This study was aimed at elucidating the role of the carboneous component in Co–carbon-containing catalysts for the hydrogenation of organic compounds. A Co-C/SiO₂ catalyst was synthesized via pyrolysis of a Co(II) complex with 1,2-diaminobenzene on silica and subsequently irradiated with 2.3 MeV electrons, producing Co-C/SiO₂*. A comprehensive characterization using XRD, TEM, IR, and Raman spectroscopy indicated minimal structural changes in the cobalt nanoparticles and carboneous materials. However, the Raman analysis revealed a slight decrease in the structural defect content in the carboneous component upon irradiation, which could occur due to defect healing. The catalytic tests, including the hydrogenation of 26 compounds, demonstrated an enhanced performance of the irradiated catalyst in 17 cases. This performance improvement was attributed to a modification of the carboneous material. It could be concluded that the carboneous components in Co-C composites contributed to their catalytic performance, probably by modifying the electronic structure of Co nanoparticles. In turn, the results provide arguments against the supposition that hydrogenation occurs on the structural defects of the carboneous material.

The study addresses a significant problem in the reproducibility and standardization of hy-drogenation catalysts. A fast and robust quality control (QC) method for Pd-based catalysts is proposed. The identity of the catalyst in the standard sample can be checked, as well as a general conclusion on the catalyst's activity can be made using the proposed method. The method is based on the hydrogenation of acylated imidazopyridine with gaseous hydrogen under mild conditions (1 atm, 40 °C), with no specialized equipment required, and is moni-tored by 19F or 1H NMR and/or UV–vis spectroscopy, which are available in all modern la-boratories. A model reaction, i.e., hydrogenation of acylated imidazopyridine, can yield three distinct products depending on the catalyst activity (under standardized conditions). The ratio of these products' content serves as a catalyst "fingerprint" for the QC. Using this method, a series of commercially available Pd-based catalysts was evaluated. The results clearly demonstrate the potential of this methodology as a reliable tool for robust testing of a wide range of catalysts for the heterogeneous hydrogenation of organic compounds, as well as for QC in lab-scale or industrial synthesis of new batches of the latter.

This study aimed to develop new catalysts, based on MoS₂, for the hydrogenation of bromoquinolines without C-Br bond cleavage. The mechanochemical exfoliation of the bulk MoS₂ in the presence of NaCl resulted in the formation of the material (MoS₂-1), consisting of flat plates of size between ca. 40 × 100 and ca. 250 × 400 nm². Similar grinding of MoS₂ in the presence of NH₄Cl produced smaller nanoplates of size between ca. 10 × 30 and ca. 50 × 300 nm² (MoS₂-2). These materials were characterized using powder XRD, TEM, SEM, Raman spectroscopy and XPS. The specific surface area of the MoS₂-1 and MoS₂-2 samples was estimated using the analysis of N₂ adsorption isotherms. Both materials were catalytically active in the hydrogenation of quinoline; 1,2,3,4-tetrahydroquinoline (THQ) was the sole product and its yield grew proportionally to the accessible surface area of the catalyst. The hydrogenation of 5- and 8-bromoquinolines in the presence of MoS₂-1 and MoS₂-2 led to the respective bromo-THQs with almost quantitative yields, while the hydrogenation of 6-bromoquinoline resulted in the formation of the respective 6-bromo-THQ with the yield up to 30%. In the case of 7-bromoquinoline, N-methylated 7-bromo-THQ was formed almost quantitatively.

Rhenium sulfide Re2S7 was obtained by reaction of KReO4 with sodium thiosulfate. Composition of the sulfide was determined by several independent methods and corresponded to formula Re2S7·3S. The material was characterized by powder XRD, TEM, SEM, EDX and XPS. It was shown that Re2S7 was X-ray amorphous and consisted of nanosized sheets, which formed aggregates of ca. 50-100 nm size. According to XPS data, Re2S7 predominantly contained Re4+, with smaller amounts of Re+5 and Re+6; the peaks of sulfur could be assigned to S2-, S22-, elementary S and SO42-. It was found that Re2S7 could act as efficient catalyst for hydrogenation of alkene, alkyne functions, nitro-group and a series of substituted quinolines and isoquinolines. Unique tolerance or Re2S7 to C-I and C-Br bonds was revealed, allowing to prepare iodo-containing tetrahydroquinolines in multigram scale. In addition, hydrogenation of thiophenes and benzothiophenes in presence of Re2S7 could be performed, leading to isolation of the respective derivatives of tetrahydrothiophene and dihydrobenzthiophene in multigram scale.