Energetics and Vibrational Analysis of Methyl Salicylate Isomers

Massaro, Richard; Dai, Yafei; Blaisten‐Barojas, Estela

doi:10.1021/jp905887m

Cited by 24 publications

(30 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Therefore MD results shows that intramolecular hydrogen bonding is very slightly weakened in liquid phases but remarkable intermolecular hydrogen bonding should be discarded, and thus, interactions between neighbour molecules should be developed mainly through dipolar interactions as for its parent molecule methyl benzoate [1]. A detailed theoretical analysis of IR results for MS was previously reported by Massaro et al [9] and experimental data were reported by Varghese et al [24]. ATR-FTIR results obtained in this work are reported in Figures 3-6.…”

Section: Resultsmentioning

confidence: 95%

“…Melandri et al [8] reported a rotational spectroscopy study on MS showing that the ground electronic state of this molecule adopts a form stabilized through the development of intramoleculecular hydrogen bonding between the hydroxyl and carbonyl groups. Massaro et al [9] reported a vibrational analysis of MS isomers showing that the lowest energy isomer is the MS1 form (Scheme 1), in which intramolecular hydrogen bonding between hydroxyl hydrogen and carbonyl oxygen is developed. These authors also showed that the form MS2 (Scheme 1), in which hydrogen bonding is developed between the hydroxyl hydrogen and the methoxy oxygen moieties is also very stable.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

On the Structure of Liquid Methyl Salicylate: the Role of Intramolecular Hydrogen Bonding

Aparício¹,

Alcalde²

2010

Eur. J. Chem.

View full text Add to dashboard Cite

A study on the structure of methyl salicylate is reported using quantum mechanical calculations, molecular dynamics simulations, vibrational spectroscopy and microwave dielectric relaxation spectroscopy tools. The reported results show that a strong intramolecular hydrogen bonding is developed between the hydroxyl hydrogen and carbonyl oxygen. This intramolecular interaction is maintained in gas and liquid phases and even when diluted in inert solvents. Interaction between neighbour molecules is developed through dipolar interactions, and thus, intermolecular hydrogen bonding should be discarded for pure liquid methyl salicylate. The interaction between neighbour methyl salicylate molecules do not lead to remarkable changes in the intramolecular hydrogen bonding. SalicylateHydrogen bonding DFT-Molecular dynamics Vibrational spectroscopy Relaxation spectroscopy

show abstract

Section: Resultsmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

On the Structure of Liquid Methyl Salicylate: the Role of Intramolecular Hydrogen Bonding

Aparício¹,

Alcalde²

2010

Eur. J. Chem.

View full text Add to dashboard Cite

show abstract

“…Three MS isomers (ketoB, enol, and ketoA) 23 in their gas phase were optimized within the hybrid B3PW91 scheme and basis sets 6-31++G, 6-311++G, 6-311++G(d), 6-31+G(3d,3p), and 6-311++G(3d,3p) to determine the ground state structures, force constants, and wave functions. These structures were then used as input to vertical excitation TDDFT calculations at the same level of theory.…”

Section: Structural Characteristics Of Ms Isomers In Excited Statesmentioning

confidence: 99%

“…Recently 23 we have reported the ground state energetics of six MS isomers calculated within density functional theory (DFT) and large basis sets. Notably, we have predicted that in the ground state ketoB is the most stable isomer followed in energy by the rotamer ketoA (Fig.…”

Section: Introductionmentioning

confidence: 99%

Theoretical investigation of the photophysics of methyl salicylate isomers

Massaro

Blaisten‐Barojas

2011

The Journal of Chemical Physics

Self Cite

View full text Add to dashboard Cite

The photophysics of methyl salicylate (MS) isomers has been studied using time-dependent density functional theory and large basis sets. First electronic singlet and triplet excited states energies, structure, and vibrational analysis were calculated for the ketoB, enol, and ketoA isomers. It is demonstrated that the photochemical pathway involving excited state intramolecular proton transfer (ESIPT) from the ketoB to the enol tautomer agrees well with the dual fluorescence in near-UV (from ketoB) and blue (from enol) wavelengths obtained from experiments. Our calculation confirms the existence of a double minimum in the excited state pathway along the O-H-O coordinate corresponding to two preferred energy regions: (1) the hydrogen belongs to the OH moiety and the structure of methyl salicylate is ketoB; (2) the hydrogen flips to the closest carboxyl entailing electronic rearrangement and tautomerization to the enol structure. This double well in the excited state is highly asymmetric. The Franck-Condon vibrational overlap is calculated and accounts for the broadening of the two bands. It is suggested that forward and backward ESIPT through the barrier separating the two minima is temperature-dependent and affects the intensity of the fluorescence as seen in experiments. When the enol fluoresces and returns to its ground state, a barrier-less back proton transfer repopulates the ground state of methyl salicylate ketoB. It is also demonstrated that the rotamer ketoA is not stable in an excited state close to the desired emission wavelength. This observation eliminates the conjecture that the near-UV emission of the dual fluorescence originates from the ketoA rotamer. New experimental results for pure MS in the liquid state are reported and theoretical results compared to them.

show abstract

“…The extent to which these bands are excited depends on the voltage applied to, and the current flowing through, the discharge gap. Figure 7 shows [88]. The "enolized" isomers are higher energy isomers corresponding to hydrogen transfer to the ketonic oxygen.…”

Section: Discussionmentioning

confidence: 99%

Molecular modeling interpretation of IMMS data collected on negative ionization of methyl salicylate using radioactive, corona discharge and photo-ionization

Spangler¹

2015

Int. J. Ion Mobil. Spec.

View full text Add to dashboard Cite

Except for electrospray ionization that was introduced later to handle biochemical analyses, the radioactive source has been the benchmark ionization source for ion mobility spectrometry. On the other hand, the licensing requirements accompanying the use of the source has created a desire to replace it with a nonradioactive source with an equivalent ionization capability. Two such sources are the discharge and photoionization sources that are capable of negatively ionizing the internally hydrogen bonded ketoB isomer of methyl salicylate. IMMS data show that if the negative reactant ions are NO 3 − ·HNO 3 (discharge source) or CO 3 − (doped photoionization source), methyl salicylate cannot be ionized. However when the sources are synchronously pulsed with a shutter grid, methyl salicylate can be ionized by the formation of the oxygen anion adduct, O 2 − ·M, similar to radioactive ionization. The ionization capability depends not only upon the partial concentration of oxygen in the immediate ionization region but also on the geometry used to construct the source. Molecular modeling shows that the UV radiation emitted by the sources will photodissociate the reactant ions that reconstitute as the energy of the UV radiation decreases during the pulsing cycle. The reconstitution of CO 3 − is delayed due to a change in geometric symmetry and is the first to leave the ionization region because of its high mobility. This allows methyl salicylate to be ionized by oxygen anions.

show abstract

Energetics and Vibrational Analysis of Methyl Salicylate Isomers

Cited by 24 publications

References 32 publications

On the Structure of Liquid Methyl Salicylate: the Role of Intramolecular Hydrogen Bonding

On the Structure of Liquid Methyl Salicylate: the Role of Intramolecular Hydrogen Bonding

Theoretical investigation of the photophysics of methyl salicylate isomers

Molecular modeling interpretation of IMMS data collected on negative ionization of methyl salicylate using radioactive, corona discharge and photo-ionization

Contact Info

Product

Resources

About