The cationization mechanism study of novel oligo (p-phenyleneethynylene)s

Abstract

Two series of new oligo(p-phenyleneethynylene)s (OPEs) O1-O4 and O5-O8, which have been proven to be one of the chief classes of molecules mainly used as the wires and other potential backbones of molecular electronic devices, have been synthesized by stepwise synthetic approach. The characterization of these oligomers was performed on MALDI TOF MS. Different cationization salts have been applied to investigate the ionization processes of these series of oligomers under MALDI conditions. The experimental results show that these oligomers display a strong tendency to undergo radical cationization and varied ionization efficiency with different cationization agents attributable to their difference in cationic diameters. Furthermore, we found that these two series of oligomers differed in ionization properties because of their different end-groups even when the same cationization agent was used. (J Am Soc Mass Spectrom 2005, 16, 1695-1701

Synthesis of Ceria-Coated Copper Oxide Particles for Direct Hydrocarbon SOFCs Anode

“…The CeO 2 powder showed broad XRD peaks and the diffraction peaks become sharper and narrower after calcination. These results are similar to other reports [10,11]. The powder synthesized from the cerium (III) nitrate/ammonia solution incorporating crystallized CuO particles consisted of CeO 2 and CuO phases.…”

Gastrointestinal stromal tumours (Br J Surg 2003; 90: 1178–1186)

“…For example, very abundant product ions at m/z 177 were observed in the MS spectra of peaks 13, 19 and 20, which was the typical result of RDA cleavage from quinoline alkaloids; by comparison with authentic compounds or literature data,29 the peaks were identified as tetrahydropalmatine, tetrahydrocoptisine and tetrahydroberineper, respectively. For peak 4, m/z 304 [M+H] + , m/z 138 [M+H–C 9 H 10 O 3 ] + and m/z 110 [M+H–2CH 2 –C 9 H 10 O 3 ] + ions were observed in the positive ion mode, the m/z 138 ion being the loss of tropine acid from the precursor ion at m/z 304, and the m/z 110 ion being the characteristic ion of scopola alkaloids as reported in the literature 30. So, peak 4 was unambiguously identified as scopolamine by comparison with an authentic standard.…”

Research on Predominant Volatile Compounds of Grass Carp Meat

“…How to utilize freshwater fish effectively and produce highly value-added products from this valuable resource has become a major research topic. As a resource provided perfect protein and nutrition, freshwater fish has an unpleasant off-flavor(earthy fish odor) which restricting its satisfaction for customers [1,2]. In this paper, the grass carp(Ctenopharyngodon idellus) were used as research object which has highest yield and more than four million tons per year.…”

“…In this paper, the grass carp(Ctenopharyngodon idellus) were used as research object which has highest yield and more than four million tons per year. The volatile compounds of grass carp were extracted and concentrated by headspace solid phase micro-extraction (HS-SPME),then the volatiles were identified by gas chromatography-mass spectrometry (GC-MS) [1,3]. The predominant volatile compounds in dorsal meat of grass carp were determined with method of odor activity value.…”