Matrix isolation study on the 1:1 hydrogen-bonded complexes [H, C, N] … [H, C, N, O]

Keresztes, Barbara; Csonka, István Pál; Lajgut, Győző György; Bazsó, Gábor; Tarczay, György

doi:10.1016/j.molstruc.2020.128535

Cited by 9 publications

(5 citation statements)

References 28 publications

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“…Similarly, photodecomposition of N-hydroxyurea and acetohydroxamic acid in argon matrices led to the formation of HNCO complexes with NH 2 OH and CH 3 OH, respectively [32,33]. Very recently, a report on the photolysis of 1,2,5-and 1,3,4-oxadiazoles was published [34]. Here, laser photolysis of 1,3,4-oxadiazole at 220 nm generated HCN• • • HNCO and HCN• • • HOCN complexes, whereas upon a secondary photolysis by a hydrogen lamp, three isocyanide complexes HCNO• • • HNC, HNCO• • • HNC and HNC• • • HOCN were detected and characterized.…”

Section: Introductionmentioning

confidence: 98%

Structure and IR Spectroscopic Properties of HNCO Complexes with SO2 Isolated in Solid Argon

2021

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FTIR spectroscopy was combined with the matrix isolation technique and quantum chemical calculations with the aim of studying complexes of isocyanic acid with sulfur dioxide. The structures of the HNCO…SO2 complexes of 1:1, 1:2 and 2:1 stoichiometry were optimized at the MP2, B3LYPD3, B2PLYPD3 levels of theory with the 6-311++G(3df,3pd) basis set. Five stable 1:1 HNCO⋯SO2 complexes were found. Three of them contain a weak N-H⋯O hydrogen bond, whereas two other structures are stabilized by van der Waals interactions. The analysis of the HNCO/SO2/Ar spectra after deposition indicates that mostly the 1:1 hydrogen-bonded complexes are present in argon matrices, with a small amount of the van der Waals structures. Upon annealing, complexes of the 1:2 stoichiometry were detected, as well.

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Section: Introductionmentioning

confidence: 98%

Structure and IR Spectroscopic Properties of HNCO Complexes with SO2 Isolated in Solid Argon

2021

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“…Molecular complexes of HNCO with NH 2 OH or CH 3 OH have been identified upon photodecomposition of N-hydroxyurea and acetohydroxamic acid, respectively [ 30 , 31 ]. Keresztes et al [ 32 ] performed photolysis using 220 nm light on 1,2,5- and 1,3,4-oxadiazoles, and HCN⋯HNCO and HCN⋯HOCN complexes were produced upon photolysis. Subsequent photoreactions using excitation with a hydrogen lamp led to the formation of three complexes of isocyanic acid: HCNO⋯HNC, HNCO⋯HNC and HNC⋯HOCN.…”

Section: Introductionmentioning

confidence: 99%

Experimental FTIR-MI and Theoretical Studies of Isocyanic Acid Aggregates

2023

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Homoaggregates of isocyanic acid (HNCO) were studied using FTIR spectroscopy combined with a low-temperature matrix isolation technique and quantum chemical calculations. Computationally, the structures of the HNCO dimers and trimers were optimized at the MP2, B3LYPD3 and B2PLYPD3 levels of theory employing the 6-311++G(3df,3pd) basis set. Topological analysis of the electron density (AIM) was used to identify the type of non-covalent interactions in the studied aggregates. Five stable minima were located on the potential energy surface for (HNCO)2, and nine were located on the potential energy surface for (HNCO)3. The most stable dimer (D1) involves a weak, almost linear N-H⋯N hydrogen bond. Other structures are bound by a N-H⋯O hydrogen bond or by O⋯C or N⋯N van der Waals interactions. Similar types of interactions as in (HNCO)2 were found in the case of HNCO trimers. Among nine stable (HNCO)3 structures, five represent cyclic forms. The most stable T1 trimer structure is characterized by a six-membered ring formed by three N-H⋯N hydrogen bonds and representing high symmetry (C3h). The analysis of the HNCO/Ar spectra after deposition indicates that the N-H⋯O hydrogen-bonded dimers are especially prevalent. Upon annealing, HNCO trimers were observed as well. Identification of the experimentally observed species relied on previous experimental data on HNCO complexes as well as computed data on HNCO homoaggregates’ vibrational spectra.

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“…29 Matrix photolysis of 1,3,4-oxadiazole results in formation of HNCO and HOCN as HCN complexes, whereas photolysis of 1,2,5oxadiazole leads to the HCNO−HCN complex, which isomerizes to HNCO− and HOCN−HCN complexes. 30,31 The three isomers, isocyanic acid, cyanic acid, and fulminic acid, have been detected in interstellar space. 29,32,33 The NCO radical was detected in space toward the dense core L483 together with HNCO, HOCN, and HCNO.…”

Section: ■ Introductionmentioning

confidence: 99%

“…HOCN was also characterized by centimeter- and millimeter-wave spectroscopy in the low-pressure gas phase diluted with an inert gas as produced from H 2 O–NCCN or H 2 O–CH 3 CN mixtures in a pulsed discharge nozzle . Matrix photolysis of 1,3,4-oxadiazole results in formation of HNCO and HOCN as HCN complexes, whereas photolysis of 1,2,5-oxadiazole leads to the HCNO–HCN complex, which isomerizes to HNCO– and HOCN–HCN complexes. , …”

Section: Introductionmentioning

confidence: 99%

CHNO – Formylnitrene, Cyanic, Isocyanic, Fulminic, and Isofulminic Acids and their Interrelationships at DFT and CASPT2 Levels of Theory

Bégué,

Lafargue-Dit-Hauret,

Dargelos

et al. 2023

J. Phys. Chem. A

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Fulminic and cyanic acids played a decisive role in the conception of isomerism 200 years ago. Cyanic (HOCN), isocyanic (HNCO), and fulminic (HCNO) acids have been detected in several interstellar sources, but isofulminic acid (HONC) is little known. Here we examine the interrelationships between the four acids and formylnitrene, HC(O)N, at the CASPT2 and three DFT levels. Formylnitrene has a triplet ground state, T 0 , a closed shell singlet (CSS), S 0 , and an open-shell singlet (OSS), S 1 , lying ∼7 and 27 kcal/ mol above T 0 , respectively. The CSS is weakly stabilized by a 12 kcal/mol bond between the N and the O atoms. A conical intersection 12 kcal/mol above T 0 permits easy T 0 −S 0 interchange. Formyl azide and formylnitrene (T 0 and S 0 ) are isomerized thermally to HNCO. HOCN is best obtained via dissociation of the nitrene (or of HNCO) to H • + NCO • radicals ∼46 kcal/mol above the T 0 nitrene. Isofulminic acid, HONC, isomerizes readily to cyanic acid, HOCN, in thermal and photochemical reactions. Fulminic acid, HCNO, can isomerize to HNCO via CSS formylnitrene. Easy tautomerization prevents the preparation of HOCN in quantity. The barrier to isomerization is strongly reduced in small hydrogen-bonded aggregates so that trace amounts of HOCN can exist in equilibrium with HNCO.

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Matrix isolation study on the 1:1 hydrogen-bonded complexes [H, C, N] … [H, C, N, O]

Cited by 9 publications

References 28 publications

Structure and IR Spectroscopic Properties of HNCO Complexes with SO2 Isolated in Solid Argon

Structure and IR Spectroscopic Properties of HNCO Complexes with SO2 Isolated in Solid Argon

Experimental FTIR-MI and Theoretical Studies of Isocyanic Acid Aggregates

CHNO – Formylnitrene, Cyanic, Isocyanic, Fulminic, and Isofulminic Acids and their Interrelationships at DFT and CASPT2 Levels of Theory

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