A new approach to produce nanoporous metals has been investigated, which is based on the dealloying of bi- or multi-component alloys. Depletion and pore formation of the alloy substrate are obtained by the transport of certain alloy components at high temperatures via volatile halogen compounds. These halogen compounds are transferred to materials acting as sinks based on their higher affinity to the respective components, and chemically bound there. Transfer via volatile halogen compounds is known from the pack cementation coating process and from high-temperature corrosion in certain industrial atmospheres. The approach was tested on different precursor alloys: Ti-43.5Al-4Nb-1Mo-0.1B (TNM-B1), TiNb42, and AlCu. Both dealloying effects and micro-scale pore formation were observed. The detailed size of the porous structures is in the range of 50 nm for both TNM-B1 and TiNB42 and 500 nm for AlCu.
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http://dx.doi.org/10.3390/ma17020498 | DOI Listing |
Org Biomol Chem
January 2025
Department of Chemistry, Faculty of Arts and Sciences, Amasya University, Amasya, Turkey.
Herein, a new metal-free, molecular chlorine-free, environmentally friendly, atom-economical, short time, inexpensive and simple operation method with mild reaction conditions for chlorination of alkenes, cyclic alkenes, ,-unsaturated carbonyl compounds, heteroaromatics, and natural products was reported with up to 96% yields using trichloroisocyanuric acid (TCCA) as the electrophilic chlorine source and TBACl as the nucleophilic chlorine source. It was demonstrated with bicyclic alkene benzonorbornadiene that regioselective chlorobromination and dibromination reactions can be carried out through TCCA/TBABr redox reactions, where TCCA acts as an oxidant in the presence of TBABr. The structures of the redox products were confirmed as a result of control experiments conducted with the newly presented DBI/TBACl and DBI/TBABr halogenation pairs.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Department of Chemistry, Gottwald Center for the Sciences, University of Richmond, Richmond, Virginia 23173, United States.
The propensities for sigma hole bonding by halogen atoms bonded to central atoms below period 2 in the periodic table remain to be systematically examined. Using iodine as our reference halogen atom, a comprehensive analysis of the tendencies for halogen and other forms of significant sigma hole bonding by simple compounds of main group atoms from H to At is accomplished. An examination of the structure and bonding of complexes formed by those iodine-substituted main group compounds and sigma donating bases (ammonia and trimethylamine) is performed to probe the viability of halogen bonding by heavy main group RM-I compounds in particular, given the historic focus on period 2.
View Article and Find Full Text PDFCureus
December 2024
Department of Neurosurgery, Hurley Medical Center, Flint, USA.
Iodoform, a halogenated organic compound, has been a cornerstone in surgical practice due to its potent antiseptic and antimicrobial properties. This comprehensive review examines the historical evolution, mechanism of action, clinical applications, and safety profile of iodoform across various surgical disciplines. Historically significant formulations like Whitehead's varnish and bismuth iodoform paraffin paste (BIPP) demonstrated remarkable efficacy in wound healing during the late 19th and early 20th centuries.
View Article and Find Full Text PDFWater Res
December 2024
Advanced Interdisciplinary Institute of Environment and Ecology, Guangdong Provincial Key Laboratory of Wastewater Information Analysis and Early Warning, Beijing Normal University, Zhuhai 519087, China. Electronic address:
In cold environments, such as polar regions and high latitudes, the freezing of aqueous solutions plays a crucial role in releasing and transforming nutrients, organic compounds, and trace gases. Freezing processes typically affect biogeochemical cycles and environmental processes by reducing the rate of chemical reactions. However, substantial studies have found that some chemical reactions may accelerate unexpectedly under freezing conditions.
View Article and Find Full Text PDFBMC Chem
January 2025
The Affiliated Ganzhou Hospital, Jiangxi Medical College, Nanchang University, Ganzhou, 341000, Jiangxi, People's Republic of China.
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