A family of four mononuclear DyIII complexes of the guanidine-based ligand L [L = tris(2-hydroxybenzylidene)triaminoguanidine] with formulas [DyLCl2(DMF)2]·DMF·CH3OH (1), [DyL2(CH3OH)2]Br·H2O·3CH3OH (2), [DyL2(H2O)2]SCN·3H2O·CH3OH (3) and [DyL2(CH3OH)2]SCN·CH3CN·CH3OH (4) were successfully prepared by varying reaction conditions. Complex 1 is seven-coordinate, with three N2O from ligand L along with two equatorially trapped DMF molecules and two axial Cl- anions, adopting pentagonal bipyramidal D5h symmetry. Complexes 2-4 have somewhat similar structures with six donor N4O2 sites from two ligands and two O from corresponding solvent molecules, featuring a N4O4 octa-coordinate environment with triangular dodecahedron D2d symmetry. Magnetic investigations indicated that complex 1 did not demonstrate single-molecule magnetic behavior, while complexes 2-4 were single-ion magnets (SIMs) under zero applied DC field with the effective energy barriers (Ueff) of 207.3 (2), 222.5 (3) and 311.7 K (4), respectively. The different types of coordinated solvent molecules and counter anions caused changes in intermolecular interactions and coordination geometries that severely affected their magnetic dynamics. The magnetic behaviors of these complexes were investigated through complete-active space self-consistent field (CASSCF) calculations with the inclusion of spin-orbit effects. Calculations revealed that the measured differences in magnetic behaviors originated mainly from intermolecular and crystal-packing effects as isolated complexes 1-4 have almost identical electronic and magnetic properties.
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Eur J Med Chem
April 2024
Department of Medicinal Chemistry, College of Pharmacy, The University of Florida, Gainesville, FL, 32610, USA; Department of Pharmaceutics, College of Pharmacy, The University of Florida, Gainesville, FL, 32610, USA; UF Translational Drug Development Core, The University of Florida, Gainesville, FL, 32610, USA.
ChemSusChem
June 2023
Institut für Anorganische Chemie, RWTH Aachen University, Landoltweg 1A, 52072, Aachen, Germany.
A new aliphatic hybrid guanidine N,O-donor ligand (TMGeech) and its zinc chloride complex ([ZnCl (TMGeech)]) are presented. This complex displays high catalytic activity for the ring-opening polymerization (ROP) of lactide in toluene, exceeding the toxic industry standard tin octanoate by a factor of 10. The high catalytic activity of [ZnCl (TMGeech)] is further demonstrated under industrially preferred melt conditions, reaching high lactide conversions within seconds.
View Article and Find Full Text PDFChemistry
October 2022
Department of Molecular and Macromolecular Chemistry Graduate School of Engineering Tokai National Higher Education and Research System, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan.
Rhodium-catalyzed acrylate synthesis from CO and ethylene was accomplished by using a guanidine-based NCN pincer ligand. The repulsion between pπ-electron of guanidine sidearms and occupied dπ orbital of rhodium center raised the level of d-electrons close to those of formerly known d -ruthenium catalyst, thereby promoting the metallalactone formation from carbon dioxide and ethylene. This work fills the absence of group-9 metal based catalyst for the acrylate synthesis and provides a designing approach for pincer-ligated d -metal catalysts to utilize pπ-dπ interaction for promoting desirable redox processes.
View Article and Find Full Text PDFJ Chromatogr A
September 2021
Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180, United States. Electronic address:
In this paper, we examined the chromatographic behavior of a new class of guanidine-based multimodal anion exchange resins. The selectivities and protein recoveries on these resins were first evaluated using linear gradient chromatography with a model acidic protein library at pH 5, 6 and 7. While a single-guanidine based resin exhibited significant recovery issues at high ligand density, a bis-guanidine based resin showed high recoveries of all but two of the proteins evaluated in the study.
View Article and Find Full Text PDFACS Omega
March 2021
Department of Chemistry, Inorganic Chemistry Section, Jadavpur University, Kolkata 700 032, India.
A family of three water-soluble half-sandwich arene-ruthenium complexes, depicted as - , having the general formula [Ru(-cymene)(L)Cl]Cl has been synthesized, where L represents (1-benzo[]imidazol-2-yl)guanidine ( ) or (benzo[]oxazol-2-yl)guanidine ( ) or (benzo[]thiazol-2-yl)guanidine ( ). The crystal structure of complex has been determined. The complexes show several absorption bands in the visible and ultraviolet regions, and they also show prominent emission in the visible region while excited near 400 nm.
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