Single-Molecule Magnets:  A New Approach To Investigate the Electronic Structure of Mn₁₂ Molecules by Scanning Tunneling Spectroscopy

Abstract

Abstract:A new approach to the deposition of Mn12 single-molecule magnet monolayers on the functionalized Au(111) surface optimized for the investigation by means of scanning tunneling spectroscopy was developed. To demonstrate this method, the new Mn 12 complex [Mn12O12(O2CC6H4F)16(EtOH)4]‚ 4.4CHCl3 was synthesized and characterized. In MALDI-TOF mass spectra the isotopic distribution of the molecular ion peak of the latter complex was revealed. The complex was grafted to Au(111) surfaces via two different short conducting linker molecules. The Mn 12 molecules deposited on the functionalized surface were characterized by means of scanning tunneling microscopy showing homogeneous monolayers of highest quality. Scanning tunneling spectroscopy measurements over a wider energy range compared with previous results could be performed because of the optimized Au(111) surface functionalization. Furthermore, the results substantiate the general suitability of short acidic linker molecules for the preparation of Mn 12 monolayers via ligand exchange and represent a crucial step toward addressing the magnetic properties of individual Mn12 single-molecule magnets.

Investigation of the stability of Mn12 single molecule magnets

“…The comparison shows that the molecules [17] have also apparently been degraded by radiation. Nonetheless, this observation is consistent with the results from STM measurements [10,18,21]. Homogeneous layers of apparently intact molecules were reported in [10,21].…”

“…Nonetheless, this observation is consistent with the results from STM measurements [10,18,21]. Homogeneous layers of apparently intact molecules were reported in [10,21]. In contrast, the direct deposition of Mn 12 -th on Au(111) yielded STM images of diffuse clusters [18], thus indicating a fragmentation in agreement with previous XAS measurements at the RGBL beamline [18].…”

“…A monolayer of Mn 12 -pfb was grafted to Au/Ti/Si via a ligand exchange reaction with 4-mercapto-tetrafluorobenzoicacid (4-MTBA) as described elsewhere [21]. XAS measurements were performed at the Russian-German beamline (RGBL) as well as at the PM-3 beamline at BESSY (Berlin) and at the D1011 beamline at MAX-lab (Lund).…”

“…The insights reveal the possibility that the integrity of Mn 12 molecules can be conserved during certain deposition procedures. 16 (EtOH) 4 ; Mn 12 -pfb) were synthesized as described elsewhere [19][20][21]. The single crystals were characterized by means of X-ray diffraction, MALDI-TOF mass spectrometry, IR spectroscopy, and SQUID.…”

Effects of bonding type and interface geometry on coherent transport through the single-molecule magnetMn12

“…Recently, molecular junctions based on single-molecule magnets ͑SMMs͒ connected to electrodes or monolayers of SMMs at surfaces, have been fabricated and their electron-transport characteristics [1][2][3][4][5][6] have been measured, as well as their mechanical, electronic, and magnetic properties. [7][8][9][10][11][12][13] Electron transport through an SMM drew a lot of attention because of the intriguing interplay between its transport properties and the internal magnetic degrees of freedom, which is absent in transport through small organic molecules.…”