Mass Spectrometry Analysis of the 1.5 nm Sphalerite−CdS Core of [Cd₃₂S₁₄(SC₆H₅)₃₆·DMF₄]

Abstract

Electrospray ionization (ESI) mass spectrometry is a soft-ionization technique that allows analysis of exact structure, composition, and stability of solution phase materials by a gas-phase technique. We describe the application of ESI techniques for the analysis of a nanoscale material, [Cd 32 S 14 (SC 6 H 5 ) 36 ‚DMF 4 ]. The ∼1.5 nm nanoscale cluster is composed of a ∼1.2 nm sphalerite-phase (cubic) CdS core consisting of six tetrahedrally coordinated S atoms and four tetrahedrally coordinated Cd atoms. By MS/MS analysis of the parent ion, cleavage along the pseudo-〈001〉 plane of the internal core is observed exposing a Cd-rich face analogous to a 〈001〉 plane in CdS. The fragmentation pattern of this nanoscale cluster provides insight into the potential fragmentation behavior of larger nanosized materials and suggests ESI may be a powerful technique for nanomaterial studies.

Characterization of Ti6O4(O2C4H5)8(OCH2CH3)8 by electrospray time of flight mass spectrometry

“…In this way relationships between chemical species detected by MS may be established. In fact, MS analysis of metal chalcogenide clusters up to 1.2 nm has suggested that cluster fragmentation occurs along pseudo-lattice planes in such materials [9].In this study, we report the ESMS and MS/MS characterization of the [Ti 6 O 4 (EtO) 8 (McO) 8 ] cluster (Figure 1) where EtO and McO denote ethoxide and methacrylate ligands, respectively. Discrete [Ti x O y L z ] clusters are stable materials, consisting of a titanium oxide core surrounded by alkoxy or carboxylic acid ligands, that are important intermediates in the conversion of Ti(OR) 4 precursors to TiO 2 glasses and sol-gel materials by either acid or base catalyzed hydrolysis [12][13][14][15][16].…”

“…While MS has been applied to the study of metal alkoxide hydrolysis mechanisms, mass spectra of isolated individual titanium oxide clusters have not previously been reported. (J Am Soc Mass Spectrom 2004, 15, 260Ϫ267) M ass spectrometry is a unique analytical tool that allows the determination of the exact mass of molecular and nano sized biological, organic, and inorganic species [1][2][3][4][5][6][7][8][9][10][11]. In polymeric systems, MS techniques have been shown to provide accurate estimates of the average size and polydispersity.…”

Single Source Precursor Growth and Characterization of CdSe Semiconductor Nanomaterial: a Crossing Study between Chemical and Physical Analyses

“…The confinement of electron-hole pairs in low size crystals enhances significantly transition efficiencies and enables one to operate at room temperature. Mass spectrometry (MS) technique provides additional data about composition, size, surface and stability of nanoparticules 5 . With MS, it is possible to detect pseudomolecular ion with the ratio mass over charge (m/z) and to get structure data by the so-called MS/MS fragmentation process 6 .…”

Effect of ionization mode in the analysis of proteolytic protein digests

“…However, the negative ion mode is a surprisingly underutilized tool in the analysis of proteins and protein digests. In particular, nanoESI has been shown to analyze oligonucleotides and peptides of low isoelectric point using both metal [21] and polyaniline [22] coated emitters as well as fused silica capillaries [23] and a wire in a pulled capillary [24]. Fewer molecules produce negative ions [25,26] and less salt adduction is observed in the negative ion mode [27], so cleaner mass spectra result.…”