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This work explores time-resolved emission imaging microscopy (TREM) for noninvasive imaging and mapping of live cells on a hitherto uncharted microsecond time scale. Simple robust molecules for this purpose have Long been sought. We have developed highly emissive, synthetically versatile, and photostable platinum(II) complexes that make TREM a practicable reality. [PtLCl], {HL = 1,3-di(2-pyridyl)benzene and derivatives}, are charge-neutral, small molecules that have Iow cytotoxicity and accumulate intracellularly within a remarkably short incubation time of 5 min, apparently under diffusion control. Their microsecond lifetimes and emission quantum yields of up to 70% are exceptionally high for transition metal complexes and permit the application of TREM to be demonstrated in a range of live cell types--normal human dermal fibroblast, neoplastic C8161 and CHO cells. [PtLCl] are thus likely to be suitable emission labels for any eukaryotic cell types. The high photostability of [PtLCl] under intense prolonged irradiation has allowed the development of tissue-friendly NIR two-photon excitation (TPE) in conjunction with transition metal complexes in live cells. A combination of confocal one-photon excitation, nonlinear TPE, and microsecond time-resolved imaging has revealed (i) preferential localization of the complexes to intracellular nucleic acid structures, in particular the nucleoli and (ii) the possibility of measuring intracellular emission lifetimes in the microsecond range. The combination of TREM, TPE, and Pt(II) complexes will be a powerful tool for investigating intracellular processes in vivo, because the long lifetimes allow discrimination from autofluorescence and open up the use of commonplace technology. fluorescence microscopy | time-resolved luminescence spectroscopy | transition metal complexes | cyclometalation

The synthesis and photophysical properties of new chormophore based pyridine-dicarboxamide ligands and related [D.sub.3] symmetric europium(III) complexes are described. The luminescence of Eu(III) was sensitized by two-photon absorption of the ligand showing the two-photon antenna effect dphenomenon.

A series of new luminescent cyclometalated platinum(II) complexes functionalized with various substituted styryl groups on the cyclometallating ligand [Pt(C-ppy-4-styryl-R)(O-(O)CCR'CHCR'C(O))] (ppy-4-styryl-R = E-4(4-(R)styryl-2-phenylpyridine) (3, R'-Me(acac); 4, R'='Bu (dpm); R=H, OMe, NEI 2, NO2)) were synthesized. Results reveal the presence of the styryl -CH=CH-double bond in all the complexes has a direct influence on their emissive properties.

The synthesis, structural, photophysical and second-order nonlinear optical (NLO) properties of a novel lanthanide terpyridyl-like complex family LLn[(N[O.sub.3]).sub.3] (Ln = La, Gd, Dy, Yb and Y) are described. The quadratic hyperpolarizability coefficient beta, measured by the harmonic light scattering (HLS) method, is found to be dependent on the nature of the metal and the examination of yttrium unambiguously has confirmed the contribution of metal f electrons to the NLO activity.

Adult Acartia congeners, A. bifilosa, A. clausi, A. discaudata and A. tonsa, have distinct seasonal and spatial distribution patterns in Southampton Water (UK), reflecting patterns of temperature and salinity, respectively. The effect of these factors on other life stages, hatch success and naupliar survival was investigated by exposing the congeners to a range of salinity (15.5-33.3) and of temperature (5-20[degrees]C). A. clausi is known to prefer more saline waters, and showed highest hatch success at 33.3 salinity. A. tonsa is most tolerant to dilution, and at 15.5 salinity it had the highest hatch success of all the congeners. Hatch success in both A. bifilosa and A. discaudata was similar over the range of salinities investigated, confirming that they are intermediate species in terms of spatial distribution. The nauplii of all species survived well at the higher salinities and best at 33.3, which allows for differential transport of the poorly swimming nauplii to the mouth of the estuary until size and swimming ability increase, after which they can then return to regions of preferred salinity. The summer species, A. clausi and A. tonsa showed higher hatch success at 20[degrees]C, whereas A. discaudata, which is present in the water column all year round, showed no significant temperature-related differences in hatch success. A. bifilosa, which diapauses over summer, showed significantly higher hatch success at 10[degrees]C than at 20[degrees]C. The physiological relationship between temperature and development time was clear; naupliar survival of all species was highest at 20[degrees]C and all congeners reached the first copepodite stage (CI) significantly faster at 20[degrees]C. However, no consistent pattern was seen for salinity. It would appear that the adult Acartidae in Southampton Water remain in regions of their preferred salinity and lay eggs there which hatch well. However, because the nauplii are not good swimmers, they are swept towards the mouth of the estuary and into areas of higher salinity, where they remain and develop into more advanced stages before moving back up the estuary to take up their adult distribution pattern.

The measurement and analysis of circular polarization in the luminescence (CPL), in the near-IR spectral region, from chiral complexes of Yb(III) and Nd(III) in solution is described. The luminescence from 4F(sub 3/2) -> 4I(sub 9/2) and 4F(sub 3/2) -> 4I(sub 11/2) transitions of Nd(III) centered at 880 and 1060 nm, respectively, shows only weak CPL signals and the usefulness of these types of polarization measurements in the near-IR is discussed.

The synthesis, the electrochemical nature and the spectroscopic and photophysical characteristics of IrLL'3+ complexes are described. The favorable properties of IrLL'3+ reveal that the Ir(III)-tpy center will not be the final recipient of the energy-harvesting mechanisms in multipartite systems built around them. Results demonstrate that the Ir-tpy-type complexes are appropriate as photoactive centers and electron relays.

The photoinduced processes taking place in molecular arrays containing porphyrins and a terpyridine ruthenium complex have been defined in glassy solvents at low temperature. A series of energy transfer steps is responsible for the deactivation of the excited states. Triplet energy transfer occurring between the peripheral porphyrins at low temperature, whose rate is measured by transient absorption spectroscopy, is mediated by the ruthenium complex spacer.