The structures, bonding, and ring-opening reactions of strained cyclic carbon-based molecules form a key component of standard textbooks. In contrast, the study of strained organometallic molecules containing transition metals is a much more recent development. A wealth of recent research has revealed fascinating nuances in terms of structure, bonding, and reactivity. Building on initial work on strained ferrocenophanes, a broad range of strained organometallic rings composed of a variety of different metals, pi-hydrocarbon ligands, and bridging elements has now been developed. Such strained species can potentially undergo ring-opening reactions to functionalize surfaces and ring-opening polymerization to form easily processed metallopolymers with properties determined by the presence of the metal and spacer. This Review summarizes the current state of knowledge on the preparation, structural characterization, electronic structure, and reactivity of strained organometallic rings with pi-hydrocarbon ligands and d-block metals.
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http://dx.doi.org/10.1002/anie.200604409 | DOI Listing |
Inorg Chem
December 2024
Institute of Nano Science and Technology, Sector-81, Mohali, Punjab 140306, India.
Among lanthanide-based single-molecule magnets (SMMs), erbium(III) is a Kramers ion, apart from dysprosium(III), which provides magnetic bistability in the presence of a suitable coordination environment. However, Er-based SMMs exhibit significantly less magnetic anisotropy than Dy because their prolate electronic density necessitates equatorially correlated ligands to minimize the charge contact with the Er atom. Here, in this work, we have computationally investigated the heteroleptic organometallic complexes with an Er(III) atom sandwiched between two distinct cyclic rings (five- and eight-membered) with the aim of tuning the magnetic anisotropy via exploiting the ligand field.
View Article and Find Full Text PDFJ Mater Chem B
December 2024
Main group Organometallics Optoelectronic Materials and Catalysis lab, Department of Chemistry, National Institute of Technology, Calicut, 673601, India.
Lipid droplets (LDs) are dynamic, multifunctional organelles critical for regulating energy balance, cell signaling, membrane formation, and trafficking. Recent studies have highlighted LDs as emerging cancer biomarkers, with cancer cells typically exhibiting a higher number and viscosity of LDs compared to normal cells. This discovery paves the way for developing molecular probes that can monitor intracellular viscosity changes within LDs, offering a powerful tool for early cancer diagnosis, recurrence monitoring, and therapeutic interventions.
View Article and Find Full Text PDFOrganometallics
December 2024
Center for Computational Quantum Chemistry, University of Georgia, Athens, Georgia 30602, United States.
Ring size effects on geometries and electronic structures were investigated for the (C H )M(C H ) ( = 4, 5, or 6; = 8, 7, or 6; + = 12; M = Ti-Ni) systems using density functional theory. The lowest-energy CHM structures for the early transition metals titanium, vanadium, and chromium are the experimentally known singlet (η-CH)Ti(η-CH), doublet (η-CH)V(η-CH), and singlet (η-CH)Cr, respectively. The likewise experimentally known singlet (η-CH)Ti, doublet (η-CH)V, and singlet (η-CH)Cr(η-CH) are the second-lowest-energy structures with only a small energy difference between the two vanadium structures.
View Article and Find Full Text PDFDalton Trans
December 2024
Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030, 128 00 Prague, Czech Republic.
C-H bond functionalisation has developed into a powerful synthetic methodology that is applicable to a wide array of substrates, including organometallic compounds. In this study, racemic, planar-chiral 1,2-dihydroferroceno[]isoquinoline and analogous helical compounds with one or two additional -fused benzene rings were synthesised by palladium-catalysed C-H bond activation/cyclisation of -[(bromoaryl)methyl]--(methylsulfonyl)aminoferrocenes. These starting materials are readily accessible from FcNHSOMe (Fc = ferrocenyl) and appropriate vicinal bromo-(bromomethyl)arenes.
View Article and Find Full Text PDFChemistry
November 2024
School of Physics and Information Technology, Shaanxi Normal University, Xi'an, 710119, China.
Polycyclic conjugated hydrocarbons have acquired increased interests recently because of their potential applications in electronic devices. On metal surfaces, the selective synthesis of four- and five-membered carbon rings remains challenging due to the presence of diverse reaction pathways. Here, utilizing the same precursor molecule, we successfully achieved substrate-controlled highly selective cycloaddition reactions towards four- and five-membered carbon rings.
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