Following a Photoinduced Reconstructive Phase Transformation and its Influence on the Crystal Integrity: Powder Diffraction and Theoretical Study

Runčevski, Tomče; Blanco-Lomas, Marina; Marazzi, Marco; Cejuela, Marcos; Sampedro, Diego; Dinnebiér, Robert E.

doi:10.1002/anie.201402515

Cited by 13 publications

(14 citation statements)

References 29 publications

(7 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the in situ photodiffraction experiments a custom-made photocell was mounted on the diffractometer. 54 Powder patterns were collected every 5 minutes during continuous irradiation with high-intensity UV light. The 11-13 o Bragg angle region was selected, and the intensities of the (101) reflections from the monomer and the dimer were followed.…”

Section: Powder X-ray Diffractionmentioning

confidence: 99%

Surface and Bulk Effects in Photochemical Reactions and Photomechanical Effects in Dynamic Molecular Crystals

Nath

Runčevski

Lai³

et al. 2015

J. Am. Chem. Soc.

Self Cite

120

117

View full text Add to dashboard Cite

The increasing number of reports on photomechanical effects in molecular crystals necessitates systematic studies to understand the intrinsic and external effectors that determine and have predictive power of their type and magnitude. Differential light absorption and product gradient between the surface and the bulk of the crystal are often invoked to qualitatively explain the mechanical response of crystals to light; however, the details on how this difference in photochemical response accounts for macroscopic effects such as surface modification, deformation, or disintegration of crystals are yet to be established. Using both bulk- and surface-sensitive analytical techniques, a rare instance of benzylidenefuranone crystals is studied here, and it is capable of several distinct types of photomechanical response including surface striation and delamination, photosalient effect (ballistic disintegration and motion), and photoinduced bending by dimerization. The results provide a holistic view on these effects and set the stage for the development of overarching theoretical models to describe the photomechanics in the ordered solid state.

show abstract

Section: Powder X-ray Diffractionmentioning

confidence: 99%

Surface and Bulk Effects in Photochemical Reactions and Photomechanical Effects in Dynamic Molecular Crystals

Nath

Runčevski

Lai³

et al. 2015

J. Am. Chem. Soc.

Self Cite

120

117

View full text Add to dashboard Cite

show abstract

“…Moreover, the method was not valid for a wide range of oxazolones. Almost at the same time Sampedro et al described that, using ultraviolet radiation, the only observable process for Z -5(4 H )-oxazolones in solution is the Z to E isomerization (Figure c, left part). − Very recently, the same group noticed the dimerization of 5(4 H )-oxazolones in solid state (Figure c, right part), in just a single case where the topochemical conditions of intermolecular C–C distances shorter than 4.2 Å (Schmidt criterion) are accomplished . Therefore, sparse results have been obtained previously in this area, since each attempted irradiation has given a different result.…”

Section: Introductionmentioning

confidence: 99%

Metal-Free [2 + 2]-Photocycloaddition of (Z)-4-Aryliden-5(4H)-Oxazolones as Straightforward Synthesis of 1,3-Diaminotruxillic Acid Precursors: Synthetic Scope and Mechanistic Studies

García‐Montero

Rodríguez

Juan

et al. 2017

ACS Sustainable Chem. Eng.

View full text Add to dashboard Cite

The direct [2+2]-photocycloaddition of (Z)-2-phenyl-4-aryliden-5(4H)-oxazolones 1 to give 1,3-diaminotruxillic cyclobutane-derivatives 2 in very good yields (75-100%) is reported. The reaction takes place by irradiation of CH2Cl2 solutions of 1 with the blue light (465 nm) provided by LED lamps of low power (around 1 W) for 72 h. Four isomers of the 1,3diaminotruxillic cyclobutanes 2 were obtained, all of them fully characterized by a combination of NMR spectroscopy and X-ray diffraction analysis. The reaction shows a certain selectivity, since one of the isomers (the epsilon) is obtained preferentially, and works for electron-releasing and electron-withdrawing substituents at the arylidene ring. A novel setup is presented for the in-line monitoring of the continuous flow photo-assisted synthesis of the cyclobutane derivatives 2 by NMR spectroscopy, with the microreactor dramatically reducing reaction times to only 30 minutes with clear product distribution of up to four isomers. The mechanism of this [2+2]photocycloaddition has been calculated by DFT methods, explaining all experimental findings. The reaction takes place through a stepwise formation of two new CC bonds through a transient diradical singlet intermediate. The isomeric distribution of the final products is not due to equilibration processes, but instead reflects the kinetic preference during the rate limiting CC bond formation step.

show abstract

“… 41 In addition, the values for the remaining bond distances (Å) and angles (°) are in the usual range of values found in the literature for related structural arrangements. 38 , 41 , 43 , 69 − 74 …”

Section: Resultsmentioning

confidence: 99%

Reactivity of (Z)-4-Aryliden-5(4H)-thiazolones: [2 + 2]-Photocycloaddition, Ring-Opening Reactions, and Influence of the Lewis Acid BF₃

et al. 2021

View full text Add to dashboard Cite

The irradiation of ( Z )-2-phenyl-4-aryliden-5(4 H )-thiazolones 2 with blue light (465 nm) in CH 2 Cl 2 solution promotes [2 + 2]-photocycloaddition of the exocyclic C=C bonds and the formation of the dispirocyclobutanes 3 . This reaction takes place with high stereoselectivity, given that the ε-isomer (1,3 head-to-tail syn coupling) is formed in more than 90% yield in most of the cases. However, irradiation of 5(4 H )-thiazolones 2 with blue light (456 nm) in dry MeOH in the presence of BF 3 ·OEt 2 leads to the monospirocyclobutanes 4 with full stereoselectivity, also affording the ε-isomer. A ring-opening reaction of only one of the thiazolone rings appears to have taken place in 4 upon methanolysis, leading to the corresponding ester and thioamide groups. The treatment of free 4-aryliden-5(4 H )-thiazolones 2 with a base in alcohol (NaOR/ROH) also produces a ring-opening reaction of the heterocycle by methanolysis, although, under these reaction conditions, further intramolecular S-attack at the exocyclic C(H)=C bond and cyclization is observed, forming the dihydrothiazoles 5 or 6 as mixtures of cis ( RS / SR )- and trans ( RR / SS )-isomers with high diastereomeric excess. trans -( RR/SS )-Dihydrothiazoles 6 can be isolated as pure diastereoisomers by column chromatography. Surprisingly, dihydrothiazoles 5 can also be obtained by the treatment of 4-aryliden-5(4 H )-thiazolones 2 with BF 3 ·OEt 2 in methanol in the absence of a base.

show abstract

Following a Photoinduced Reconstructive Phase Transformation and its Influence on the Crystal Integrity: Powder Diffraction and Theoretical Study

Cited by 13 publications

References 29 publications

Surface and Bulk Effects in Photochemical Reactions and Photomechanical Effects in Dynamic Molecular Crystals

Surface and Bulk Effects in Photochemical Reactions and Photomechanical Effects in Dynamic Molecular Crystals

Metal-Free [2 + 2]-Photocycloaddition of (Z)-4-Aryliden-5(4H)-Oxazolones as Straightforward Synthesis of 1,3-Diaminotruxillic Acid Precursors: Synthetic Scope and Mechanistic Studies

Reactivity of (Z)-4-Aryliden-5(4H)-thiazolones: [2 + 2]-Photocycloaddition, Ring-Opening Reactions, and Influence of the Lewis Acid BF₃

Contact Info

Product

Resources

About

Following a Photoinduced Reconstructive Phase Transformation and its Influence on the Crystal Integrity: Powder Diffraction and Theoretical Study

Cited by 13 publications

References 29 publications

Surface and Bulk Effects in Photochemical Reactions and Photomechanical Effects in Dynamic Molecular Crystals

Surface and Bulk Effects in Photochemical Reactions and Photomechanical Effects in Dynamic Molecular Crystals

Metal-Free [2 + 2]-Photocycloaddition of (Z)-4-Aryliden-5(4H)-Oxazolones as Straightforward Synthesis of 1,3-Diaminotruxillic Acid Precursors: Synthetic Scope and Mechanistic Studies

Reactivity of (Z)-4-Aryliden-5(4H)-thiazolones: [2 + 2]-Photocycloaddition, Ring-Opening Reactions, and Influence of the Lewis Acid BF3

Contact Info

Product

Resources

About

Reactivity of (Z)-4-Aryliden-5(4H)-thiazolones: [2 + 2]-Photocycloaddition, Ring-Opening Reactions, and Influence of the Lewis Acid BF₃