13diynes

1,3-diynes, also written as 1,3-diynes or simply diynes, are a class of organic compounds that contain two carbon–carbon triple bonds separated by a single bond. The simplest example is butadiyne, HC≡C–C≡CH. In general, 1,3-diynes have the motif R–C≡C–C≡C–R′, where substituents on the ends can vary. The structure is linear along the diyne axis, giving a rigid, conjugated system that can influence reactivity and materials properties.

These compounds are valuable building blocks in organic synthesis and materials science. The conjugated diynes can be used to construct more complex aromatic or polycyclic systems through cycloaddition and cyclization reactions. They serve as precursors to natural product motifs and to functional materials such as polymers and organic electronics components due to their extended π system and rigidity.

Synthesis of 1,3-diynes is well developed. Common methods include oxidative coupling of terminal alkynes (the Glaser or Hay couplings) using copper salts and oxidants to form symmetric diynes. Unsymmetrical diynes can be prepared via sequential coupling, or by double elimination of dihalides, or by cross-coupling strategies employing transition-metal catalysts. Other routes generate diynes from alkynyl precursors through carbon–carbon bond-forming steps tailored to the desired substitution pattern.

Safety and handling vary with the specific diyne; many are reactive and can decompose or polymerize under heat or exposure to air. Proper laboratory precautions are advised, especially for highly conjugated or unsubstituted species. Overall, 1,3-diynes are versatile and widely used in synthesis and materials science due to their robust, linear, conjugated framework.