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Michael G. B. Drew

Bio: Michael G. B. Drew is an academic researcher from University of Reading. The author has contributed to research in topics: Ligand & Crystal structure. The author has an hindex of 61, co-authored 1315 publications receiving 24747 citations. Previous affiliations of Michael G. B. Drew include Indian Association for the Cultivation of Science & University of Malaya.


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TL;DR: The improvement in the ligand's properties on replacing the bipyridine unit with a phenanthroline unit far exceeds what was anticipated based on ligand design alone.
Abstract: The synthesis, lanthanide complexation, and solvent extraction of actinide(III) and lanthanide(III) radiotracers from nitric acid solutions by a phenanthroline-derived quadridentate bis-triazine ligand are described The ligand separates Am(III) and Cm(III) from the lanthanides with remarkably high efficiency, high selectivity, and fast extraction kinetics compared to its 2,2′-bipyridine counterpart Structures of the 1:2 bis-complexes of the ligand with Eu(III) and Yb(III) were elucidated by X-ray crystallography and force field calculations, respectively The Eu(III) bis-complex is the first 1:2 bis-complex of a quadridentate bis-triazine ligand to be characterized by crystallography The faster rates of extraction were verified by kinetics measurements using the rotating membrane cell technique in several diluents The improved kinetics of metal ion extraction are related to the higher surface activity of the ligand at the phase interface The improvement in the ligand's properties on replacing the bip

296 citations

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TL;DR: In this paper, the 3-hydroxypicolinic acid (HpicOH) was characterized using photoluminescence, infrared, Raman and H-1 NMR spectroscopy, and elemental analysis.
Abstract: New lanthanide complexes of 3-hydroxypicolinic acid (HpicOH) were prepared: [Ln(H2O)(picOH)(2)(mu-HpicO)].3H(2)O (Ln = Eu, Tb, Er). The complexes were characterized using photoluminescence, infrared, Raman, and H-1 NMR spectroscopy, and elemental analysis. The crystal structure of [Eu(H2O)(picOH)(2)(mu-HpicO)] . 3H(2)O 1 was determined by X-ray diffraction. Compound 1 crystallizes in a monoclinic system with space group P2(1)/c and cell parameters a = 9.105(13) Angstrom, b = 18.796(25) Angstrom, and c = 13.531(17) Angstrom, and beta = 104.86(1) deg. The 3-hydroxypicolinate ligands coordinate through both N,O- or O,O- chelation to the lanthanide ions, as shown by X-ray and spectroscopic results. Photoluminescence measurements were performed for the Eu(III) and Tb(III) complexes; the Eu(III) complex was investigated in more detail. The Eu(III) compound is highly luminescent and acts as a photoactive center in nanocomposite materials whose host matrixes are silica nanoparticles.

225 citations

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TL;DR: Encirclement of the neutral macrocycle around the dumbbell-shaped pyridinium cation in the [2]rotaxane produced a dramatic increase in its selectivity for chloride anions as compared to the noninterlocked cation.
Abstract: The development of an acyclic chloride anion template in which the chloride anion is coordinatively unsaturated and available for subsequent complexation to various hydrogen bond donating components is described. This template orients a neutral hydrogen bond donating ligand and a pyridinium cation orthogonally to one another. Incorporation of second-sphere interactions between the ligand and the pyridinium cation improved the efficacy of the chloride template. These results were exploited in the construction of a chloride anion-templated [2]rotaxane which, after anion template removal, was studied with regards to its anion recognition properties. Encirclement of the neutral macrocycle around the dumbbell-shaped pyridinium cation in the [2]rotaxane produced a dramatic increase in its selectivity for chloride anions as compared to the noninterlocked cation. This is interpreted as a function of the anion template used to create the [2]rotaxane superstructure.

221 citations

Journal ArticleDOI
TL;DR: New hydrophobic, tetradentate nitrogen heterocyclic reagents, 6,6'-bis-(5,6-dialkyl-1,2,4-triazin-3-yl)-2,2'-bipyridines (BTBPs) have been synthesised and show different conformations described as cis, trans, cis and trans, Trans, trans respectively.
Abstract: New hydrophobic, tetradentate nitrogen heterocyclic reagents, 6,6′-bis-(5,6-dialkyl-1,2,4-triazin-3-yl)-2,2′-bipyridines (BTBPs) have been synthesised. These reagents form complexes with lanthanides and crystal structures with 11 different lanthanides have been determined. The majority of the structures show the lanthanide to be 10-coordinate with stoichiometry [Ln(BTBP)(NO3)3] although Yb and Lu are 9-coordinate in complexes with stoichiometry [Ln(BTBP)(NO3)2(H2O)](NO3). In these complexes the BTBP ligands are tetradentate and planar with donor nitrogens mutually cisi.e. in the cis, cis, cis conformation. Crystal structures of two free molecules, namely C2-BTBP and CyMe4-BTBP have also been determined and show different conformations described as cis, trans, cis and trans, trans, trans respectively. A NMR titration between lanthanum nitrate and C5-BTBP showed that two different complexes are to be found in solution, namely [La(C5-BTBP)2]3+ and [La(C5-BTBP)(NO3)3]. The BTBPs dissolved in octanol were able to extract Am(III) and Eu(III) from 1 M nitric acid with large separation factors.

194 citations


Cited by
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Journal ArticleDOI
10 Mar 1970

8,159 citations

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TL;DR: Anion recognition chemistry has grown from its beginnings with positively charged ammonium cryptand receptors for halide binding to a plethora of charged and neutral, cyclic and acyclic, inorganic and organic supramolecular host systems for the selective complexation, detection, and separation of anionic guest species.
Abstract: Anion recognition chemistry has grown from its beginnings in the late 1960s with positively charged ammonium cryptand receptors for halide binding to, at the end of the millennium, a plethora of charged and neutral, cyclic and acyclic, inorganic and organic supramolecular host systems for the selective complexation, detection, and separation of anionic guest species. Solvation effects and pH values have been shown to play crucial roles in the overall anion recognition process. More recent developments include exciting advances in anion-templated syntheses and directed self-assembly, ion-pair recognition, and the function of anions in supramolecular catalysis.

3,145 citations

Journal ArticleDOI

2,877 citations