Electronic and Magnetic Properties of Mn12 Molecular Magnets on Sulfonate and Carboxylic Acid Prefunctionalized Gold Surfaces

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• 作者：Fabrizio Moro ; Roberto Biagi ; Valdis Corradini ; Marco Evangelisti ; Alessandro Gambardella ; Valentina De Renzi ; Umberto del Pennino ; Eugenio Coronado ; Alicia Forment-Aliaga ; Francisco M. Romero
• 刊名：The Journal of Physical Chemistry C
• 出版年：2012
• 出版时间：July 19, 2012
• 年：2012
• 卷：116
• 期：28
• 页码：14936-14942
• 全文大小：426K
• 年卷期：v.116,no.28(July 19, 2012)
• ISSN：1932-7455

文摘

Structural, electronic, and magnetic properties of [Mn₁₂O₁₂(bet)₁₆(EtOH)₄](PF₆)₁₄路4CH₃CN路H₂O (in short Mn₁₂bet, bet = betaine = ⁺N(CH₃)₃-CH₂鈥揅OO^{鈥?/sup>) single-molecule magnets (SMMs) deposited on previously functionalized gold surfaces have been investigated. Self-assembled monolayers (SAMs) either of sodium mercaptoethanesulfonate (MES) or mercaptopropionic acid (MPA) are used as functionalization to avoid the direct interaction between the Mn₁₂bet molecules and the Au surface with the aim of preserving the main functional properties of the molecules. Scanning tunneling microscopy (STM) and X-ray photoemission spectroscopy (XPS) analysis show deposited Mn₁₂bet SMMs well-isolated from each other and uniformly distributed on both MES and MPA SAMs. X-ray absorption spectroscopy (XAS) studies show that the oxidation state of the mixed-valence Mn₁₂bet core is largely reduced to Mn2+ when molecules are deposited on MES-SAM, whereas in the case of MPA-SAM the relative weights of Mn2+, Mn3+, and Mn4+ in the Mn₁₂bet core are preserved. Despite the substantial retaining of their electronic properties, the magnetization of Mn₁₂bet molecules deposited on MPA-SAM measured by X-ray magnetic circular dichroism (XMCD) is perturbed with respect to the pristine molecules.}