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Stable Alignment of Tautomers at Room Temperature in Porphyrin 2D Layers
Author(s) -
Bussetti Gianlorenzo,
Campione Marcello,
Riva Michele,
Picone Andrea,
Raimondo Luisa,
Ferraro Lorenzo,
Hogan Conor,
Palummo Maurizia,
Brambilla Alberto,
Finazzi Marco,
Duò Lamberto,
Sassella Adele,
Ciccacci Franco
Publication year - 2014
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.201301892
Subject(s) - tautomer , intramolecular force , porphyrin , materials science , molecule , bistability , chemical physics , hydrogen bond , photochemistry , optoelectronics , stereochemistry , chemistry , quantum mechanics , physics
A major challenge in molecular electronics is to develop logic devices based on a truly intramolecular switching mechanism. Recently, a new type of molecular device has been proposed where the switching characteristic is mediated by the bistability in the position of the two hydrogen atoms which can occupy different, energetically equivalent positions (tautomerization) in the inner cavity of porphyrins and naphthalocyanines. Up to now, such a reaction has only been exploited at low temperatures and induced or detected through atomic scale manipulation. In addition, the unpredictability of the tautomer orientation currently excludes molecular interconnection to functional electronic circuits. Here, full evidence is provided that, following a newly proposed growth strategy, 2D layers of metal‐free tetraphenylporphyrins (H 2 TPP) show frozen tautomerization even at room temperature on macroscopic domains, with the H atoms aligned along a direction settled a priori. This behavior is ascribed to the buckling of the molecule, anchored to the substrate, which removes the degeneracy between the two tautomer alignments. On this basis, a new way to exploit uniaxially oriented H 2 TPP tautomers in a first elementary logic device is proposed.