Among the other porous materials, porous organic polymers have already proved as a valuable alternative for the selective adsorption of CO2 over N2. In a rational design of new porous...

A combined strategy utilizing experimental (infrared, nuclear magnetic resonance, circular dichroism, X-ray) and computational (time-dependent density functional theory) techniques is illustrated on tripeptides to investigate their chiroptical properties. Eight stereoisomers of monosubstituted ferrocene, Boc-Pro-Pro-Ala-NHFc, have been prepared and conformationally characterized in depth to reach some guidelines for a future design of ferrocene-based chromophores. The origin of the sign change in circular dichroism spectra near the absorption maximum of a ferrocene chromophore (about 470 nm) is strongly correlated with the sign of the dihedral angle describing deviation of the directly attached amide plane from planarity of the cyclopentadienyl ring. These findings may provide some guidelines for the design of new chiroptical ferrocene-based probes for the assignment of the screw-sense preference of short peptides.

The experimental (infrared, nuclear magnetic resonance, circular dichroism) and computational (density functional theory) methods allowed us to demonstrate the potential of the ferrocene chromophore to translate chiral information stored at N‐terminally attached l‐Ala, and transmitted through achiral (Aib)n sequence (n=1 to 3), into a characteristic signal in circular dichroism spectra near 470 nm. The sufficiently long tetrapeptide forms a robust and highly organized 310 helices capable of perturbing the environment of the highly symmetric ferrocene chromophore in an asymmetric manner. The origin of the sign in the circular dichroism spectra of the ferrocene chromophore (near the 470 nm) strongly correlates with the sign of the dihedral angle χ, accounting for a rotation of a substituent attached to the cyclopentadienyl ring that depends on the helicity of peptide sequence. These observations may help us in the design of future ferrocene‐based probes for the assignment of the screw‐sense preference of short peptides.

Inner surface potential, one of the most important variables affecting the interfacial equilibrium of metal oxide aqueous systems, obtained by means of single crystal electrode gives valuable information about electrical charging of the metal oxide/aqueous electrolyte solution interfaces. The influence of the potential determining ions and ionic strength on the measured electrode potential as well as time of the equilibration, direction of the titration and the effect of the magnetic stirring enables the critical examination of the processes which take place during the interfacial equilibrium. For that purpose, the selected metal oxides (hematite, ceria, sapphire, and rutile) and fluorite single crystal electrodes were examined.

The effect of attaching the achiral, cyclic 1-aminocyclohexanecarboxylic acid (Ac6c) directly to the aminoferrocene unit (Ac6c−NH−Fc) appears to be a promising route for the development of a new chiroptical sensor based on a ferrocene chromophore. Three new compounds (Boc−AA−Ac6c−NH−Fc; AA = L-Ala, L-Val, L-Phe) were synthesized, spectroscopically characterized (IR, NMR, CD), and conformationally analyzed (DFT). The chiral information was transferred from the L-amino acid to the ferrocene chromophore by the predominant formation of P-helical structures with ten-membered hydrogen-bonded rings (β-turns). The perturbation of the ferrocene chromophore and the appearance of the negative CD signal near 470 nm originates from a relative orientation of the directly linked amide and cyclopentadienyl planes, described by the dihedral angle χ. The sterically demanding Ac6c amino acid makes trans-like configurations more favorable and thus restricts the dihedral angle χ, which then leads to the appearance of the negative peak near 470 nm in the CD curve.