Jump to main content
Jump to site search

Issue 1, 2011
Previous Article Next Article

Redox chemistry in thin layers of organometallic complexes prepared using ion soft landing

Author affiliations

Abstract

Soft landing (SL) of mass-selected ions is used to transfer catalytically-active metal complexes complete with organic ligands from the gas phase onto an inert surface. This is part of an effort to prepare materials with defined active sites and thus achieve molecular design of surfaces in a highly controlled way. Solution-phase electrochemical studies have shown that VIVO(salen) reacts in the presence of acid to form VVO(salen)+ and the deoxygenated VIII(salen)+ complex—a key intermediate in the four electron reduction of O2 by vanadium–salen. In this work, the VVO(salen)+ and [NiII(salen) + H]+ complexes were generated by electrospray ionization and mass-selected before being deposited onto an inert fluorinated self-assembled monolayer (FSAM) surface on gold. A time dependence study after ion deposition showed loss of O from VVO(salen)+ forming VIII(salen)+ over a four-day period, indicating a slow interfacial reduction process. Similar results were obtained when other protonated molecules were co-deposited with VVO(salen)+ on the FSAM surface. In all these experiments oxidation of the VIII(salen)+ product occurred upon exposure to oxygen or to air. The cyclic regeneration of VVO(salen)+ upon exposure to molecular oxygen and its subsequent reduction to VIII(salen)+ in vacuum completes the catalytic cycle of O2reduction by the immobilized vanadium–salen species. Moreover, our results represent the first evidence of formation of reactive organometallic complexes on substrates in the absence of solvent. Remarkably, deoxygenation of the oxo-vanadium complex, previously observed only in highly acidic non-aqueous solvents, occurs on the surface in the UHV environment using an acid which is deposited into the inert monolayer. This acid can be a protonated metal complex, e.g. [NiII(salen) + H]+, or an organic acid such as protonated diaminododecane.

Graphical abstract: Redox chemistry in thin layers of organometallic complexes prepared using ion soft landing

Back to tab navigation
Please wait while Download options loads

Supplementary files

Publication details

The article was received on 09 Aug 2010, accepted on 11 Oct 2010 and first published on 12 Nov 2010


Article type: Paper
DOI: 10.1039/C0CP01457E
Citation: Phys. Chem. Chem. Phys., 2011,13, 267-275
  •   Request permissions

    Redox chemistry in thin layers of organometallic complexes prepared using ion soft landing

    W. Peng, G. E. Johnson, I. C. Fortmeyer, P. Wang, O. Hadjar, R. G. Cooks and J. Laskin, Phys. Chem. Chem. Phys., 2011, 13, 267
    DOI: 10.1039/C0CP01457E

Search articles by author