Probing the adsorption mechanism in thiamazole bound to the silver surface with Surface-enhanced Raman Scattering and DFT

Biswas, Nandita; Thomas, Susy; Sarkar, Anjana; Mukherjee, Tulsi; Kapoor, Sudhir

doi:10.1016/j.cplett.2009.08.022

Cited by 25 publications

(10 citation statements)

References 27 publications

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“…Functional Theory (DFT)) have also shown the thione form to be favored energetically 59,60  a finding that is confirmed by the higher-level calculations reported here. The present work also compares and contrasts the UV photophysics displayed by methimazole with those of imidazole 39 and thiol-containing molecules.…”

Section: Introductionsupporting

confidence: 85%

“…52,54,55 The N−H proton is labile in solution, 56,57 but the thione form again dominates the equilibrium, 56,58 with one NMR study reporting (solvent-dependent) mole fractions in the range of 0.98−1.00. 57 Prior computational studies (second-order Møller−Plesset perturbation theory (MP2) and density functional theory (DFT)) have also shown the thione form to be favored energetically, 59,60 a finding that is confirmed by the higher-level calculations reported here. The present work also compares and contrasts the UV photophysics displayed by methimazole with those of imidazole 39 and thiol-containing molecules.…”

Section: Introductionsupporting

confidence: 76%

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Photofragment Translational Spectroscopy Studies of H Atom Loss Following Ultraviolet Photoexcitation of Methimazole in the Gas Phase

et al. 2018

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The ultraviolet (UV) photodissociation of gas phase methimazole has been investigated by H Rydberg atom photofragment translational spectroscopy methods at many wavelengths in the range 222.5-275 nm and by complementary electronic structure calculations. Methimazole is shown to exist predominantly as the thione tautomer, 1-methyl-2(3H)-imidazolinethione, rather than the commonly given thiol form, 2-mercapto-1-methylimidazole. The UV absorption spectrum of methimazole is dominated by the S 4 S 0 transition of the thione tautomer, which involves electron promotion from an a′ (p y) orbital localized on the sulfur atom to a σ* orbital localized around the N-H bond. Two H atom formation pathways are identified following UV photoexcitation. One, involving prompt, excited state N-H bond fission, yields vibrationally cold but rotationally excited methimazolyl (Myl) radicals in their first excited () electronic state. The second yields H atoms with an isotropic recoil velocity distribution peaking at low kinetic energies but extending to the energetic limit allowed by energy conservation given a ground state dissociation energy D 0 (Myl-H) ~24 000 cm-1. These latter H atoms are attributed to the unimolecular decay of highly vibrationally excited S 0 parent molecules. The companion electronic structure calculations provide rationales for both fragmentation pathways and the accompanying product energy disposals, and highlight similarities and differences between the UV photochemistry of methimazole and that of other azoles (e.g. imidazole) and with molecules like thiourea and thiouracil that contain similar N-C=S motifs.

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Section: Introductionsupporting

confidence: 85%

Section: Introductionsupporting

confidence: 76%

Photofragment Translational Spectroscopy Studies of H Atom Loss Following Ultraviolet Photoexcitation of Methimazole in the Gas Phase

et al. 2018

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“…Finally, in the 1400-1500 cm -1 region no strong band appears, while the band at higher frequency, around 1580 cm -1 , is missing. SERS spectra of TZ in silver colloids were analyzed by Biswas et al, 25 who proposed chemisorption of the ligand through both the sulfur atom and the ring nitrogen atom of the thiolate anion. SERS spectra in gold colloids, instead, are not reported so far in the literature.…”

Section: Sers Spectra In Gold Colloidsmentioning

confidence: 99%

Raman and DFT study of methimazole chemisorbed on gold colloidal nanoparticles

Muniz‐Miranda

Pedone

2016

Phys. Chem. Chem. Phys.

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The adsorption of methimazole on gold colloidal nanoparticles was investigated using a combination of surface-enhanced Raman scattering and density functional theory calculations, which allowed identifying the thiolate anion as the molecular species chemically interacting with the active sites of the gold surface, modeled as zero-charge metal adatoms, only through the sulfur atom. This result can be important for the use of these ligand/metal nanohybrids in the process of drug delivery. Moreover, functionalized gold nanoparticles are able to promote the Raman enhancement in the red-light region as well as in the near-infrared, where generally no fluorescence emission occurs. This paves the way for the use of these nanosystems in a biological environment, even in vivo experiments.

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“…Raman spectroscopy of thiols, especially mercaptans, has been amply used also for the study of the interaction with Ag surfaces and nanoparticles. Techniques such as Surface Enhanced Raman Spectroscopy (SERS) have been found particularly useful for this task18–24. Several of these studies employed also density functional theory to support the experimental findings.…”

Section: Introductionmentioning

confidence: 99%

Calculations of the infrared and Raman spectra of simple thiols and thiol–water complexes

Kieninger¹,

Ventura²

2010

Int J of Quantum Chemistry

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ABSTRACT:The frequencies and intensities of infrared and Raman spectra of H 2 S, CH 3 SH, CH 3 CH 2 SH, and CH 2 ¼ ¼CHCH 2 SH, isolated and complexed with one water molecule acting as a proton acceptor were calculated at the ab initio and density functional level. Hartree-Fock, MP2 and CCSD(T) methods were used both for the geometry optimization and spectra calculations at the molecular orbital level. The B3LYP, PBE0, and M06 exchange-correlation potentials were employed to calculate the same properties at the DFT level. Both Pople basis sets, 6-31þG(d) and 6-311þþG(3df,2pd), and Dunning basis sets, aug-cc-pVTZ and aug-cc-pVQZ, were used. SH and CS frequency shifts upon water complexation were studied, and a discussion is performed on the expected relation between the CH and CS Raman activities, in view of their usefulness for studies in protein chemistry. Scaling factors for the vibrational frequencies were obtained for all the combination of methods and basis sets, and shown to be completely similar to the ones present in the literature when available. Scaling factors for the M06 method are presented for the first time with these basis sets.

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Probing the adsorption mechanism in thiamazole bound to the silver surface with Surface-enhanced Raman Scattering and DFT

Cited by 25 publications

References 27 publications

Photofragment Translational Spectroscopy Studies of H Atom Loss Following Ultraviolet Photoexcitation of Methimazole in the Gas Phase

Photofragment Translational Spectroscopy Studies of H Atom Loss Following Ultraviolet Photoexcitation of Methimazole in the Gas Phase

Raman and DFT study of methimazole chemisorbed on gold colloidal nanoparticles

Calculations of the infrared and Raman spectra of simple thiols and thiol–water complexes

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