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Iodine that sustains electronic and information materials
Published in Tatsuo Kaiho, Iodine Made Simple, 2017
THABB synthesis is shown in the reaction formula. Synthesis consists of various processes, including introducing the side chain (R), creating a triphenylene ring and condensing them. Among these processes, demethylation reaction of hexamethyoxytriplenylene (HMT) is important. Only a small amount is needed, and reaction may proceed even with boron triboromide. However, this reagent is difficult to use in an industrial capacity due to reasons such as high cost, high level of corrosiveness, and susceptibility to decomposition with moisture in the air. Hydrobromic acid was also considered as an option, but reactivity was insufficient, and complete removal of the six methyl group to obtain a high-purity intermediate (HHT) was difficult. If a low-purity HHT is used to create THABB, orientation would be time consuming. At this point, hydrogen iodide (HI) was introduced. By demethylation with HI, highly pure THABB synthesis could be realized [23b,c].
Luminescent Lanthanide Probes as Diagnostic and Therapeutic Tools
Published in Astrid Sigel, Helmut Sigel, Metal Ions in Biological Systems, 2004
With respect to the triplet-to-metal ion transfer, two series of compounds have been studied in detail and are often referred to: (i) EuIIIand TbIII polyaminocarboxylates for which the quantum yield upon ligand excitation becomes sizeable when ΔE(3ππ*-5DJ) > 2000 cm−1 [12]. When this gap is smaller, energy back transfer occurs (kback), and (ii) complexes with triphenylene-substituted calix[4]arenes for which the ideal ΔE(3ππ*-5DJ) gap is around 3500 cm−1 [13]. Note that E(3ππ*) refers to the zero-phonon transition.
Assessing cancer hazards of bitumen emissions – a case study for complex petroleum substances
Published in Critical Reviews in Toxicology, 2018
Anthony J. Kriech, Ceinwen A. Schreiner, Linda V. Osborn, Anthony J. Riley
A significant amount of research has been conducted to chemically characterize bitumen emissions under normal application conditions (NIOSH 2000; Kriech et al. 2002). Emissions comprise predominantly straight chain hydrocarbons with lesser amounts of cycloalkanes (approximately 70% aliphatic/30% aromatic). The aromatic portion includes alkyl benzenes, polar and semipolar compounds. Much of the polycyclic aromatic compound (PAC) composition is in the form of alkylated species (primarily alkyl-naphthalenes, alkyl-fluorenes and alkyl-anthracenes) and includes sulfur heterocyclic materials (primarily alkyl benzothiophene and alkyl-dibenzothiophenes). The most prominent of the parent, unalkylated PACs detected in workplace exposures for paving and roofing workers include acenaphthene, anthracene, fluoranthene, fluorene, naphthalene, phenanthrene and pyrene (Kriech et al. 2007; Cavallari et al. 2012a). Normal paving worker exposures contain only trace levels of parent unalkylated PACs, primarily of the 2- and 3-ring variety. Some 4-ring PACs have been reported in fume condensates generated to mimic paving worker exposures (pyrene and triphenylene (Clark et al. 2011) and eight 4–6 ring PACs have been reported in fume condensates generated to mimic roofing worker exposures (Clark et al. 2011), all at trace levels (<0.08–8 ppm) except for pyrene, a noncarcinogenic 4-ring PAC, at ≤33 ppm.