An unsymmetrical bis(tridentate) ligand LH in which one binding site can be readily deprotonated forms a kinetically inert [Co(III)L(2)](+) complex which can be used as a "corner" species for the "Coupe du Roi" assembly of trans,trans-[Co(2)M(2)L(4)](6+) metallogrids (M = Fe(II), Co(II), Cu(II), Zn(II)). In the mixed Co(III)/Co(II) species, the oxidation states appear to be localised. In solution, the ligand LH forms octacationic, homometallic [2 × 2] grids with the individual labile metal ions Fe(II), Co(II), Cu(II), Zn(II), seemingly as mixtures of all possible isomers arising from the unsymmetrical nature of the ligand. In the solid state, however, [Zn(4)L(4)](CF(3)SO(3))(8)·4CH(3)CN crystallises as a single species where the cation has S(4) symmetry. This stereoselectivity in the crystalline lattice is associated with interactions between the cation and triflate anions which can again be analysed in terms of the Coupe du Roi concept.
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http://dx.doi.org/10.1039/c1dt11226k | DOI Listing |
Environ Res
December 2024
Yanshan Earth Critical Zone and Surface Fluxes Research Station, College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, 100049, China. Electronic address:
N-termini Cyano group (CN) in metal hexacyanoferrates (MHCF) have been identified as specific-affinity sites for palladium (Pd), but C-termini CN do not effectively serve as Pd adsorption sites due to their stronger bonds with the metal ligands (M), which reduces the activity and density of CN. Herein, the optimization of directional coordination of cyano group C/N-termini by modulating the electronic structure of the M (Fe, Co, and Ni) in MHCF was investigated to reinforce the Pd recovery. Spectroscopic analyses and DFT calculations revealed that NiHCF exhibited N-site mono-coordination, whereas CoHCF displayed C-site mono-coordination due to spin-exchange interactions, leading to the strengthened N-Co bonds and weakened Fe-C bonds.
View Article and Find Full Text PDFBiometals
November 2024
Center for Global Health Research, Saveetha Medical College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Chennai, Tamil Nadu, India.
In this study, a novel ligand, benzilmonoximethiocarbohydrazide-O-methoxybenzaldehyde (HBMToMB), was synthesized and subsequently complexed with Cu(II), Fe(II), Co(II), Ni(II), and Mn(II) ions. The metal complexes were comprehensively characterized using techniques such as NMR, IR, Mass Spectrometry, UV-Vis, elemental analysis (CHNS), and magnetic susceptibility measurements. The complexes exhibited superior antibacterial and antifungal activity compared to the free ligand.
View Article and Find Full Text PDFChem Sci
December 2024
Jagiellonian University, Faculty of Chemistry Gronostajowa 2 30-387 Kraków Poland +48 12 686 24 89.
Inorg Chem
December 2024
Department of Chemistry, University of Colorado Boulder, Boulder, Colorado 80309, United States.
Mono-β-diketonate compounds have been fleetingly observed in base metal catalyzed reactions, which are of current interest as alternatives to precious metal catalyzed reactions. Their isolation has been challenging due to synthetic and structural limitations of acac-type ligands, leading to the development of a related NacNac ligand platform. Herein we report the synthesis of a β-diketone capable of kinetically stabilizing relevant catalytic intermediates.
View Article and Find Full Text PDFBiomacromolecules
December 2024
Department of Chemical Engineering & Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada.
Hyaluronic acid (HA) is a biomedically relevant polymer widely explored as a component of hydrogels. The prevailing approaches for cross-linking HA into hydrogels require chemically modifying the polymer, which can increase processing steps and complicate biocompatibility. Herein, we demonstrate an alternative approach to cross-link HA that eliminates the need for chemical modifications by leveraging the interactions between metal cations and the negatively charged, ionizable functional groups on HA.
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