Molecular Tweezers as Synthetic Receptors: Molecular Recognition of Electron-Deficient Aromatic and Aliphatic Substrates

Interactions with Aromatic Rings in Chemical and Biological Recognition

“…The results are striking: the concave surface features convergent π‐electron systems (Figure 8 c) that lead to a considerably larger negative potential within the tweezer's interior than at the exterior. This observation explains the experimentally observed high preference of receptor 9 (Figure 8 b) for complexing electron‐deficient guests in its interior in a position parallel to the central naphthalene spacer 126b. This result demonstrates the importance of molecular receptor topology: evaluation of host–guest complexation processes needs to take into account the complementarity of both the shape and molecular electrostatic potential (MEP).…”

Structure and Dynamics of the Host-Guest Complex of a Molecular Tweezer: Coupling Synthesis, Solid-State NMR, and Quantum-Chemical Calculations

“…A solid‐state investigation has the advantage that the guest remains complexed on the timescale of the NMR experiment and, thus, the structure and dynamics of the host–guest complex can be probed directly. An X‐ray single‐crystal structure is available for 1 @ 2 ;2b therefore, this study offers the opportunity to check the reliability of our approach and to demonstrate that additional complementary insight can be provided. …”

Beltlike Macrocycles with Four and Eight (Cyclopentadienyl)(cyclobutadienyl)cobalt Building Blocks, Formed by Stepwise Oligomerization of 1,6-Cyclodecadiyne Units

“…The side products of the intermolecular [2+2] cycloaddition had masses of exactly twice those of 4 a and 4 b , respectively. Based on the analytical data, we assign the octameric structures 5 a and 5 b to these products, respectively10. Quasi‐linear oligomers were not detected.…”

“…The conformation of 6 in the solid state is also interesting (Figure 1, bottom). The syn position of all three {CpCo} fragments forces the two alkyne chains towards each other, which leads to a distance of about 10.5 Å, in a tweezerlike arrangement 2, 10. The flexibility of the ten‐membered‐ring units should provide enough mobility to allow the possibility of a cobalt‐induced ring closure and formation of inclusion complexes.…”