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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Nouveaux ligands hétérocycliques et leurs complexes métalliques : étude des propriétés magnétiques / New heterocyclic ligands and their metal complexes : study of their magnetic properties

Tran, Diem Ngan 31 October 2008 (has links)
Dans le premier temps, nous avons préparé de nouveaux hétérocycles azotés comprenant des unités 1,2,4-triazine : btrz, cpytrz, pytrz, bpy-pytrz et pytrz. Ensuite, nous avons observé leur aptitude à la complexation des ions métalliques d10 (CuI, AgI, ZnII) en utilisant l’analyse en spectrométrie UV-Visible, spectrométrie de Masse ESIMS, Résonance Magnétique Nucléaire, et Diffraction de Rayons X. En outre, avec le ligand bpy-pytrz, son complexe CuI est un hélicate double-brin dinucléaire dont l’orientation H-H (Head to Head) ou H-T (Head to Tail) sera déterminée grâce à la structure RX. Par ailleurs, nous avons obtenu pour la première fois des monocristaux d’un complexe entre l’ion uranium UO2(NO3)2 et le ligand bpy-pytrz. Dans une seconde partie, la synthèse de séquences bipyridine-bisdiazines-pont 2-oxapropylène est présentée à savoir les séquences : bpy-bpz, bpy-bpm, bpy-btz2,2’ et bpy-btz4,4’. L’étude de leurs modes de complexation avec des ions métalliques 3dn (NiII, CoII, CuII) a été réalisée. Enfin, des résultats intéressants sur les propriétés magnétiques (ferromagnétisme) de ces complexes ont été obtenus et concernent en particulier des complexes neutres dinucléaires du NiII . / Fistly, new nitrogen heterocycles containing 1,2,4-triazine units have been prepared: btrz, cpytrz, pytrz, bpy-pytrz et pytrz. Then, their complexation behaviour have been studied with d10 transition metal ions (CuI, AgI, ZnII) by UV-Vis, Nuclear Magnetic Resonance, ESI-MS and X-ray diffraction spectrometries. Particularly, the bpy-pytrz ligand CuI complex gave a dinuclear double-strand helicate, of which H-H (Head to Head) or H-T (Head to Tail) conformation will be determined by X-ray diffraction. Elsewere, for the first time we were able to obtained suitable single crystals of the Uranium (UO2(NO3)2) complex with bpy-pytrz ligand. Secondly, the synthesis of sequential 2-oxapropylene-bridged bipyridine-bisdiazine strands (bpy-bpz, bpy-bpm, bpy-btz2,2’, bpy-btz4,4’) has been reported. Their complexation behaviour with 3dn transition metal ions (CoII, NiII, CuII) have been studied in solution and in solid phases. Finally, preliminary interesting results have been achieved on the magnetic properties of their complexes and concerned particularly the dinuclear NiII neutral complexes.
2

Syntheses and reactions of some ligands containing both phosphorus (III) and organonitrile

Harper, Daniel P. January 1981 (has links)
4-Cyanobutyl(diphenyl)phosphine,(C6H5)2P(CH2)4CN, was synthesized from (C6H5)2POCH3 and Cl(CH2)4CN. This new ligand was reacted with Na2PdC14 to form PdCl2[(C6H5)2P(CH2)4CN]2, The ligand and the complex were identified with spectroscopic data and through elemental analyses.Methyl(diphenyl)phosphine oxide was synthesized from (C6H5)2PC1, CH30H, and CH3I and then reduced with A1H3 to provide (C6H5)2PCH3. This final product was identified using nmr spectroscopic data.Reaction of the cyano group in (C6H5)2P(CH2)2CN with C2H50H, H20, and HC1 provided (C6H5)2P(CH2)2C02C2H5. This phosphine-ester was reacted with Na2PdCl4 to form the complex PdC1 [(C6H5)2P(CH2)2C02C2H5]2. The ligand and the complex were identified with spectroscopic data and through elemental analyses.Reactions of the cyano group were carried out. (C6H5)2P(CH2)3CN was reacted with A1H3 in an attempt to form the corresponding amine. 2-Cyanoethyl(diphenyl)phosphine was reacted with C2H50H and HC1 to form the imidate by the Pinner Reaction. These reactions were studied using nmr and it spectroscopic data.
3

Functional analysis of ligand recognition by the glucocorticoid receptor /

Lind, Ulrika, January 1900 (has links)
Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 4 uppsatser.
4

Hybrid multidentate ligands : amido phosphine complexes of the Group VIII metals

MacNeil, Patricia Ann January 1983 (has links)
The hybrid ligands HN(SiMe₂CH₂PPh₂)₂ and HN(CgH₅CH₂)(SiMe₂CH₂PPh₂) react readily with n-butyl lithium to yield the corresponding lithium salts. Metathesis of Group VIII transition metal halides with LiN(SiMe₂CH₂PPh₂)₂ produces a variety of amido phosphine complexes. For the nickel triad, these derivatives have the formula [MCIN(SiMe₂CH₂PPh₂)₂] (M = Ni, Pd, Pt); a variety of rhodium and iridium complexes [M(L)N(SiMe₂CH₂PPh₂)₂] (M = Rh, Ir; L = CO, n²-C₈H₁₄,C₂H₄,PMe₃,PPh₃) and [M(C0D)N(CgH₅CH₂)(SiMe₂CH₂PPh₂)] (M = Rh, Ir; COD = 1,5-cyclooctadiene) have also been prepared and characterized. Single crystal x-ray structural analysis of [NiClN(SiMe₂CH₂PPh₂)₂] indicates that it adopts a distorted square planar stereochemistry, whereas the palladium analogue [PdClN(SiMe₂CH₂PPh₂)₂] is almost perfectly square planar. Based primarily on spectral data, all of these Group VIII amido phosphines are assigned square planar geometries with mutually trans phosphines, with the tridentate ligand coordinated to the metal through the amide nitrogen and both phosphine centres. The amino phosphine dichlorides, [MCI₂NH(SiMe₂CH₂PPh₂)₂] (M = Ni, Pd, Pt) are prepared from the free ligand. The nickel derivative, [NiCl₂NH(SiMe₂CH₂PPh₂)₂], has been shown by crystallographic analysis to have a very distorted tetrahedral geometry; no interaction between the NH moiety and the nickel centre is observed. Reaction of these amino phosphines with triethyl amine cleanly produces the corresponding amido phosphines. [NiClN(SiMe₂CH₂PPh₂)₂] reacts at low temperatures with Grignards or alkyl lithium reagents to yield a series of hydrocarbyl complexes [Ni(R)N(SiMe₂CH₂PPh₂)₂] (R = Me, allyl, vinyl, phenyl). These alkyl (aryl) complexes react readily at room temperature under one atmosphere of carbon monoxide to give Ni(0) species, [Ni(C0)₂N(C0R)(SiMe₂CH₂PPh₂)₂], in which the ligand chelates in a bidentate fashion (through the phosphines) owing to migration of the acyl group to the amide nitrogen. For the methyl and phenyl derivatives, the intermediate Ni(II) acyl complexes have also been isolated. As shown by crystal structural analysis, insertion of CO into the nickel vinyl bond results in an n²-acryloyl Ni(0) species in which the hybrid ligand has undergone further rearrangement to an imidate structure. Some of the rhodium and iridium amidophosphines, lM(L)N(SiMe₂CH₂PPh₂)₂] (M = Rh, L = n²-C₈H₁₄,PPh₃; M = Ir, L = n²-C₈H₁₄, C₂H₄) and [M(COD)N(C₆H₅CH₂) (SiMe₂CH₂PPh₂)] (M = Rh.Ir) are catalyst precursors for the homogeneous hydrogenation of simple olefins under mild conditions (1 atm. H2, 22°C). For the rhodium amido phosphines, olefin isomerization is a competing process with hydrogenation, whereas with [lr(n –C₈H₄)N(SiMe₂CH₂PPh₂)₂] only straightforward reduction is observed. A number of iridium(III) amido phosphine hydrides has been prepared The five-coordinate, 16-electron complex [Ir(H)₂N(SiMe₂CH₂PPh₂)₂], formed from [Ir(n² -C₈H₁₄)N(SiMe₂CH₂PPh₂)₂] under dihydrogen, reacts readily with neutral ligands to stereoselectively produce mer cis-[Ir(H)₂(L)(SiMe₂-PPh₂)₂] (L = CO, PMe₃). Oxidative addition of dihydrogen to [Ir(L)N(SiMe₂CH₂PPh₂)₂] (L = PMe₃, PPh₃) produces hydride derivatives in which the tridentate ligand is coordinated facially. X-ray analysis of fac cis-[Ir(H)₂(PMe₃)N(SiMe₂CH₂PPh₂)₂] has provided conclusive evidence for this facial stereochemistry. The amine trihydrides fac and mer [Ir(H)₃NH(SiMe₂CH₂PPh₂)₂have been characterized; their formation formally corresponds to a ligand-assisted heterolytic cleavage of dihydrogen. / Science, Faculty of / Chemistry, Department of / Graduate
5

Studies towards the development of novel multidentate ligands /

Magqi, Nceba. January 2007 (has links)
Thesis (M.Sc. (Chemistry)) - Rhodes University, 2007.
6

SYNTHESIS AND COMPARATIVE BIOLOGICAL ACTIVITIES OF CONFORMATIONALLY RESTRICTED ENKEPHALIN ANALOGS.

Hurst, Robin. January 1984 (has links)
No description available.
7

Synthetic models for metalloenzymes containing sulfur, nitrogen and oxygen donors

Spencer, Douglas J. E. January 2000 (has links)
No description available.
8

Redox-active host molecules for anion recognition

Kingston, Justine E. January 1996 (has links)
No description available.
9

Zirconium and lanthanide complexes supported by chelating diamido ligands

O'Connor, Paul Eric. 10 April 2008 (has links)
No description available.
10

The syntheses and reactivity of polydentate PNNP ligands and macrocyclic polyphosphine ligands

Chen, Yang 01 January 1998 (has links)
No description available.

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