Structural assignment of disialylated biantennary N-glycan isomers derivatized with 2-aminopyridine using negative-ion multistage tandem mass spectral matching

To investigate the possibility of structural assignment based on negative-ion multistage tandem mass (MS(n)) spectral matching, four isomers of disialylated biantennary N-glycans (alpha2-6 and/or alpha2-3 linked sialic acid on alpha1-6 and alpha1-3 antennae) derivatized with 2-aminopyridine (PA) were analyzed by employing high-performance liquid chromatography/electrospray ionization linear ion trap time-of-flight mass spectrometry (HPLC/ESI-LIT-TOFMS), which uses helium gas for ion trapping and collision-induced dissociation (CID). It is shown that the MS(2) spectra derived from each precursor ion [M-2H](2-) are reproducible and useful for distinguishing the four isomers. Thus, they can be assigned by negative-ion MS(2) spectral matching based on correlation coefficients. In addition, MS(3) spectra derived from D-type fragment ions clearly differentiate the alpha2-3- or alpha2-6-linked sialic acid on the alpha1-6 antenna due to their characteristic spectral patterns. The C(4)-type fragment ions, which are produced from both the alpha1-6 and alpha1-3 antennae, show the characteristic MS(3) spectra reflecting alpha2-3- or alpha2-6- linkage type or a mixture of both types. Thus, the differentiation and assignment of these disialylated biantennary N-glycan isomers can also be supported with the MS(3) spectra of C(4)- and D-type ions.     

Zwitterionic pi-radical involving EDT-TTF-imidazole and F4TCNQ: redox properties and self-assembled structure by hydrogen-bonds and multiple S...S interactions

The reaction between an imidazole-functionalized EDT-TTF and F(4)TCNQ produced a zwitterionic pi-radical, which formed a self-assembled structure by the cooperation of hydrogen-bonds and multiple S...S interactions and exhibited three-step oxidation processes and a high electrical conductivity as a single-component organic molecule.     

Photophysical and electrochemical behavior of thin solid films based on a three-dimensional ruthenium complex network

RuL ₃ ²⁺ (L=2,2′-bipyridine-4,4′-diphosphonic acid) thin solid films were fabricated by three-dimensional linking between the phosphonic acid substituents of L and Zr(O)Cl₂. The RuL₃ chromophores in the films are electronically independent of each other in the ground state and give emission spectra essentially identical to that of RuL ₃ ²⁺ in solution, although the emission lifetime is much shorter. The films are electrochemically active, showing pseudo-reversible oxidation behavior in cyclic voltammetry. A preliminary attempt has been made to apply these films to photoelectrochemical cells.     

Component factors and induced subgraphs

Let G and K be connected graphs such that | G| = n|K| (n ≥ 2) and let p be a fixed integer satisfying 1 < p < n. We prove that if G \ A has a K-factor for every connected subgraph A with |A| = p|K|, then G also has a K-factor. © 1996 John Wiley & Sons, Inc.     

Windmill-Like Porphyrin Arrays as Potent Light-Harvesting Antenna Complexes

Up to 14 porphyrin rings are present in the title compounds 1 , which are readily available with high regioselectivity from linear nickel–zinc porphyrins. Upon irradiation with light a rapid energy transfer from the peripheral porphyrin rings to the diporphyrin core takes place.     

Synthesis of poly(hydroxymethylene-co-ethylene) by hydrogenation of the ethylene and carbon monoxide copolymer obtained by radical initiator with Ru/α-alumina and oxygen gas permeability

A new polymer (polyalcohol) was synthesized by hydrogenation of an ethylene carbon monoxide (CO) copolymer produced by a radical method with a catalyst and H₂. The Ru/α-alumina catalyst systems showed an excellent activity for hydrogenation of the radical copolymer of CH₂CH₂ and CO. Films prepared by melting and pressing the synthesized polyalcohol had a high gas barrier property and high tensile modulus. This new polymer has hydroxymethylenic units [ CH(OH) ] and ethylenic units [ CH₂CH₂ ] in its molecular structure. The new functional polymer poly(hydroxymethylene-co-ethylene),  [ CH(OH) ]_n[ CH₂CH₂ ]_m , is amorphous and has excellent and important properties as a high oxygen gas barrier film for wrapping and storage. This may be attributed to the new structure of poly(hydroxymethylene-co-ethylene) (PHME as an IUPAC name), or ethylene methine alcohol copolymer (EMOH as a generic name), compared to the other ethylene vinyl alcohol copolymer (EVOH as a generic name),  [ CH₂CH₂ ]_m [ CH₂CH(OH) ]_n , which is used as one of the highest gas barrier polymers. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 889–900, 1998