Ethynyl(di)thiolates and -(di)selenolates: from the synthesis to potential applications

• Applicant: Professor Dr. Uwe Ruschewitz
• Subject Area: Solid State and Surface Chemistry, Material Synthesis
• Term: since 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 423432238

For many years, the Ruschewitz group has been investigating binary and ternary acetylides of alkali and alkaline earth metals, whereby in particular the ternary alkali metal transition metal acetylides synthesized by us represent an interesting class of materials at the border between ionic and semiconducting properties. Since 2018, we have succeeded for the first time in synthesizing acetylides of selenium (A(I)SeC2H with A(I) = Na, K, Rb, Cs), which contain the previously unknown linear –SeC2H anion in crystalline form. In the meantime, we were also able to present compounds with the composition A(I)SC2H (A(I) = Na, K, Rb, Cs), which contained the -SC2H anion, isolobal to ubiquitous thiocyanate. In this project, transition metal compounds with these anions shall be synthesized for the first time and the properties of these two ligands in complexes will be investigated, always in comparison to the well-known thiocyanate and selenocyanate ligands. Investigations on the thermal stability of these anions, their reactivity with respect to oxidation and the formation of dimers or polymers are also aims of this work. In 2022 we published Li2[SeC2Se] x 2NH3, which contains the extremely unusual ("exotic") dianion -Se-C2-Se-. This is also present in compounds of the composition A(I)2E2C2 with A(l) = Na, K, Rb, Cs and E = Se, Te. By oxidation with iodine or bromine, SeCx polymers should be accessible, for which an increased conductivity is expected and which could possibly be interesting in the field of optoelectronics. Similarly, high conductivities are expected for coordination polymers based on aromatic bis(ethinylselenolates), which we also want to synthesize in the proposed project for the first time. Thus, based on the compounds described in the first project, this follow-up proposal aims to show ways how materials can be obtained, for which interesting applications, e.g. in the field of optoelectronics, are to be expected. In addition to the planned syntheses and analyses, the project also includes accompanying quantum mechanical calculations on individual molecular fragments as well as extended solids.

• DFG Programme: Research Grants