Atomistic Molecular Dynamics Simulations of ABA-Type Polymer Peptide Conjugates: Insights into Supramolecular Structures and their Circular Dichroism Spectra.

A combination of atomistic molecular dynamics (aMD) simulations and circular dichroism (CD) analysis is used to explore supramolecular structures of amphiphilic ABA-type triblock polymer peptide conjugates (PPC). Using the example of a recently introduced PPC with pH- and temperature responsive self-assembling behavior [Otter et al., Macromolecular Rapid Communications 2018, 39, 1800459], this study shows how molecular dynamics simulations of simplified fragment molecules can add crucial information to CD data, which helps to correctly identify the self-assembled structures and monitor the folding/unfolding pathways of the molecules. The findings offer insights into the nature of structural transitions induced by external stimuli, thus contributing to the understanding of the connection of microscopic structures with macroscopic properties.

Substitution Effects on the Photophysical and Photoredox Properties of Tetraaza[7]helicenes.

A series of substituted derivatives of tetraaza[7]helicenes were synthesized and the influence of the substitution on their photophysical and photoredox-catalytic properties was studied. The combination of their high fluorescence quantum yields of up to 0.65 and their circularly polarized luminescence (CPL) activity results in CPL brightness values (BCPL ) that are among the highest recorded for [7]helicenes so far. A sulfonylation/hetarylation reaction using cyanopyridines as substrates for photoinduced electron transfer (PET) from the excited helicenes was conducted to test for viability in photoredox catalysis. DFT calculations predict the introduction of electron withdrawing substituents to yield more oxidizing catalysts.