We describe a novel two-step method, starting from bulk silicon wafers, to construct DNA conjugated silicon nanoparticles (SiNPs). This method first utilizes reactive high-energy ball milling (RHEBM) to obtain alkene grafted SiNPs. The alkene moieties are subsequently reacted with commercially available thiol-functionalized DNA via thiol–ene click chemistry to produce SiNP DNA conjugates wherein the DNA is attached through a covalent thioether bond. Further, to show the utility of this synthetic strategy, we illustrate how these SiNP ODN conjugates can detect cancer-associated miR-21 via a fluorescence ON strategy. Given that an array of biological molecules can be prepared with thiol termini and that SiNPs are biocompatible and biodegradable, we envision that this synthetic protocol will find utility in salient SiNP systems for potential therapeutic and diagnostic applications.

A facile and efficient method using high energy ball milling (HEBM) to produce surfaces with a static and advancing contact angle in the superhydrophobic regime consisting of alkyl-passivated crystalline silicon particles is described. Deposition of the functionalized silicon material forms stable films on a variety of surfaces due to strong hydrophobic interactions between the individual particles. The process offers the ability to control the particle size from a micro-scale to a nano-scale region and thus to tune the surface roughness. Because of changing surface morphology and the decreasing surface roughness of the films due to the increasing milling times the static and dynamic contact angles follow a polynomial function with a maximum dynamic advancing contact angle of 171°. This trend is correlated to the commonly used Wenzel and Cassie-Baxter models.High energy ball milling presents a facile and efficient method to produce alkyl-passivated monocrystalline silicon particles for superhydrophobic coatings of arbitrary surfaces.

New single source precursors to hexagonal gallium sulfide (GaS) were investigated. Four organometallic compounds containing a Ga2S2 ring core, [R2Ga(μ-SSiR′3R′3)]2 (R = Me, Et; R′ = Ph, iPr), were prepared and thermally decomposed to give chemically pure gallium sulfide. The decomposition temperatures as measured by TGA range from 200 to 350 °C and the resulting solid powders were found to be the hexagonal phase of GaS by XRD. The decomposition of the ethyl gallium derivatives were found to proceed by the initial loss of ethylene (TGA–EGA) followed by an unresolved second mode of decomposition to give hexagonal GaS. In contrast, the methyl gallium derivatives decomposed in one uniform stage to yield gallium sulfide. The precursors with isopropylsilyl groups were generally more volatile and decomposed at lower temperatures than the triphenylsilyl derivatives.

Two complexes of the type (R2PCH2CH2PR2)Pd(dba) have been prepared by the reaction of Pd2(dba)3·CHCl3 with R2PCH2CH2PR2 (R=iPr (1), 74%; Cy (2), 57%; dba=dibenzylideneacetone). X-ray crystallographic studies of 1 and 2 reveal that the coordinated dba ligand adopts an s-trans, s-trans conformation in which the palladium is coordinated to one CC bond in an η2-fashion. Variable temperature, 1H- and 31P{H}-NMR spectroscopy of 1 show two distinct dynamic processes in solution. In the 1H-NMR spectra, a rapid intramolecular exchange of coordinated and uncoordinated CC bonds is observed with the estimated ΔGex‡ being 14 kcal mol−1. In the 31P{H}-NMR spectra, a facile interconversion of the predominant s-trans, s-trans conformer with the minor s-trans, s-cis, and s-cis, s-cis conformers begins to occur at higher temperatures. Molecular mechanics calculations place the relative energies of the three isomers at 0, 0.9, and 4.7 kcal mol−1, respectively. An intramolecular mechanism for double bond exchange is proposed to occur via a symmetric transition state involving the s-cis, s-cis conformer. Strong coordination of dba to palladium in 1 is proposed to account for slow reactions with PhX where the relative rates of oxidative addition were found to increase in the order of X=Cl≪Br