A catalytic methodology for the conversion of amides to amines is reported. Of the 25 examples described, 14 examples involve the reduction of N-trifluoroacetamides to the corresponding ...trifluoroethylamines. These reductions are achieved by catalytic hydrosilylation of the amide mediated by an electrophilic phosphonium cation (EPC) catalyst.
The synthesis and characterization of an (arsino)phosphaketene, As(PCO){N(Dipp)(CH2)}2 (Dipp=2,6‐diisopropylphenyl) is reported along with its subsequent reactivity with B(C6F5)3. When reacted in a ...stoichiometric ratio, B(C6F5)3 drove the insertion of the P=C bond of the phosphaketene into one of the As−N bonds of the arsino functionality, affording an acid‐stabilized, seven‐membered, cyclic arsaphosphene. In contrast, when catalytic amounts of B(C6F5)3 were employed, dimeric species, which formed through a formal 2+2 cycloaddition of the cyclic arsaphosphene, were generated. The cyclic arsaphosphene product represents the first example of such a compound in which the two substituents are arranged in a cis‐configuration.
Reagent and promoter: Stoichiometric and catalytic reactions between B(C6F5)3 and an (arsino)phosphaketene, As(PCO){N(Dipp)(CH2)}2 (Dipp=2,6‐diisopropylphenyl) are reported. In a stoichiometric ratio, an acid‐stabilized, cyclic cis‐arsaphosphene was isolated. In contrast, when catalytic amounts of B(C6F5)3 were employed, dimeric species, which form through a formal 2+2 cycloaddition of the cyclic arsaphosphene, were generated.
The use of a bis(diphenyl)phosphine functionalized β‐diketiminato ligand, HC{(CH3)C}2{(ortho‐P(C6H5)22C6H4)N}2− (PNac), as a support for germanium(II) and tin(II) chloride and phosphaketene ...compounds, is described. The conformational flexibility and hemilability of this unique ligand provide a versatile coordination environment that can accommodate the electronic needs of the ligated elements. For example, chloride ion from (PNac)ECl (E=Ge, Sn) affords the cationic germyliumylidene and stannyliumylidene species (PNac)E+ in which the pendant phosphine arms associate more strongly with the Lewis acidic main group element centers, providing further electronic stabilization. In a similar fashion, chemical decarbonylation of the germanium phosphaketene (PNac)Ge(PCO) with tris(pentafluorophenyl)borane affords a “push–pull” stabilized phosphinidene in which one of the phosphine groups of the ligand backbone associates with the low valent phosphinidene center.
The synthesis and reactivity of a family of germanium(II) and tin(II) complexes supported by a bis(diphenyl)phosphine functionalized β‐diketiminato ligand is reported, including an intramolecularly stabilized “push–pull” phosphinidene.
Clusters of the main group elements phosphorus and arsenic, commonly categorized as Zintl clusters, have been known for over a century. And, only now is the application of these systems as catalysts ...for organic synthesis being investigated. In this work, boranes are tethered via an aliphatic linker to Zintl-based clusters and their Lewis acidity is examined experimentally, by the Gutmann-Beckett test and competency in the hydroborative reduction of six organic substrates, as well as computationally, by fluoride ion affinity and hydride ion affinity methods. The effects of tuning the aliphatic linker length, substituents at the boron, and changing the cluster from a seven-atom phosphorus system to a seven-atom arsenic system on reactivity are studied.
Urban drinking water security in Gujarat Mehta, Meera; Mehta, Dinesh; Vavaliya, Jaladhi
Journal of social and economic development,
06/2021, Letnik:
23, Številka:
Suppl 1
Journal Article
Recenzirano
Odprti dostop
Gujarat has made important strides to ensure that most parts of the state become water secure. In 2005, Gujarat was one of the few states that recognized that its urban areas were its ‘engines of ...growth’ and made significant investments in urban infrastructure. A state-wide water supply grid was constructed to transfer inter-basin water from perennial surface water sources to water-scarce areas. While these schemes have improved household-level access to municipal water supply, service levels have not improved. In this paper, we argue that along with infrastructure creation, there is a need to focus on monitoring, operation and maintenance of existing system and improving efficiency. We analyze information available from the performance assessment system (PAS) setup by the CEPT University for monitoring of urban services in India. It has annual information of water service delivery in all the urban areas of Gujarat from 2010. We assess urban drinking water supply on three key aspects: equity, service quality and financial sustainability. We also identify a few key intervention areas related to increased accountability, efficiency and equity in delivery of water supply services.
Near-infrared fluorescence mapping with indocyanine green dye is a recent advancement in minimally invasive segmental resection. This technique has not yet been reproduced, validated, or objectively ...evaluated in a large prospective case series. We hypothesized that near-infrared fluorescence mapping is associated with an increased oncological margin distance from the tumor, over and above the best judgment of the surgeon.
This was a phase 2 prospective cohort trial in patients who are undergoing robotic segmentectomy for lung tumors <3 cm. The predicted intersegmental plane was first identified by consensus between 2 thoracic surgeons. The true plane was then mapped by indocyanine green injection. A 7-item binary rating scale was used for the evaluation of feasibility, reproducibility, and added oncological margin distance from the tumor. The margin distance between the tumor and the true plane was compared with the margin distance between the tumor and the predicted plane.
Fifty-three patients were enrolled between September 2016 and May 2018 and 31 patients (58.4%) received the planned operation with indocyanine green mapping. In 74.2% of cases (23 out of 31), a score of 7 out of 7 was achieved, indicating the true intersegmental plane identified by indocyanine green mapping was different than the predicted plane identified by the surgeon. In 61.2% (19 out of 31) of those cases, the mean additional margin distance from the tumor to the staple line attributable to the indocyanine green mapping was 2.41 ± 1.6 cm. The overall complication rate was 18.5% (10 out of 53) and there were no deaths.
Near-infrared fluorescence mapping in robotic segmentectomy is associated with increased oncological margin length, over and above the best judgment of the surgeon, in the majority cases where it is used.
Background
Pneumothorax (PTX) and pneumomediastinum (PM), collectively termed here “air leak”, are now well described complications of severe COVID-19 pneumonia across several case series. The ...incidence is thought to be approximately 1% but is not definitively known.
Objectives
To report the incidence and describe the demographic features, risk factors and outcomes of patients with air leak as a complication of COVID-19.
Methods
A retrospective observational study on all adult patients with COVID-19 admitted to Watford General Hospital, West Hertfordshire NHS Trust between March 1st 2020 and Feb 28th 2021. Patients with air leak were identified after reviewing both chest radiographs (CXRs) and axial imaging (CT Thorax) with confirmatory radiology reports inclusive of the terms PTX and/or PM.
Results
Air leak occurred with an incidence of 0.56%. Patients with air leak were younger and had evidence of more severe disease at presentation, including a higher median CRP and number of abnormal zones affected on chest radiograph. Asthma was a significant risk factor in the development of air leak (OR 13.4 4.7-36.4), both spontaneously and following positive pressure ventilation. CPAP and IMV were also associated with a greater than six fold increase in the risk of air leak (OR 6.4 2.5-16.6 and 9.8 3.7-27.8 respectively). PTX, with or without PM, in the context of COVID-19 pneumonia was almost universally fatal whereas those with alone PM had a lower risk of death.
Conclusion
Despite the global vaccination programme, patients continue to develop severe COVID-19 disease and may require respiratory support. This study demonstrates the importance of identifying that deterioration in such patients may be resultant from PTX or PM, particularly in asthmatics and those managed with positive pressure ventilation.
Although Zintl ions and phases have been known for more than a century, their application as tools to build organic molecules is underdeveloped. Here, a range of Zintl ions and phases were surveyed ...in the hydrophosphination of alkynes, alkenes, and imines with diphenylphosphine to afford useful organophosphine products. Further investigations with diphenylphosphine in the absence of the unsaturated organic substrates revealed the formation of the diphenylphosphide anion, allowing for the conclusion that the role of the Zintl species is as an initiator in these transformations.
Ketones are efficiently deoxygenated in the presence of silane using highly electrophilic phosphonium cation (EPC) salts as catalysts, thus affording the corresponding alkane and siloxane. The ...influence of distinct substitution patterns on the catalytic effectiveness of several EPCs was evaluated. The deoxygenation mechanism was probed by DFT methods.
Taking out the O: The salts of the title cations were used in the catalytic stepwise hydrosilylation and deoxygenation of ketones. The dependency of the reaction outcome on Lewis acidity was investigated. In addition, the mechanism of the reduction was probed experimentally as well as with DFT calculations.
The first fully characterized boron-functionalized heptaphosphide Zintl cluster, (BBN)P72– (12–), is synthesized by dehydrocoupling HP72–. Dehydrocoupling is a previously unprecedented reaction ...pathway to functionalize Zintl clusters. Na(18-c-6)21 was employed as a transition metal-free catalyst for the hydroboration of aldehydes and ketones. Moreover, the greenhouse gas carbon dioxide (CO2) was efficiently and selectively reduced to methoxyborane. This work represents the first examples of Zintl catalysis where the transformation is transition metal-free and where the cluster is noninnocent.
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