The synthesis, characterization, and electrochemistry of molecular cobaloxime/organocobaloxime: catalysts for cycloaddition of carbon dioxide and epoxides

Chemical fixation of CO2into cyclic carbonates by azo-containing Schiff base metal complexes

“…The coupling of carbon dioxide and various epoxides catalyzed by complexes were investigated under different reaction conditions (Table 4, entries 1-9). Catalytic experiments were carried out at optimized conditions, which were determined at our 50 previous studies [32][33][34][35] . Five different types of organic bases were used as co-catalysts.…”

“…The catalytic experiments were carried out in optimized conditions, which were determined in our previous studies. [32][33][34][35] Five different types of organic bases were used as co-catalysts. Also, two different types of ionic liquids (IL) as catalysts were investigated.…”

Synthesis of the Multinuclear Cobaloxime Complexes via Click Chemistry as Catalysts for the Formation of Cyclic Carbonates from Carbon Dioxide and Epoxides

“…The FT-IR spectra of the multinuclear cobaloxime (1-8) complexes were compared with those of the free dioxime (L( 1−3) H 2 ) ligands in order to monitor the change in the vibration frequency of the coordination sites, which a small frequency shift in its position may be because of the formation of Co(III)←N or Co(III)←NH 2 dative bonds in these complexes, as expected. 17 Next, the powerful evidence for the transformation of chlorine to azido group could be seen in the FT-IR spectra of the azido-functionalized multinuclear cobaloxime complexes (4-6) and the characteristic absorption band of the azido groups were observed at 2021 cm −1 for complex (4), at 2017 cm −1 for complex (5) (figure S1b) and at 2035 cm −1 for complex (6) as very strong peaks, consecutively. The click reaction between azidated multinuclear cobaloxime complexes (4-6) and propargyl alcohol was proven by the disappearance of the azide peak at 2035-2017 cm −1 (figure S1b) and presence of the aromatic triazole ring stretching peak at about ∼1650 cm −1 (figure S1c) as new peak in the final FT-IR spectra of triazole containing multinuclear cobaloxime complexes (7 and 8), which support the formation of the 1,2,3-triazole containing multinuclear cobaloxime complexes (7 and 8) ( L( 1−3) H 2 ) were significantly different field shift compared to the multinuclear cobaloxime complexes (1-8), which is powerful evidence to the formation of the multinuclear cobaloxime complexes (1-8) and confirm the complex formation via imine nitrogen coordination to Co(III) ion.…”

“…Catalytic experiments were carried out at optimized conditions, which were determined in previous studies. 13,17,22,23 To optimize the reaction conditions for the ECH/CO 2 cycloaddition reactions, different parameters (epoxide, base, reaction time, and temperature and CO 2 pressure) were investigated, in which DMAP was used as a co-catalyst. The results are summarized in table S1.…”

“…Similar effect was observed in our previous studies. 13,17,22 In addition to DMAP (4-(dimethylamino) pyridine), CH 3 CN (acetonitrile), C 5 H 5 N (pyridine), NEt 3 (triethylamine) and PPh 3 (triphenylphosphine) were tested to expand the range of the co-catalysts with the cobaloxime complex (1) as catalyst ( figure S5). This showed that C 5 H 5 N (pyridine) was the best co-catalyst for this system with a yield of 90% of 4-(chloromethyl)-1, 3-dioxolan-2-one (ECHC) in high selectivity.…”