2-Dimensional analytic approach for anion differentiation with chromofluorogenic receptors

By linking the urea moiety at the 1,8 positions of the carbazole fragment, we synthesized host systems 1, 2, and 3 having both chromogenic and fluorogenic signaling subunits. The spectral changes in both the signaling subunits could be easily analyzed via a simple 2-dimensional (2D) analytic approach described here, which enables us to differentiate the given set of anions. Structural studies are also reported.X117171sciescopu

Mass-balanced H-1/H-2 isotope dipeptide tag for simultaneous protein quantitation and identification

Mass-balanced H-1/H-2 isotope dipeptide tags (MBITs) are presented for simultaneous protein quantitation and identification. MBIT is derived from N-acetyl-Ala-Ala dipeptide and conjugated to primary amines of target peptides. H-1/H-2 isotopes are encoded in the methyl groups of N-acetylated dipeptide: one tag deuterated on the N-acetyl group and another on the C-terminal alanine. MBIT-linked peptides comigrate in reversed-phase liquid chromatography without significant H-1/H-2 isotope effects and provide 2-plex quantitation signals at 114 and 117 Th as well as peptide sequence information upon MS/MS analysis with MALDI TOF/TOF. MBIT shows good quantitation linearity in a concentration range of 20-250 fmol. The performance of MBIT on protein quantitation and identification is further tested with yeast heat-shock protein (Hsp82p) obtained from three different physiological states. MBIT using nanogram-scale samples produces the relative abundance ratios comparable to those obtained from optical imaging of microgram-scale samples visualized with SYPRO Ruby stain. The MBIT strategy is a simple and low-cost alternative for 2-plex quantitation of proteins and offers possibilities of tuning the 2-plex signal mass window by replacing the N-terminal alanine with other amino acid residues.X111110sciescopu

Organic-inorganic hybrid compounds of Li with bisimidazole derivatives: Li ion binding study and topochemical properties

The imidazole-based ligands, bis(imidazol-1-yl) methane (Bizm, 1a) and (pyrenyl) bis(imidazol-1-yl) methane (Pbizm, 2a) were prepared. With LiClO4, these two compounds formed two novel organic-inorganic hybrid materials: a 3D network polymer Li(Bizm)center dot ClO4 (1b) and a 1D chain polymer Li(Pbizm)(2)center dot ClO4 (2b). The intriguing topological and physiochemical characteristics of 1b and 2b are reported on the basis of the X-ray single-crystal structure analysis and Li ion binding studies.X1166sciescopu