Testing the Potential of the Ferrocene Chromophore as a Circular Dichroism Probe for the Assignment of the Screw-Sense Preference of Tripeptides

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 conformationally characterized in depth reach some guidelines for a future design ferrocene-based chromophores. The origin the sign change dichroism spectra near absorption maximum ferrocene chromophore (about 470 nm) strongly correlated with dihedral angle describing deviation directly attached amide plane from planarity cyclopentadienyl ring. These findings may provide new probes assignment screw-sense preference short peptides.