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Non‐Covalent Chemistry on Surface‐Confined, Isolated Dendrimers
Author(s) -
van Manen H.J.,
Auletta T.,
Dordi B.,
Schönherr H.,
Vancso G.J.,
van Veggel F.C.J.M.,
Reinhoudt D.N.
Publication year - 2002
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200290011
Subject(s) - dendrimer , supramolecular chemistry , materials science , molecule , covalent bond , monolayer , nanotechnology , self assembled monolayer , ligand (biochemistry) , moiety , microcontact printing , chemistry , polymer chemistry , stereochemistry , organic chemistry , biochemistry , receptor
A “bottom‐up” fabrication of nanometer‐scale dendritic structures via the growth of isolated, nanosized supramolecular structures on gold surfaces is presented. A novel dendritic wedge containing peripheral pyridines and a focal dialkylsulfide chain ( 9 ) was synthesized and its coordination chemistry in solution was tested with a second‐generation Fréchet dendron functionalized with a focal SCS Pd II pincer moiety ( 13 ). Replacement of the labile acetonitrile in 13 by the pyridine groups of 9 converts dendritic wedge 9 into fourth‐generation metallodendron 9 · 13 4 in one step. Based on these results the spatially confined growth on a gold surface was studied. The dendritic molecules with reactive pyridine groups at the periphery ( 9 ) were first spatially isolated by inserting them into decanethiol self‐assembled monolayers (SAMs) on a gold surface. Subsequently, the peripheral pyridines were reacted via metal–ligand coordinative interactions by exposing the monolayer to a solution of dendritic wedges containing focal SCS Pd II pincer moieties ( 13 ). The isolated molecules inserted into the original SAM in the first step were resolved by ex‐situ tapping‐mode atomic force microscopy (TM‐AFM). The subsequent Pd II –pyridine coordination resulted in a significant increase in size of the individually resolved molecules. Reference experiments demonstrated that the increased size of the isolated dendrimers on the gold substrate was a result of specific metal–ligand interactions. The methodology presented herein allows the creation of surface‐confined architectures and potentially provides a viable complement to currently employed “top‐down” methods in nanofabrication.