The PF(6)(-) salt of a platinum(II) complex changes from yellow to red and becomes intensely luminescent upon exposure to aqueous ClO(4)(-). The response is remarkably selective. Spectroscopic changes are consistent with anion exchange resulting in shortening of the intramolecular PtPt distances between the square planar cations.

Square-planar platinum(II) complexes of the 4-dodecyloxy-2,6-bis(N-methylbenzimidazol-2 0 -yl) pyridine ligand have been blended into a series of methacrylate polymers. Each of the polymer films displayed vapochromic (yellow to red) and vapoluminescent behaviour as a result of the vapour induced change in the Pt-Pt interactions. The solid-state absorption and emission properties of the films were characterized, and the influence of the polymer matrix on the vapochromic response was investigated. Notably, the rate of recovery of the yellow colour after vapour-exposure was found to be dependent on the T g of the matrices, and the response can be effectively erased and the materials restored to the original yellow colour within minutes by simply heating above their T g . The polymer-complex blends also displayed interesting mechanochromic and mechanoluminescent properties upon deformation either by compression, scratching, or stretching. The accumulated data are consistent with a solvato-or mechanoinduced structural rearrangement that results in a shortening of the Pt-Pt distances.

Molecular recognition of an aqueous pertechnetate (TcO4(-)) anion is fundamentally challenging partly due to the charge-diffuse nature of this anion, which hampers design of new technologies for its separation and detection. To address this gap, simple salts of transition metal complexes that undergo a distinct spectroscopic change upon exposure to aqueous anions were explored. The Pt(II) complex [Pt(tpy)Br]SbF6 (tpy = 2,2';6',2″-terpyridine) undergoes a dramatic color change and intense luminescence response upon TcO4(-) uptake due to concomitant enhancement of Pt···Pt interactions. The spectroscopic response was highly selective and quantitative for aqueous TcO4(-) among other competing anions. Complementary Raman spectroscopy and microscopy techniques, structural determination, and theoretical methods were employed to elucidate the mechanism of this response at the molecular level.

Superheated heavy water can be used as the eluent for reversed-phase chromatography with on-line HPLC-NMR and HPLC-NMR-MS detection. The method has been demonstrated for the separation of model drugs (analgesics and caffeine) on a poly(styrene-divinylbenzene) stationary phase in isothermal and temperature-programmed modes. One-and two-dimensional spectra could be obtained with less interference from the mobile phase than with conventional HPLC-NMR eluents. Unlike supercritical fluid chromatography-NMR, the spectra could be measured at room temperature and atmospheric pressure. The combination of superheated water HPLC-NMR-MS chromatography enables both NMR and MS spectra to be obtained simultaneously for the same sample.

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