Photochromism and polarization spectroscopy of p-methyl(thiobenzoyl)acetone

Gorski, Aleksander; Posokhov, Yevgen O.; Hansen, Bjarke Knud Vilster; Spanget‐Larsen, Jens; Jasny, J.; Duus, Fritz; Hansen, Poul Erik; Waluk, Jacek

doi:10.1016/j.chemphys.2006.06.033

Cited by 9 publications

(8 citation statements)

References 42 publications

(32 reference statements)

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“…The results of this work reveal for 2 a similar phototransformation pattern as previously proposed for thioacetylacetone (1) [21], p-methyl(thiobenzoyl)acetone (3) [22], and monothiobenzoyl-methane (4) [20]. Thus, the most stable initial structure corresponds in all compounds to the ''closed'' hydrogen-bonded enol (form a in Scheme 1), and the main photochromic product to an ''open'', nonchelated enethiol (form c).…”

Section: Discussionsupporting

confidence: 78%

“…These assignments, identical to those proposed previously for 1 [21], 3 [22], and 4 [20], are not surprising, in view of the above-discussed similarities in the kinetic and thermodynamic parameters of the four b-thioxoketones. The general, substituent-independent pattern of the photoreaction is thus confirmed.…”

Section: Resultssupporting

confidence: 69%

“…For instance, thioacetylacetone (1) can exist in a multitude of rotameric and tautomeric forms, including enol, enethiol, and diketo configurations (Scheme 1). In our recent studies of 1 [21] and two related molecules, p-methyl(thiobenzoyl)acetone (3) [22] and monothiodibenzoylmethane (4) [20,23], the use of electronic and IR spectroscopy in solutions, glasses, polymers and rare gas matrices, supplemented by linear dichroism studies on partially aligned samples was combined with calculations of the electronic and vibrational structure of various possible forms. Based on the vibrational analysis, structural assignments were proposed.…”

Section: Introductionmentioning

confidence: 99%

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Photochromism in p-methylbenzoylthioacetone and related β-thioxoketones

et al. 2007

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Section: Discussionsupporting

confidence: 78%

Section: Resultssupporting

confidence: 69%

Section: Introductionmentioning

confidence: 99%

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Photochromism in p-methylbenzoylthioacetone and related β-thioxoketones

et al. 2007

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“…Thioketones tend to be rather unstable but a number of β-hydroxy thioketones are stabilized by strong intramolecular OH···S=C hydrogen bonding. Particular interest has been devoted to the molecular and vibrational structure of monothioacetylacetone enol ( 12 ) and its derivatives [ 103 , 104 , 105 , 106 ]. The OH stretching bands in these compounds are generally weak and diffuse and they frequently escape detection.…”

Section: β-Hydroxy Thiocarbonyl Compoundsmentioning

confidence: 99%

NMR and IR Investigations of Strong Intramolecular Hydrogen Bonds

2017

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For the purpose of this review, strong hydrogen bonds have been defined on the basis of experimental data, such as OH stretching wavenumbers, νOH, and OH chemical shifts, δOH (in the latter case, after correction for ring current effects). Limits for O–H···Y systems are taken as 2800 > νOH > 1800 cm−1, and 19 ppm > δOH > 15 ppm. Recent results as well as an account of theoretical advances are presented for a series of important classes of compounds such as β-diketone enols, β-thioxoketone enols, Mannich bases, proton sponges, quinoline N-oxides and diacid anions. The O···O distance has long been used as a parameter for hydrogen bond strength in O–H···O systems. On a broad scale, a correlation between OH stretching wavenumbers and O···O distances is observed, as demonstrated experimentally as well as theoretically, but for substituted β-diketone enols this correlation is relatively weak.

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“…In the above-mentioned cases the species were identified by means of IR and UV measurements. [24][25][26][27][28] Here, we present another, novel approach, based on laser irradiation in the magnet combined with in situ NMR detection. This methodology provides an interesting possibility for studies of photoinduced reactions, although a number of technical difficulties have to be overcome.…”

Section: Introductionmentioning

confidence: 99%

Arresting consecutive steps of a photochromic reaction: studies of β-thioxoketones combining laser photolysis with NMR detection

Pietrzak

Dobkowski

Gorski

et al. 2014

Phys. Chem. Chem. Phys.

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Photochromism of monothiodibenzoylmethane has been studied in a number of environments at different temperatures. Direct laser irradiation of a sample located in the NMR magnet allowed in situ monitoring of the phototransformation products, determining their structure, and measuring the kinetics of the back reaction. These observations, along with the data obtained using electronic and vibrational spectroscopies for rare gas matrix-isolated samples, glasses, polymers, and solutions, as well as the results of quantum-chemical calculations, provide insight into the stepwise mechanism of the photochromism in β-thioxoketones. At low temperature in rigid matrices the electronic excitation leads to the formation of the -SH exorotamer of the (Z)-enethiol tautomer. In solutions, further steps are possible, producing a mixture of two other non-chelated enethiol forms. Photoconversion efficiency strongly depends on the excitation wavelength. Analysis of the mechanisms of the photochromic processes indicates a state-specific precursor: chelated thione-enol form in the excited S2(ππ*) electronic state. The results show the potential of using laser photolysis coupled with NMR detection for the identification of phototransformation products.

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Photochromism and polarization spectroscopy of p-methyl(thiobenzoyl)acetone

Cited by 9 publications

References 42 publications

Photochromism in p-methylbenzoylthioacetone and related β-thioxoketones

Photochromism in p-methylbenzoylthioacetone and related β-thioxoketones

NMR and IR Investigations of Strong Intramolecular Hydrogen Bonds

Arresting consecutive steps of a photochromic reaction: studies of β-thioxoketones combining laser photolysis with NMR detection

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