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Two Morphologies of Stable, Highly Ordered Assemblies of a Long‐Chain‐Substituted [2 × 2]‐Grid‐Type Fe II Complex Adsorbed on HOPG
Author(s) -
Mourran Ahmed,
Ziener Ulrich,
Möller Martin,
Breuning Esther,
Ohkita Masakazu,
Lehn JeanMarie
Publication year - 2005
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200500064
Subject(s) - chemistry , supramolecular chemistry , highly oriented pyrolytic graphite , crystallography , scanning tunneling microscope , monolayer , ligand (biochemistry) , alkyl , graphite , nanotechnology , crystal structure , organic chemistry , materials science , biochemistry , receptor
The programmed self‐assembly of a multimetallic grid‐type supramolecular architecture and its hierarchical organization on graphite are described. The doubly functionalized 4,6‐bis(2,2'‐bipyridyl‐6‐yl)‐2‐phenylpyrimidine derivative 1 , equipped with CH 2 OC 16 H 33 moieties at the terminal pyridine rings, was designed as a new bis(tridentate) ligand and synthesized using Stille‐type coupling reactions. Treatment of ligand 1 with Fe(BF 4 ) 2 · 6H 2 O in CHCl 3 /CH 3 CN led to the spontaneous formation of a [2 × 2]‐grid‐type Fe II complex 2 in quantitative yield. The self‐assembled tetranuclear complex 2 was adsorbed onto highly oriented pyrolytic graphite (HOPG) and studied by scanning tunneling microscopy (STM), which showed two morphologies of highly ordered two‐dimensional arrays of the metallo‐supramolecular architectures. The resulting monolayers of the grid‐type complex 2 are much more stable than that obtained from the corresponding unsubstituted grid‐type complex owing to the additional attractive forces between the hexadecyl moieties in 2 and the HOPG surface. Moreover, the reproducibility of the STM images of the hexadecyl‐substituted grid 2 was strongly improved compared to the unsubstituted one. These results suggest that the introduction of long alkyl chains into metallo‐supramolecular architectures would have general advantages for their organization and STM investigation on HOPG. Details of the preparation and the STM investigation of ligand 1 are also presented. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)