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in subjects: "Ligands"

open access

NRPreTo: A Machine Learning-Based Nuclear Receptor and Subfamily Prediction Tool

Article asserts that the nuclear receptor (NR) superfamily includes phylogenetically related ligand-activated proteins, which play a key role in various cellular activities. The authors developed Nuclear Receptor Prediction Tool (NRPreTo), a two-level NR prediction tool with a unique training approach where in addition to the sequence-based features used by existing NR prediction tools, six additional feature groups depicting various physiochemical, structural, and evolutionary features of prot… more

Date: May 30, 2023

Creator: Madugula, Sita Sirisha; Pandey, Suman; Amalapurapu, Shreya & Bozdag, Serdar

Item Type: Article

Partner: UNT College of Engineering

open access

Neutron Activation Analysis: Clinical and Biological Studies of Manganese

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: Report

Partner: UNT Libraries Government Documents Department

open access

Oxygen atom transfer catalysis by dioxidomolybdenum(VI) complexes of pyridyl aminophenolate ligands

This article synthesizes and characterizes a series of new cationic dioxidomolybdenum(VI) complexes [MoO₂(Lⁿ)]PF₆ (2–5) with the tripodal tetradentate pyridyl aminophenolate ligands HL²-HL⁵.

Date: April 21, 2021

Creator: Hossain, Kamal; Schachner, Jörg A.; Haukka, Matti; Richmond, Michael G.; Mösch-Zanetti, Nadia C.; Lehtonen, Ari et al.

Item Type: Article

Partner: UNT College of Science

open access

Actinide tetra-N-heterocyclic carbene ‘sandwiches’

Article preparing highly-symmetrical, thorium and uranium octakis-carbene ‘sandwich’ complexes by ‘sandwiching’ the An(IV) cations between two anionic macrocyclic tetra-NHC ligands. The complexes are characterized by a range of experimental methods and DFT calculations.

Date: May 10, 2021

Creator: DeJesus, Joseph F.; Kerr, Ryan W. F.; Penchoff, Deborah A.; Carroll, Xian B.; Peterson, Charles C.; Arnold, Polly L. et al.

Item Type: Article

Partner: University of North Texas

open access

Radiation Laboratory, University of Notre Dame. Quarterly report, April 1, 1977--June 30, 1977. [One paragraph summaries of various investigations]

Investigations in progress include: ionization potentials of H/sub 2/O from molecular orbital and valence bond wavefunctions; early events in pulse-irradiated polar liquids; epithermal trapping of electrons; range of photoionized electrons in high-mobility liquids using field-dependent mobility; scattering of exciton by the impurity; model molecular orbital studies of the chemisorption of atomic hydrogen and oxygen on aluminium surfaces; laser induced fluorescence and the geometry of the excite… more

Date: July 13, 1977

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Binding of carbon dioxide to metal macrocycles: Toward a mechanistic understanding of electrochemical and photochemical carbon dioxide reduction

Efforts were made to find effective catalysts for photochemical and electrochemical reduction of CO[sub 2]. We are studying the factors controlling excited-state lifetimes, electron-transfer rates to mediators/catalysts, properties of reduced mediators, binding of small molecules to reduced mediators, and reactivity of the mediators to yield the desired products. This document describes some of the results of binding on CO[sub 2] to metal macrocycles. The electrocatalytic activity of cobalt mac… more

Date: January 1, 1993

Creator: Fujita, E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Studies of fundamental properties of rutherfordium (Element 104) using organic complexing agents

Chemical properties of rutherfordium (Rf) have been investigated with the organic ligands triisooctylamine (TIOA), tributylphosphate (TBP), and thenoyltrifluoroacetone (TTA). The TIOA studies showed that Rf behaves differently than Th and Eu and most similarly to Zr, only Zr and Rf extract from 12 M HCI. This result is further evidence that Rf is a Group 4 element. Studies with TBP showed that Rf chemical behavior differed from the other Group 4 elements. The extraction by TBP at different chlo… more

Date: April 1, 1992

Creator: Czerwinski, K. R.

Item Type: Thesis or Dissertation

Partner: UNT Libraries Government Documents Department

open access

[Laser flash photolysis, EPR and Raman studies of liquids at elevated pressures]

The proposed research will solve a number of analytical chemical problems in solutions with measurement techniques that benefit from the use of elevated hydrostatic pressures: stopped-flow spectrophotometry (Gd[sup 3+] + L(ligand), [RuL[sub 5]H[sub 2]O][sup 2+], laser flash photolysis of Mo(CO)[sub 6] + L, flash photolysis of binuclear metalloproteins), EPR spectroscopy (Gd[sup 3+] ion-exchanged into ETS-10 and ETAS-10 molecular sieves), laser flash photolysis kinetic studies of Mo(CO)[sub 6]-2… more

Date: January 1, 1992

Creator: Eyring, E. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Reaction of Tris(cyclopentadienyl)uranium compounds with amines, azides, and related ligands

The trivalent uranium compound, (MeC{sub 5}H{sub 4}){sub 3}U(thf), serves as a one- or two-electron reducing agent towards azides, RN{sub 3}. These reactions produce either the uranium(IV) azide, (MeC{sub 5}H{sub 4}){sub 3}UN{sub 3}, or uranium(V) imides, (MeC{sub 5}H{sub 4}){sub 3}UNR. The role of steric and electronic effects upon this reaction has been investigated using several series of azides. For Me{sub 3}XN{sub 3}, the imides are produced when X = C or Si, both products are formed when … more

Date: December 1, 1989

Creator: Rosen, Robert Keith

Item Type: Thesis or Dissertation

Partner: UNT Libraries Government Documents Department

open access

sup 31 P NMR analysis of coal moieties bearing -OH, -NH, and -SH functions

NMR reagents for the speciation and quantitation of labile-hydrogen functional groups and sulfur groups in coal ligands have been synthesized and evaluated. These reagents, which contain the NMR-active nuclei {sup 31}p, {sup 119}Sn or {sup 195}pt, were designed to possess improved chemical shift resolution over reagents reported in the literature. Our efforts were successful in the case of the new {sup 31}p and {sup 119}Sn reagents we developed, but the {sup 195}pt work on sulfur groups was onl… more

Date: August 31, 1991

Creator: Verkade, J. G.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Radon: Chemical and physical processes associated with its distribution

Assessing the mechanisms which govern the distribution, fate, and pathways of entry into biological systems, as well as the ultimate hazards associated with the radon progeny and their secondary reaction products, depends on knowledge of their chemistry. Our studies are directed toward developing fundamental information which will provide a basis for modeling studies that are requisite in obtaining a complete picture of growth, attachment to aerosols, and transport to the bioreceptor and ultima… more

Date: January 1, 1992

Creator: Castleman, A. W., Jr.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Ab initio studies of transition-metal dihydrogen chemistry

Examples of transition metal complexes containing dihydrogen ligands are investigated using ab initio electronic structure calculations employing effective core potentials. Calculated geometrical structures and relative energies of various forms of WL/sub 5/(H/sub 2/) complexes (L = CO, PR/sub 3/) are reported, and the influence of the ligand on the relative stabilities of the dihydrogen and dihydride forms is studied. The possible intramolecular mechanisms for H/D scrambling are investigated i… more

Date: January 1, 1988

Creator: Kober, E. M. & Hay, P. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

01-ERD-111 - The Development of Synthetic High Affinity Ligands

The aim of this project was to develop Synthetic High-Affinity Ligands (SHALs), which bind with high affinity and specificity to proteins of interest for national security and cancer therapy applications. The aim of producing synthetic ligands for sensory devices as an alternative to antibody-based detection assays and therapeutic agents is to overcome the drawbacks associated with antibody-based in next-generation sensors and systems. The focus area of the project was the chemical synthesis of… more

Date: February 5, 2004

Creator: Perkins, J; Balhorn, R; Cosman, M; Lightstone, F & Zeller, L

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Effective crystal fields in the rare earth pnictides

Various contributions to the effective 4f electron crystal fields in the rare earth pnictides are estimated and compared. These include the direct interaction with the ligand electrostatic field and effects associated with the 5d band electrons.

Date: July 1, 1976

Creator: Herbst, J. F.; Bak, P. & Watson, R. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Silver(I) and Copper(I) Complexes from Homoleptic to Heteroleptic: Synthesis, Structure and Characterization

A plethora of novel scientific phenomena and practical applications, such as solid-state molecular solar cells and other optoelectronic devices for energy harvesting and lighting technologies, have catalyzed us to synthesize novel compounds with tunable properties. Synthetic routes, single crystal structures, and spectral and materials properties are described. Reactions of Ag(I) and Cu(I) precursors with various types of ligands -- including the azolates, diimines, and diiphosphines -- lead to… more

Date: December 2018

Creator: Almotawa, Ruaa Mohammed

Item Type: Thesis or Dissertation

Partner: UNT Libraries

open access

Polymer-based separations: Synthesis and application of polymers for ionic and molecular recognition. Triennial performance report, August 1, 1989--July 31, 1992

Polymer-based separations have utilized resins such as sulfonic, acrylic, and iminodiacetic acid resins and the XAD series. Selective polymeric reagents for reaction with a targeted metal ion were synthesized as polymers with two different types of functional groups, each operating on the ions through a different mechanism. There are 3 classes of DMBPs (dual mechanism bifunctional polymers). Research during this period dealing with metal ion recognition focused on two of these classes (reductio… more

Date: January 1, 1992

Creator: Alexandratos, S. D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Architectural Design Criteria for f- Block Metal Ion Sequestering Agents--Final Report

The objective of this project is to facilitate the ligand development process for f-block metal ions, i.e., the actinides and lanthanides, by developing an accurate set of criteria for the design of ligand architectures. To achieve this objective we first combine theory and experiment to understand the nature of fundamental interactions in selected metal-ligand systems. These design criteria provide a basis for proposing improved Ligand architectures. We then incorporate this understanding with… more

Date: June 15, 2000

Creator: Hay, Benjamin P.; Dixon, David A.; Lumetta, Gregg J.; Rapko, Brian M.; Roundhill, David M.; Rogers, R D. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

A Frontier Molecular Orbital determination of the active sites on dispersed metal catalysts

An angular overlap calculation has been used to determine the s, p and d orbital energy levels of the different types of surface sites present on a dispersed metal catalysts. The basis for these calculations is the reported finding that a large number of catalyzed reactions take place on single atom active sites on the metal surface. Thus, these sites can be considered as surface complexes made up of the central active atom surrounded by near-neighbor metal atom ``ligands`` with localized surfa… more

Date: November 1, 1992

Creator: Augustine, R. L. & Lahanas, K. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

[Bifunctional chelates of Rh-105, Au-199, and other metallic radionuclides as potential radiotherapeutic agents]

Progress during this period is reported under the following headings: Diethylenetriamine based and related bifunctional chelating agents and their complexation with Rh-105, Au-198, Pd-109, cu-67, In-111, and Co-57; studies of Pd-109, Rh-105 and Tc-99m with bifunctional chelates based on phenylenediamine; establishment of an appropriate protein assay method for conjugated proteins; studies of new bifunctional Bi, Tri and tetradentate amine oxime ligands with Rh-105; IgG and antibody B72.3 conjug… more

Date: December 31, 1991

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

[Electron transfer activation of thiophene]. Progress report

This report is divided into: reduction of coordinated thiophenes,protonation of reduced thiophene complexes, bimetallic thiophene desulfurization, thermal decomposition of {eta}{sup 4}-thiophene complexes, metal ion-promoted hydrolysis of thiophenes, thermal fragmentation of hydrolyzed thiophene ligands, and organic chemistry of hydrolyzed thiophene ligands.

Date: September 1, 1993

Creator: Rauchfuss, T. B.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Organometallic chemistry of bimetallic compounds. [Annual report]

Hydrogenation of alkynes by the heterobimetallic compound C{sub 5}H{sub 5}(CO){sub 2}Re({mu}-H)Pt(H)(PPh{sub 3}){sub 2} is being studied. The compound C{sub 5}Me{sub 5}(CO){sub 2}Re{double_bond}Re(CO){sub 2}C{sub 5}Me{sub 5} was synthesized; its chemistry is being studied. Compounds discovered in a reinvestigation of a spurious report of (C{sub 5}Me{sub 5})Co{double_bond}Co(C{sub 5}Me{sub 5}), are being studied. The deuterioformylation of alkenes using wide bite angle phosphines will be studied. more

Date: July 1, 1992

Creator: Casey, C. P.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

[Laser flash photolysis, EPR and Raman studies of liquids at elevated pressures]

The proposed research will solve a number of analytical chemical problems in solutions with measurement techniques that benefit from the use of elevated hydrostatic pressures: stopped-flow spectrophotometry (Gd{sup 3+} + L(ligand), [RuL{sub 5}H{sub 2}O]{sup 2+}, laser flash photolysis of Mo(CO){sub 6} + L, flash photolysis of binuclear metalloproteins), EPR spectroscopy (Gd{sup 3+} ion-exchanged into ETS-10 and ETAS-10 molecular sieves), laser flash photolysis kinetic studies of Mo(CO){sub 6}-2… more

Date: October 1, 1992

Creator: Eyring, E. M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Catalytic hydrogenation of carbon monoxide. Technical research progress report, December 15, 1992--December 14, 1993

Focus of this project is on developing new approaches for hydrogenation of carbon monoxide to produce organic oxygenates at mild conditions. The strategies to accomplish CO reduction are based on favorable thermodynamics manifested by rhodium macrocycles for producing a series of intermediates implicated in the catalytic hydrogenation of CO. Metalloformyl complexes from reactions of H{sub 2} and CO, and CO reductive coupling to form metallo {alpha}-diketone species provide alternate routes to o… more

Date: December 1, 1993

Creator: Wayland, B. B.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Highly nucleophilic acetylide, vinyl, and vinylidene complexes. Progress report

The research was divided into the following: studies of nucleophilic and chiral acetylide complex [Cp(CO)(PPh{sub 3})Mn-C{triple_bond}CR]{sup {minus}}; nucleophilic addition of carbene anions to organic ligands on electrophilic complexes; halide-promoted carbonylation of imido ligands; binuclear Fe{sub 2} complexes with bridging organonitrogen ligands; addition and cycloaddition reactions of carbyne complex [Cp(CO){sub 2}Re{triple_bond}CTol]{sup +}; addition and cycloaddition reactions of methy… more

Date: June 15, 1992

Item Type: Report

Partner: UNT Libraries Government Documents Department