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1. Photochemistry of N ‐Phenyl Dibenzothiophene Sulfoximine ^†

   https://doi.org/10.1111/php.13456  

   Isor, Ankita; Hommelsheim, Renè; Cone, Grant W.; Frings, Marcus; Petroff, II, John T.; Bolm, Carsten; McCulla, Ryan D. (June 2021, Photochemistry and Photobiology)

   Abstract Sulfoximines are popular scaffolds in drug discovery due to their hydrogen bonding properties and chemical stability. In recent years, the role of reactive intermediates such as nitrenes has been studied in the synthesis and degradation of sulfoximines. In this work, the photochemistry ofN‐phenyl dibenzothiophene sulfoximine [5‐(phenylimino)‐5H‐5λ⁴‐dibenzo[b,d]thiopheneS‐oxide] was analyzed. The structure resembles a combination ofN‐phenyl iminodibenzothiophene and dibenzothiopheneS‐oxide, which generate nitrene and O(³P) upon UV‐A irradiation, respectively. The photochemistry ofN‐phenyl dibenzothiophene sulfoximine was explored by monitoring the formation of azobenzene, a photoproduct of triplet nitrene, using direct irradiation and sensitized experiments. The reactivity profile was further studied through direct irradiation experiments in the presence of diethylamine (DEA) as a nucleophile. The studies demonstrated thatN‐phenyl dibenzothiophene sulfoximine underwent S–N photocleavage to release singlet phenyl nitrene which formed a mixture of azepines in the presence of DEA and generated moderate amounts of azobenzene in the absence of DEA to indicate formation of triplet phenyl nitrene. 

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2. Enhancing the performance of a fused-ring electron acceptor via extending benzene to naphthalene

   https://doi.org/10.1039/c7tc04520d  

   Zhu, Jingshuai; Wu, Yang; Rech, Jeromy; Wang, Jiayu; Liu, Kuan; Li, Tengfei; Lin, Yuze; Ma, Wei; You, Wei; Zhan, Xiaowei (January 2018, Journal of Materials Chemistry C)

   We compared an indacenodithiophene(IDT)-based fused-ring electron acceptor IDIC1 with its counterpart IHIC1 in which the central benzene unit is replaced by a naphthalene unit, and investigated the effects of the benzene/naphthalene core on the optical and electronic properties as well as on the performance of organic solar cells (OSCs). Compared with benzene-cored IDIC1, naphthalene-cored IHIC1 shows a larger π-conjugation with stronger intermolecular π–π stacking. Relative to benzene-cored IDIC1, naphthalene-cored IHIC1 shows a higher lowest unoccupied molecular orbital energy level (IHIC1: −3.75 eV, IDIC1: −3.81 eV) and a higher electron mobility (IHIC1: 3.0 × 10 −4 cm 2 V −1 s −1 , IDIC1: 1.5 × 10 −4 cm 2 V −1 s −1 ). When paired with the polymer donor FTAZ that has matched energy levels and a complementary absorption spectrum, IHIC1-based OSCs show higher values of open-circuit voltage, short-circuit current density, fill factor and power conversion efficiency relative to those of the IDIC1-based control devices. These results demonstrate that extending benzene in IDT to naphthalene is a promising approach to upshift energy levels, enhance electron mobility, and finally achieve higher efficiency in nonfullerene acceptor-based OSCs. 

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3. Two metal–organic frameworks based on Sr ²⁺ and 1,2,4,5-tetrakis(4-carboxyphenyl)benzene linkers

   https://doi.org/10.1107/S2056989021011361  

   Usman, Muhammad; Ogebule, Lydia; Castañeda, Raúl; Oskolkov, Evgenii; Timofeeva, Tatiana (December 2021, Acta Crystallographica Section E Crystallographic Communications)

   Two structurally different metal–organic frameworks based on Sr 2+ ions and 1,2,4,5-tetrakis(4-carboxyphenyl)benzene linkers have been synthesized solvothermally in different solvent systems and studied with single-crystal X-ray diffraction technique. These are poly[[μ 12 -4,4′,4′′,4′′′-(benzene-1,2,4,5-tetrayl)tetrabenzoato](dimethylformamide)distrontium(II)], [Sr 2 (C 34 H 18 O 8 )(C 3 H 7 NO) 2 ] n , and poly[tetraaqua{μ 2 -4,4′-[4,5-bis(4-carboxyphenyl)benzene-1,2-diyl]dibenzoato}tristrontium(II)], [Sr 3 (C 34 H 20 O 8 ) 2 (H 2 O) 4 ]. The differences are noted between the crystal structures and coordination modes of these two MOFs, which are responsible for their semiconductor properties, where structural control over the bandgap is desirable. Hydrogen bonding is present in only one of the compounds, suggesting it has a slightly higher structural stability. 

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4. T3P-Promoted Synthesis of a Series of 2-Aryl-3-phenyl-2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4-ones and Their Activity against the Kinetoplastid Parasite Trypanosoma brucei

   https://doi.org/10.3390/molecules26206099  

   Silverberg, Lee J.; Mal, Tapas K.; Pacheco, Carlos N.; Povelones, Megan L.; Malfara, Madeline F.; Lagalante, Anthony F.; Olsen, Mark A.; Yennawar, Hemant P.; Sobhi, Hany F.; Baney, Kayla R.; et al (October 2021, Molecules)

   null (Ed.)

   A series of fourteen 2-aryl-3-phenyl-2,3-dihydro-4H-pyrido[3,2-e][1,3]thiazin-4-ones was prepared at room temperature by T3P-mediated cyclization of N-phenyl-C-aryl imines with thionicotinic acid, two difficult substrates. The reactions were operationally simple, did not require specialized equipment or anhydrous solvents, could be performed as either two or three component reactions, and gave moderate–good yields as high as 63%. This provides ready access to N-phenyl compounds in this family, which have been generally difficult to prepare. As part of the study, the first crystal structure of neutral thionicotinic acid is also reported, and showed the molecule to be in the form of the thione tautomer. Additionally, the synthesized compounds were tested against T. brucei, the causative agent of Human African Sleeping Sickness. Screening at 50 µM concentration showed that five of the compounds strongly inhibited growth and killed parasites. 

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5. The Pursuit of Perphenylterphenyls

   https://doi.org/10.1002/chem.202200931  

   Du, Yuchen; McSkimming, Alex; Mague, Joel_T; Pascal, Jr., Robert_A (June 2022, Chemistry – A European Journal)

   Abstract Tetradecaphenyl‐p‐terphenyl (2) was synthesized from 2,3,5,6‐tetraphenyl‐1,4‐diiodobenzene (11) by two methods. Ullmann coupling of11with pentaphenyliodobenzene (9) gave compound2in 1.7 % yield, and Sonogashira coupling of11with phenylacetylene, followed by a double Diels‐Alder reaction of the product diyne12with tetracyclone (6), gave2in 1.5 % overall yield. The latter reaction also gave the monoaddition product 4‐(phenylethynyl)‐2,2′,3,3′,4′,5,5′,6,6′‐nonaphenylbiphenyl (13) in 4 % overall yield. The X‐ray structures of compounds2and13show them to possess core aromatic rings distorted into shallow boat conformations. Density functional calculations indicate that these unusual structures are not the lowest energy conformations in the gas phase and may be the result of packing forces in the crystal. In addition, while uncorrected DFT calculations indicate that the strain energy in compound2is approximately 50 kcal/mol, dispersion‐corrected DFT calculations suggest that it is essentially unstrained, due to compensating, favorable, intramolecular interactions of its many phenyl rings. An attempted synthesis of tetradecaphenyl‐o‐terphenyl (4) by reaction of diphenylhexatriyne (14) with three equivalents of tetracyclone at 350 °C gave only the diadduct 2‐(phenylethynyl)‐2′,3,3′,4,4′,5,5′,6,6′‐nonaphenylbiphenyl (15) in 17 % yield. Even higher temperatures failed to produce4and lowered the yield of15, perhaps due to rapid decomposition of the starting materials. Ullmann coupling of 3,4,5,6‐tetraphenyl‐1,2‐diiodobenzene (16) and compound9also failed to give compound4. 

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