19188-18-2Relevant articles and documents
Long Vibrational Lifetime R-Selenocyanate Probes for Ultrafast Infrared Spectroscopy: Properties and Synthesis
Daniels, Robert,Fayer, Michael D.,Fica-Contreras, Sebastian M.,Hoffman, David J.,Pan, Junkun,Sotzing, Gregory,Yassin, Omer
, p. 8907 - 8918 (2021/08/23)
Ultrafast infrared vibrational spectroscopy is widely used for the investigation of dynamics in systems from water to model membranes. Because the experimental observation window is limited to a few times the probe's vibrational lifetime, a frequent obstacle for the measurement of a broad time range is short molecular vibrational lifetimes (typically a few to tens of picoseconds). Five new long-lifetime aromatic selenocyanate vibrational probes have been synthesized and their vibrational properties characterized. These probes are compared to commercial phenyl selenocyanate. The vibrational lifetimes range between 400 and 500 ps in complex solvents, which are some of the longest room-temperature vibrational lifetimes reported to date. In contrast to vibrations that are long-lived in simple solvents such as CCl4, but become much shorter in complex solvents, the probes discussed here have ～400 ps lifetimes in complex solvents and even longer in simple solvents. One of them has a remarkable lifetime of 1235 ps in CCl4. These probes have a range of molecular sizes and geometries that can make them useful for placement into different complex materials due to steric reasons, and some of them have functionalities that enable their synthetic incorporation into larger molecules, such as industrial polymers. We investigated the effect of a range of electron-donating and electron-withdrawing para-substituents on the vibrational properties of the CN stretch. The probes have a solvent-independent linear relationship to the Hammett substituent parameter when evaluated with respect to the CN vibrational frequency and the ipso 13C NMR chemical shift.
A convenient, transition metal-free synthesis of difluoromethyl selenoethers from organic selenocyanates and TMSCF2H
Dong, Tao,Nie, Jing,Zhang, Cheng-Pan
, p. 5642 - 5649 (2018/08/22)
An efficient and transition metal-free method for the synthesis of aryl or alkyl difluoromethyl selenides (RSeCF2H) from the corresponding selenocyanates (RSeCN) and TMSCF2H/t-BuOK is described. The reaction performed in THF at 0 °C for 24 h or at room temperature for 6 h supplied a series of RSeCF2H in good to high yields. The successful preparation of difluoromethylselenolated sulfadimethoxine derivative and the scaled-up synthesis of 1-benzyl-5-((difluoromethyl)selanyl)indoline, as examples, suggested good practicability of this method. Advantages of the reaction include mild reaction conditions, good functional group tolerance, a wide range of substrates, and high efficiency. This protocol offered a number of novel difluoromethyl selenoethers, which would accelerate use of such compounds in the areas of life science.
Trifluoromethylselenolation of Aryldiazonium Salts: A Mild and Convenient Copper-Catalyzed Procedure for the Introduction of the SeCF3 Group
Nikolaienko, Pavlo,Rueping, Magnus
supporting information, p. 2620 - 2623 (2016/02/27)
The straightforward introduction of the trifluoromethylseleno group into aromatic and heteroaromatic compounds is accomplished by the utilization of readily available aryldiazonium tetrafluoroborates, potassium selenocyanate, and Ruppert-Prakash reagent. The reaction tolerates a wide range of aromatic and heteroaromatic diazonium salts and is also amenable to the synthesis of pentafluoroethyl selenoethers. Furthermore, the methodology can be applied directly starting from anilines.
