Open Access. Powered by Scholars. Published by Universities.®

Physical Sciences and Mathematics Commons

Open Access. Powered by Scholars. Published by Universities.®

2003

Chemistry

PDF

Institution
Keyword
Publication
Publication Type

Articles 481 - 490 of 490

Full-Text Articles in Physical Sciences and Mathematics

Solving Chemical Problems Of Environmental Importance Using Cavity Ring-Down Spectroscopy, Dean B. Atkinson Jan 2003

Solving Chemical Problems Of Environmental Importance Using Cavity Ring-Down Spectroscopy, Dean B. Atkinson

Chemistry Faculty Publications and Presentations

Cavity ring-down (CRD) is a sensitive variant of traditional absorption spectroscopy that has found increasing use in a number of chemical measurement applications. This review focuses on applications of cavity ring-down spectroscopy that will be of interest to environmental chemists and analytical chemists working on environmental problems. The applications are classified into direct monitoring approaches, indirect analysis methods and ancillary studies and a differentiation is made between field-tested instruments and proof of principle studies.


Synthesis And Characterization Of A Polypyridyl Ru(Ii)-Alloxazine Complex For Adsorption On Tio2-Coated Ito Electrodes, Manisha A. Patel Jan 2003

Synthesis And Characterization Of A Polypyridyl Ru(Ii)-Alloxazine Complex For Adsorption On Tio2-Coated Ito Electrodes, Manisha A. Patel

Masters Theses

TiO2-coated conducting glass electrodes can be modified by attachment of redox-active molecules to the TiO2 surface. This thesis describes the synthesis and characterization of a polypyridyl Ru(II) complex that can be covalently bound to a TiO2 surface through the carboxylate groups of 2,2'-bipyridine-4,4' -dicarboxylic acid, H2dcbpy. In addition, the bound complex contains a redox-active alloxazine derivative, pptd, which is capable of 2e-/2H+ transfers. Thus the TiO2-coated electrode is modified with a transition metal complex capable of shuttling H-atoms to substrates in solution. Synthesis of the PF6- salt …


Comparison Between Hydrogen And Dihydrogen Bonds Among H3bnh3, H2bnh2, And Nh3, T. Kar, Steve Scheiner Jan 2003

Comparison Between Hydrogen And Dihydrogen Bonds Among H3bnh3, H2bnh2, And Nh3, T. Kar, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

Several possible binary complexes among ammonia-borane, aminoborane, and ammonia, via hydrogen and/or dihydrogen bonds, have been investigated to understand the effect of different hybridization. Møller–Plesset second-order perturbation theory with aug-cc-pVDZ basis set was used. The interaction energy is corrected for basis set superposition error, and the Morokuma–Kitaura method was employed to decompose the total interaction energy. Like H3BNH3, the sp2 hybridized H2BNH2 also participates in H- and dihydrogen bond formation. However, such bonds are weaker than their sp3 analogs. The contractions of BN bonds are associated with blueshift in …


Approaches To The Synthesis Of Novel Triptycene Dendrimers And Hyperbranched Poly(Phenylene Sulfides) And Poly(Phenylene Sulfones), Alfredo Mellace Jan 2003

Approaches To The Synthesis Of Novel Triptycene Dendrimers And Hyperbranched Poly(Phenylene Sulfides) And Poly(Phenylene Sulfones), Alfredo Mellace

Seton Hall University Dissertations and Theses (ETDs)

.


Investigation Of Model Cell Membrane Disruption Via Fluorescence And Light Scattering Techniques, Imara Charles Jan 2003

Investigation Of Model Cell Membrane Disruption Via Fluorescence And Light Scattering Techniques, Imara Charles

Seton Hall University Dissertations and Theses (ETDs)

.


Chlorobenzenes And Chloronitrobenzenes Interaction With Iron (O), Manuel Alejandro Serratos Jan 2003

Chlorobenzenes And Chloronitrobenzenes Interaction With Iron (O), Manuel Alejandro Serratos

Masters Theses

Degradation of chlorobenzene, dichlorobenzenes and chloronitrobenzenes (ClB, x-Cl2B and x-ClNO2B) was tested by trying to make them react with metallic iron, Fe (0), in water solvent.

The experiments consisted of optimizing the parameters of the reactions (like minimum mass of iron needed) and analytical detection conditions. Analytical techniques used were gas and liquid chromatography (GC and HPLC), mass spectrometry (MS) and UV-Vis spectroscopy.

No substances other than the initial ClB and x-Cl2B were detected in their tests with Fe (0) after shaking for periods of up to three days, although 10%weight average decreases in concentration were observed.

The ClNO2B isomers …


Dmap As A Catalyst For Carbon Acylation: Elucidation Of Mechanistic Pathway, Including Spectral Characterization Of The Putative Reactive Intermediate, Jagadish K. Boppisetti Jan 2003

Dmap As A Catalyst For Carbon Acylation: Elucidation Of Mechanistic Pathway, Including Spectral Characterization Of The Putative Reactive Intermediate, Jagadish K. Boppisetti

Masters Theses

3-Phenylbenzofuranone, when deprotonated with sodium hydride, forms an extended enolate system which, when treated with excess alkyl chloroformates, affords only oxygen-acylated products, as opposed to the usually desired carbon-functionalized derivatives. It was discovered that such molecules, when treated with a catalytic amount of 4- (N, N-dimethylamino)pyridine (DMAP), rearrange quantitatively to the carbon acylated isomers.

These migrations, which are accompanied by a deep blue color, are proposed to involve a reactive intermediate. This intermediate, which is postulated as an ion pair charge transfer (IPCT) complex, has been closely studied in order to gain a better understanding of the …


Bismuth Compounds In Organic Synthesis. Synthesis Of Resorcinarenes Using Bismuth Triflate, Ram S. Mohan, Katherine E. Peterson, Russell C. Smith Dec 2002

Bismuth Compounds In Organic Synthesis. Synthesis Of Resorcinarenes Using Bismuth Triflate, Ram S. Mohan, Katherine E. Peterson, Russell C. Smith

Ram S. Mohan

Bismuth triflate (5 mol%) smoothly catalyzes the condensation of aromatic and aliphatic aldehydes with resorcinol to give tetrameric cyclic products, resorcinarenes. With benzaldehyde, the product is obtained as a mixture of two diastereomers and the ratio of the diastereomers depends on reaction time. On the other hand, a single diastereomer is obtained with aliphatic aldehydes. The low toxicity and ease of handling of bismuth compounds coupled with fast reaction times make this method an attractive alternative to the existing methods for resorcinarene formation


Bismuth Compounds In Organic Synthesis. Deprotection Of Ketoximes Using Bismuth Bromide-Bismuth Triflate, Ram S. Mohan, Joshua N. Arnold, Patrick D. Hayes, Robert L. Kohaus Dec 2002

Bismuth Compounds In Organic Synthesis. Deprotection Of Ketoximes Using Bismuth Bromide-Bismuth Triflate, Ram S. Mohan, Joshua N. Arnold, Patrick D. Hayes, Robert L. Kohaus

Ram S. Mohan

Ketoximes undergo deprotection in CH3CN/acetone/H2O (3:6:1) in the presence of 20–40 mol% BiBr3/5 mol% Bi(OTf)3. Bismuth(III) salts are relatively non-toxic, insensitive to air and inexpensive. These features coupled with the use of a relatively non-toxic solvent system make this method an attractive alternative to existing routes for deprotection of ketoximes.


Reactions Of Boranes And Metallaboranes With Phosphines, Lawrence Barton, Oleg Volkov, Mitsuhiro Hata, Paul Mcquade, Nigam P. Rath Dec 2002

Reactions Of Boranes And Metallaboranes With Phosphines, Lawrence Barton, Oleg Volkov, Mitsuhiro Hata, Paul Mcquade, Nigam P. Rath

Nigam Rath

This paper reports extensions of the well-established field of phosphine–borane chemistry. Linked clusters, for example, {[(PPh3)2(CO)OsB4H7-3-BH2-PPh2]2 [(Fe(C5H4)2]}, are formed in reactions of rigid backboned bidentate phosphines with {2,2,2-(PPh3)2(CO)-nido-2-OsB5H9]. Reaction of bidentate phosphines with the unsaturated clusters [8,8-PPh3)2-nido-8,7-RhSB9H10] and [9,9-(PPh3)2-nido-9,7,8-RhC2B8 H11] leads to the isolation of novel species such as {1-(PPh3)[1,3-(µ-dppm)]-closo -1,2-RhSB9H8},with a dppm molecule bridging adjacent metal and boron vertices in the cage, [1,1-(ç2-dppe)-3-(ç1-dppm)-closo-1,2-RhSB 9H8], a mixed ligand system, and {9,9-ç2-[(ç2-BH3)PPh2PCH2 PPh2]-nido- 9,7,8-RhC2B8H11} which contains a bidentate dppm BH3 moiety. The formation of bidentate phosphine-linked main group transition-metal moieties such as [BH3PPh2(CH)nPPh2IrCp*Cl2] is also described as is an example of …