The aim of this work was to prepare a novel class of (64)Cu(II) labeled complexes with the new macrocyclic ligands 1,10-dithia-4,7-diazacyclododecane-3,8-dicarboxylic acid (NEC-SE, 1), 1,10-dithia-4,7-diazacyclotridecane-3,8-dicarboxylic acid (NEC-SP, 2) and 1,10-dithia-4,7-diazacyclotetradecane-3,8-dicarboxylic acid, (NEC-SB, 3 ) to evaluate the usefulness of these macrocycles for potential utility as (64)Cu(II) chelators. The corresponding non-radioactive complexes [Cu(NEC-SE)] x 3H(2)O (4), [Cu(NEC-SP)] x 3H(2)O (5) and [Cu(NEC-SB)] (6) were prepared and their (64)Cu-analogs, [(64)Cu(NEC-SE)] (7) and [(64)Cu(NEC-SP)] (8) and [(64)Cu(NEC-SB)] (9) were produced in >98% radiochemical purity. Rats were injected with complex 7, 8 or 9 and were euthanized at 1, 4 and 24 h. All three complexes are cleared from the blood over the first hour following injection but there is poor clearance of this activity over 24 h. A similar pattern of retention was noted in the liver where the levels of activity in this tissue at 1 h are not statistically different from those at 24 h. Molecular mechanics and DFT studies were performed on the complexes in order to gain insight into the lower stability.
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http://dx.doi.org/10.1039/b808831d | DOI Listing |
J Am Chem Soc
January 2025
Van 't Hoff Institute for Molecular Sciences, University of Amsterdam, 1098 XH Amsterdam, Netherlands.
We present the synthesis, structural analysis, and remarkable reactivity of the first carbon nanohoop that fully incorporates ferrocene in the macrocyclic backbone. The high strain imposed on the ferrocene by the curved nanohoop structure enables unprecedented photochemical reactivity of this otherwise photochemically inert metallocene complex. Visible light activation triggers a ring-opening of the nanohoop structure, fully dissociating the Fe-cyclopentadienyl bonds in the presence of 1,10-phenanthroline.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
University of Basel, Department of Chemistry, St. Johanns-Ring 19, 4056, Basel, SWITZERLAND.
Despite the growing importance of planar chiral macrocyclophanes owing to their unique properties in different areas of chemistry, methods that are effective in controlling their planar chirality are restricted to certain molecular scaffolds. Herein, we report the first Pd(0)-catalyzed enantioselective intermolecular C-H arylation that induces planar chirality by installing bulky aryl groups through dynamic kinetic resolution (DKR). A computer-assisted approach allowed a fine-tuning of the structure of the employed chiral bifunctional phosphine-carboxylate ligands to achieve high enantioselectivities.
View Article and Find Full Text PDFChemistry
January 2025
Australian National University, Research School of Chemistry, Sullivans Creek Road, ACT 2601, Canberra, AUSTRALIA.
Constrained peptides possess excellent properties for identifying lead compounds in drug discovery. While it has become increasingly straightforward to discover selective high-affinity peptide ligands, especially through genetically encoded libraries, their stability and bioavailability remain significant challenges. By integrating macrocyclization chemistry with bismuth binding, we generated series of linear, cyclic, bicyclic, and tricyclic peptides with identical sequences.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, Faculty of Science, Kyushu University, Motooka 744, Nishi-ku, Fukuoka 819-0395, Japan.
The factors controlling the catalytic activity in photochemical hydrogen evolution reaction (HER) are studied in detail for two macrocyclic cobalt compounds bearing two N-heterocyclic carbenes and two pyridyl donors ( and , where has a methoxy substituent on each pyridyl ligand). The present study adopts an aqueous photosystem consisting of EDTA, [Ru(bpy)] (bpy = 2,2'-bipyridine), and MV (MV = methylviologen) at pH = 5. Both catalysts are shown to promote HER in a similar efficiency (TON = 12-13 in 6 h), revealing a minor contribution of the electron-donating methoxy substituents.
View Article and Find Full Text PDFMolecules
December 2024
Centre for Research University Services (CeSAR), Università degli Studi di Cagliari, S.S. 554 Bivio per Sestu, 09042 Monserrato, Italy.
2,8-Dithia-5-aza-2,6-pyridinophane () has been used as a receptor unit in the construction of the conjugated redox chemosensor 5-ferrocenylmethyl-2,8-dithia-5-aza-2,6-pyridinophane (). In order to further explore the coordination chemistry of , and comparatively, that of its structural analogue 2,11-dithia-5,8-diaza-2,6-pyridinophane (), featuring two secondary nitrogen atoms in the macrocyclic unit, the crystal structures of the new synthesised complexes [Pb()(ClO)]·½CHCN, [Cu()](ClO)·CHCN and [Cd()(NO)]NO were determined by X-ray diffraction analysis. The electrochemical response of towards the metal ions Cu, Zn, Cd, Hg, and Pb was investigated by cyclic voltammetry (CV) in CHCl/CHCN 0.
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