The synthesis of reversible oligomer/polymers is fascinating both from the perspective of the fundamental understanding as well as their applications, ranging from biomedical to self‐healing smart ...materials. On the other hand, the reactions that occur in single‐crystal‐to‐single‐crystal (SCSC) fashion offer great details of the structure, geometry and stereochemistry of the product. However, SCSC 2+2 oligomerization is rather difficult and rare. Further, till date there are no reports for a reversible 2+2 oligomerization in SCSC fashion. In this work, four halogen‐substituted acrylic dienone molecules were deliberately designed and their ability to participate in 2+2 cycloaddition reaction in solid state was studied under visible light. Despite of having the required alignment of double bonds of dienes in all four crystal structures, they were found to exhibit variable reactivities given the differences in their weak intermolecular interactions such as halogen⋅⋅⋅halogen, halogen⋅⋅⋅π and C−H⋅⋅⋅O interactions. Notably, one of these materials exhibits reversible oligomerization in a SCSC manner.
The first single‐crystal‐to‐single‐crystal reversible 2+2 photo‐oligomerization of conjugated dienones under visible light is reported.
Ethylene, propylene, and benzene were investigated as molecules for extracting methoxy intermediate species formed during the cyclic partial oxidation of methane in Cu-exchanged zeolites, promising ...materials for the step-wise methane-to-methanol (MTM) reaction. 13C-labeled reaction studies reveal that alkenes preferentially undergo oligomerization followed by cracking, while benzene is successfully methylated, forming toluene. Benzene methylation further showcases the methyl species to behave similar to surface methoxy species formed on Brønsted acid sites in methanol-to-hydrocarbon (MTH) reaction. However, benzene is only able to extract a fraction of the methyl species compared to the methanol produced with water extraction, indicating either steric or intrinsic mechanistic effects to limit the full potential of the methyl pool inside the framework. We infer the presence of reactive methoxy species on Brønsted acid sites generated under reaction conditions, revealing their potential as a synthetic platform to form additional products from methane.
•Benzene reacts with the methoxy intermediate in the Cu-zeolite forming toluene.•Benzene and water access different amounts of methoxy; more than one type of methoxy.•Cu(I)-species formed after methane activation affect ethylene oligomerization.•Propylene oligomerizes independently of Cu species, BAS, or methoxy presence.
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