Experimental Chemistry II, CH 463 & 463H Poster Abstracts for 2007
Department of Chemistry Oregon State University
June 7, 2007 1:30 3:30
Gilbert Addition 313
1-2007. ROOM TEMPERATURE VS. 77K PHOSPHORESCENCE OF 4-BROMO-4'-FLUOROBENZOPHENONE Sarah K. Furrer, Oregon State University, Department of Chemistry, Oregon, 97331.
Comparable results were obtained of the phosphorescence for a room temperature 6.52mM "quantum dot" PMMA composite and a 6.66 mM EPA glass (at 77 K) of 4-bromo-4-fluorobenzophenone. The npi* max for emission was 439 nm in both cases, where the excitation npi* max for the room temperature sample was 377 nm and at 77 K it was at 330 nm. The emission lifetimes were 1.50E-04 s and 7.00E-04 s in the PMMA sample and 6.11E-04 s for the 77 K glass sample. For both samples the oscillator strength of the npi* emission was weakly forbidden for the benzophenone.
2-2007. QUANTITATIVE UV PHOTOCHEMISTRY OF 4-CHLORO-4-FLUOROBENZOPHENONE J. C. Albus, Department of Chemistry, Oregon State University, Oregon 97331
4-chloro-4-fluorobenzophenone is a compound veiled in mystery. Very little data has been compiled to characterize it in anyway; thus, it will be interesting to characterize its photophysics. A UV spectrometer and a phosphorescence spectrometer will be used to determine the lifetime and IAC value, which then can be used to fill in a variety of photophysical parameters on a Jablonski diagram for the npi* and pipi* transitions. The values will be compared to the lifetime and oscillator strength calculated using HyperChem and Gaussian. From the measurements already taken, 4-chloro-4-benzophenone has 5 discernable energy levels for the pipi* and a very short lifetime for the phosphorescence.
3-2007. PHOTOPHYSICAL DIFFERENCES OF 4-IODOBENZOPHENONE IN DIFFERENT SOLVENTS. M.A. Jones, Department of Chemistry, Oregon State University , Corvallis , Oregon 97330
Solutions with 4-iodobenzophenone were used to study the UV absorbance of the ketone. The more polar solvent, EPA, causes a blue shift in UV absorption spectra for the npi* transition (S0-S1). This increase in energy is due to the interaction of the polar protic solvent EPA with the nonbonding lone pair of electrons on the carbonyl in the ketone.
4-2007. EFFECTS OF SOLVENT PROPERTIES ON PHOTOPHYSICAL PARAMETERS OF UV INDUCED TRANSITIONS IN 4-CHLORO-4-ETHOXYBENZOPHENONE. Kaleb I. Jentzsch Oregon State University Chemistry Dept. Corvallis, OR. 97331.
The photophysical parameters for UV induced electronic transitions have been experimentally calculated for 4-chloro-4-ethoxybenzophenone in both a polar and a non-polar solvent based on measured UV absorbance and phosphorescence. The n-pi* transitions corresponding to S0 to S1 and T1 to S0 display calculated photophysical parameters that give supporting evidence for the stabilization of the molecule in the more polar solvent. Specifically, as compared to the methylcyclohexane the EPA solution exhibits a stronger molar absorptivity, a higher energy lambda max, a shorter transition lifetime, and an oscillator strength closer to one.
5-2007. PHOSPHORESCENCE OF 4-CHLORO-4-ETHYLBENZOPHENONE IN EPA AND METHYLCYCLOHEXANE. B.L. Anderson, Department of Chemistry, Oregon State University, Corvallis, 97331
4-chloro-4-ethylbenzophenone shows a blue shift between the solvents EPA and methylcyclohexane. The methylcyclohexane shows the vibrational modes inside the electronic envelope and has a lifetime of 7 ms. The molecule in EPA has a T1 lifetime of 5 ms and S1 shows less fine structure at room temperature. Jablonski diagrams will be presented for both solvents. The npi* transition was fitted with the carbonyl transition progression of 1350 cm-1 for methylcyclohexane and 1400 cm -1 for EPA.
6-2007. SYNTHESIS OF TETRAHYDROPYRAN-2,3-DIOL FOR STUDIES ON RHENIUM CATALYSIS OF CARBOHYDRATES. Brian Knight, Dr. Gables Research Group, Department of Chemistry, Oregon State University-Corvallis, Oregon 97330.
Tetrahydro-2,3-diol was synthesized. Its structural similarities to carbohydrates make it the simplest molecule for understanding the affects of the heterocyclic oxygen on rhenium catalysis of a vicinal diol as it relates to a carbohydrates. The tetrahydropyran-2,3-diol has a cis-trans and ring opening equilibria as well as an equilibrium with its dimer form, all of which cause structural determinism by spectroscopy to be difficult. The diol was determined by C-13 NMR spectroscopy.
7-2007. SYNTHESIS OF 4-BROMO-4-CHLOROBENZOPHENONE BY FRIEDEL-CRAFTS ACYLATION. Marcus A. Chiodo, Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-4501.
Benzophenones are relatively safe compounds that have potential applications in polymers and as UV absorbers. I specifically investigated the synthesis of 4-bromo-4-chlorobenzophenone. This was done by using a Friedel-Crafts Acylation process analogous to Leslie G. Groves and Eustace E. Turners 1929 procedures. A total of 7.7514 g (0.0262 mol) of product was recovered, corresponding to a 10.95% yield.
8-2007. PROPELLANE: AN UNUSUAL MOLECULE. Narumol Jariyasopit; Dr.Joseph Nibler; Department of Chemistry, Oregon State University, Corvallis, Oregon 97331.
The structure, bond lengths and electron density of propellane were studied using Gaussian. The question examined centers on the axial bond for which the carbon-carbon separation is similar to that of a normal carbon-carbon single bond. However, this bonding arrangement places all four carbon-carbon bonds of the axial carbons on one side. The result of ab initio calculation to examine the nature of the axial carbon-carbon bond will be described.
9-2007. QUANTITATIVE PHOTOCHEMICAL REDUCTION OF 4-METHYLBENZOPHENONE TO A BENZOPINACOL. Mallory S. McAfee, Department of Chemistry, Oregon State University, Oregon, 97331.
4-methylbenzophenone was irradiated for differing amounts of time in a photoreactor to determine the quantum efficiency of the photochemical reaction to the benzopinacol. Formation of the benzopinacol occurs as excited S1 electrons rapidly intersystem cross into the excited T1 vibration state. This excited state reacts with solvent to produce ketyl free radicals. Using IR spectrometry the concentrations of benzophenone remaining was measured by comparison to four standards. It was determined that as irradiation time increased so did the amount of benzophenone reacted. Quantum efficiency for this reaction is 1.92. Therefore the reaction occurs due to interactions with photons and side reactions between the solvent dimethylketyl radicals and the benzophenone.
10-2007. SYNTHESIS AND CHARACTERIZATION OF 4-CHLORO-4'-METHYLBENZOPHENONE. Brian Theobald, Department of Chemistry, Oregon State University, Corvallis, OR 97331.
4-chloro-4'-methylbenzophenone was synthesized using toluene and 4-chlorobenzoyl chloride and AlCl3 as the catalyst by the Friedel-Crafts acylation method. Characterizations of the final purified product included IR, 1H-NMR, 13C-NMR and melting point. To further characterize the product a COSY-NMR and HSQC-NMR were also carried out and will be presented.
11-2007. EFFECT OF POLARITY OF SOLVENTS ON 4-BROMO-4'-METHYLBENZOPHENONE. Laura S. Christ, Department of Chemistry, Oregon State University-Corvallis, Oregon 97331
A solvent study was done on 4-bromo-4-methylbenzophenone. Solutions in EPA (polar) and methylcyclohexane (nonpolar) were prepared from solid 4-bromo-4-methylbenzophenone. The two solutions were analyzed and compared using UV spectroscopy and low temperature emission-excitation spectrophotometry. The polarity of the solvent has an effect on the number of transitions observed and how likely they are to be allowed, as more energy-level transitions were observed and the transitions were more highly allowed in the polar solvent. The photophysical parameters for the npi* carbonyl transition, from S0 to S1, are found to be very similar in the two solvents.
12-2007 PHOTOREDUCTION QUANTUM EFFICIENCY OF 4-CHOROBENZOPHENONE. D.P. Dunatchik, Department of Chemistry, Oregon State University, Oregon 97331
When exposed to U.V. radiation 4-chlorobenzophenone undergoes a photochemical reduction to form the pinacol. It is possible to monitor the progress of this reduction by IR spectroscopy. As the reduction progresses the carbonyl peak corresponding to the ketone of 4-chlorobenzophenone gets smaller resulting from the conversion of the ketone to the pinacol. Monitoring the conversion of the ketone during a known time of UV radiation and comparing this to known standard concentrations the photoreduction quantum efficiency can be determined.
13-2007. SOLVENT STUDY OF 4,4-DICHLOROBENZOPHENONE IN POLAR ETHANOL VS. NONPOLAR METHYLCYCLOHEXANE. Tyler J Steinke, Oregon State University 973301.
The polarity of ethanol gives the pipi* S0 to S2 oscillator strength a high number of 0.523, compared to the non-polar methylcyclohexane for the same transition at 0.385. Ethanols polarity also affects the n pi* free electron transfer due to the hydrogen bonding that can occur with the nonbonding electrons from the carbonyl shortening lambda max. This shortening makes the transition higher in energy and ultimately making the energy barrier for this forbidden state greater than it would be in the non-polar solvent; ethanol had a lambda max of 333 nm while the methylcyclohexane had a max of 347 nm. To further support the effects of solvent on the absorbance and photophysical properties of the 4,4-dichlorobenzophenone the short lifetime in ethanol vs. a longer one for the methylcylcohexane along with shorter lambda max values relating to intensity of the peaks confirm that a polar solvent is a more effective solvent when calculating the properties of this particular benzophenone.
14-2007 PHOTOPHYSICAL STUDY OF POLAR AND NONPOLAR SOLVENTS FOR 4-FLUOROBENZOPHENONE. Kaleb M. Stinger, Oregon State University, Oregon 97331.
EPA and methylcyclohexane were used to study the UV absorbance and phosphorescence of the ketone in 4-fluorobenzophenone. This is the results of the study for the polar solvent EPA and the non polar solvent methylcyclohexane.
15-2007. SYNTHESIS OF 4-FLUORO-4'-METHYLBENZOPHENONE. Grant T. Farr.
The stated goal of this laboratory was to synthesize a substituted benzophenone and then characterize it using NMR, IR, and Melting Point considerations. This poster will focus on the selected benzophenone of 4-fluoro-4-methylbenzophenone which was synthesized using a Friedel Craft Acylation method from toluene and p-fluorobenzoyl chloride with aluminum chloride as a catalyst and carbon disulfide as an initial solvent. Obtained 5.0521 g of pure 4-fluoro-4-methylbenzophenone giving a percent yield of 20.1%. This was confirmed by positive scans of C13 NMR, H1 NMR, F19 NMR, IR, and melting point of 96-97°C which were are comparable to literature data for the benzophenone.
16-2007. DIFFICULTIES DURING CHARACTERIZATION AND SYNTHESIS OF 4,4'-DIMETHYLBENZOPHENONE. Melinda R. Stoelk, Oregon State University, Corvallis, OR 97331
17-2007. SYNTHESIS AND CHARACTERIZATION OF 4-BROMO-4'-METHOXYBENZOPHENONE. Wesley S. Williams, Department of Chemistry, Oregon State University, Corvallis, OR 97331.
4-bromo-4'-methoxybenzophenone was synthesized, purified, and characterized using melting point, IR, 1-HNMR, and 13-CNMR. The melting point was observed between 153-154.2 oC. The synthesis produced 0.042 mol of product with a 40% yield.
18-2007. QUANTITATIVE PHOTOCHEMISTRY OF 4-BROMOBENZOPHENONE. R.C. Huber. Department of Chemistry, Oregon State University, Oregon, 97331.
The photochemical reduction of 4-bromobenzophenone was studied in this experiment. A photochemical reduction requires the absorption of light to overcome the activation energy of the system. With the absorption of a photon the 4-bromobenzophenone moves from the ground state to the n-pi*, where the electrons are still paired. Through intersystem crossing (ISC) the electrons become parallel; this is the T1, triplet state. In this state the molecule will undergo homolytic cleavage, which reduces the benzophenone to a diphenyl ketyl radical. Once this has happened twice, the two diphenyl ketyl radicals will come together to form the benzopinacol. The quantum efficiency was determined to be 0.17.
19-2007. 4,4-Dimethoxybenzophenone Solvent Study. Liecong Zhen, Department of Chemistry, Oregon State University, Corvallis, Oregon 97331.
In the excitation experiment at 77K, a shift in lambda max to shorter wavelength in the more polar EPA compared to the non-polar methylcyclohexane is found for the npi* transition (S0-S1). The lambda max in EPA is 318 nm, while in methylcyclohexane it is 328 nm. There is no experimental evidence for an npi* transition at room temperature in the UV in EPA, however it is observed in methylcyclohexane. In addition, vibrational fine structure is also observed at room temperature in methylcyclohexane. The triplet T1 to S0 lifetime for 4,4-dimethoxybenzophenone observed at 77K in EPA and in methylcyclohexane is 0.015s and 0.011s, respectively, showing that there is little change in the forbidden character of this transition in both polar and non-polar solvents.
20-2007. PHOSPHORESCENCE LIFETIME OF (4-CHLOROPHENYL)4-PROPYLPHENYL) METHANONE IN PMMA AND EPA. Shannon L. Williamson, Department of Chemistry, Oregon State University, Corvallis, Oregon 97331.
The phosphorescence lifetime of (4-chlorophenyl)(4-propylphenyl) methanone was determined in two different ways. The first made use of a frozen glass prepared from benzophenone dissolved in EPA and cooled with liquid nitrogen; the second method was a solution in MMA that was polymerized and cured under vacuum. The triplet (T1) lifetime was found to be 6.44 ms in the EPA glass and 3.45 ms for the PMMA sample.
21-2007. PHOTOCHEMISTRY OF 4-METHOXYBENZOPHENONE Narumol Jariyasopit, Department of Chemistry, Oregon State University, Corvallis, Oregon, 97331
Photochemistry of 4-methoxybenzophenone was studied in different solvents. The quantitative study was carried out using methylcyclohexane as solvent. The solution was irradiated for different periods of time which allowed us to obtain the relationship of change in number of moles and number of photons used. For qualitative study, the saturated solution, using isopropyl alcohol as solvent, was irradiated for certain time. Subsequently, benzopinacol formed was characterized by IR and NMR.
Albus, Joshua C. Anderson, Britta L. Chiodo, Marcus A. Christ, Laura Dunatchik, Andrew Farr, Grant T. Furrer, Sarah K. Haggstrom, Elizabeth A. Huber, Rachel C. Jariyasopit, Narumol (1) Jariyasopit, Narumol (2) Jentzsch, Kaleb I. Jones, Matthew A. Knight, Brian Mc Afee, Mallory S. Steinke, Tyler J. Stinger, Kaleb Stoelk, Melinda R. Theobald, Brian R. Warkentin, Jason L. Williams, Wesley S. Williamson, Shannon L. Zhen, Liecong