Self-assembled monolayers (SAMs) were formed on gold colloids in 50% aqueous ethanol in the presence of alkanethiols, HS(CH2) n R, where R represents a series of neutral and acidic functional groups. Chemiadsorption of alkanethiols onto the gold colloids significantly changed the rates of flocculation of the gold dispersions; the magnitudes of these pH-dependent changes were a function of chain length, n, and the terminal functionality, R, in a manner consistent with formation of SAMs on the colloid surface. The reduced rate of dissolution of alkanethiol-treated colloids by wet chemical etchants, transmission electron microscopy, and X-ray photoelectron spectroscopy data further support the formation of SAMs.

Cadmium telluride nanoclusters were prepared by vapor-phase deposition of elemental tellurium in Na+−zeolite A, followed by partial exchange of the zeolite with aqueous Cd(NO3)2, and reduction with hydrogen at 450 °C. The stability of the nanoclusters in environments that normally cause rapid Ostwald ripening or oxidation (air, water, and Br2/MeOH) was greatly enhanced by exchanging the Na+−zeolite with K+ after the Te0 deposition and hydrogen reduction steps. Exchange of K+ for Na+ narrows the effective pore diameter of zeolite A from 4.0 to 3.3 Å, inhibiting the diffusion of larger atoms, ions, and molecules (Te0, Te2-, and Br2). Distinct absorption maxima in diffuse reflectance UV−visible spectra and sharp exciton peaks in low-temperature excitation spectra verified the presence of quantum-confined CdTe. These spectral features are largely unchanged when the material, in its K+-exchanged form, is exposed to air and water for periods of months. Under the same conditions, materials in the Na+ form are rapidly degraded. TEM micrographs of the K+-exchanged materials show 20−50 Å diameter nanoclusters dotted throughout the zeolite matrix. The partial loss of host crystallinity observed in X-ray diffraction patterns suggests that the process of cluster formation involves aggregation within the large cages of the zeolite and local destruction of the pore network.

In addition to the well-known SO2 loss, there are several additional fragmentation pathways that gas-phase anions derived from N-phenyl benzenesulfonamides and its derivatives undergo upon collisional activation. For example, N-phenyl benzenesulfonamide fragments to form an anilide anion (m/z 92) by a mechanism in which a hydrogen atom from the ortho position of the benzenesulfonamide moiety is specifically transferred to the charge center. Moreover, after the initial SO2 elimination, the product ion formed undergoes primarily, an inter-annular H2 loss to form a carbazolide anion (m/z 166) because the competing intra-annular H2 loss is significantly less energetically favorable. Results from tandem mass spectrometric experiments conducted with deuterium-labeled compounds confirmed that the inter-ring mechanism is the preferred pathway. Furthermore, N-phenyl benzenesulfonamide and its derivatives also undergo a phenyl radical loss to form a radical ion with a mass-to-charge ratio of 155, which is in violation of the so-called "even-electron rule."

Collision-induced dissociation (CID) mass spectra of differently substituted glucosinolates were investigated under negative-ion mode. Data obtained from several glucosinolates and their isotopologues ((34)S and (2)H) revealed that many peaks observed are independent of the nature of the substituent group. For example, all investigated glucosinolate anions fragment to produce a product ion observed at m/z 195 for the thioglucose anion, which further dissociates via an ion/neutral complex to give two peaks at m/z 75 and 119. The other product ions observed at m/z 80, 96 and 97 are characteristic for the sulfate moiety. The peaks at m/z 259 and 275 have been attributed previously to glucose 1-sulfate anion and 1-thioglucose 2-sulfate anion, respectively. However, based on our tandem mass spectrometric experiments, we propose that the peak at m/z 275 represents the glucose 1-thiosulfate anion. In addition to the common peaks, the spectrum of phenyl glucosinolate (beta-D-Glucopyranose, 1-thio-, 1-[N-(sulfooxy)benzenecarboximidate] shows a substituent-group-specific peak at m/z 152 for C(6)H(5)-C(=NOH)S(-), the CID spectrum of which was indistinguishable from that of the anion of synthetic benzothiohydroxamic acid. Similarly, the m/z 201 peak in the spectrum of phenyl glucosinolate was attributed to C(6)H(5)-C(=S)OSO(2)(-).