A Practical Synthesis of Bridged Diarylacetylenes

An efficient and practical synthesis of bridged diarylacetylenes in multigram quantities has been successfully carried out using high-yielding (classical) synthetic methods and readily available starting materials. The structural analysis of the representative bridged diarylacetylenes by X-ray crystallography strongly suggests that conformations, bending of the linear triple bond, and the angle between the mean planes of aromatic rings in various bridged diarylacetylenes are governed by the p−π conjugation among the aromatic rings and the ethereal groups. Furthermore, the synthetic scheme also allows the preparation of (appropriately) bromo-substituted bridged diarylacetylenes which hold potential for their future usage for the preparation of polymeric analogues as well as the hexaarylbenzene derivatives for potential applications in the emerging area of molecular electronics and nanotechnology

FHBC, a Hexa‐\u3cem\u3eperi\u3c/em\u3e‐hexabenzocoronene–Fluorene Hybrid: A Platform for Highly Soluble, Easily Functionalizable HBCs with an Expanded Graphitic Core

Materials based upon hexa‐peri‐hexabenzocoronenes (HBCs) show significant promise in a variety of photovoltaic applications. There remains the need, however, for a soluble, versatile, HBC‐based platform, which can be tailored by incorporation of electroactive groups or groups that can prompt self‐assembly. The synthesis of a HBC–fluorene hybrid is presented that contains an expanded graphitic core that is highly soluble, resists aggregation, and can be readily functionalized at its vertices. This new HBC platform can be tailored to incorporate six electroactive groups at its vertices, as exemplified by a facile synthesis of a representative hexaaryl derivative of FHBC. Synthesis of new FHBC derivatives, containing electroactive functional groups that can allow controlled self‐assembly, may serve as potential long‐range charge‐transfer materials for photovoltaic applications

A Search for Blues Brothers: X-ray Crystallographic/Spectroscopic Characterization of the Tetraarylbenzidine Cation Radical as a Product of Aging of Solid Magic Blue

Magic blue (MB+˙ SbCl6− salt), i.e. tris-4-bromophenylamminium cation radical, is a routinely employed one-electron oxidant that slowly decomposes in the solid state upon storage to form so called ‘blues brothers’, which often complicate the quantitative analyses of the oxidation processes. Herein, we disclose the identity of the main ‘blues brother’ as the cation radical and dication of tetrakis-(4-bromophenyl)benzidine (TAB) by a combined DFT and experimental approach, including isolation of TAB+˙ SbCl6− and its X-ray crystallography characterization. The formation of TAB in aged magic blue samples occurs by a Scholl-type coupling of a pair of MB followed by a loss of molecular bromine. The recognition of this fact led us to the rational design and synthesis of tris(2-bromo-4-tert-butylphenyl)amine, referred to as ‘blues cousin’ (BC: Eox1 = 0.78 V vs. Fc/Fc+, λmax(BC+˙) = 805 nm, εmax = 9930 cm−1 M−1), whose oxidative dimerization is significantly hampered by positioning the sterically demanding tert-butyl groups at the para-positions of the aryl rings. A ready two-step synthesis of BC from triphenylamine and the high stability of its cation radical (BC+˙) promise that BC will serve as a ready replacement for MB and an oxidant of choice for mechanistic investigations of one-electron transfer processes in organic, inorganic, and organometallic transformations

Charge Delocalization in Self-Assembled Mixed-Valence Aromatic Cation Radicals

The spontaneous assembly of aromatic cation radicals (D+•) with their neutral counterpart (D) affords dimer cation radicals (D2+•). The intermolecular dimeric cation radicals are readily characterized by the appearance of an intervalence charge-resonance transition in the NIR region of their electronic spectra and by ESR spectroscopy. The X-ray crystal structure analysis and DFT calculations of a representative dimer cation radical (i.e., the octamethylbiphenylene dimer cation radical) have established that a hole (or single positive charge) is completely delocalized over both aromatic moieties. The energetics and the geometrical considerations for the formation of dimer cation radicals is deliberated with the aid of a series of cyclophane-like bichromophoric donors with drastically varied interplanar angles between the cofacially arranged aryl moieties. X-ray crystallography of a number of mixed-valence cation radicals derived from monochromophoric benzenoid donors established that they generally assemble in 1D stacks in the solid state. However, the use of polychromophoric intervalence cation radicals, where a single charge is effectively delocalized among all of the chromophores, can lead to higher-order assemblies with potential applications in long-range charge transport. As a proof of concept, we show that a single charge in the cation radical of a triptycene derivative is evenly distributed on all three benzenoid rings and this triptycene cation radical forms a 2D electronically coupled assembly, as established by X-ray crystallography

Interdisciplinary research in Rajasthan, India: exploring the role of culture and art to support rural development and water management

This paper examines the role of art and culture in supporting rural development in the context of critical water challenges. It focuses on an interdisciplinary network and research programme conducted in 2018 with the village of Jhakhoda, in Rajasthan, India. The village has experienced years of declining water quality and has recently turned to rainwater harvesting and other conservation measures as a means to address water challenges. The research team sought to support local NGO and village efforts through creative, regionally specific forms of cultural activity. Through our project, we found that arts approaches can contribute to changes in the way people understand water and environmental challenges and can play a significant role in working towards sustainable water futures

Differential unfolded protein response during Chikungunya and Sindbis virus infection: CHIKV nsP4 suppresses eIF2α phosphorylation

10.1186/1743-422X-10-36Virology Journal10

Fatal outcome in acute fatty liver of pregnancy and review of literature

Acute fatty liver of pregnancy (AFLP) is an uncommon life-threatening disorder of pregnancy seen commonly in third trimester. When not diagnosed at right time it can lead to hepatic failure, encephalopathy, coagulopathy, maternal and fetal mortality. The clinical symptoms and signs are nonspecific, and it needs to be identified early in order to prevent poor outcome. The gold standard for diagnosis of AFLP is liver biopsy, which is difficult in an acute setting and in abnormal coagulation profile hence the diagnosis is usually based on clinical criteria   Early termination of pregnancy and good intensive care support are the mainstay of management. The authors here presented a case report where even early delivery and good critical care failed to prevent maternal mortality. Review of literature regarding etiopathogenesis, management and recurrences of AFLP are also discussed

Efficacy of betadine vaginal toileting before caesarean section in postoperative infections

Background: The objective of the current study was to evaluate the efficacy of preoperative betadine vaginal toileting in reducing post caesarean infections (endometritis, febrile illness, wound sepsis).Methods: This prospective longitudinal study was conducted at Maulana Azad Medical College, New Delhi over 3 months among 200 women who underwent caesarean delivery. Inclusion criteria were defined as women undergoing caesarean section. Exclusion criteria included placenta previa, active genital herpes, cord prolapse, chorioamnionitis, allergy to iodine. After taking informed consent, subjects were divided into two groups by simple randomization method using computer generated random numbers- Group 1 (case) - subjects who underwent 5% povidone iodine sponge stick cleansing in all the fornices and walls of vagina for 30 seconds after foley’s catheter insertion and before abdominal scrubbing. Group 2 (control) - subjects who didn't receive betadine vaginal toileting before caesarean section Subjects were followed for 10 days postpartum (or till suture removal/ discharge from hospital, whichever was late). Demographic data, operative details and postoperative parameters were compared between the two groups.Results: Both groups were matched for baseline patients’ characteristics (age, BMI, gestational age, operative time). Women who received preoperative betadine vaginal toileting had markedly less incidence of endometritis (case-3%, control-10%, p<0.05), overall postoperative morbidity (case-13%, control-33%, p<0.001). Incidence of postoperative febrile illness (case-6%, control-12%, p>0.05) and wound sepsis (case-5%, control-12%, p>0.05) were found to be less but not significant between both groups.Conclusions: Preoperative vaginal cleansing helps in reducing postoperative morbidity by decreasing incidence of postoperative infection