By: Jingyuan Ma Introduction This lab introduced techniques used in the Penn/Merck High-Throughput Experimentation Center. The Suzuki-Miyaura reaction was implemented using 4 reagents, an assigned inorganic base, an assigned solvent, and pre-dosed phosphine ligands. TLC and HPLC were used to qualitatively analyze the reactivity trends of 24 reaction screens, which were all conducted under room temperature and controlled settings. The following overall reaction was conducted to catalyze sp2-sp2 carbon-carbon bonding through the use of a palladium catalyst: The following is […]
I. Purpose To study how stress affects a system’s equilibrium and to determine the concentration of the complex ion in solutions of unknown concentration as well as the equilibrium constant. Procedure LeChatelier’s Principle Part 1 Solid sodium chloride was poured into a test tube and the test tube was then filled ¾ full of distilled water. The solution was then decanted into a second test tube and Cl– ions in the form of concentrated HCl were added. Part 2 A […]
Understanding Diels-Alder Stereochemistry: Key Reactions and Products The Diels-Alder reaction between cyclopentadiene and maleic anhydride — documented in the student report below — is one of the most studied [4+2] cycloadditions in organic chemistry. Before examining that experiment, this section addresses several closely related reactions that build on the same mechanistic principles and are frequently studied in advanced coursework. 5-Fluorocyclopentadiene + Maleic Anhydride: Major Product and Stereochemistry When 5-fluoro-1,3-cyclopentadiene reacts with maleic anhydride, the fluorine substituent at C-5 breaks the […]
By: Jaime Rodriguez Background: In this experiment, the concentrations of KMnO4 in each test tube were considered similar if their respective colors were similar. This step is what made it possible to calculate the amount of hydrogen peroxide in the original solution of melted ice. Unfortunately, the human eye is not keen to accurately detect the change in color intensity; therefore the colors in both test tubes may not have been very similar at all. Besides this method, there is […]
By: Juno Kim and Nicole Introduction The goal of this experiment was to determine the mass percent of manganese in an unknown steel sample using methods of visible spectroscopy and volumetric analysis. The two methods were then analyzed and compared to decide the better method for determining the composition of Mn in the unknown steel. In both methods, the unknown steel was digested in hot concentrated Nitric acid, HNO3, and analyzed for transition metals. An accurate analysis of steel […]
By: Ludmila Novikova Abstract: Before X-ray diffraction of crystals was applied to determine the arrangement of atoms in 1913, little was known about the geometric and stereochemical shape of molecules and about the science of crystallography in general. In fact, the atomic theory of matter was not completely accepted because there was no theory available to explain the existence of compounds of the same composition (Flack, 372). X-ray crystallography presented us with methods that would allow us to strike a […]