These are preliminary reports that have not been peer-reviewed. They should not be regarded as conclusive, guide clinical practice/health-related behavior, or be reported in news media as established information. For more information, please see our FAQs.
Preprints are manuscripts made publicly available before they have been submitted for formal peer review and publication. They might contain new research findings or data. Preprints can be a draft or final version of an author's research but must not have been accepted for publication at the time of submission.
submitted on 02.10.2020 and posted on 05.10.2020by Abhishek Singh, Reman K. Singh, G Naresh Patwari
The rational design of conformationally
controlled foldable modules can lead to a deeper insight into the
conformational space of complex biological molecules where non-covalent
interactions such as hydrogen bonding and π-stacking are known to play a
pivotal role. Squaramides are known to have excellent hydrogen bonding capabilities
and hence, are ideal molecules for designing foldable modules that can mimic
the secondary structures of bio-molecules. The π-stacking induced folding of
bis-squaraines tethered using aliphatic primary and secondary-diamine linkers
of varying length is explored with a simple strategy of invoking small
perturbations involving the length linkers and degree of substitution. Solution
phase NMR investigations in combination with molecular dynamics simulations
suggest that bis-squaraines predominantly exist as extended conformations. Structures
elucidated by X-ray crystallography confirmed a variety of folded and extended
secondary conformations including hairpin turns and 𝛽-sheets which are determined by the hierarchy of
π-stacking relative to N–H···O hydrogen bonds.