In situ generation of chiroptically-active gold-peptide superstructures promoted by iodination
Pigliacelli, C.a, Sanjeeva, K.B.b, Nonappaa, Pizzi, A.b, Gori, A.c, Bombelli, F.B.b, Metrangolo, P.a,b
a Hyber Center of Excellence, Department of Applied Physics, Aalto University, Puumiehenkuja 2, Espoo, FI-00076, Finland
b Laboratory of Supramolecular and Bio-Nanomaterials (SBNLab), Department of Chemistry, Materials, and Chemical Engineering Giulio Natta, Politecnico di Milano, via L. Mancinelli 7, Milano, 20131, Italy
c Istituto di Chimica Del Riconoscimento Molecolare, CNR, via M. Bianco 9, Milano, 20131, Italy
Peptide-mediated routes to the synthesis of plasmonic nanoparticles have been drawing increasing attention for the development of chiroptically active nanoscale architectures. However, designing a multifunctional peptide able to drive the formation of structurally defined nanomaterials endowed with specific functionalities is still challenging. In this work, iodination has been devised as a strategy to strengthen Au-reduction capability of the amyloidogenic peptide DFNKF and combine it with its distinctive self-assembly features. Thanks to the Au-mediated C-I activation on the phenylalanine iodobenzenes, the peptides yield efficient Au-reduction ability promoting the synthesis of Au nanoparticles, and simultaneously working as templates for their spontaneous self-assembly into spherical superstructures endowed with chiroptical activities. The reaction occurs in situ through a one-pot process in aqueous media. The generality of this approach has been demonstrated using an iodinated derivative of the peptide KLVFF, which also showed reducing and templating abilities forming chiroptically active helical superstructures decorated with Au nanoparticles.
