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Substitution Chemistry of the Cobalt Complexes [Co₂(CO)₆(PhC≡CR) (R=Ph, H) and PhCCo₃(CO)₉] with the Diphosphine Ligands [Bis(diphenylphosphino)maleic Anhydride (BMA) and (Z)-Ph₂PCH=CHPPh₂]. Reversible Chelate-to-Bridge Diphosphine Ligand Exchange, Phosphorus-Carbon Bond Cleavage and Phosphorus-Carbon Bond Formation

Description: The tricobalt cluster PhCCo3(CO)9 (1) reacts with the bidentate phosphine ligand 2,3-bis(diphenylphosphino)maleic anhydride (bma) in the presence of added Me3NO to give the diphosphine-substituted cluster PhCCo3(CO)7(bma) (2). Cluster 2 is unstable in solution, readily losing CO to afford Co3(CO)6[(μ2-η2/η1-C(Ph)C=C(PPh2)C(O)OC(O)](μ2-PPh2) (3) as the sole observed product. VT-31P NMR measurements on cluster 2 indicate that the bma ligand functions as both a chelating and a bridging ligand. At … more
Date: December 1994
Creator: Yang, Kaiyuan
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Substitution Chemistry of Ruthenium Clusters with the Diphosphine Ligands: 4,5-Bis(Diphenylphosphino)-4-Cyclo-Penten-1,3-Dione (bpcd), (Z)-Ph₂PCH=CHPP₂ and 3,4-Bis(Diphenylphosphino)-5-Methoxy-2(5H)-Furanone (bmf)

Description: The chemistry of transition metal clusters has been a fast developing area of organometallic research in recent years. Compared to mononuclear metal complexes, polynuclear clusters offer more opportunities to study cooperative effects and electron reservoir properties between contiguous metal centers, in addition to functioning as storehouses for the release of catalytically active small fragments capable of exhibiting heterosite subtrate activation. Theoretically, metal clusters are intermedia… more
Date: May 1997
Creator: Shen, Huafeng
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Synthesis of Gold Complexes From Diphosphine Ligands and Screening Reactions of Heterocyclic Acetylacetonato (ACAC) Ligands with Transitional Metal Complexes

Description: Syntheses of diphosphine gold (I) complexes from gold THT and two ligands, 4, 5-bis (diphenylphosphino)-4-cyclopenten-1, 3-dione (BPCD) and 2,3-bis(diphenylphosphino)-N-phenylmaleimide (BPPM), were done separately. The reactions happened under ice conditions followed by room temperature conditions and produced two diphosphine gold (I) complexes in moderated yield. Spectroscopic results including nuclear magnetic resonance (NMR) and X-ray crystallography were used to study and determine the str… more
Date: August 2015
Creator: Nyamwihura, Rogers
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries

Diphosphine Ligand Activation Studies with Organotransition-Metal Compounds

Description: Thermolysis of CoRu(CO)7(m -PPh2) (1) in refluxing 1,2-dichloroethane in the presence of the diphosphine ligands 2,3-bis(diphenylphosphino)maleic anhydride (bma) and 4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (bpcd) furnishes the new mixed-metal complexes CoRu(CO)4(μ -P-P)(μ -PPh2) [where P-P = bma (3); bpcd (6)], along with trace amounts of the known complex CoRu(CO)6(PPh3)(μ -PPh2) (4). The requisite pentacarbonyl intermediates CoRu(CO)5(μ -P-P)(μ -PPh2) [where P-P = bma (2); bpcd (5)… more
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Date: December 2000
Creator: Wang, Jiancheng
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Studies of the Mechanisms of Reactions of Binary Metal Carbonyls

Description: A kinetic study of the reactions of Group VI-B hexacarbonyls with primary amine and halide ligands was undertaken in order to determine the possible mechanisms of these reactions. As well as the expected dissociative pathway, the reactions with the primary amines were seen to proceed by a concurrent pathway which was dependent upon the ligand concentration. Since nitrogen donor ligands are expected to be poor donor ligands, the mechanism proposed was a "dissociative interchange" mechanism which… more
Date: May 1977
Creator: Pardue, Jerry E.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Investigation of Copper-Natural Ligand Complexes by RP-HPLC Photodiode Array UV-VIS and Fluorescence Detection

Description: In this study, reversed phase HPLC with dual UV photodiode (PDA) and fluorescence (FL) detection were used to investigate copper complexes with fulvic, caffeic, vanillic, salicylic, and adipic acids. Application of the RE method provided valuable information on the retention behavior and spectral characteristics of FA and model compounds. Even though the method was only applicable to VA, the use of the PDA detector allowed the UV-V is scanning of the separated peaks. This allowed the comparison… more
Date: August 1992
Creator: Liao, Jing-Piin
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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A Reinvestigation of the Kinetics and Mechanism of Ligand Exchange in Mu-(2,2,8,8-Tetramethyl-3, 7-Dithianonane)-Decacarbonylditungsten(0)

Description: This student is interested in reinvestigating the kinetics and mechanism of the bridged compound in l,2-dichloroethane with triisopropyl phosphite and in finding the reasons why the values of competition ratio k₋₂ /k₃ in this reaction are so large.
Date: August 1988
Creator: Liao, Jing-Piin
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Kinetic Study of Ligand Exchange in mu-(2,2,8,8-Tetramethyl-3,7- Dithianonane)-Decacarbonylditungsten(0)

Description: The substitution reaction of (DTN)W2 (CO)10 with P(OCH(CH3 )2 )3 is a stepwise reaction. The kinetics of step 1 follow the equation: -d[substrate] /dt = kld [substrate] + k la [substrate] [ligand]. Thus the mechanism of step 1 is expected to be a competition between dissociative and associative pathways. The kinetics of step 2 follow the equation: -d[(DTN)W(CO)5]/dt = k2dk3[(DTN)W(CO)5][ligand]/k-2[DTN] + k3[ligand] The plot of kobsd versus [ligand] thus is a hyperbolic curve and the plot of 1… more
Date: May 1982
Creator: Yang, Sang-Nin
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Driving Oxygen Coordinated Ligand Exchange at Nanocrystal Surfaces using Trialkylsilylated Chalcogenides

Description: A general, efficient method is demonstrated for exchanging native oxyanionic ligands on inorganic nanocrystals with functional trimethylsilylated (TMS) chalcogenido ligands. In addition, newly synthesized TMS mixed chalcogenides leverage preferential reactivity of TMS-S bonds over TMS-O bonds, enabling efficient transfer of luminescent nanocrystals into aqueous media with retention of their optical properties.
Date: November 11, 2010
Creator: Caldwell, Marissa A.; Albers, Aaron E.; Levy, Seth C.; Pick, Teresa E.; Cohen, Bruce E.; Helms, Brett A. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Kinetics and Mechanisms of Ligand Exchange Reactions of Chelate Complexes

Description: Certain ligand substitution reactions proceed to a complete displacement of the chelate ligand. Certain reactions proceed through a mechanism involving an initial fission of the tungsten-sulfur bond to afford a coordinatively-unsaturated intermediate which is rapidly attacked by chlorobenzene. The resulting solvated intermediate establishes an equilibrium which involves desolvation-solvation. Although main group organometallic chemistry has received a great deal of attention, this discussion wi… more
Date: May 1989
Creator: Cortés, José E. (José Enrique)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Kinetics and Mechanism of Reactions of Disubstituted Octahedral Metal Carbonyls with Phosphorus Donor Ligands and Germanium Tetraiodide

Description: The kinetics and mechanism of the reactions of (tmpa)W-(CO)^ and (tmen)W(CO)^ (tmpa = N,N,N',N'-tetramethy1-1,3-diaminopropane and tmen = N,N,N1,N1-tetramethylethylenediamine) with four phosphorus donor ligands (triisopropyl phosphite, triphenyl phosphite, triphenylphosphine and "constrained phosphite", 4-methyl-2,6,7-trioxa-l-phosphabicylo[2.2.2]octane) in xylene have been investigated in detail. These reactions were found to take place by the ring-opening of the bidentate ligand in a reversib… more
Date: August 1976
Creator: Moradi-Araghi, Ahmad
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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New Proton-Ionizable, Calixarene-Based Ligands for Selective Metal Ion Separations

Description: The project objective was the discovery of new ligands for performing metal ion separations. The research effort entailed the preparation of new metal ion complexing agents and polymers and their evaluation in metal ion separation processes of solvent extraction, synthetic liquid membrane transport, and sorption. Structural variations in acyclic, cyclic, and bicyclic organic ligands were used to probe their influence upon the efficiency and selectivity with which metal ion separations can be pe… more
Date: June 4, 2012
Creator: Bartsch, Richard A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Synthesis and X-ray Diffraction Structures of 2-(2-thienylidene)-4,5-bis-(diphenylphosphino)-4-cyclopenten-1,3-dione and fac-BrRe(CO)3[2-(2-thienylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione]

Description: Treatment of 4,5 bis-(diphenylphosphino)-cyclopenten-1,3 dione with thiophene carboxyaldehyde in dichloromethane, in the presence of molecular sieves results in a new heterocyclic compound, 2-(2-thienylidene)-4,5-bis(diphenylphosphino)-4-cyclopenten-1,3-dione (ligand), with a high yield. This product was characterized by using both IR and NMR spectroscopic techniques and the solid-state structure of the ligand was determined using X-ray crystallography. When the ligand was treated with the solv… more
Date: December 2005
Creator: Pingali, Aparna
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
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Neutron Activation Analysis: Clinical and Biological Studies of Manganese

Description: A strong motivation for metabolic investigations of essential metals lies with the simple fact that these elements are primordial metabolites and building blocks of living matter, a truism largely forgotten today. Among them, the metals of the first transition group display high physical and chemical flexibility: They can concomitantly coordinate natural or artificial ligands; they can regulate electron and proton transport; they can act as catalysts or as cofactors to catalysis.
Date: December 24, 1963
Creator: Cotzias, G. C.; Papavasiliou, P. S. & Miller, S. T.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Final Activity Report: The Effects of Iron Complexing Ligands on the Long Term Ecosystem Response to Iron Enrichment of HNLC waters

Description: Substantial increases in the concentrations of the stronger of two Fe(III) complexing organic ligand classes measured during the mesoscale Fe enrichment studies IronEx II and SOIREE appeared to sharply curtailed Fe availability to diatoms and thus limited the efficiency of carbon sequestration to the deep. Detailed observations during IronEx II (equatorial Pacific Ocean) and SOIREE (Southern Ocean –Pacific sector) indicate that the diatoms began re-experiencing Fe stress even though dissolved F… more
Date: July 30, 2013
Creator: Trick, Charles Gordon
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Electrophilic metal alkyl chemistry in new ligand environments

Description: Cationic group 4 and actinide Cp{sub 2}MR{sup +} metallocenes, and isolobal neutral group 3 and lanthanide Cp{sub 2}MR analogs, are exceptionally reactive in insertion and {sigma}-bond metathesis processes, and have been exploited extensively in catalysis and synthesis, most notably single-site olefin polymerization. The objectives of recent work were to design new electrophilic metal alkyls based on non-Cp{sub 2}M structures, and to exploit these systems in fundamental and applied studies rela… more
Date: September 11, 2002
Creator: Jordan, Richard F.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Influence of Fluorine Substitution on the Properties of Metal Chelate Compounds

Description: From introduction: "This is the first of three articles dealing with the influence of fluorine substitution in the ligand on the properties of metal chelate compounds. Although the primary purpose of this project was to study the influence of fluorine substitution on the properties -- particularly light absorption -- of uranyl compounds, copper chelates were chosen for preliminary study as model substances, because they are easily prepared."
Date: June 9, 1955
Creator: Belford, R. Linn; Martell, Arthur E. & Calvin, Melvin, 1911-1997
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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A Ferrocene-Based Catecholamide Ligand: the Consequences of Ligand Swivel for Directed Supramolecular Self-Assembly

Description: A ferrocene-based biscatecholamide ligand was prepared and investigated for the formation of metal-ligand supramolecular assemblies with different metals. Reaction with Ge(IV) resulted in the formation of a variety of Ge{sub n}L{sub m} coordination complexes, including [Ge{sub 2}L{sub 3}]{sup 4-} and [Ge{sub 2}L{sub 2}({mu}-OMe){sub 2}]{sup 2-}. The ligand's ability to swivel about the ferrocenyl linker and adopt different conformations accounts for formation of many different Ge{sub n}L{sub m}… more
Date: February 4, 2010
Creator: Mugridge, Jeffrey; Fiedler, Dorothea & Raymond, Kenneth
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Hydrogen-Deuerium Exchange between TpRu(PMe3)(L)X (L = PMe3 and X = OH, OPh, Me, Ph, or NHPh; L = NCMe and X = Ph) and Deuterated Arene Solvents: Evidence for Metal-Mediated Processes

Description: This article discusses evidence for metal-mediated processes.
Date: May 24, 2006
Creator: Feng, Yuee; Lail, Marty; Foley, Nicholas A.; Gunnoe, T. Brent; Barakat, Khaldoon A.; Cundari, Thomas R., 1964- et al.
Item Type: Refine your search to only Article
Partner: UNT College of Arts and Sciences
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Synthetic Approaches to (smif)₂Ti (smif=1,3-di-(2-pyridyl)-2-azaallyl) Reveal Redox Non-Innocence and C-C Bond-Formation

Description: Article discussing synthetic approaches to (smif)₂Ti(smif=1,3-di-(2-pyridyl)-2-azallyl) revealing redox non-innocence and C-C bond-formation.
Date: July 25, 2012
Creator: Frazier, Brenda A.; Wolczanski, Peter T.; Keresztes, Ivan; DeBeer, Serena 1973-; Lobkovsky, Emil B.; Pierpont, Aaron W. et al.
Item Type: Refine your search to only Article
Partner: UNT College of Arts and Sciences
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A Priori Assessment of the Stereoelectronic Profile of Phosphines and Phosphites

Description: This article discusses research that has demonstrated the utility of a rigorously calibrated, molecular mechanics/semiempirical quantum mechanical protocol for developing stereoelectronic (Tolman) maps for phosphine ligands.
Date: March 15, 2003
Creator: Cooney, Katharine D.; Cundari, Thomas R., 1964-; Hoffman, Norris W.; Pittard, Karl A.; Temple, M. Danielle & Zhao, Yong
Item Type: Refine your search to only Article
Partner: UNT College of Arts and Sciences
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