One of our long-term research interests focuses on the synthesis and characterisation of ternary acetylides. Numerous ternary alkali metal transition metal acetylides have been reported by our group for d¹⁰ configured metals like Pd(0), Pt(0), Cu⁺, Ag⁺ and Au⁺. All these compounds were only obtained as microcrystalline powders so that X-ray powder diffraction data of high quality were needed to solve and refine their crystal structures unambiguously.

In all these compounds the acetylide anions coordinate end-on to the d¹⁰ metal (ion) resulting in a linear coordination and polymeric chains as structural fragment (see Fig. 1).

Main Publications

Ternary Alkali Metal Transition Metal Acetylides A₂MC₂ with A = Na, K and M = Pd, Pt

S. Hemmersbach, B. Zibrowius, W. Kockelmann, and U. Ruschewitz, Chemistry, A European Journal 2001, 7, 1952-1958.

Novel Ternary Alkali Metal Silver Acetylides M^IAgC₂  (M^I = Li, Na, K, Rb, Cs)

W. Kockelmann und U. Ruschewitz, Angew. Chem. Int. Ed. 1999, 38, 3492-3495.

One aim of our current work is the substitution of these transition metals (ions) by Cd²⁺ or Zn²⁺ cations to obtain an e.g. tetrahedral coordination sphere so that the formation of 3D networks is conceivable.

As a strong dependence of the direct bandgap of ternary Pd acetylides A₂PdC₂ upon the respective A⁺ cation (A = Na, K, Rb) was observed, we are attempting to synthesize quaternary acetylides of composition A’A’’PdC₂ to fine-tune the electronic properties of these compounds.

Further Literature

U. Ruschewitz, Coord. Chem. Rev. 2003, 244, 115-136.

U. Ruschewitz, Z. Anorg. Allg. Chem. 2006, 632, 705-719.

M. Weiß und U. Ruschewitz, Z. Anorg. Allg. Chem. 1997, 623, 1208-1210.

U. Ruschewitz, Z. Anorg. Allg. Chem. 2001 , 627, 1231-1235.

H. Billetter, T. Wallraff, U. Schwarz, R. I. Smith, U. Ruschewitz, Z. Anorg. Allg. Chem. 2010, 636, 1834-1838.

U. Cremer, W. Kockelmann, M. Bertmer, U. Ruschewitz, Solid State Sciences 2002, 4, 247-253.

J. Offermanns, U. Ruschewitz, C. Kneip, Z. Anorg. Allg. Chem. 2000, 626, 649-654.