Cyanation of Aryl Bromides with K4[Fe(CN)6] Catalyzed by Dichloro[bis{1-(dicyclohexylphosphanyl)piperidine}]palladium, a Molecular Source of Nanoparticles, and the Reactions Involved in the Catalyst-Deactivation Processes was written by Gerber, Roman;Oberholzer, Miriam;Frech, Christian M.. And the article was included in Chemistry – A European Journal in 2012.Synthetic Route of C6H5NS This article mentions the following:
Dichloro[bis{1-(dicyclohexylphosphanyl)piperidine}]palladium [(P{(NC5H10)(C6H11)2})2PdCl2] (1) is a highly active and generally applicable C-C cross-coupling catalyst. Apart from its high catalytic activity in Suzuki, Heck, and Negishi reactions, compound 1 also efficiently converted various electronically activated, nonactivated, and deactivated aryl bromides, which may contain fluoride atoms, trifluoromethane groups, nitriles, acetals, ketones, aldehydes, ethers, esters, amides, as well as heterocyclic aryl bromides, such as pyridines and their derivatives, or thiophenes into their resp. aromatic nitriles with K4[Fe(CN)6] as a cyanating agent within 24 h in NMP at 140 鎺矯 in the presence of only 0.05 mol % catalyst. Catalyst deactivation processes showed that excess cyanide efficiently affected the mol. mechanisms as well as inhibited the catalysis when nanoparticles were involved, owing to the formation of inactive cyanide complexes, such as [Pd(CN)4]2-, [(CN)3Pd(H)]2-, and [(CN)3Pd(Ar)]2-. Thus, the choice of cyanating agent is crucial for the success of the reaction because there is a sharp balance between the rate of cyanide production, efficient product formation, and catalyst poisoning. For example, whereas no product formation was obtained when cyanation reactions were examined with Zn(CN)2 as the cyanating agent, aromatic nitriles were smoothly formed when hexacyanoferrate(II) was used instead. The reason for this striking difference in reactivity was due to the higher stability of hexacyanoferrate(II), which led to a lower rate of cyanide production, and hence, prevented catalyst deactivation processes. This pathway was confirmed by the colorimetric detection of cyanides: whereas the conversion of 灏?solvato-浼?cyanocobyrinic acid heptamethyl ester into dicyanocobyrinic acid heptamethyl ester indicated that the cyanide production of Zn(CN)2 proceeded at 25 鎺矯 in NMP, reaction temperatures of >100 鎺矯 were required for cyanide production with K4[Fe(CN)6]. Mechanistic investigations demonstrate that palladium nanoparticles were the catalytically active form of compound 1. In the experiment, the researchers used many compounds, for example, 3-Methylthiophene-2-carbonitrile (cas: 55406-13-8Synthetic Route of C6H5NS).
3-Methylthiophene-2-carbonitrile (cas: 55406-13-8) belongs to nitriles. Nitriles are polar, as indicated by high dipole moments. As liquids, they have high relative permittivities, often in the 30s. Nitrile groups in organic compounds can undergo a variety of reactions depending on the reactants or conditions. A nitrile group can be hydrolyzed, reduced, or ejected from a molecule as a cyanide ion.Synthetic Route of C6H5NS
Referemce:
Nitrile – Wikipedia,
Nitriles – Chemistry LibreTexts