• Metallacycles;
  • Zirconium;
  • Titanium;
  • Alkyne ligands;
  • Cycloalkynes;
  • Cumulenes
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The cover picture shows the coupling of an alkyne and [3]cumulene on a zirconium atom to form a seven-membered metallacycloalkyne and a five-membered metallacyclic complex. The reaction is reminiscent of an imaginary Chinese creature, The Black Tortoise (Xuanwu; “Genbu” in Japanese), in which a snake coils around a tortoise. Both the tortoise and the snake are looking at a sphere, which represents a zirconium atom, in a way similar to how the alkyne and the [3]cumulene interact with the metal. The background shows the sunrise at New Year taken from the ruins of Ichiya Castle at Odawara. Details are discussed in the article by N. Suzuki et al. on p. 347 ff.