Abstract
Herein we report the synthesis and characterization of a new series of synthesized mono- and trinuclear cobaloxime/organocobaloximes from ketone that act as catalysts for cyclic carbonate synthesis from CO2 and epoxides under appropriate conditions (2 h, 100 °C and 1.6 MPa pressure). These reactions were carried out with and without co-catalyst, namely, 4-dimethylaminopyridine (DMAP), pyridine (py), triethyl amine (NEt3) or triphenyl phosphine (PPh3). In the catalytic experiments, the 4-dimethylaminopyridine (DMAP) was used as co-catalyst, since the DMAP was a more active base with higher yield compared to other Lewis bases. In addition, various factors influencing the cycloaddition reaction, such as co-catalyst, temperature, CO2 pressure and reaction time, were investigated. A dioxime ligand (LH2) (1) was obtained in two steps from 4-methylpropiophenone as ketone. Reaction of CoCl2.6H2O with the dioxime ligand (LH2) (1) and 4-tertbutyl pyridine afforded six-coordinate mononuclear cobaloxime or organocobaloxime (2-3) complexes. The mononuclear cobaloxime or organocobaloxime (2-3) complexes were used as precursors for building trinuclear cobaloximes or organocobaloxime (4-11) complexes. All compounds were fully characterized by 1H and 13C NMR spectra, FT-IR spectra, UV-Vis spectra, molar conductivity measurements, melting point measurements, magnetic susceptibility measurements, and LC-MS spectroscopic studies as well as by cyclic voltammetry.
Original language | English |
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Pages (from-to) | 150-159 |
Number of pages | 10 |
Journal | Journal of Organometallic Chemistry |
Volume | 767 |
DOIs | |
Publication status | Published - 15 Sept 2014 |
Funding
This work was supported by the Technological and Scientific Research Council of Turkey TUBITAK (Project No: 111T944 ).
Funders | Funder number |
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Technological and Scientific Research Council of Turkey TUBITAK | 111T944 |
Keywords
- Carbon dioxide
- Cobaloxime
- Cyclic carbonate
- Electrochemistry
- Spectroscopy