Self-Assembled Monolayers of Single-Molecule Magnets [TbPc′(SR)82] on Gold

Citation

Glebe, Ulrich; Weidner, Tobias; Baio, Joe E.; Schach, Denise; Bruhn, Clemens; Buchholz, Axel; Plass, Winfried; Walleck, Stephan; Glaser, Thorsten; & Siemeling, Ulrich (2012). Self-Assembled Monolayers of Single-Molecule Magnets [TbPc′(SR)82] on Gold. ChemPlusChem, 77(10), 889-897.

Abstract

The magnetic properties of the bis(phthalocyaninato)terbium complexes [TbPc′(SR)82] (1) containing eight β-positioned long-chain alkylthio substituents SR (a: R=n-C8H17, b: R=n-C12H25) were studied by SQUID measurements, which revealed that both compounds are single-molecule magnets with an effective energy barrier for spin reversal significantly higher than that found for pristine bis(phthalocyaninato)terbium [Tb(Pc)2]. Thin films on gold were fabricated from 1 a and 1 b by chemisorption from solution and were characterised by near-edge X-ray absorption fine structure (NEXAFS) and X-ray photoelectron spectroscopy (XPS). In the case of 1 a, atomic force microscopy (AFM) was used in addition. The results are in accord with the formation of self-assembled monolayers which contain the macrocyclic rings mainly in an approximately horizontal orientation. The chemisorption is primarily due to the peripheral SR substituents, giving rise to coordinatively bound thioether units, whose alkyl chains are in an almost parallel orientation with respect to the surface. In the case of 1 b, covalently attached thiolate units were also observed, indicating that the chemisorption process can lead to carbon–sulfur bond cleavage. In addition, the crystal structure of 1 a was determined.

Keyword(s)

magnetic properties
monolayers
nexafs spectroscopy
Self-assembly
X-ray photoelectron spectroscopy

Reference Type

Journal Article

Secondary Title

ChemPlusChem

Author(s)

Glebe, Ulrich
Weidner, Tobias
Baio, Joe E.
Schach, Denise
Bruhn, Clemens
Buchholz, Axel
Plass, Winfried
Walleck, Stephan
Glaser, Thorsten
Siemeling, Ulrich

Year Published

2012

Date Published

1325376000

Volume Number

Issue Number

Pages

889-897

ISSN/ISBN

2192-6506

DOI

10.1002/cplu.201200043