Multiwall carbon nanotubes (MWNTs) were synthesized via the decomposition of CCl4 in supercritical CO2 at 175 degrees C and 27.6 MPa using an iron-encapsulated dendrimer as a growth catalyst. The average diameter of resultant nanotubes was 20-25 nm, obtained after a 24-h reaction time. Our conditions represent the first application for CX4 precursors, as well as the lowest-reported temperature regime for carbon nanotube growth, allowing the use of other temperature-sensitive catalytic substrates.

Pseudotetrahedral, conformationally as well as configurationally stable 1-bromo-3-chloro-5-fluoro- (4) and 1-bromo-3-chloro-5-fluoro-7-iodoadamantane (5) (and some related compounds) were prepared by our recently devised phase-transfer catalytic halogenation protocol; the optical antipodes of 4 were separated by HPLC on chiral phase in ee > 99%, and the absolute configurations were assigned by matching observed and computed circular dichroism spectra. Structure 5 is the first chiral aliphatic hydrocarbon containing all stable (nonradioactive) halogens; its structure was proven by NMR spectroscopy and by X-ray crystal data. We emphasize that the combination of experiment and theory is very powerful in assigning absolute configurations even for molecules without typical chromophors, with small values for the optical rotation, and without an atom at the stereogenic center.

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Though the diversity of applications involving supercritical fluids (SCFs) continue to mount in virtually every sector of the scientific workplace, this environmentally-friendly medium is only briefly mentioned in undergraduate curricula; most often without hands-on laboratory experience. A new experimental module featuring this technology was introduced into an undergraduate inorganic chemistry laboratory. Nanoparticles of copper and aluminum oxide were formed using a variety of novel procedures, with scanning electron microscopy (SEM–EDS) and transmission electron microscopy (TEM) utilized for characterization. While particles of aluminum oxide were found to average 100 nm with sufficient aggregation, the copper nanoparticles were much smaller in diameter, with less agglomeration. A discussion of overall student sentiment and pedagogical outcomes from this module is also provided.