George Ferguson

Bio: George Ferguson is an academic researcher from University of Guelph. The author has contributed to research in topics: Crystal structure & Hydrogen bond. The author has an hindex of 40, co-authored 572 publications receiving 7474 citations. Previous affiliations of George Ferguson include Durham University & University of St Andrews.

Synthesis, x-ray crystal structures, and cation-binding properties of alkyl calixaryl esters and ketones, a new family of macrocyclic molecular receptors

Abstract: Des calix[n]arenes (n=4, 6, 8) portant des cetoesters sont etudies; pour n=4, ils presentent a l'etat solide une conformation en cone, leurs cryptates avec des metaux alcalins sont egalement etudies dans le but d'evaluer leurs proprietes ionophores

Chemically modified calix[4]arenes. Regioselective synthesis of 1,3-(distal) derivatives and related compounds. X-Ray crystal structure of a diphenol-dinitrile

Abstract: p-tert-Butylcalix[4]arene has been chemically modified in a regioselective manner at the 1,3-(distal) phenolic groups of the lower rim using electrophiles such as ethyl bromoacetate, chloroacetone, bromopinacolone, chloroacetonitrile, and prop-2-ynyl bromide. X-Ray diffraction analysis of one of these 1,3-derivatives reveals that it exists in a highly distorted cone conformation. Crystals of the dinitrile 7 are triclinic, space group P, with two molecules in a cell of dimensions a= 13.191 (3), b= 16.755(3), c= 10.424(1)A; α= 100.32(1), β= 93.23(1), γ= 84.89(2)°. The structure was solved by direct methods and refined by full-matrix least squares calculations; R= 0.066 for 4155 observed reflections. The two phenolic rings (A and C) are tilted (interplanar angle 102.3°) so as to place the hydroxy groups inside the cavity, whereas rings B and D bearing OCH2CN moieties are almost parallel to each other (interplanar angle 13.3°). This arrangement allows for relatively facile intramolecular hydrogen bond formation between proximal hydroxy and ether functional groups [O(H)⋯ O 2.941(3) and 2.903(3)A]. These products are useful precursors of other 1,3-disubstituted derivatives including double calixarenes and of a variety of tetrasubstituted calix[4]arenes with dual functionality on the lower rim.

Structure and solution stability of indium and gallium complexes of 1,4,7-triazacyclononanetriacetate and of yttrium complexes of 1,4,7,10-tetraazacyclododecanetetraacetate and related ligands: kinetically stable complexes for use in imaging and radioimmunotherapy. X-Ray molecular structure of the indium and gallium complexes of 1,4,7-triazacyclononane-1,4,7-triacetic acid

Abstract: Of the four triazacycloalkanetriacetic acids screened for their ability to bind 111ln, triazacyclononanetriacetate bound indium most quickly and formed a complex whose dissociation as a function of pD was monitored by 13C NMR spectrometry using a labelled ligand (k296 1.8 × 10–1 dm3 mol–1 s–1) in the pD range 0 to –0.6. The corresponding gallium complex is even more stable with respect to acid dissociation and may be observed by 71Ga NMR spectrometry both in vitro(δGa+ 171 ppm) and in vivo. Crystal structures of the neutral gallium and of the protonated indium complexes are reported. The syntheses of a series of octadentate ligands are described and their relative efficiency to bind 90Y reported. Ligands based on tetraazacyclododecane bind 90Y most rapidly, and tetraazacyclododecanetetraacetate forms a strong complex with yttrium (log Ks 24.9, 298 K) which dissociates at low pH (< 2) as measured by HPLC and 13C NMR spectrometry.

Synthesis, X-ray crystal structures, and cation transfer properties of alkyl calixaryl acetates, a new series of molecular receptors

Abstract: Calix[4]-, [6]-, and [8]-arenes have been converted into a series of alkyl acetates which show significant phase-transfer activity and selectivity towards alkali metal picrates; the X-ray crystal structure of two members of the series, (1b) and (2d), have been determined.

Chemical Redox Agents for Organometallic Chemistry

Abstract: 1. Advantages of Chemical Redox Agents 878 2. Disadvantages of Chemical Redox Agents 879 C. Potentials in Nonaqueous Solvents 879 D. Reversible vs Irreversible ET Reagents 879 E. Categorization of Reagent Strength 881 II. Oxidants 881 A. Inorganic 881 1. Metal and Metal Complex Oxidants 881 2. Main Group Oxidants 887 B. Organic 891 1. Radical Cations 891 2. Carbocations 893 3. Cyanocarbons and Related Electron-Rich Compounds 894

Asymmetric Transition Metal-Catalyzed Allylic Alkylations.

Abstract: Efficient and reliable amplification of chirality has borne its greatest fruit with transition metal-catalyzed reactions since enantiocontrol may often be imposed by replacing an achiral or chiral racemic ligand with one that is chiral and scalemic While the most thoroughly developed enantioselective transition metal-catalyzed reactions are those involving transfer of oxygen (epoxidation and dihydroxylation)1,2 and molecular hydrogen,3 the focus of this review is on the area of enantioselective transition metal-catalyzed allylic alkylations which may involve C-C as well as C-X (X ) H or heteroatom) bond formation4-9 The synthetic utility of transitionmetal-catalyzed allylic alkylations has been soundly demonstrated since its introduction nearly three decades ago10-21 In contrast to processes where the allyl moiety acts as the nucleophilic partner, we will limit our discussion to processes which result in nucleophilic displacements on allylic substrates (eq 1) Such reactions have been recorded with a broad