14diynes

14diynes, more commonly referred to as 1,4-diynes, are organic compounds featuring two carbon–carbon triple bonds (alkynes) arranged at the 1 and 4 positions along a carbon backbone. In the simplest acyclic examples, the two alkyne units are separated by two single bonds, giving a motif such as H–C≡C–CH2–CH2–C≡C–H. The alkynes can be terminal or internal, and many substitutions exist, including aryl or heteroatom attachments at one or both ends.

The 1,4-diyne motif also appears in various substituted forms, including aryl-1,4-diynes where para-substituted aromatic rings connect the terminal alkynes. These compounds are valued in synthetic and materials chemistry for their extended conjugation, rigidity, and potential to undergo cyclizations and polymerizations to construct more complex polycyclic and polymeric structures.

Preparation methods for 1,4-diynes include double Sonogashira couplings of dihalogenated precursors with terminal alkynes, Glaser-type oxidative couplings of terminal alkynes, and other coupling strategies that assemble the two alkyne units in a 1,4-relationship. The choice of method depends on the desired substitution pattern and whether a linear or branched skeleton is targeted.

Applications of 1,4-diynes span organic synthesis and materials science. They serve as versatile building blocks for polyynes, polycyclic aromatic compounds, and macrocyclicities; they are used in the design of conjugated polymers and molecular electronics. Their reactivity is influenced by substituents and the degree of conjugation between the two alkyne units. Caution is advised, as with many alkynes, to follow standard safety protocols to minimize exposure to reactive and potentially volatile compounds.