Photoelectron spectra of C 60 and C 70 , ionized with ultrashort laser pulses, are measured with a momentum-mapimaging electron spectrometer. Above the photon energy, 1.6 eV, the spectra are essentially structureless and well described by Boltzmann distributions, with temperatures on the order of 10 4 K. This result is similar to previous results for C 60 using a time-of-flight electron spectrometer, which are confirmed in this study. Comparisons of electron energy distributions recorded for identical laser intensities but for different pulse durations demonstrate unambiguously that a significant fraction of the electrons are emitted in quasithermal processes and results argue strongly against a field ionization or direct multiphoton ionization mechanism. For electron energies above the photon energy, which account for about half the intensity, the whole signal is consistent with this quasithermal emission.

The interactions between anionic or zwitterionic liposomes and a water-soluble, DNA-binding photochromic spiropyran are studied using UV/vis absorption and linear dichroism (LD) spectroscopy. The spectral characteristics as well as the kinetics of the thermal isomerization process in the absence and presence of the two different liposome types provide information about the environment and whether or not the spiropyran resides in the liposome membrane. By measuring LD on liposomes deformed and aligned by shear flow, further insight is obtained about interaction and binding geometry of the spiropyran at the lipid membranes. We show that the membrane interactions differ between the two types of liposomes used as well as the isomeric forms of the spiropyran photoswitch.

Synthesis of bis-4,5-diazafluoren-9-one silver(I) nitrate I, (dafone = 4,5-diazafluoren-9-one) and low temperature X-ray single crystal structure of [Ag(4,5-diazafluoren-9-one) 2 NO 3 ], crystal form 1, and a re-determination of [Ag(4,5-diazafluoren-9-one) 2 ]NO 3 ·H 2 O, crystal form 2 are presented.Crystal form 1 has a distorted trigonal planar coordination geometry around Ag(I) with an N-Ag-N bond angle of 123.45(7)°. Crystal form 2 has a perfect linear coordination around Ag, with N-Ag-N 180.0°. Compound I was characterized by 1 H-NMR, biological activity and ESI-MS in DMSO at room temperature. The biological activity was determined against 6 different resistant clinical isolates; two Gram-positive (Staphylococcus aureus and Streptococcus pyogenes) and four Gramnegative (Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirabilis, and Salmonella sp.) in comparison with 15 known antibiotics used in the treatment of diabetic foot infections.Compound I showed broad spectrum activity against all the test organisms. Proteus mirabilis, Staphylococcus aureus and Proteus mirabilis were the most sensitive clinical isolates (MIC = 4, 6 and 4 µg/ml, respectively). Three different hydrogels containing I or Ag 2 SO 4 were prepared and the antimicrobial activity against Pseudomonas aeruginosa (ATCC 15442) compared, showing more or less equal activity on a weight basis, but I seems to have a significant better performance per silver ion. The Ag(I) complex also binds more effectively to calf thymus DNA than the dafone ligand itself. reaction was performed in an acetonitrile/water mixture at room temperature, only crystals of [Ag(dafone) 2 ]NO 3 ·H 2 O, 2 were formed. But when an ethanol/water mixture was used with heating, prismatic crystals of [Ag(dafone) 2 NO 3 ], 1 and needles of [Ag(dafone) 2 ]NO 3 ·H 2 O, 2 were collected from the same batch. Synthesis of silver loaded hydrogelsTo vary degrees of cross linking of the hydrogels different molecular weights of dimethacrylated PEG (polyethylene glycol) monomers (PEGDMA) were used and three gels containing different ratios of PEGDMA8k, PEGDMA20k, TEGDA (triethylene glycol diacrylate) and PEGDA700 were prepared with water as a solvent.Silver sulphate (2% and 6% by weight) and 1 (2%) with 1% photoinitiator was added and the mixtures cured with a UV Lamp giving nine different gels. Notable differences in appearance of the produced gels were noted: while the gels with 1 were white/transparent much like a nonsilver containing gel, the gels with Ag 2 SO 4 were severely discoloured, see Figure 1. Figure 1. Dimethacrylated PEG gels with left: 2% 1, right: 2% Ag 2 SO 4Crystal Structures The two structures are strikingly different, we will therefore first present each structure and in conjunction make appropriate comments, and thereafter we will bring up the points that are of general interest in dafone coordination chemistry.Crystallographic data and refinement parameters for crystal forms 1 and 2 are listed in Table 1, Accepted manuscript New Journal of Chemistry, 35,[640][641]...

The radiative cooling of positively charged fullerene and endohedral fullerene fragments of C60, C70, C84, and La@C82 has been measured in a time-of-flight mass spectrometer. The radiative cooling is measured via its influence on the metastable decay. The emissivity extracted from the data is between 4x10(-4) and 13x10(-4). These values agree fairly well with the emissivity calculated from considering the low-energy tail of the surface plasmon. No major difference is found in the emission behavior of empty and endohedral fullerenes.

We report that DNA molecules can be intercalated and macroscopically oriented in the aqueous interstitia of a lyotropic lamellar liquid crystal. Using UV-vis linear dichroism and fluorescence spectroscopy we show that double-stranded oligonucleotides (25 base pairs) in the water-octanoate-decanol system remain base-paired in the B conformation and are confined in two dimensions, with the helix axis preferentially parallel to the lipid bilayer surfaces but free to rotate within this plane. The degree of helix confinement and the corresponding 2-D orientation can be improved by decreasing the thickness of the water interstitia via the fraction of water in the ternary mixture. Not surprisingly, the corresponding singlestranded oligonucleotides are not aligned, with their persistence length being short in comparison to the lamellar interstitium thickness. We propose this as a model system for studying interactions of DNAligand complexes near a lipid bilayer membrane which we demonstrate by using dye probes that are either covalently attached to one end of the oligonucleotide or reversibly bound by intercalation between the base pairs. Three cationic dyes, all strongly bound by intercalation to DNA when free in solution, are found to not bind to DNA but to prefer the membrane surface. The covalently attached Cy5 also binds to the bilayer while Cy3 tends to end-stack to the oligonucleotide duplex. The orientation of Cy5 parallel to the membrane indicates that electrostatic surface binding predominates over insertion into the hydrophobic interior of the membrane. Anionic and zwitterionic dyes (FAM and ROX) are found to remain randomly oriented in the water between the lipid bilayer surfaces.