Student Works
Permanent URI for this community
Research papers, presentations, projects, and other works by students at Virginia Tech. For dissertations, masters theses, and undergraduate theses, please see the Virginia Tech Electronic Theses & Dissertations (ETD) collection. Additionally, some student works are in Honors College collections.
Browse
Browsing Student Works by Department "Chemistry"
Now showing 1 - 11 of 11
Results Per Page
Sort Options
- The chemistry and use of pyrroline ring systems in the synthesis of natural productsPersichini, Phillip John (Virginia Tech, 1994)
- Controlled patterning of self-assembled monolayer filmsSporakowski, Laura (Virginia Tech, 1993)This paper is a critical review of three current methods used in patterning self-assembled monolayer films. It begins with an introduction to monolayer films and their potential uses. This is followed by a discussion of self-assembly and the various experimental methods used to form monolayer films. The discussion focuses mainly on silanes as the compounds used to form the films, but it also includes thiols and carboxylic acids. The mechanism for self-assembly is reviewed too. Various characterization techniques are presented next. Wettability, ellipsometry, XPS, UV-vis spectroscopy, IR spectroscopy, Raman spectroscopy, SIMS, STM, and AFM are all presented and their applications to thin film characterization are mentioned. Following the characterization techniques is a section on patterning. The three methods analyzed include patterning procedures by Kleinfeld and co-workers, Wrighton and Whitesides and co-workers, and Calvert and co-workers. It is concluded that the method by Kleinfeld and co-workers requires too many steps and too much time; the method by Wrighton and Whitesides and co-workers does not produce in-plane patterns but rather stepped ones; and the method by Calvert and coworkers requires expensive equipment not readily available to all laboratories. In addition, none of these three patterning methods can create features any smaller than in the micrometer range. Three more recent patterning methods by Wrighton and Whitesides are presented next. They are micromachining, microwriting, and "rubber stamping" and they are capable of producing pattern features in the hundreds of nanometers range. This is an improvement but it is still not the ideal of being able to pattern molecule by molecule. Suggestions for future research follow the analysis of the patterning methods.
- The development of laboratory sessions for a introductory course in nuclear magnetic resonance spectroscopyIannaccone, Gennaro A. (Virginia Tech, 1991-11-05)The history and philosophy underlying the design of the experimental component of an intensive introductory course in Nuclear Magnetic Resonance Spectroscopy (NMR) is presented. The concept of a "hands on" experience is used to transform the complete NMR novice into a competent operator. In addition to exposing the student to classical elucidation tools, advanced techniques, such as two dimensional and solid state NMR, are introduced. Through the use of unknowns, participants are encouraged to develop practical problem solving strategies. The detailed contents of the twenty-six experiments developed for the laboratory sessions are reviewed. The five day course schedule, and a coversheet, containing pertinent references for each experiment, is included. An examination of the unknowns utilized in the course, and a glossary of NMR terms is also presented.
- Nitrocellulose literature review characterization and application to modern gun propellantsWorrell, William J. (Virginia Tech, 1990)Clearly, nitrocellulose characterization is a difficult task. However, previous investigators have developed the required methodology for application to new studies. Solution properties of nitrocellulose are especially complex, depending on solvent properties, temperature, nitrocellulose molecular weight characteristics and nitrocellulose DOS homogeneity. The realization of the time dependance of these properties has added to the complexity. Mechanical characterization of nitrocellulose propellants appears to be an emerging technology. The morphological intricacy of nitrocellulose propellants in addition to the chemical complexity of nitrocellulose has hampered direct correlation of the polymeric properties of nitrocellulose wi th propellant mechanical behavior and subsequently ballistic performance.
- Noble Metal Organometallic Complexes Display Antiviral Activity against SARS-CoV-2Chuong, Christina; DuChane, Christine M.; Webb, Emily M.; Rai, Pallavi; Marano, Jeffrey M.; Bernier, Chad M.; Merola, Joseph S.; Weger-Lucarelli, James (MDPI, 2021-05-25)SARS-CoV-2 emerged in 2019 as a devastating viral pathogen with no available preventative or treatment to control what led to the current global pandemic. The continued spread of the virus and increasing death toll necessitate the development of effective antiviral treatments to combat this virus. To this end, we evaluated a new class of organometallic complexes as potential antivirals. Our findings demonstrate that two pentamethylcyclopentadienyl (Cp*) rhodium piano stool complexes, Cp*Rh(1,3-dicyclohexylimidazol-2-ylidene)Cl2 (complex 2) and Cp*Rh(dipivaloylmethanato)Cl (complex 4), have direct virucidal activity against SARS-CoV-2. Subsequent in vitro testing suggests that complex 4 is the more stable and effective complex and demonstrates that both 2 and 4 have low toxicity in Vero E6 and Calu-3 cells. The results presented here highlight the potential application of organometallic complexes as antivirals and support further investigation into their activity.
- Some factors affecting performance in general chemistrySrinivasan, Gita (Virginia Tech, 1993)The importance of a good education is for students to develop a love of learning and to try to get them to pursue higher goals. To educate the students and to drag them up to a certain minimal level of achievement is not an insignificant task³⁹ The process has to start at the high school level if not earlier. Many high schools other than the 'schools for the gifted' suffer from lack of sufficiently qualified teachers and/or facilities and other equipment due to lack of finances. Moreover, not enough students are exposed to the sciences at the high school due to various levels of tracking. There are not sufficient staff development programs to encourage teachers to improve their competency. Many students consider the sciences and especially chemistry, boring and difficult to comprehend. Many students due to lack of facilities are not given the chance to work in the laboratories to learn the subject matter. There is no coordination between high school teachers and college professors. This country also does not have a national curriculum with the result that students enter college with widely differing abilities. There are commercialized institutions who have admission standards which depend on the students ability to pay rather than student potential thereby lowering the standards of higher education in this country. This eventually poses a problem for the industries who have to deal with mediocre workers who have insufficient knowledge about their subject matter. Due to insufficient preparation at the pre-college level, many of these students do not understand the material and need remediation programs. It is necessary to have sufficient faculty members who are dedicated to improving the quality of education and who find satisfaction in doing so. Unfortunately some of the major causes of faculty resentment are undercompensation compared with their colleagues in industry and their students apparent lack of interest and unwillingness to learn the subject matter. It is necessary for every department to maintain its standards and present a united front in spite of complaints from poor performers and hence should not admit any student into a course for which he/she is not qualified³⁹. For the students to come in with the right attitude and a desire to perform well, it is necessary to put pressure on the students to do well. From the survey conducted at Virginia Tech, it is evident that student performance is much more strongly influenced by their prior experiences rather than their experiences at college. It is also evident that there is a correlation between attendance and grades and that those students who have a desire to perform well and come to class regularly do get good grades. Class size was not considered to be a major problem though it was indicated that they wanted to be forced to study hard. Motivated students found help sessions to be useful. In addition to the many changes which are needed to combat the above stated problems it is also necessary to ensure that students accept responsibility for learning and approach it with the right attitude and spirit and put in serious effort in what they do so that they may be productive members of this society.
- Stereochemical Control of Polyketides through Asymmetric Aldol ReactionLou, Samuel (Virginia Tech, 2000-04-29)Polyketides are a group of complex natural products that can inhibit the growth of bacteria, viruses, fungi, and tumor cells. Most polyketides are very difficult to extract from bacteria. Therefore, numerous syntheses of polyketide-related synthons have been attempted. However, controlling the stereochemistry of the polyketide poses the most challenging task for researchers. The aim of this report is to discuss control of the stereochemistry of the polyketide-related synthons in asymmetric aldol reactions. Several important methodologies for stereochemical control in the aldol reaction exist. The first approach is to control the enolate geometry and the aldehyde (or ketone) geometry. The second approach is to use a chiral auxiliary and chiral ligands. The third approach is to use a chiral catalyst, which is the most efficient method if the catalyst operates with complete efficiency. Proposed transition states are also described to explain the resulting stereochemistry of the aldol adduct.
- A study of the effect of changes of procedure in a standard sulfate determinationBragg, Arthur Dane (Virginia Polytechnic Institute, 1952-06-05)The work done by the author indicates that when %s is determined by gravimetric methods as indicated the volume and concentration of reagents used is very important. It appears that an excess of KBr solution will cause results to be high. An excess of acid in the precipitating solution will cause results to be low.
- Synthesis and characterization of poly(oxazoline) rotaxanes and literature review on separation, detection and identification of cyclic oligomers in poly(ethylene terephthalate) and poly(ε-caprolactam)Lim, Christina Go (Virginia Tech, 1991-07-02)Several methods have been developed to determine the cyclic oligomer content in PET. Isolation procedures can be classified as those involving extraction, such as with solvents like chloroform, dioxane, and xylene, and those involving dissolution followed by precipitation in solvents like dimethylformamide and 1-methylnaphthalene. The amount of cyclic oligomer obtained is largely dependent upon the method used, as well as the type, drawing, and thermal history of the PET used.Various methods for separation of cyclic oligomers have also been developed using GPC and thin-layer chromatography.
- A synthesis of 3-acetyl-6-methoxybenzaldehyde utilizing the Fries reactionDuffey, Donald Creagh (Virginia Polytechnic Institute, 1953)Introduction: In the yea.rs since World War II there has been an increasing number of attempts to produce various types of effective herbicides, and as a result of the extensive time and labor required for random testing of synthetic compounds, the search for selective plant-killers has turned toward naturally occurring substances...
- Transition metals as anti-tumoral agents: some structure-function relationships of the platinum group metalsFlynn, Allison (Virginia Tech, 1994-06-05)
Since the discovery that cis-diamminedichloroplatinum (II) possessed great antitumor properties, researchers have been synthesizing and screening metal coordination complexes for their potential anti-tumor activity. Hundreds of compounds have been tested, and few compounds possessed anti-tumor activity. This paper examines how the physical and chemical properties of complexes of the platinum group metals affect their toxicity and anti-tumor activity.