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. 2025 Jul 7;129(28):6350–6355. doi: 10.1021/acs.jpca.5c03245

Preparation and Photochemistry of Hydroxy Isocyanate

Guohai Deng †, Caio M Porto †, Artur Mardyukov †, Peter R Schreiner †,*
PMCID: PMC12278247  PMID: 40619678

Abstract

We describe the first spectroscopic identification of hitherto experimentally unreported hydroxy isocyanate HONCO, a potential candidate for interstellar medium and prebiotic chemistry. This planar chain molecule was prepared in the gas phase through flash vacuum pyrolysis of phenyl N-hydroxycarbamate at 650 °C and was subsequently trapped in argon matrices at 3.5 K. Its characterization was accomplished by means of matrix isolation IR and UV/vis spectroscopy together with quantum chemical computations. Upon UV light (λ = 313 nm) irradiation, HONCO decomposes into hydrogen-bonded complexes of HON and HNO with CO.

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Introduction

Isocyanates (R–NCO) play a critical role not only in the synthesis of biologically active heterocycles, the fabrication of polyurethane materials, and the degradation of pesticides but also in astrochemistry and even prebiotic chemistry. The latter originates from their role in the synthesis of amino acids, in the polymerization of peptides, and in the production of nucleotides as well as nucleosides. To date, only five isocyanate derivatives have been detected in the interstellar medium (ISM): the •NCO radical (4), which is the simplest molecule containing a peptide bond backbone; isocyanic acid HNCO (5), the first detected isocyanate species in space; N-protonated isocyanic acid H2NCO+ (6); , methyl isocyanate CH3NCO (7) − and ethyl isocyanate CH3CH2NCO (8). Hence, the fundamental properties such as structures, spectral data, and photochemistry of simple isocyanates have been the focus of numerous experimental and theoretical investigations. −

Hitherto experimentally unreported parent HONCO (1) is implied in the combustion of organic compounds and atmospheric reactions , and can be regarded an interstellar molecular candidate formed from the combination of the interstellar species HO and NCO. Theoretical studies indicate that 1 might also form in the oxidation of HCN/HNC in oxygen-rich gaseous mixtures or via the CH + NO2, NH + CO2, N + HOCO, and HCO + NO reactions. − A recent ab initio study at the CCSD­(T)/CBS level of theory on the stationary structures of the HCNO2 stoichiometry found that chain-like, planar 1 is the most stable species among 20 identified minima. Hence, while the molecular structure and spectroscopic properties of 1 have been computationally studied well, 1 has not been identified experimentally. Milligan and co-workers proposed 1 as a quasi-linear chain molecule generated from the UV–vis light photolysis of HN3 in CO2 matrixes at low temperatures. However, only the next higher-lying HNCO2 isomer, HNC­(O)­O, was spectroscopically identified. This was subsequently explained by computations of the S0 and S1 states of 1, which indicate that it is unstable under UV/vis light irradiation. Intermediate 1 (and its higher congeners with H being replaced by an aryl or alkyl group) was suggested in the synthesis of hydroxylamine-derived heterocycles. Here we report the first preparation and spectroscopic characterization of 1 and outline its unreported photoreactivity (see Scheme ).

1. Hydroxy Isocyanate HONCO (1) Generated from Phenyl N-Hydroxycarbamate (2) through Pyrolysis and Trapping in an Argon Matrix and Subsequent Photoisomerization to 3, 3′; Structures of Isocyanates 4–8 Detected in the Interstellar Medium (ISM).

1

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Methods

Experimental Methods

For the matrix isolation studies, we used an RDK 408D2 closed-cycle refrigerator cold head and an F-70 compressor system equipped with an inner polished CsI window for IR measurements. IR spectra were recorded between 7000 and 350 cm–1 with a resolution of 0.7 cm–1 with a Bruker Vertex 70 FTIR spectrometer and UV/vis spectra were recorded with a JASCO V-670 spectrophotometer equipped with an inner sapphire window. A high-pressure-mercury lamp equipped with a monochromator (LOT Quantum Design) or a low-pressure-mercury lamp (Gräntzel) fitted with a Vycor filter were used for irradiation.

For the high-vacuum flash pyrolysis experiment, we used a home-built, water-cooled oven, which was directly connected to the vacuum shroud of the cryostat. The pyrolysis zone consisted of a heatable 90 mm long quartz tube with an inner diameter of 7 mm, monitored by a Ni/CrNi thermocouple. The travel distance of the sample from the pyrolysis zone to the matrix was ∼45 mm. Phenyl N-hydroxycarbamate (2) (abcr) was evaporated from a Schlenk tube at 85 °C into a quartz pyrolysis tube. All pyrolysis products were co-condensed with a large excess of argon (typically 100–120 mbar from a 2000 mL storage bulb) on both sides of the matrix window at a rate of ∼1 mbar min–1, based on the pressure inside the Ar balloon. Pyrolyses were carried out at 650 °C. D2O was mixed with PhOC­(O)­N­(H)­OH to obtain PhOC­(O)­N­(D)­OH, PhOC­(O)­N­(H)­OD, and PhOC­(O)­N­(D)­OD and excessive D2O was removed from the mixture under reduced pressure.

Computational Methods

Initial geometry optimizations were performed with Gaussian 16, Revision C.01 at the B3LYP/def2-TZVP level of theory. − Coupled cluster computations with single, double, and perturbative included triple substitutions, CCSD­(T), − were carried out using the Dunning correlation consistent split valence basis sets cc-pVTZ and aug-cc-pVTZ with the CFOUR software package. The dominant excitation of the lowest computed state of 1 was >99%. Additionally, the T1 diagnostic and the largest T2 amplitude were computed to be 0.0184 and −0.0703, respectively, both from the CCSD­(T) computations. Taken together, these results strongly suggest that the ground state and low-lying excited states are well-described within a single-reference framework.

Results and Discussion

The title molecule 1 was synthesized by flash vacuum pyrolysis (FVP) of phenyl N-hydroxycarbamate (2) at 650 °C. Specifically, 2 was evaporated at 85 °C and subjected to pyrolysis in a quartz tube. The pyrolysis products were mixed with excess argon before being condensed onto a cold matrix window at a temperature of 3.5 K.

The infrared (IR) spectrum of the pyrolysis products and the spectral changes upon irradiation in an Ar matrix are shown in Figure (Figure S1 shows the raw IR spectrum of the pyrolysis of 2 in the Supporting Information). The decomposition of 2 is evident by the observation of phenol (b, 3639/3634, 1504/1501, 1176, and 689/687 cm–1) among the pyrolysis products. Besides the strong bands of CO2 (c, 2345.3 and 663.6 cm–1) and HNCO (d, 3516.8, 3505.7, 2259.0, 769.8, and 573.7 cm–1), and the weak bands of 2, CO (e, 2138.7 cm–1) and NO (f, 1872.2 cm–1), we detected a new product (1, Figure S1) with IR bands at 3610.3, 2196.9, 1449.4, 1246.1, 862.5, 686.2, and 516 cm–1. The experimentally observed band positions are in remarkable concordance with the CCSD­(T)/cc-pVTZ computed anharmonic IR frequencies at 3651.3, 2259.0, 1441.5, 1241.6, 862.5, 686.3, and 515.6 cm–1 for the remaining product 1 (Table ). In particular, the strongest band at 2196.9 cm–1 can be assigned to the NCO antisymmetric stretching mode, which is very close to that in CH3ONCO (2196.9 cm–1, Ar matrix) and PhONCO (2200.6 cm–1, Ne matrix; 2197.6 cm–1, Ar matrix). Another strong band at 3610.3 cm–1 belongs to the characteristic stretching vibration of the OH moiety in 1, which is blue-shifted compared to that in anti-syn HONSO at 3548.6 cm–1 (N2 matrix). The assignments of these bands were also supported by the d-substitution experiment based on the characteristic isotopic shifts. For example, the stretching vibration of the OH groups in d-1, at 2669.0 cm–1, was red-shifted by 941.3 cm–1 (calc: 953.4 cm–1). The intense absorption band at 2196.9 cm–1 exhibited a red shift of 6.9 cm–1 (CCSD­(T)/cc-pVTZ: harmonic, 0 cm–1; anharmonic, 4.5 cm–1) in d-1. The combination band at 2158.3 cm–1 (calc: 1331.4 + 851.9 cm–1) was also found for d-1. The good agreement between the CCSD­(T)/cc-pVTZ anharmonically computed and experimentally measured frequencies of the 1 and d-1 isotopologues strongly supports the successful preparation of 1 and d-1 (Figure and Table ).

1.

1

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IR spectra showing the pyrolysis products of 2 with subsequent trapping in an argon matrix at 3.5 K. a) IR spectrum of 1 computed at CCSD­(T)/cc-pVTZ (anharmonic). b) IR difference spectra showing the photochemistry of 1 after irradiation with λ = 313 nm in argon at 3.5 K. Downward bands assigned to 1 disappear while upward bands assigned to 3 and 3′ appear after 20 min irradiation. c) IR spectrum of d-1 computed at CCSD­(T)/cc-pVTZ (anharmonic). d) IR difference spectra showing the photochemistry of d-1 after irradiation with λ = 313 nm in argon at 3.5 K. Bands pointing downward assigned to d-1 disappear and bands pointing upward assigned d-3 and d-3′ after 20 min irradiation.

1. Experimentally Observed and Computed IR Frequencies of 1 and d-1 at the CCSD­(T)/cc-pVTZ Level Using Second-Order Vibrational Perturbation Theory (VPT2) (Band Origins (cm–1) and Computed Intensities (km mol–1) in Parentheses).

  1
 d-1
  
Mode Harmonic Anharmonic Ar, 3.5 K Harmonic Anharmonic Ar, 3.5 K Approx Assignment
9 (A′) 3841.6 (94) 3651.3 (71) 3610.3 (30) 2798.9 (43) 2697.7 (36) 2669.0 (17) OH str
8 (A′) 2253.4 (623) 2209.0 (516) 2196.9 (100) 2253.3 (623) 2204.5 (769) 2190.0 (100) NCO asym str
7 (A′) 1493.2 (56) 1441.5 (3) 1449.4 (12) 1365.0 (<1) 1331.4 (<1) – HON bend
6 (A′) 1269.5 (48) 1233.0 (38) 1241.6 (7) 1027.5 (78) 1006.3 (185) 1000.7 (25) NO str + HON bend.
5 (A′) 883.1 (51) 858.2 (46) 862.5 (14) 874.3 (36) 851.9 (35) 855.6 (8) NO str
4 (A′) 694.6 (17) 690.0 (14) 686.3 (6) 692.6 (16) 688.2 (15) 684.6 (6) NCO bend.
3 (A′) 514.3 (9) 514.1 (9) 515.6 (3) 513.1 (12) 512.2 (12) 514.7 (5) NOC bend.
2 (A″) 226.2 (8) 217.7 (9) – 221.6 (8) 214.5 (9) –  
1 (A″) 204.9 (127) 171.1 (113) – 150.9 (65) 134.7 (64) –  
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a

Not observed.

Irradiation of the pyrolysis products in argon at 313 nm results in about 90% decomposition of HONCO after 30 min and the formation of two new groups of IR bands. Interestingly, HNC­(O)­O, HC­(O)­NO, and HN­(O)­CO) were not identified. Considering the previously reported photochemistry of covalent isocyanates and more recently the novel phosphinyl radical HPNCO• conversion to •NPH···CO and •PNH···CO complexes upon UV light irradiation, six possible products with H-bonding interactions were investigated computationally at B3LYP-D3­(BJ)/def2-TZVP (Figure S2).

Two groups of bands at 3364.4/2165.4/1127.2 cm–1 (3) and 2744.1/2145.6/1568.9 cm–1 (3′) are assigned to NOH···CO in the triplet ground state and ONH···CO in the singlet ground state, respectively, by comparison with the computed IR frequencies (Table S1 and Table S2). Both complexes have C s symmetry. For product 3, the strong band at 3364.4 cm–1 with an isotopic shift of −874.1 cm–1 (calc.: −942 cm–1) can readily be assigned to the H–O stretching mode, which is red-shifted compared to free HON (3467.2 cm–1, Ar matrix). For product 3′, the first band at 2744.1 cm–1 shows an H/D isotope shift of −732.1 cm–1 (calc.: −766 cm–1) that is attributed to the H–N vibrational mode. This band is very close to the same vibrational mode of free HNO (2715.1 cm–1, Ar matrix). The CO vibrations in both complexes (2165.4 cm–1, 3; 2145.6 cm–1, 3′) are blue-shifted in comparison to the band at 2138.5 cm–1 for free CO in the same Ar matrix, and they show very small H/D isotopic shifts (+0.6 cm–1, 3; +0.3 cm–1, 3′). Similarly small blue shifts of the CO vibration were also observed for •NPH···CO, •PNH···CO and H2O2···CO. The two sets of IR bands for the characteristic HO/CO and HN/CO stretching modes and the H/D isotopic shifts as well as the computed frequencies (Table S1 and Table S2) strongly suggest assignment to the NOH···CO and ONH···CO complexes. The formation of these is due to the matrix effect that the photofragments HON/HNO and CO can not readily escape from the rigid Ar matrix cage. , Similar arguments apply to the fact that we did not observe the dissociation of 1 into HO• and •NCO, because the barrier for radical–radical recombination will be small relative to the high exothermicity of this reaction. Second, the two radicals cannot escape the matrix cage and therefore would recombine very rapidly upon ending the irradiation. Attempts to convert NOH···CO into ONH···CO failed.

Along with the IR analysis, we carried out UV/vis experiments for the characterization of 1 (Figure ). The UV/vis spectrum of matrix-isolated 1 displays a broad absorption band at λmax = 203 nm. Consistent with the IR observation, the intensity of the 203 nm band decreases when irradiated at 313 nm. The broad band at 203 nm correlates well with the computed value at 202 nm (f = 0.031) at the TD-B3LYP/def2-TZVP level of theory. This band arises from a HOMO → LUMO+4 excitation, which correlates with a π → π* transition (Figure ).

2.

2

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Solid line: UV/vis spectrum of 1 trapped at 10 K in Ar. Dashed lines: After irradiation of 1 at λ = 313 nm for 15 and 45 min in argon at 10 K. Inset: TD-B3LYP/def2-TZVP computed the electronic transitions for 1.

The molecular structures of 1 and the two hydrogen-bonded complexes 3 and 3′ computed at B3LYP/def2-TZVP are shown in Figure and Figure S2, and these results are consistent with previous theoretical reports on the structures of 1 and its isomers. According to these, planar C s -1 has a singlet ground state with a nearly linear NCO fragment. The second most stable isomer, HNC­(O)­O, lies +10.3 kcal mol–1 above 1 at B3LYP/def2-TZVP [5.5 kcal mol–1 at CCSD­(T)/CBS].

3.

3

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Computed potential energy profile for the decomposition of HONCO (1) at CCSD­(T)/aug-cc-pVTZ//B3LYP-D3­(BJ)/def2-TZVP. The energies are in kcal mol–1 and are ZPVE corrected, i.e., ΔH 0.

As to the two hydrogen-bonded complexes, C s -3 has an A″ triplet ground state with symmetry, while C s-3′ possesses an A′ singlet ground state. The computed singlet–triplet energy separation Δ­(E ST) of C s -3 is +25.0 kcal mol–1 at CCSD­(T)/aug-cc-pVTZ//B3LYP-D3­(BJ)/def2-TZVP, while that of C s -3′ is −38.9 kcal mol–1. The dissociation energy (D e) of C s -3 is 2.8 kcal mol–1, about twice that of 3′ (1.3 kcal mol–1) (Figure S2). The noncovalent hydrogen bond length in 3 (2.099 Å) is significantly shorter than that in •NPH···CO (2.438 Å) resulting in a smaller D e of 1.5 kcal mol–1 for the latter. The stronger H-bond in C s -3 also accounts for the larger blue shift (+26.9 cm–1) of the CO stretching frequency as compared to that in •NPH···CO (+5.5 cm–1) relative to free CO. In less stable C s -3′, the intermolecular hydrogen bond length is 2.500 Å, consistent with C s -3′ having a lower dissociation energy. In both complexes, the carbon atom of the CO moiety serves as the hydrogen bond acceptor. Such complexes have also been observed with water and ammonia.

To better understand the photochemistry of 1, the potential energy profile for the decomposition of 1 was explored computationally at the CCSD­(T)/aug-cc-pVTZ//B3LYP-D3­(BJ)/def2-TZVP level of theory (Figure ). In line with the thermal persistence of 1 in the gas phase, we computed two barriers for its highly endothermic dissociation to HO•/•NCO and H•/•ONCO. The absence of •NCO and •ONCO is in accordance with the high bond dissociation energies for the O–N (51.6 kcal mol–1) and H–O (87.2 kcal mol–1) bonds of 1, and the matrix cage effects as noted above. The activation barrier (TS1) for the CO-elimination to give the high-lying HON···CO complex is 59.5 kcal mol–1. The initially generated HON···CO complex is barely stable and will likely further isomerize to singlet C s -3 via a barrierless transition state; this reaction is exothermic by 7.2 kcal mol–1. The second process refers to the intramolecular rearrangement from C s -3 to C s -3′, which needs to surmount a barrier of 23.5 kcal mol–1. The overall reaction giving C s -3′ is exothermic by −10.9 kcal mol–1.

Conclusions

We describe the first preparation and IR as well as UV/vis spectroscopic characterization of hydroxy isocyanate HONCO, a potential candidate molecule in the interstellar medium relevant to prebiotic chemistry. The firm spectroscopic evidence of HONCO is important in the context of the abiotic formation of amino acids and peptides for which isocyanates are likely to be important intermediates. Our studies aid the identification of HONCO in extraterrestrial environments.

Supplementary Material

jp5c03245_si_001.pdf (501.9KB, pdf)

Acknowledgments

This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Advanced Grant No. 101054751 “COLDOC” to P.R.S.). Views and opinions expressed are those of the authors only and do not necessarily reflect those of the European Union or the European Research Council. Neither the European Union nor the granting authority can be held responsible for them. We acknowledge Dennis Gerbig, Stephen M. Goodlett, and Akkad Danho for their generous help during the development of this work.

The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acs.jpca.5c03245.

  • Experimental infrared spectra, computed structures, vibrational frequencies, and atomic coordinates and energies (PDF)

The authors declare no competing financial interest.

Published as part of The Journal of Physical Chemistry A special issue “Joseph S. Francisco Festschrift”.

References

  1. Thakur A., Louie J.. Advances in Nickel-catalyzed Cycloaddition Reactions to Construct Carbocycles and Heterocycles. Acc. Chem. Res. 2015;48:2354–2365. doi: 10.1021/acs.accounts.5b00054. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Delebecq E., Pascault J.-P., Boutevin B., Ganachaud F.. On the Versatility of Urethane/urea Bonds: Reversibility, Blocked Isocyanate, and Non-isocyanate Polyurethane. Chem. Rev. 2013;113:80–118. doi: 10.1021/cr300195n. [DOI] [PubMed] [Google Scholar]
  3. Sendijarevic V., Sendijarevic A., Sendijarevic I., Bailey R. E., Pemberton D., Reimann K. A.. Hydrolytic Stability of Toluene Diisocyanate and Polymeric Methylenediphenyl Diisocyanate Based Polyureas under Environmental Conditions. Environ. Sci. Technol. 2004;38:1066–1072. doi: 10.1021/es035072f. [DOI] [PubMed] [Google Scholar]
  4. Pascal, R. ; Boiteau, L. ; Commeyras, A. . From the Prebiotic Synthesis of α-Amino Acids Towards a Primitive Translation Apparatus for the Synthesis of Peptides. In Prebiotic Chemistry: From Simple Amphiphiles to Model Protocells; Topics in Current Chemistry, Vol. 259; Walde, P. , Ed.; Springer: Berlin, 2005. [Google Scholar]
  5. Choe J. C.. Can Cytosine, Uracil, and Thymine Be Formed from HC3N and H2NCO+ in Interstellar Space? ApJ. 2021;914:136. doi: 10.3847/1538-4357/abfd34. [DOI] [Google Scholar]
  6. Schneider C., Becker S., Okamura H., Crisp A., Amatov T., Stadlmeier M., Carell T.. Noncanonical RNA Nucleosides as Molecular Fossils of an Early Earth-Generation by Prebiotic Methylations and Carbamoylations. Angew. Chem. In. Ed. 2018;57:5943–5946. doi: 10.1002/anie.201801919. [DOI] [PubMed] [Google Scholar]
  7. Marcelino N., Agúndez M., Cernicharo J., Roueff E., Tafalla M.. Discovery of the Elusive Radical NCO and Confirmation of H2NCO+ in Space. Astron. Astrophys. 2018;612:L10. doi: 10.1051/0004-6361/201833074. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Snyder L. E., Buhl D.. Interstellar Isocyanic Acid. ApJ. 1972;177:619. doi: 10.1086/151739. [DOI] [Google Scholar]
  9. Gupta H., Gottlieb C. A., Lattanzi V., Pearson J. C., McCarthy M. C.. Laboratory Measurements and Tentative Astronomical Identification of H2NCO+ . ApJL. 2013;778:L1. doi: 10.1088/2041-8205/778/1/L1. [DOI] [Google Scholar]
  10. Halfen D. T., Ilyushin V. V., Ziurys L. M.. Interstellar Detection of Methyl Isocyanate CH3NCO in Sgr B2­(N): A Link from Molecular Clouds to Comets. ApJ. 2015;812:L5. doi: 10.1088/2041-8205/812/1/L5. [DOI] [Google Scholar]
  11. Cernicharo J., Kisiel Z., Tercero B., Kolesniková L., Medvedev I. R., López A., Fortman S., Winnewisser M., Lucia F. C. de, Alonso J. L.. et al. A Rigorous Detection of Interstellar CH3NCO: An Important Missing Species in Astrochemical Networks. Astron. Astrophys. 2016;587:L4. doi: 10.1051/0004-6361/201527531. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Gorai P., Bhat B., Sil M., Mondal S. K., Ghosh R., Chakrabarti S. K., Das A.. Identification of Prebiotic Molecules Containing Peptide-like Bonds in a Hot Molecular Core, G10.47 + 0.03. ApJ. 2020;895:86. doi: 10.3847/1538-4357/ab8871. [DOI] [Google Scholar]
  13. Ligterink N. F. W., Ahmadi A., Coutens A., Tychoniec Ł., Calcutt H., van Dishoeck E. F., Linnartz H., Jørgensen J. K., Garrod R. T., Bouwman J.. The Prebiotic Molecular Inventory of Serpens SMM1. Astron. Astrophys. 2021;647:A87. doi: 10.1051/0004-6361/202039619. [DOI] [Google Scholar]
  14. Rodriguez-Almeida L. F., Rivilla V. M., Jimenez-Serra I., Melosso M., Colzi L., Zeng S., Tercero B., de Vicente P., Martin S., Requena-Torres M. A., Rico-Villas F., Martin-Pintado J.. et al. First Detection of C2H5NCO in the ISM and Search of Other Isocyanates Towards the G+0.693–0.027 Molecular Cloud. Astron. Astrophys. 2021;654:L1. doi: 10.1051/0004-6361/202141989. [DOI] [Google Scholar]
  15. Wang L., Jiang X., Trabelsi T., Wang G., Francisco J. S., Zeng X., Zhou M.. Spectroscopic Study of [Mg, H, N, C, O] Species: Implications for the Astrochemical Magnesium Chemistry. J. Am. Chem. Soc. 2024;146:4162–4171. doi: 10.1021/jacs.3c13144. [DOI] [PubMed] [Google Scholar]
  16. Wang L., Jiang X., Sun B., Trabelsi T., Francisco J. S., Zeng X., Zhou M.. Spectroscopy and Photochemistry of [Al, N, C, O, H]: Connectivity to Aluminium-Bearing Species in the Universe. Chem.Eur. J. 2024;30:e202401397. doi: 10.1002/chem.202401397. [DOI] [PubMed] [Google Scholar]
  17. Trabelsi T., Davis M. C., Fortenberry R. C., Francisco J. S.. Spectroscopic Investigation of Al, N, C, O Refractory Molecules. J. Chem. Phys. 2019;151:244303. doi: 10.1063/1.5125268. [DOI] [PubMed] [Google Scholar]
  18. Haupa K. A., Tarczay G., Lee Y.-P.. Hydrogen Abstraction/Addition Tunneling Reactions Elucidate the Interstellar H2NCHO/HNCO Ratio and H2 Formation. J. Am. Chem. Soc. 2019;141:11614–11620. doi: 10.1021/jacs.9b04491. [DOI] [PubMed] [Google Scholar]
  19. Qin Y., Lu B., Rauhut G., Hagedorn M., Banert K., Song C., Chu X., Wang L., Zeng X.. The Simplest, Isolable, Alkynyl Isocyanate HC≡CNCO: Synthesis and Characterization. Angew. Chem. In. Ed. 2019;58:17277–17281. doi: 10.1002/anie.201911102. [DOI] [PubMed] [Google Scholar]
  20. Rim K. T., Hershberger J. F.. A Diode Laser Study of the Product Branching Ratios of the CH + NO2 Reaction. J. Phys. Chem. A. 1998;102:4592–4595. doi: 10.1021/jp981362k. [DOI] [Google Scholar]
  21. Cicerone R. J., Zellner R.. The Atmospheric Chemistry of Hydrogen Cyanide (HCN) J. Geophys. Res. 1983;88:10689–10696. doi: 10.1029/JC088iC15p10689. [DOI] [Google Scholar]
  22. Ziurys L. M.. The Chemistry in Circumstellar Envelopes of Evolved Stars: Following the Origin of the Elements to the Origin of Life. Proc. Natl. Acad. Sci. U.S.A. 2006;103:12274–12279. doi: 10.1073/pnas.0602277103. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Tao Y., Ding Y., Li Z., Huang X., Sun C.-C.. Theoretical Study on Reaction Mechanism of the Methylidyne Radical with Nitrogen Dioxide. J. Phys. Chem. A. 2001;105:3388–3399. doi: 10.1021/jp003717h. [DOI] [Google Scholar]
  24. Tao Y., Ding Y., Li Z., Huang X., Sun C.-C.. Theoretical Study on Triplet Potential Energy Surface of the CH­(2Π) + NO2 Reaction. J. Phys. Chem. A. 2001;105:9598–9610. doi: 10.1021/jp012481u. [DOI] [Google Scholar]
  25. Fontijn A., Shamsuddin S. M., Crammond D., Marshall P., Anderson W. R.. Kinetics of the NH Reaction with H2 and Reassessment of HNO Formation from NH + CO2, H2O. Combust. Flame. 2006;145:543–551. doi: 10.1016/j.combustflame.2005.12.012. [DOI] [Google Scholar]
  26. Dibble T. S., Zeng Y.. Potential Energy Profiles for the N + HOCO Reaction and Products of the Chemically Activated Reactions N + HOCO and H + HOCO. Chem. Phys. Lett. 2010;495:170–174. doi: 10.1016/j.cplett.2010.06.075. [DOI] [Google Scholar]
  27. Kulkarni S. A., Koga N.. Ab Initio and Density Functional Investigation of Reactions of NO with XCO (X = H, F, Cl) J. Phys. Chem. A. 1998;102:5228–5235. doi: 10.1021/jp972541p. [DOI] [Google Scholar]
  28. Tourchi A. E., Benabdelkrim A., Hammoutène D., Ben Yaghlane S., Abdallah H. H., Ben Said R., Linguerri R., Hochlaf M.. Theoretical Characterization of the Structure and Spectroscopy of HCNO2 Isomers and Applications. J. Phys. Chem. A. 2020;124:11061–11071. doi: 10.1021/acs.jpca.0c09027. [DOI] [PubMed] [Google Scholar]
  29. Puzzarini C., Linguerri R., Hochlaf M.. Insights into the Molecular Structure and Spectroscopic Properties of HONCO: An Accurate Ab Initio Study. J. Phys. Chem. A. 2023;127:9502–9512. doi: 10.1021/acs.jpca.3c05741. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Milligan D. E., Jacox M. E., Charles S. W., Pimentel G. C.. Infrared Spectroscopic Study of the Photolysis of HN3 in Solid CO2 . J. Chem. Phys. 1962;37:2302–2310. doi: 10.1063/1.1733002. [DOI] [Google Scholar]
  31. Ivanovich R. A., Polat D. E., Beauchemin A. M.. Oxygen-Substituted Isocyanates: Blocked (Masked) Isocyanates Enable Controlled Reactivity. Adv. Synth. Catal. 2017;359:4289–4293. doi: 10.1002/adsc.201701046. [DOI] [Google Scholar]
  32. Frisch, M. J. ; Trucks, G. W. ; Schlegel, H. B. ; Scuseria, G. E. ; Robb, M. A. ; Cheeseman, J. R. ; Scalmani, G. ; Barone, V. ; Petersson, G. A. ; Nakatsuji, H. ; et al. Gaussian 16; revision C.01; Gaussian, Inc.: Wallingford, CT, 2016. [Google Scholar]
  33. Weigend F., Ahlrichs R.. Balanced Basis Sets of Split Valence, Triple Zeta Valence and Quadruple Zeta Valence Quality for H to Rn: Design and Assessment of Accuracy. Phys. Chem. Chem. Phys. 2005;7:3297–3305. doi: 10.1039/b508541a. [DOI] [PubMed] [Google Scholar]
  34. Stephens P. J., Devlin F. J., Chabalowski C. F., Frisch M. J.. Ab Initio Calculation of Vibrational Absorption and Circular Dichroism Spectra Using Density Functional Force Fields. J. Phys. Chem. 1994;98:11623–11627. doi: 10.1021/j100096a001. [DOI] [Google Scholar]
  35. Becke A. D.. Density-functional Thermochemistry. III. The Role of Exact Exchange. J. Chem. Phys. 1993;98:5648–5652. doi: 10.1063/1.464913. [DOI] [Google Scholar]
  36. Pople J. A., Head-Gordon M., Raghavachari K.. Quadratic Configuration Interaction. A General Technique for Determining Electron Correlation Energies. J. Chem. Phys. 1987;87:5968–5975. doi: 10.1063/1.453520. [DOI] [Google Scholar]
  37. Pople J. A., Krishnan R., Schlegel H. B., Binkley J. S.. Electron Correlation Theories and Their Application to the Study of Simple Reaction Potential Surfaces. Int. J. Quantum Chem. 1978;14:545–560. doi: 10.1002/qua.560140503. [DOI] [Google Scholar]
  38. Bartlett R. J., Purvis G. D.. Many-body Perturbation Theory, Coupled-pair Many-electron Theory, and the Importance of Quadruple Excitations for the Correlation Problem. Int. J. Quantum Chem. 1978;14:561–581. doi: 10.1002/qua.560140504. [DOI] [Google Scholar]
  39. Dunning T. H.. Gaussian Basis Sets for Use in Correlated Molecular Calculations. I. The Atoms Boron Through Neon and Hydrogen. J. Chem. Phys. 1989;90:1007–1023. doi: 10.1063/1.456153. [DOI] [Google Scholar]
  40. Kendall R. A., Dunning T. H. Jr, Harrison R. J.. Electron Affinities of the First-row Atoms Revisited. Systematic Basis Sets and Wave Functions. J. Chem. Phys. 1992;96:6796–6806. doi: 10.1063/1.462569. [DOI] [Google Scholar]
  41. Stanton, J. F. ; Gauss, J. ; Cheng, L. ; Harding, M. E. ; Matthews, D. A. ; Szalay, P. G. , with contributions from Auer, A. A. ; Bartlett, R. J. ; Benedikt, U. ; Berger, C. ; et al. For the current version, see http://www.cfour.de.
  42. Gor G. Y., Tapio S., Domanskaya A. V., Räsänen M., Nemukhin A. V., Khriachtchev L.. Matrix-isolation Study of The Phenol-water Complex and Phenol Dimer. Chem. Phys. Lett. 2011;517:9–15. doi: 10.1016/j.cplett.2011.09.089. [DOI] [Google Scholar]
  43. Gómez Castaño J. A., Fantoni A., Romano R. M.. Matrix-isolation FTIR study of Carbon Dioxide: Reinvestigation of the CO2 Dimer and CO2···N2 complex. J. Mol. Struct. 2008;881:68–75. doi: 10.1016/j.molstruc.2007.08.035. [DOI] [Google Scholar]
  44. Zeng X., Bernhardt E., Beckers H., Banert K., Hagedorn M., Liu H.. Formyl Azide: Properties and Solid-state Structure. Angew. Chem. In. Ed. 2013;52:3503–3506. doi: 10.1002/anie.201209288. [DOI] [PubMed] [Google Scholar]
  45. Zeng X., Beckers H., Willner H., Stanton J. F.. Elusive Diazirinone, N2CO. Angew. Chem. In. Ed. 2011;50:1720–1723. doi: 10.1002/anie.201006745. [DOI] [PubMed] [Google Scholar]
  46. Dozova N., Krim L., Alikhani M. E., Lacome N.. Vibrational Spectra and Structures of H2O-NO, HDO-NO, and D2O-NO Complexes. An IR Matrix Isolation and DFT Study. J. Phys. Chem. A. 2006;110:11617–11626. doi: 10.1021/jp0625614. [DOI] [PubMed] [Google Scholar]
  47. Li H., Wu Z., Li D., Wan H., Xu J., Abe M., Zeng X.. Direct Observation of Methoxycarbonylnitrene. Chem. Commun. 2017;53:4783–4786. doi: 10.1039/C7CC01926B. [DOI] [PubMed] [Google Scholar]
  48. Wan H., Xu J., Liu Q., Li H., Lu Y., Abe M., Zeng X.. Contrasting Photolytic and Thermal Decomposition of Phenyl Azidoformate: The Curtius Rearrangement Versus Intramolecular C-H Amination. J. Phys. Chem. A. 2017;121:8604–8613. doi: 10.1021/acs.jpca.7b07969. [DOI] [PubMed] [Google Scholar]
  49. Chen C., Wang L., Zhao X., Wu Z., Bernhardt B., Eckhardt A. K., Schreiner P. R., Zeng X.. Photochemistry of HNSO2 in Cryogenic Matrices: Spectroscopic Identification of the Intermediates and Mechanism. Phys. Chem. Chem. Phys. 2020;22:7975–7983. doi: 10.1039/D0CP00962H. [DOI] [PubMed] [Google Scholar]
  50. Zhu B., Jiang J., Lu B., Li X., Jiang X., Rauhut G., Zeng X.. Phosphenic Isocyanate (O2PNCO): Gas-phase Generation, Characterization, and Photodecomposition Reactions. Chem. Commun. 2022;58:10703–10706. doi: 10.1039/D2CC03178G. [DOI] [PubMed] [Google Scholar]
  51. Jiang J., Huang L., Zhu B., Fan W., Wang L., Zhang I. Y., Fang W., Trabelsi T., Francisco J. S., Zeng X.. Hydrogen-Bonded Complexes of HPN· and HNP· Radicals with Carbon Monoxide. Angew. Chem. In. Ed. 2025;64:e202414456. doi: 10.1002/anie.202414456. [DOI] [PubMed] [Google Scholar]
  52. Maier G., Reisenauer H. P., De Marco M.. Isonitroso Hydrogen (Hydroxy Nitrene, HON) Angew. Chem., Int. Ed. 1999;38:108–110. doi: 10.1002/(SICI)1521-3773(19990115)38:1/2&#x0003c;108::AID-ANIE108&#x0003e;3.0.CO;2-U. [DOI] [Google Scholar]
  53. Mardyukov A., Hernández F. J., Song L., Crespo-Otero R., Schreiner P. R.. Experimentally Delineating the Catalytic Effect of a Single Water Molecule in the Photochemical Rearrangement of the Phenylperoxy Radical to the Oxepin-2­(5H)-one-5-yl Radical. J. Am. Chem. Soc. 2024;146:19070–19076. doi: 10.1021/jacs.4c03461. [DOI] [PubMed] [Google Scholar]
  54. Barclay A. J., van der Avoird A., McKellar A. R. W., Moazzen-Ahmadi N.. The Water-Carbon Monoxide Dimer: New Infrared Spectra, ab initio Rovibrational Energy Level Calculations, and an Interesting In-termolecular Mode. Phys. Chem. Chem. Phys. 2019;21:14911–14922. doi: 10.1039/C9CP02815C. [DOI] [PubMed] [Google Scholar]
  55. Surin L. A., Potapov A., Dolgov A. A., Tarabukin I. V., Panfilov V. A., Schlemmer S., Kalugina Y. N., Faure A., van der Avoird A.. Rotational Study of the NH3-CO Complex: Millimeter-wave Measurements and ab initio Calculations. J. Chem. Phys. 2015;142:114308. doi: 10.1063/1.4915119. [DOI] [PubMed] [Google Scholar]

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