Related Experiment Video
Updated: Apr 8, 2026
Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
Revisiting acene dimers: A comprehensive theoretical study of a less explored conformer
Nikita A Matsokin1, Mikhail Kalinin2, Andrea Buchwald3
1Institute of Nanotechnology, Karlsruhe Institute of Technology, Kaiserstraße 12, 76131 Karlsruhe, Germany.
None:
Dimers of the acenes naphthalene, anthracene, tetracene, and pentacene are shown to have a C2 symmetric X-shaped lowest minimum structure, while slipped-stacked and cross-shaped minima have higher energies. This is shown at the B3LYP-D3(BJ)/def2-TZVP level of theory and validated with the PNO-LCCSD(T)-F12 method. A SAPT analysis provides insight into the nature of the interaction. Finally, we performed experimental UV-Vis spectroscopy and fluorescence studies to shed light on assembling in solution. The comparison of computed UV-spectra of different dimers with experimental results helps in understanding the association process.
Related Concept Videos
02:39Nomenclature of Alkynes
02:37Structure and Physical Properties of Alkynes
In nature, compounds containing both carbon and hydrogen are known as "hydrocarbons". Aliphatic hydrocarbons are compounds whose molecules contain saturated single bonds (i.e., alkanes) or unsaturated double or triple bonds. Alkenes contain carbon–carbon double bonds and have a structural formula CnH2n. Unsaturated hydrocarbons containing carbon–carbon triple bonds are called "alkynes" and are structurally represented by the formula CnH2n-2.
The...
01:29Diels–Alder Reaction: Characteristics of Dienes
Characteristics of the diene
Conformation
The simplest example of a diene is 1,3-butadiene, an acyclic conjugated π system. At room temperature, the molecule exists as a mixture of s-cis and s-trans conformers by virtue of rotation around the carbon–carbon single bond. Although the s-trans isomer is more stable,...
01:13¹H NMR: Complex Splitting
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied...
01:29UV–Vis Spectroscopy: Woodward–Fieser Rules
02:42Acidity of 1-Alkynes
The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.