Some post-Wernerian coordination chemistry

More hydra than Janus – Non-classical coordination modes in complexes of oligopyridine ligands

“…Hypodentate bonding modes are emerging both as interesting and important isolated species and as postulated intermediates in the formation and dissociation of chelate complexes of these ligands as well as in novel dynamic processes. Although originally formulated for oligopyridines, the hypodentate concept has found broader acceptance, especially in the study of polydentate amines [15,16,17,18,19,2021,22,23,24,25,26,27,28,29,30,31,32,33,34,35]. The description hypodentate has been used to refer both to the ligand and to the complexes incorporating such ligands.…”

Syntheses, Structures, and Photophysical Properties of Eu and Lu Diketonates with a Neutral Polydentate Imidazolylmethanamine Ligand

“…To date, only a few complexes containing Schiff base ligands with imidazole rings have been reported 39. The reactions between the ligand 1 (NNO) and the neutral lanthanide complexes [Ln(tta) 3 · n H 2 O] (Ln = Eu, Lu) result in the formation of the substituted products [Ln(tta) 3 (NNO)] [Ln = Eu ( 2 ), Lu ( 3 )] in high yield (Scheme ).…”

“…[39] The reactions between the ligand 1 (NNO) and the neutral lanthanide complexes [Ln(tta) 3 The compositions and structures of 2 and 3 were established by NMR spectroscopy, IR spectroscopy, and ESI mass spectrometry. [39] The reactions between the ligand 1 (NNO) and the neutral lanthanide complexes [Ln(tta) 3 The compositions and structures of 2 and 3 were established by NMR spectroscopy, IR spectroscopy, and ESI mass spectrometry.…”

gem-Diol and Hemiacetal Forms in Formylpyridine and Vitamin-B6-Related Compounds: Solid-State NMR and Single-Crystal X-ray Diffraction Studies

“…In addition, no nuclear magnetic resonance (NMR) studies have been performed to these compounds. In particular, solid-state NMR ( ss -NMR) has allowed overcoming the challenges inherent in studying noncrystalline materials that cannot be characterized by single-crystal X-ray diffraction techniques, being an ideal technique to focus on the possibility to render the gem -diol forms and their stability, obtained from the corresponding carbonyl monomers commonly used in the area. ,,− …”

“…10−13 gem-Diol moieties in metal complexes containing pyridine carbonyl compounds have so far been elucidated through single-crystal X-ray diffraction studies, but the electronic effects of the ligands have been not taken into account. In this sense, a Cu(II) complex with 2-formylpyridine molecules (A 1 ) presents the gem-diol moiety in single crystals obtained from water solutions and CuCl 2 , 14 demonstrating that the presence of water affects the functionalization of the ligand, preventing the aldehyde form in the crystal lattice of the copper complex. In contrast, the lower reactivity of the aldehyde group in 3formylpyridine (A 3 ) toward the addition of water explains that, in the different reported complexes with copper 15 or zinc 16 ions, the formyl group remains in aqueous media.…”