218 research outputs found
Structure and bonding of [(SIPr)AgX] (X = Cl, Br, i and OTf)
© 2015 The Royal Society of Chemistry.A series of iso-structural complexes [(SIPr)AgX] (X = Cl, Br, I, OTf; SIPr = 1,3-bis(2,6-diisopropylphenyl)imidazolidene) were synthesised, including the first example of a N-heterocyclic carbene silver(i) complex containing an O-bound triflate. Bond Energy Dissociation and Natural Orbitals for Chemical Valence bond analyses (BEDA & ETS-NOCV) revealing a significant NHC → M σ-back-donation, which influences the stability and sigma-donicity of these complexes.Link_to_subscribed_fulltex
A supramolecular recyclable catalyst for aqueous Suzuki-Miyaura coupling
© The Royal Society of Chemistry 2015. A water-soluble, supramolecular catalytic system has been designed based on inclusion complexation between a hydrophobic palladium(ii)-dipyrazole complex bearing an adamantyl (Ad) molecular recognition moiety and a complementary, hydrophilic β-cyclodextrin (β-CD) derivative. The single-crystal molecular structure of the Pd(ii) complex was determined and its host-guest inclusion complexation with heptakis(2,6-di-O-methyl)-β-CD (dmβ-CD) in an aqueous medium was confirmed by 2D NOESY 1H NMR spectroscopy. The catalyst showed high activity for Suzuki-Miyaura coupling of hydrophilic aryl bromides with aryl boronic acids in aqueous organic solvents. In the presence of n-Bu4NBr as a stabilizer, the catalyst-containing reaction solution can be recycled and reused multiple times to catalyze the coupling reaction of fresh substrates once the product has been removed by centrifugation. This work demonstrates a supramolecular complex approach, non-covalently modifying a water insoluble metal complex to provide a water-soluble inclusion system to serve as a recyclable catalyst for potential application in green chemical synthesis. This journal isLink_to_subscribed_fulltex
Elucidating structure-property relationships in the design of metal nanoparticle catalysts for the activation of molecular oxygen
A novel synthetic strategy for the design of metal nanoparticles by extrusion of anionic chloride precursors from a porous copper chlorophosphate framework has been devised for the sustainable aerobic oxidation of vanillyl alcohol (4-hydroxy-3-methoxybenzyl alcohol) to vanillin (4-hydroxy-3-methoxybenzaldehyde) using a one-step, base-free method. The precise nature of the Au, Pt, and Pd species has been elucidated for the as-synthesized and thermally activated analogues, which exhibit fascinating catalytic properties when subjected to diverse activation environments. By employing a combination of structural and spectroscopic characterization tools, it has been shown that analogous heat treatments have differing effects on extrusion of a particular metal species. The most active catalysts in this series of materials were the extruded Pt nanoparticles that were generated by reduction in H2, which exhibit enhanced catalytic behavior, when compared to its Au or Pd counterparts, for industrially significant, aerobic oxidation reactions
Substituted Metal Carbonyls XV. Crystal and Molecular Structures of Two Isomorphous Singly Diphosphine-Bridged Complexes(OC)5(mu-dppf)M(CO)5. CH2Cl2 (M = Cr, Mo;Dppf = (PPh2C5H4)2Fe)
Substituted Metal Carbonyls XX. Unexpected Formation of Two Diphenylphosphine Complexes From the Oxidation of Pentacarbonylrhenate by Chlorodiphenylphosphine. Crystal and Molecular Structures of eq-Re2( CO)9(PPh2H) and Cis-ReCl(CO)4(PPh2H)
Substituted metal carbonyls. I. Molybdenum carbonyl complexes containing unidentate and bridging diphosphines: One-pot syntheses
Trimethylamine N-oxide (TMNO)-initiated decarbonylations of Mo(CO)6 followed by phosphine additions yield the complexes Mo(CO)5(Ph2PCH2PPh2), which consists of a unidentate diphosphine, and the dinuclear phosphine-bridged complexes Mo2(CO)10(μ-Ph2P(CH2)nPPh2) (where n = 2, 3) at ambient temperatures. The IR and NMR (1H and 31P) spectroscopic and structural properties of these complexes are presented and discussed. Some thermal analytical data are summarised. © 1987.Link_to_subscribed_fulltex
Substituted metal carbonyls. Part 5. Convenient syntheses of some group 6 phosphine and pyridine substituted penta- and tetra-carbonyls and isolation of the singly bridging 1,2-bis(4-pyridyl)ethylene dimetal decacarbonyl complexes
Link_to_subscribed_fulltex
- …