Gas phase ion chemistry of an ion mobility spectrometry based explosive trace detector elucidated by tandem mass spectrometry.

The gas phase ion chemistry for an ion mobility spectrometer (IMS) based explosive detector has been elucidated using tandem mass spectrometry. The IMS system, which is operated with hexachloroethane and isobutyramide reagent gases and an ion shutter type gating scheme, is connected to the atmospheric pressure interface of a triple quadrupole mass spectrometer (MS/MS). Product ion masses, daughter ion masses, and reduced mobility values for a collection of nitro, nitrate, and peroxide explosives measured with the IMS/MS/MS instrument are reported.

Cu(II) cross-linked antiparallel dipeptide duplexes using heterofunctional ligand-substituted aminoethylglycine.

Two artificial dipeptides containing both a pendant monodentate (pyridine (py)) and tridentate (terpyridine (tpy) or phenyl terpyridine (varphi-tpy)) ligand on an aminoethylglycine (aeg) backbone have been synthesized. These oligopeptides are fully characterized by one and two-dimensional NMR spectroscopy, mass spectrometry, and elemental analysis. The ligands were chosen because they coordinate Cu(2+) to form [Cu(py)(tpy)](2+) complexes; when bound to the dipeptide scaffold, Cu(2+) chelation cross-links the strands to form double-stranded duplex structures with an antiparallel arrangement.

Inorganic biomimetic nanostructures.

Supramolecular structures modeled after biological systems (DNA and enzymes) are being developed to simultaneously mimic natural biological functions including catalysis, information storage, and self-assembly and to engineer novel electronic and magnetic properties. Structural mimics of nucleic acids containing multiple metal-coordinating ligands, and comprising natural and artificial bases or completely synthetic systems, create stable double-stranded structures with new electronic, spectroscopic, and magnetic properties. Supramolecular inorganic mimics of enzymatic function, including metallonucleases and metalloproteases, have begun to be constructed.

Tetraplatinated artificial oligopeptides afford high affinity intercalation into dsDNA.

This paper reports the binding of an artificial tetrapeptide to which are tethered four Pt(II) complexes (i.e., [Pt(tpy)(py)]48+) with a 12 base pair duplex DNA oligonucleotide.