Soft-Landing Isolation of Multidecker V2(benzene)3 Complexes in an Organic Monolayer Matrix:  An Infrared Spectroscopy and Thermal Desorption Study

Nagaoka, Shuhei; Matsumoto, Takeshi; Ikemoto, Kaori; Mitsui, Masaaki; Nakajima, Atsushi

doi:10.1021/ja068442j

Cited by 73 publications

(87 citation statements)

References 19 publications

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“…Previous studies by Nakajima and co-workers have demonstrated that small organometallic ions may penetrate into SAMs as opposed to staying on top of the monolayer when deposited from the gas phase. 67,68,101 We propose that the significantly larger Au 11 L 5 3+ clusters are less likely to penetrate into the monolayers than the smaller organometallic ions due to their greater steric repulsion. This proposition is supported by previous data which showed that cluster ions soft landed onto SAMs at low kinetic energy are readily desorbed from the surfaces, complete with retention of charge, without substantial fragmentation using TOF-SIMS.…”

Section: ■ Introductionmentioning

confidence: 96%

Coverage-Dependent Charge Reduction of Cationic Gold Clusters on Surfaces Prepared Using Soft Landing of Mass-Selected Ions

2012

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The ionic charge state of monodisperse multiply charged cationic gold clusters on surfaces may be controlled by selecting the coverage of mass-selected ions soft landed onto a substrate. Polydisperse diphosphine-capped gold clusters were synthesized in solution and introduced into the gas phase by electrospray ionization. Mass selection was employed to isolate a multiply charged cationic cluster species (Au 11 L 5 3+ , m/z = 1409, L = 1,3-bis(diphenylphosphino)-propane) which was delivered to the surfaces of four different self-assembled monolayers on gold (SAMs) at controlled coverages of 10 11 and 10 12 clusters. Employing the spatial profiling capabilities of in situ time-of-flight secondary ion mass spectrometry (TOF-SIMS), it is shown that, in addition to the chemical functionality of the monolayer (as demonstrated previously: ACS Nano 2012, 6, 573), the coverage of cationic gold clusters on the surface may be used to control the relative abundance of different charge states of the soft landed multiply charged clusters. In the case of a 1H,1H,2H,2H-perfluorodecanethiol monolayer (FSAM) almost complete retention of charge by the deposited Au 11 L 5 3+ clusters was observed at a lower coverage of 10 11 clusters. In contrast, at a higher coverage of 10 12 clusters, pronounced reduction of charge to Au 11 L 5 2+ and Au 11 L 5 + was observed on the FSAM. When soft landed onto 16-and 11-mercaptohexadecanoic acid surfaces on gold (16,11-COOH-SAMs), the mass-selected Au 11 L 5 3+ clusters exhibited partial reduction of charge to Au 11 L 5 2+ at lower coverage and additional reduction of charge to both Au 11 L 5 2+ and Au 11 L 5 + at higher coverage. On the surface of the 1-dodecanethiol (HSAM) monolayer, the most abundant charge state was found to be Au 11 L 5 2+ at lower coverage and Au 11 L 5 + at higher coverage, respectively. A coverage-dependent electron tunneling mechanism is proposed to account for the observed reduction of charge of mass-selected multiply charged gold clusters soft landed on SAMs. The results demonstrate that one of the critical parameters that influence the chemical and physical properties of supported metal clusters, ionic charge state, may be controlled by selecting the coverage of charged species soft landed onto surfaces. ■ INTRODUCTIONThe highly size-dependent physical and chemical properties 1−5 of small metal clusters have made them the focus of considerable research attention in the chemistry and materials science communities. The eventual goal of much of this research is to develop economical techniques for the scalable synthesis of metal clusters of an exact size and composition. Such precise methods will enable the rational assembly of cluster-based materials 6,7 with desired attributes from welldefined metal particles having distinctive optical, 8−10 electronic, 11−13 or catalytic properties. 14,15 Indeed, metal nanoparticles have already shown considerable promise for applications in photothermal therapeutic treatments, 16 as contrast agents in biological and cellular imaging, ...

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Section: ■ Introductionmentioning

confidence: 96%

Coverage-Dependent Charge Reduction of Cationic Gold Clusters on Surfaces Prepared Using Soft Landing of Mass-Selected Ions

2012

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“…The collision energy ranged between 10 and 20 eV. The soft-landed molecules on the SAMs were stable because the desorption energy calculated from the TPD experiments was high (143). These experiments were performed with V 2 (benzene) 3 + multidecker complex ions, which were landed onto a 1-octadecanethiol SAM at a kinetic energy of approximately 20 eV (143,144).…”

Section: Soft Landing and Its Applications In Organometallicsmentioning

confidence: 99%

Probing Molecular Solids with Low-Energy Ions

Bag

Bhuin

Natarajan

et al. 2013

Annual Rev. Anal. Chem.

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Ion/surface collisions in the ultralow-to low-energy (1-100-eV) window represent an excellent technique for investigation of the properties of condensed molecular solids at low temperatures. For example, this technique has revealed the unique physical and chemical processes that occur on the surface of ice, versus the liquid and vapor phases of water. Such instrumentdependent research, which is usually performed with spectroscopy and mass spectrometry, has led to new directions in studies of molecular materials. In this review, we discuss some interesting results and highlight recent developments in the area. We hope that access to the study of molecular solids with extreme surface specificity, as described here, will encourage investigators to explore new areas of research, some of which are outlined in this review.

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“…To date, a multitude of techniques have been applied for this purpose including secondary ion mass spectrometry (SIMS) 19,[97][98][99][100] , temperature programmed desorption and reaction 50,52 , laser desorption and ionization 101 , pulsed molecular beam reaction 102 , infrared spectroscopy (FTIR and Raman) 98,103,104 , surface enhanced Raman spectroscopy 103,105 , cavity ringdown spectroscopy 106 , xray photoelectron spectroscopy 35,107 , scanning tunneling microscopy 33,[108][109][110][111] , atomic force microscopy [112][113][114] , and transmission electron microscopy 39 . However, to most accurately characterize surfaces prepared or modified by ion soft landing, it is crucial that the analysis be performed in situ without exposure of the substrate to the environment in the laboratory.…”

Section: Introductionmentioning

confidence: 99%

“…However, to most accurately characterize surfaces prepared or modified by ion soft landing, it is crucial that the analysis be performed in situ without exposure of the substrate to the environment in the laboratory. Previous analyses conducted in situ have provided insight into phenomena such as the reduction of ionic charge of soft landed ions over time 37,38,115,116 , the desorption of soft landed ions from surfaces 52 , the efficiency and kinetic energy dependence of ion reactive landing 14,81 , and the influence of size on the catalytic activity of clusters and nanoparticles deposited onto surfaces 117 . By way of example, in our laboratory, we have systematically studied the charge reduction kinetics of protonated peptides on the surfaces of different SAMs 3 .…”

Section: Introductionmentioning

confidence: 99%

In Situ SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions

Johnson

Gunaratne

Laskin

2014

JoVE

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Soft landing of mass-selected ions onto surfaces is a powerful approach for the highly-controlled preparation of materials that are inaccessible using conventional synthesis techniques. Coupling soft landing with in situ characterization using secondary ion mass spectrometry (SIMS) and infrared reflection absorption spectroscopy (IRRAS) enables analysis of well-defined surfaces under clean vacuum conditions. The capabilities of three soft-landing instruments constructed in our laboratory are illustrated for the representative system of surface-bound organometallics prepared by soft landing of mass-selected ruthenium tris(bipyridine) dications, [Ru(bpy) 3 ] 2+ (bpy = bipyridine), onto carboxylic acid terminated self-assembled monolayer surfaces on gold (COOH-SAMs). In situ time-of-flight (TOF)-SIMS provides insight into the reactivity of the soft-landed ions. In addition, the kinetics of charge reduction, neutralization and desorption occurring on the COOH-SAM both during and after ion soft landing are studied using in situ Fourier transform ion cyclotron resonance (FT-ICR)-SIMS measurements. In situ IRRAS experiments provide insight into how the structure of organic ligands surrounding metal centers is perturbed through immobilization of organometallic ions on COOH-SAM surfaces by soft landing. Collectively, the three instruments provide complementary information about the chemical composition, reactivity and structure of well-defined species supported on surfaces. Video LinkThe video component of this article can be found at

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Soft-Landing Isolation of Multidecker V₂(benzene)₃ Complexes in an Organic Monolayer Matrix: An Infrared Spectroscopy and Thermal Desorption Study

Cited by 73 publications

References 19 publications

Coverage-Dependent Charge Reduction of Cationic Gold Clusters on Surfaces Prepared Using Soft Landing of Mass-Selected Ions

Coverage-Dependent Charge Reduction of Cationic Gold Clusters on Surfaces Prepared Using Soft Landing of Mass-Selected Ions

Probing Molecular Solids with Low-Energy Ions

<em>In Situ</em> SIMS and IR Spectroscopy of Well-defined Surfaces Prepared by Soft Landing of Mass-selected Ions

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