A general strategy for the synthesis of hindered N- and P-based donors is presented whereby the strongly electron releasing N-heterocyclic olefin (NHO) unit, IPr[double bond, length as m-dash]CH-, (IPr[double bond, length as m-dash]CH- = [(HCNDipp)2C[double bond, length as m-dash]CH](-); Dipp = 3,6-(i)Pr2C6H2) is linked to terminally bound phosphine and amine donors. Preliminary coordination chemistry is presented involving phosphine (IPr[double bond, length as m-dash]CH)PR2 (R = (i)Pr and Ph) and amine (IPr[double bond, length as m-dash]CH)NMe2 ligands and the Lewis acids BH3 and AuCl. Interestingly, (IPr[double bond, length as m-dash]CH)NMe2 binds AuCl through an exocyclic olefin unit, while the softer phosphorus centers in (IPr[double bond, length as m-dash]CH)PR2 coordinate to yield Au-P linkages; thus the reported NHO-based ligands exhibit tunable binding modes to metals.
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http://dx.doi.org/10.1039/c6dt00299d | DOI Listing |
Environ Geochem Health
January 2025
College of Resource and Environmental Engineering, Hubei Key Laboratory for Efficient Utilization and Agglomeration of Metallurgic Mineral Resource, Wuhan University of Science and Technology, Wuhan, 430081, People's Republic of China.
Cadmium (Cd) contamination in aquatic systems is a widespread environmental issue. In this study, a solid waste iron tailings and biochar hybrid (Fe-TWBC) was successfully synthesized derived from co-pyrolysis of peanut shell and tailing waste (Fe-TW). Characterization analyses showed that the metal oxides from solid waste iron tailings successfully loaded onto the biochar surface, with more functional groups in Fe-TWBC.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Tsinghua university, Beijing, Beijing, China.
Background: Successive cleavages of amyloid precursor protein C-terminal 99 residues (APP-C99) by human γ-secretase result in amyloid-β peptides (Aβs) of varying lengths, the main constituents of amyloid plaques in Alzheimer's disease patients. Most cleavages have a step size of three residues, as exemplified by sequential generation of Aβ49, Aβ46, Aβ43, and Aβ40.
Method: To elucidate the mechanism of substrate cleavage, we determined atomic structures of human γ-secretase bound individually to APP-C99, Aβ49, Aβ46, and Aβ43.
J Comput Chem
January 2025
Chemistry Department, Southern Methodist University, Dallas, Texas, USA.
Using the QM/MM methodology and a local mode analysis, we investigated a character and a strength of FeS bonds of heme groups in oxidized and reduced forms of Bacterioferritin from Azotobacter vinelandii. The strength of the FeS bonds was correlated with a bond length, an energy density at a bond critical point, and a charge difference of the F and S atoms. Changing the oxidation state from ferrous to ferric generally makes the FeS bonds weaker, longer, more covalent, and more polar.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Nanotechnology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), P. O. Box: 31535-1897, Karaj, Iran.
Herein, an efficient and feasible approach was developed to oxidize low-cost agricultural waste (quinoa husk, QS) for the synthesis of carboxylated nanocellulose (CNC). The as-prepared rod-like CNCs (average diameter of 10 nm and length of 103 nm) with a high specific surface area (173 m/g) were utilized for the immobilization of a model protease enzyme (PersiProtease1) either physically or via covalent attachment. For chemical immobilization, CNCs were firstly functionalized with N, N'-dicyclohexylcarbodiimide (DCC) to provide DCNCs nanocarrier which could covalently bond to enzyme trough nucleophilic substitution reaction and formation of the amide bond between DCNCs and enzyme.
View Article and Find Full Text PDFNat Commun
January 2025
Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR, United Kingdom.
Inorganic semiconductors based on heavy pnictogen cations (Sb and Bi) have gained significant attention as potential nontoxic and stable alternatives to lead-halide perovskites for solar cell applications. A limitation of these novel materials, which is being increasingly commonly found, is carrier localization, which substantially reduces mobilities and diffusion lengths. Herein, CuSbSe is investigated and discovered to have delocalized free carriers, as shown through optical pump terahertz probe spectroscopy and temperature-dependent mobility measurements.
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