The conformational preferences of peptides are strongly determined by hydrogen bonding interactions. Intermolecular solute-solvent interactions compete with intramolecular interactions, which typically stabilize the secondary structure of the peptide. The analysis...
Benchmarking functionals and basis sets for the computational prediction of molecular properties is usually done on very small model systems. Larger organic molecules containing heavier second row atoms are not...
Thioureas are well-known structural motifs in supramolecular anion recognition. Their conformational preferences are typically characterized by detailed NMR spectroscopy and crystallography, which are often complemented with computational results from geometry...
Utilizing experimental and computational vibrational circular dichroism (VCD) spectroscopy, we explored the conformational preferences of a series of chiral C3‐symmetric octaazacryptands with tris(2‐aminoethyl)‐amine head groups derived from valine. While the spectra of the smallest azacryptand with p‐phenyl linkers and its elongated derivative with p‐biphenyls linker were found to match well with the computed spectra, the computed conformational preferences of the m‐biphenyl‐based azacryptand did not seem to reflect the conformations dominating in chloroform solution. A detailed analysis revealed that structural changes resulting in a collapsed cage structure gave a notably better match with the experiment. It could subsequently be concluded from the VCD analysis, that the octaazacryptands prefer a collapsed structure, which is not predicted by density functional theory (DFT) calculations as the global minimum structures. These findings are expected to have consequences also for future studies on inclusion complexes of such azacryptands.
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