 2 et production de la carbodiimide correspondante.

show abstract

Section: Uv-laser-induced Photochemistry Of Matrix-isolated 5pptmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Structure, vibrational spectroscopy, and photochemistry of 5-phenoxy-1-phenyltetrazole in argon and nitrogen cryomatrices

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…Tautomerism has been extensively studied in a great variety of azoles [5][6][7][8] as well as in other similar systems, including tetrazoles. [9][10][11][12][13][14][15][16][17][18][19][20][21][22] In these studies, the preference for a specific a) Author to whom correspondence should be addressed. Electronic mail: reva@qui.uc.pt tautomer or tautomers at different proportions, according to the physical state of the compound, has been established.…”

Section: Introductionmentioning

confidence: 99%

Tetrazole acetic acid: Tautomers, conformers, and isomerization

Araujo-Andrade

Reva

Fausto

2014

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

Monomers of (tetrazol-5-yl)-acetic acid (TAA) were obtained by sublimation of the crystalline compound and the resulting vapors were isolated in cryogenic nitrogen matrices at 13 K. The conformational and tautomeric composition of TAA in the matrix was characterized by infrared spectroscopy and vibrational calculations carried out at the B3LYP/6-311++G(d,p) level. TAA may adopt two tautomeric modifications, 1H- and 2H-, depending on the position of the annular hydrogen atom. Two-dimensional potential energy surfaces (PESs) of TAA were theoretically calculated at the MP2/6-311++G(d,p) level, for each tautomer. Four and six symmetry-unique minima were located on these PESs, for 1H- and 2H-TAA, respectively. The energetics of the detected minima was subsequently refined by calculations at the QCISD level. Two 1H- and three 2H-conformers fall within the 0-8 kJ mol(-1) energy range and should be appreciably populated at the sublimation temperature (∼330 K). Observation of only one conformer for each tautomer (1ccc and 2pcc) is explained in terms of calculated barriers to conformational rearrangements. All conformers with the cis O=COH moiety are separated by low barriers (less than 10 kJ mol(-1)) and collapse to the most stable 1ccc (1H-) and 2pcc (2H-) forms during deposition of the matrix. On the trans O=COH surfaces, the relative energies are very high (between 12 and 27 kJ mol(-1)). The trans forms are not thermally populated at the sublimation conditions and were not detected in matrices. One high-energy form in each tautomer, 1cct (1H-) and 2pct (2H-), was found to differ from the most stable form only by rotation of the OH group and separated from other forms by high barriers. This opened a perspective for their stabilization in a matrix. 1cct and 2pct were generated in the matrices selectively by means of narrow-band near-infrared (NIR) irradiations of the samples at 6920 and 6937 cm(-1), where the first OH stretching overtone vibrations of 1ccc and 2pcc occur. The reverse transformations could be induced by irradiations at 7010 and 7030 cm(-1), transforming 1cct and 2pct back to 1ccc and 2pcc, also selectively. Besides the NIR-induced transformations, the photogenerated 1cct and 2pct forms also decay in N2 matrices back to 1ccc and 2pcc spontaneously, with characteristic decay times of hours (1H) and tens of minutes (2H). The decay mechanism is rationalized in terms of the proton tunneling. In crystals, TAA exists exclusively as 1H-tautomer. By contrast, the tautomeric composition of the matrix-isolated monomers was found to consist of both 1H- and 2H-tautomers, in comparable amounts. A mechanistic discussion of the tautomerization process occurring during sublimation, accounting also for the observed minor decomposition of TAA leading to CO2 and 5-methyl-tetrazole, is proposed.

show abstract

“…It was also demonstrated that the ligands are non-toxic while their corresponding copper complexes proved highly cytotoxic toward several cancer cell lines, suggesting their application in chelant-based antineoplastic chemotherapy. Although useful as tools for selective sequestration of Cu(II), with possible impact in medicine and environmental remediation, tetrazole-saccharinates proved photolabile due to the photoreactivity of the tetrazole moiety [ 18 , 21 , 22 ]. Optimization of the saccharinate-based conjugates, involving replacement of the partner heterocycle, yielded thiadiazolyl-saccharinates with remarkable properties [ 19 ].…”

Section: Introductionmentioning

confidence: 99%

On the Development of Selective Chelators for Cadmium: Synthesis, Structure and Chelating Properties of 3-((5-(trifluoromethyl)-1,3,4-thiadiazol-2-yl)amino)benzo[d]isothiazole 1,1-dioxide, a Novel Thiadiazolyl Saccharinate

et al. 2021

View full text Add to dashboard Cite

Aquatic contamination by heavy metals is a major concern for the serious negative consequences it has for plants, animals, and humans. Among the most toxic metals, Cd(II) stands out since selective and truly efficient methodologies for its removal are not known. We report a novel multidentate chelating agent comprising the heterocycles thiadiazole and benzisothiazole. 3-((5-(trifluoromethyl)-1,3,4-thiadiazol-2-yl)amino)benzo[d]isothiazole 1,1-dioxide (AL14) was synthesized from cheap saccharin and characterized by different techniques, including single crystal X-ray crystallography. Our studies revealed the efficiency and selectivity of AL14 for the chelation of dissolved Cd(II) (as compared to Cu(II) and Fe(II)). Different spectral changes were observed upon the addition of Cd(II) and Cu(II) during UV-Vis titrations, suggesting different complexation interactions with both metals.

show abstract

Genesis of rare molecules using light-induced reactions of matrix-isolated tetrazoles

Cited by 41 publications

References 84 publications

Structure, vibrational spectroscopy, and photochemistry of 5-phenoxy-1-phenyltetrazole in argon and nitrogen cryomatrices

Structure, vibrational spectroscopy, and photochemistry of 5-phenoxy-1-phenyltetrazole in argon and nitrogen cryomatrices

Tetrazole acetic acid: Tautomers, conformers, and isomerization

On the Development of Selective Chelators for Cadmium: Synthesis, Structure and Chelating Properties of 3-((5-(trifluoromethyl)-1,3,4-thiadiazol-2-yl)amino)benzo[d]isothiazole 1,1-dioxide, a Novel Thiadiazolyl Saccharinate

Contact Info

Product

Resources

About