Synthesis of a New Cobalt(II) Complex Compound Containing 2,2′-Bipyridyl Ligand and Its Catalytic Properties in the Formation of CO2-Sorbing Oligomers

As an element, cobalt has a very interesting coordination chemistry and great potential to participate in the formation of a variety of complex compounds, that play a significant role in the synthesis of catalytic systems. In the present work, a new cobalt(II) complex compound with an unusual and rare structure, not previously described in the literature, was synthesized. This complex has two 2,2′-bipyridyl ligands, a water molecule and, most interestingly, a sulfate(VI) anion in the Co(II) coordination sphere. Its use and catalytic properties were studied in the oligomerization of selected olefins, where it acted as a precatalyst. The achieved catalytic activity values were rather high (<100 g mmol⁻¹ h⁻¹ ⋅ bar⁻¹), except for the oligomerization process of 2,3-dibromo-2-propen-1-ol using MAO. The obtained oligomers were subjected to structural (FT-IR, SEM, MALDI-TOF-MS) and thermal (TG, DSC) analysis, and the results allowed to characterize their physicochemical properties. The conducted process allowed to determine the effect of the applied activator on the catalytic activity, as well as the structural and thermal properties of the obtained oligomers. In addition, the specific surface area and sorption properties of the oligomerization products were studied, and one of them showed very high CO₂ sorption values (<1.6 mmol g⁻¹).