West, N.G.; Seoudi, R.S.; Barlow, A.J.; Qi, D.; Puskar, L.; Borgo, M.P. D.; Kulkarni, K.; Adda, C.G.; Pan, J.; Aguilar, M.-I.; Perlmutter, P.; Mechler, A.: A two-dimensional metallosupramolecular framework design based on coordination crosslinking of helical oligoamide nanorods. Materials Advances 1 (2020), p. 1134-1141
10.1039/d0ma00123f
Open Accesn Version

Abstract:
Spontaneous formation of nanostructured materials of defined structure and morphology is a crucialmilestone toward realizing true bottom-up nanofabrication. Supramolecular recognition offers unparalleledspecificity, selectivity and geometric flexibility to design hierarchical nanostructures. However, competitionbetween similar binding motifs and the dynamic nature of the attachment imposes a severe limitation onthe complexity of the achievable structures. Here we outline a design based on two distinct binding motifsin a supramolecular fibrous assembly to realize a metallosupramolecular framework (MSF). Controlledgeometries were achieved by one-dimensional supramolecular assembly of substituted oligoamide units.The assembly of the monomers yields nanorods of sub-nanometer diameter and lengths in the 100mmrange. Addition of Cu2+led to the formation of well aligned two-dimensional arrays on mica surface.Vibrational spectroscopy confirmed that the backbone amide moieties are not affected by metal addition.XPS and NEXAFS results suggest that Cu(II) is reduced in the process to a mixture of Cu(I) and Cu(0), likely inan interaction with the amine moiety of the imidazole side chain. Our results indicate that the twodimensional superstructure is based on the formation of polynuclear metal complexes between theoligoamide nanorods, thus the structure is confirmed to be a metallosupramolecular framework.