Phenolic Porphyrins Assembled at Surfaces: Hydrogen-Bonding and Binary Systems

Tuesday, May 13, 2014: 08:20
Bonnet Creek Ballroom X, Lobby Level (Hilton Orlando Bonnet Creek)
J. P. Hill (WPI Center for Materials Nanoarchitectonics), Y. Wakayama (National Institute for Materials Science), Y. Xie (East China University of Science and Technology), Q. Ji, and K. Ariga (WPI Center for Materials Nanoarchitectonics)
Supramolecular arrangement of porphyrins and other molecules has great potential in the fields of molecular information storage and sensing due to their ease of deposition and good chemical and thermal stabilities. In particular, porphyrins of relatively large molecular weights can be applied in thermal deposition while tetrapyrrole molecules have had an extensive synthetic chemistry developed, which enables synthesis of complex derivatives. In this work, we present complementary examples of porphyrin nanoarchitectonics. Starting from simple symmetrical phenol derivatives, we describe the effects of steric hindrance about the respective hydroxyl groups1,2 and also the effects of conformational variation on the self-assembly structures.3 We also investigated fabrication of binary molecular monolayers using two different porphyrin molecules tetrakis(3,5-di-t-butyl-4-hydroxyphenyl) porphyrin and tetrakis(4-pyridyl) porphyrin by deposition in ultrahigh vacuum.4 This leads to two unusual heteromolecular monolayer structures were observed with one exhibiting good separation of molecules within the monolayer.  Meanwhile, a synthetic nanoarchitectonic approach was used to prepare self-assembled molecular nanowires at a mica substrate. The nanowires could be observed growing using atomic force microscopy (AFM) and the network structures of the nanowires can be influenced by manipulation using the AFM probe tip.4,5Formation of molecular monolayers with chromophores positioned remote from the substrate surface will also be discussed.


(1) J. P. Hill, Y. Wakayama, W. Schmitt, T. Tsuruoka, T. Nakanishi, P. A. Karr, M. L. Zandler, A. L. McCarty, F. D’Souza, L. R. Milgrom, K. Ariga, Chem. Commun. 2006, 2320–2322 (2) J. P. Hill, Y. Wakayama, M. Akada, Katsuhiko Ariga, J. Phys. Chem. C. 2007, 111, 16174–16180 (3) J. P. Hill, Y. Wakayama, K. Ariga, Phys. Chem. Chem. Phys. 2006, 8, 5034–5037 (4) J. P. Hill, Y. Xie, M. Akada, Y. Wakayama, L. K. Shrestha, Q. Ji, K. Ariga, Langmuir (2013) 29(24), 7291–7299 (5) Y. Xie, M. Akada, J. P. Hill, Q. Ji, R. Charvet K. Ariga, Chem. Commun. 2011, 47, 2285–2287.

Figure. Self-assembled phenol-substituted porphyrins on Cu(111) surface.