Synthesis of beta-Imino Carbonyl Enolato Complexes by Reaction of Nickel(II), Palladium(II), and Copper(II) Acetates with the Enaminodiones (MeOCO)(RCO)CC(R')NH(2) (R = Me, OMe; R' = Et, EtOCO)

Anionic Bismuth-Oxido Carboxylate Clusters with Transition Metal Countercations

Six new anionic bismuth-oxido clusters containing trifluoroacetate ligands were prepared. These include two new Bi₆O₈ clusters: [M(NCMe)₂(H₂O)₄]₃[Bi₆(μ₃-O)₄(μ₃-OH)₄(CF₃CO₂)₁₂] with an octahedral Bi₆O₄(OH)₄ core (M = Ni, 1a; Co, 1b) and four Bi₄O₂ clusters, {[Co(NCMe)₆][Bi₄(μ₃-O)₂(CF₃CO₂)₁₀]}_n (2a), {[Co{HC(MeCO)₂(MeCNH)}₂][Bi₄(μ₃-O)₂(CF₃CO₂)₁₀]·2[CF₃CO₂]·2[CF₃CO₂H]·2[H₂O]}_n (2b), {[Cu(NCMe)₄]₂[Bi₄(μ₃-O)₂(CF₃CO₂)₁₀]·2[CF₃CO₂H]}_n (2c), and {[Me₄N]₂[Bi₄(μ₃-O)₂(CF₃CO₂)₁₀]·2[CF₃CO₂H]}_n (2d). These are among the first bismuth-oxido anionic clusters synthesized, and the first to have transition metal countercations. The Bi₆O₈ anion in 1a and 1b is a high-symmetry octahedron. Additionally, two of the new Bi₄O₂ clusters are arranged in 1D polymeric structures via bridging carboxylate ligands. The cation in compound 2c had not been previously characterized and was also observed in the synthesis of [Co{HC(MeCO)₂(MeCNH)}₂][Bi(NO₃)₆] (3). The new compounds were characterized using single crystal X-ray crystallography and elemental analysis.

Resonance-Assisted Hydrogen Bonding as a Driving Force in Synthesis and a Synthon in the Design of Materials

Resonance-assisted hydrogen bonding (RAHB), a concept introduced by Gilli and co-workers in 1989, concerns a kind of intramolecular H-bonding strengthened by a conjugated π-system, usually in 6-, 8-, or 10-membered rings. This Review highlights the involvement of RAHB as a driving force in the synthesis of organic, coordination, and organometallic compounds, as a handy tool in the activation of covalent bonds, and in starting moieties for synthetic transformations. The unique roles of RAHB in molecular recognition and switches, E/Z isomeric resolution, racemization and epimerization of amino acids and chiral amino alcohols, solvatochromism, liquid-crystalline compounds, and in synthons for crystal engineering and polymer materials are also discussed. The Review can provide practical guidance for synthetic chemists that are interested in exploring and further developing RAHB-assisted synthesis and design of materials.