Mass spectrometry (MS), a hundred-year-old subject, has been a technique of profound importance to molecular science. Its impact in solid-state materials science has not been evident, although many materials of modern science, such as fullerenes, have their origins in MS. Of late, mass spectrometric interface with materials is increasingly strengthened with advances in atomically precise clusters of noble metals. Advances in instrumentation along with recent developments in synthetic approaches have expanded the chemistry of clusters, and new insights into matter at the nanoscale are emerging. High-resolution MS coupled with soft ionization techniques enable efficient characterization of atomically precise clusters. Apart from that, techniques such as ion mobility, tandem MS, etc. reveal structural details of these systems. Growth, nucleation, and reactivity of clusters are also probed by MS. Some of the recent advancements in this field include the development of new hyphenated techniques. Finer structural details may be obtained by coupling MS with spectroscopic tools, such as photoelectron spectroscopy, vacuum ultraviolet spectroscopy, etc. With such advancements in instrumentation, MS can evolve into a universal tool for the characterization of materials. The present review captures highlights of this area. © 2019, The Author(s).

Pradeep Thalappil

Department Of Chemistry

Papri Chakraborty

Mass spectrometry

Photoelectron Spectroscopy

Ultraviolet spectroscopy

Vacuum applications

High resolution

HYPHENATED TECHNIQUES

MOLECULAR SCIENCE

SOLID-STATE MATERIALS

SPECTROSCOPIC TOOL

Structural details

Synthetic approach

VACUUM ULTRAVIOLET SPECTROSCOPY

Interfaces (materials)

Fulltext

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

NPG Asia Materials

Rapid solution-state exchange dynamics in nanoscale pieces of matter is revealed, taking isotopically pure atomically precise clusters as examples. As two isotopically pure silver clusters made of 107 Ag and 109 Ag are mixed, an isotopically mixed cluster of the same entity results, similar to the formation of HDO, from H 2 O and D 2 O. This spontaneous process is driven by the entropy of mixing and involves events at multiple time scales. Copyright © 2019 The Authors.

Science Advances

Rapid isotopic exchange in nanoparticles

Collision cross sections (CCSs) of ligand-protected metal clusters were evaluated using ion mobility mass spectrometry. The targets used in this study were phosphine-protected clusters [PdAu8(PPh3)8]2+ and [Au9(PPh3)8]3+, for which the total structures have been resolved by single-crystal X-ray analysis. The arrival time distributions of [PdAu8(PPh3)8]2+ as a function of the He flow rate in a cell located just in front of a traveling wave ion mobility cell filled with N2 buffer gas demonstrated that it got converted to another structural isomer having a smaller CCS, with the increase in the nominal collision energy. A similar phenomenon was observed for [Au9(PPh3)8]3+. These results were explained by the collisional excitation and cooling with the buffer gas inducing the conversion of the packing arrangement of the ligands rather than the atomic structure of the metallic core: the ligand layer was converted from disordered to the closely packed arrangement found in a single crystal during this process. This study showed that the ligand layer with a disordered arrangement in solution was retained during desolvation upon electrospray ionization and was annealed into the most stable closely packed arrangement by collisions. © 2018 American Chemical Society.

Journal of Physical Chemistry C

Interconversions of Structural Isomers of [PdAu8(PPh3)8]2+ and [Au9(PPh3)8]3+ Revealed by Ion Mobility Mass Spectrometry

We report the formation of supramolecular adducts between monolayer-protected noble metal nanoclusters and fullerenes, specifically focusing on a well-known silver cluster, [Ag29(BDT)12]3-, where BDT is 1,3-benzenedithiol. We demonstrate that C60 molecules link with the cluster at specific locations and protect the fragile cluster core, enhancing the stability of the cluster. A combination of studies including UV-vis, high-resolution electrospray ionization mass spectrometry, collision-induced dissociation, and nuclear magnetic resonance spectroscopy revealed structural details of the fullerene-functionalized clusters, [Ag29(BDT)12(C60)n]3- (n = 1-9). Density functional theory (DFT) calculations and molecular docking simulations affirm compatibility between the cluster and C60, resulting in its attachment at specific positions on the surface of the cluster, stabilized mainly by π-π and van der Waals interactions. The structures have also been confirmed from ion mobility mass spectrometry by comparing the experimental collision cross sections (CCSs) with the theoretical CCSs of the DFT-optimized structures. The gradual evolution of the structures with an increase in the number of fullerene attachments to the cluster has been investigated. Whereas the structure for n = 4 is tetrahedral, that of n = 8 is a distorted cube with a cluster at the center and fullerenes at the vertices. Another fullerene, C70, also exhibited similar behavior. Modified clusters are expected to show interesting properties. © 2018 American Chemical Society.

ACS Nano

Fullerene-Functionalized Monolayer-Protected Silver Clusters: [Ag29(BDT)12(C60)n]3- (n = 1-9)

Gas phase clusters of noble metals prepared by laser desorption from the bulk have been investigated extensively in a vacuum using mass spectrometry. However, such clusters have not been known to exist under ambient conditions to date. In our previous work, we have shown that in-source fragmentation of ligands can be achieved starting from hydride and phosphine co-protected silver clusters leading to naked silver clusters inside a mass spectrometer. In a recent series of experiments, we have found that systematic desorption of ligands of the monolayer protected atomically precise silver cluster can also occur in the atmospheric gas phase. Here, we present the results, wherein the [Ag 18 H 16 (TPP) 10 ] 2+ (TPP = triphenylphosphine) cluster results in the formation of the naked cluster, Ag 17 + along with Ag 18 H + without mass selection, outside the mass spectrometer, in air. These cationic naked metal clusters are prepared by passing electrosprayed ligand protected clusters through a heated tube, in the gas phase. Reactions with oxygen suggest Ag 17 + to be more reactive than Ag 18 H + , in agreement with their electronic structures. The more common thiolate protected clusters produce fragments of metal thiolates under identical processing conditions and no naked clusters were observed. © 2018 The Royal Society of Chemistry.

Nanoscale

Preparation of gas phase naked silver cluster cations outside a mass spectrometer from ligand protected clusters in solution

We present isomerism in a few supramolecular adducts of atomically precise nanoparticles, [Ag29(BDT)12∩(CD)n]3- (n = 1-6), abbreviated as I where BDT and CD are 1,3-benzenedithiol and cyclodextrins (α, β and γ), respectively; ∩ symbolizes an inclusion complex. The different host-guest complexes of I were characterized in the solution state as well as in the gas phase. The CDs (α, β and γ) encapsulate a pair of BDT ligands protecting the Ag29 core. This unique geometry of the supramolecular adducts makes the system similar to octahedral complexes of transition metals, which manifest various isomers. These isomers of I (n = 2-4) were separated by ion mobility mass spectrometry (IM MS). We proposed structures of all the inclusion complexes with the help of IM MS measurements and molecular docking, density functional theory (DFT), and collision cross section (CCS) calculations. Copyright © 2018 American Chemical Society.

Journal of the American Chemical Society

Isomerism in Supramolecular Adducts of Atomically Precise Nanoparticles

The emerging interface of mass spectrometry with materials

Journal	NPG Asia Materials
Publisher	Nature Publishing Group
ISSN	18844049
Open Access	No