Ionothermal Synthesis of Selenido Metalates in Tunable Aryl Alkyl Ionic Liquids (TAAILs)

We report on the first reactions of selenido germanates in tunable aryl alkyl ionic liquids (TAAILs), namely, the treatment of [K₄(H₂O)₃][Ge₄Se₁₀] with SnCl₄·5H₂O in (Ph4-BrC₆Im)[NTf₂], (Ph4-BrC₈Im)[NTf₂], (Ph4-BrC₁₂Im)[NTf₂], (Ph2-MeC₈Im)[NTf₂], and (Ph4-OMeC₈Im)(NTf₂), in the presence of 2,6-dimethylmorpholine (DMMP) as a basic auxiliary agent (PhY-X denotes a Ph group in the 1-position of the imidazolium cation (Im); the numeral Y specifies the ortho (2) or para (4) position of a substituent X at the Ph ring; and Cn denotes a linear alkyl substituent with n C atoms in the 3-position of the Im ring; NTf₂ = bis(trifluoromethan)sulfonimide). The use of different TAAILs allowed the observation of different products: (Cat)₂₄[Ge₂₄Sn₃₆Se₁₃₂] (1), (Ph2-MeC₈Im)₂(DMMPH)₂[Ge1.4Sn4.6Se₁₄] (2), (Cat)₆[GeSn₈Se₂₁] (3), (Cat)₂[Sn₃Se₇] (4), and (DMMPH)₄[Ge₄Se₁₀] (5). The compounds comprise cations from the corresponding TAAIL or (DMMPH)⁺, which is the monoprotonated derivative of DMMP that forms in situ (note that in some cases, extreme disorder of the cations did not allow their localization on the difference Fourier map; these are referred to as 'Cat' in their formula). We discuss the anionic substructures in comparison to those of known compounds based on Ge, Sn, and Se atoms and report the effect of the different architectures on optical absorption properties.