2050-75-1

2,3-Dichloronaphthalene (2,3-DCN) and 2,3-dibromonaphthalene (2,3-DBN) were synthesized, purified and used to grow single crystals in the form of thin plates. X-ray crystallographic studies, performed for the first time, showed that molecules in both isostructural crystals are arranged in the herringbone pattern. These crystals, lightly doped with terrylene (Tr), appeared to be very good systems for optical single-molecule studies. Fluorescence excitation spectra of single Tr molecules at 5 K in excess of the dominating purely electronic (0, 0) and intense vibronic line of ～250 cm-1 frequency had a new, “184 cm-1” line, absent in the spectrum of isolated (D2h) Tr. Quantum-chemistry calculations indicated that this new line was the fingerprint of the deformation of the Tr molecule in the crystal structure, which lowered its symmetry to C2h

Thirteen new compounds belonging to series 2-amino-6-(5,10-dioxo-2,3-diphenyl-5,10-dihydrobenzo[g]quinoxalin-7-yl)-4-(substituted)phenylpyridine-3-carbonitrile (6a-m) were synthesized by multistep synthetic scheme. The newly synthesized compounds were screened for their antimycobacterial activity by L.J. Slope (Conventional) Method. Compound 6h with 4-N(CH3)2 group at phenyl ring of above mentioned position has been reported as most active antimycobacterial compound and compound 6k with 4-CH3 substitution at phenyl above mentioned position has been reported as the least active antimycobacterial compound.

Eleven new compounds diones namely, 7-[3-(substituted) phenylprop-2-enoyl]-2,3-diphenyl- 5H,10H-benzo[g]quinoxaline-5,10-dione (6a-k) were synthesized by multistep synthetic scheme. The newly synthesized compounds were submitted for their in vitro antimycobacterial activity against Mycobacterium tuberculosis H37Rv by L.J. Slope (Conventional) Method. Compound 6e having 4-OCH3 at phenyl ring attached to 3-position of prop-2-enoyl group has been observed as the most active antimycobacterial compound, while compound 6h having 4-CF3 group on the above-mentioned position has been observed as the least active antimycobacterial compound of the newly synthesized series.

The degradation of 1,2,3,4-tetrachloronaphthalene (CN-27) featuring a one-side fully-chlorinated aromatic ring, was evaluated over three of the prepared rod-like Fe-Al composite oxides (FeAl-1, FeAl-5 and FeAl-10). The results showed that their reactive activities were in the order of FeAl-5 ≈ FeAl-10 ? FeAl-1, which could be attributed to their different pore structural properties and reactive sites caused by the different phase interaction between iron species and the γ-Al2O3. The generation of trichloronaphthalenes (1,2,3-TrCN and 1,2,4-TrCN, i.e. CN-13 and CN-14), dichloronaphthalenes (1,2-DiCN, 1,3-DiCN, 1,4-DiCN and 2,3-DiCN, i.e. CN-3, CN-4, CN-5 and CN-10) and monochloronaphthalenes (1-MoCN and 2-MoCN, i.e. CN-1 and CN-2) suggested the occurrence of successive hydrodechlorination reactions. The amount of CN-14 exceeded that of CN-13 from 71.5% to 77.7% across the three different systems, revealing the preferred occurrence of the first hydrodechlorination step at the β-position. This is dissimilar to the preference at the α-position observed during the dechlorination of octachloronaphthalene (CN-75) over micro/nano Fe3O4. The structural differences between one-side and two-side fully-chlorinated aromatic rings would have a pronounced impact on the reactivity of the chlorine substitution position. The major hydrodechlorination pathway was judged to be CN-27 → CN-14 → CN-4 → CN-2. Additionally, the detected 1,2,3,4,6-pentachloronaphthalene (CN-50) and 1,2,4,6/7-tetrachloronaphthalenes (CN-33/34) suggested the reverse chlorination reaction also happened while the hydrodechlorination reaction was occurring. The C-Cl bond dissociation energies (BDEs) of the parent and daughter polychlorinated naphthalene (PCN) congener were calculated using density functional theory (DFT), to achieve a deeper understanding of a different product yield distribution.

The Bergman cycloaromatization reaction efficiently converts easily prepared acyclic enediynes into aromatic rings. In order to prepare larger, functionalized fused aromatic systems using this reaction, a thorough understanding of how functionalization affects cycloaromatization is necessary. We present here our studies on the influence of substituents at three different functionalization sites on cycloaromatization, and how these functional groups can be tailored to prepare more complex systems.

During the oxidative degradation of carbonaceous material on fly ash, besides PCDD/F, PCPh, PCBz, PCB, polychlorinated naphthalenes (PCN or Cl(x)N) are formed. Thermal experiments were carried out with fly ash from a municipal waste incinerator at 300°C and reaction times of 0.5 h up to 4 h. For the study an analytical method using GC/MS was developed similar to that, used in dioxin-analysis. Isomer specific identification of chloronaphthalenes formed on fly ash was realized by comparison of Cl(x)N from technical PCN- mixtures (Halowax). For quantification of the PCN formed, 13C- labelled PCB-standards were used as internal standards because no 13C- labelled PCN- compounds were available. Both, technical PCN-mixtures and PCN formed on fly ash show a characteristic pattern of Cl(x)N-congeners according to their difference in formation. Cl2N - Cl3N were formed most and Cl1N - Cl3N were also found in the gas phase in high amounts. A single isomer 1,2,3,5,6,7-Cl6N, known as a strongly bioaccumulating and toxic PCN, is formed in higher amounts together with 1,2,3,4,6,7-Cl6N.

Reaction of 1-bromo-3,4-benzo-6,6-dichlorobicyclohexane with potassium tert-butoxide in tetrahydrofuran yields 2-chloronaphthalene along with nine other naphthalenes which result from solvent incorporation or reaction with nucleophile (Br-, Cl-, t-BuO-).Use of tetrahydrofuran-d8 as the solvent leads to the incorporation of two deuterium atoms into the chloronaphthalene.This result is interpreted in terms of a 1,3-dehydronaphthalene opening to the diradical, followed by abstraction of deuterium atoms from the solvent.The products which result from incorporation of solvent would then arise by dimerization of radical pairs.The remaining products are thought to arise from nucleophilic addition to the closed form of the dehydronaphthalene.