Both bands are indicative of a protonated carboxylate group on the anthracene. Other common features at the functional group region are the presence of the carboxylate symmetric band at 1384 [cm.sup.-1] v(CO[O.sub.s.sup.-]) together with broad v(C=N) of the polypyridyl group at 1593,1516, and 1451 [cm.sup.-1] .
The B3LYP/6-31G theoretical calculations showed that the electronic structures of anthracene derivatives are perturbed by the side substitutes on the anthracene block, and the slight variation of the electronic structures results in the enhanced electron accepting ability and the decrease of the HOMOLUMO energy gap, which is the origin of the shifting of emission wavelength to the blue-green region .
The structure and carbon numbering together with the positions of K and L regions for all Benzo(a) anthracenes
under investigation were depicted in Chart (1).
Although TWAs for specific PAHs are not given in these workplace standards, the OSHA analytical method for coal tar pitch volatiles specifies target concentrations for selected PAHs, including phenanthrene, anthracene, pyrene, chrysene, and benzo[a]pyrene (33).
Engine run-up/ Background/ tarmac (ng/ hangar (ng/ Activity/location [m.sup.3]) [m.sup.3]) Phenanthrene 25.0 16.6 Anthracene 9.7 1.7 Pyrene <MDL <MDL Chrysene <MDL <MDL Benzo[a]pyrene 4.1 0.1 Mean PAS2000CE 568 14.8 Max PAS2000CE 3,804 67.0 Taxi/ AGE/ hangar (ng/ tarmac (ng/ Activity/location [m.sup.3]) [m.sup.3]) Phenanthrene 24.1 278.5 Anthracene <MDL 27.8 Pyrene 0.9 189.4 Chrysene <MDL <MDL Benzo[a]pyrene 0.5 4.0 Mean PAS2000CE NA 21.9 Max PAS2000CE NA 1,712 ERO-loading/ OSHA target C-130H cargo concentrations Activity/location bay (ng/[m.sup.3]) (ng/[m.sup.3])(a) Phenanthrene 70.1 8,880 Anthracene 6.6 790 Pyrene 42.9 9,000 Chrysene <MDL 3,270 Benzo[a]pyrene 0.8 2,490 Mean PAS2000CE 1,009 -- Max PAS2000CE 4,010 --
Trip blanks (unexposed SPMDs) contained low concentrations (<65 ng/mL) of naphthalene, C1- to C3-naphthalene, phenanthrene and anthracene
. One trip blank (site 1) contained 2000 ng/mL of total C2-chrysene, while for other trip blanks, chrysenes were not detectable.
These compounds are suitable as they contain the anthracene
moiety, which is prone to oxidation by singlet oxygen via a selective [4p+2p] addition of this species to the central ring of the anthracene