Volatile β-Diketonate Rb-Co Complexes: Effect of Incorporation of 18-Crown-6 Ether as a Neutral Ligand

Heterometallic β-diketonate complexes MI[M(L)n], containing s-block elements, are of significant interest due to their potential application in the synthesis of halide perovskites. However, for MI = Rb, such compounds remain poorly studied, and information regarding their crystal structures is lacking. Complex Rb[Co(hfac)3] (1) and the previously unknown complex [Rb(18C6)][Co(hfac)3] (2), where hfac represents the hexafluoroacetylacetonate ion CF3COCHCOCF $$_{3}^{ - }$$ and 18C6 denotes the crown ether 18-crown-6, have been investigated using elemental analysis, IR spectroscopy, single-crystal X-ray diffraction, powder X-ray diffraction, and thermogravimetric analysis. Both complexes exhibit a chain-like structure, with the introduction of the neutral ligand 18C6 effectively reducing the number of interactions between the cation and the complex anion [Co(hfac)3]–. Notably, both heterometallic complexes demonstrate greater thermal stability compared to Rb(hfac), with complex 1 partially transitioning into the gas phase even under atmospheric pressure.