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Theory and Experiment:. Student Explorations in the Collection and Interpretation of Thermochemical and Spectroscopic Data. James B. Foresman York College of PA York PA 17405 USA JForesma@YCP.EDU http://goose.ycp.edu/~jforesma. Molecular Modeling Exercises.
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Theory and Experiment: Student Explorations in the Collection and Interpretation of Thermochemical and Spectroscopic Data James B. Foresman York College of PA York PA 17405 USA JForesma@YCP.EDU http://goose.ycp.edu/~jforesma
Molecular Modeling Exercises Context: Laboratory Setting (so time to solution is a consideration)
Molecular Modeling Exercises Focus: Visualizing Chemistry (linking benchtop to molecular level)
Molecular Modeling Exercises Outcome: Understanding Computer Models and Programs (both the mechanics of using the tools and realizing the strengths and limitations of the models)
The Software: Create Process Visualize
The Software: Create Process Visualize HyperChem Spartan PCModel Chem3D GaussView WebMO MOE Cache Many Others
The Software: Create Process Visualize HyperChem Spartan PCModel Chem3D GaussView WebMO MOE Cache Many Others HyperChem Spartan PCModel Chem3D Gaussian ADF Jaguar Gamess Many Others
The Software: Create Process Visualize HyperChem Spartan PCModel Chem3D GaussView WebMO MOE Cache Many Others HyperChem Spartan PCModel Chem3D Gaussian ADF Jaguar Gamess Many Others HyperChem Spartan PCModel Chem3D GaussView Molekel gOpenMol T3D, MOE Many Others
Example: Phenolphthalein Color Change Acid-Base titrations are routinely performed in introductory courses. Why does the solution containing the indicator turn pink?
Example: Phenolphthalein Color Change www.cambridgesoft.com
Example: Phenolphthalein Color Change www.gaussian.com
Example: Phenolphthalein Color Change www.cambridgesoft.com
Compare theoretical uv/VIS spectra of the two forms H2In In2-
Compare HOMO and LUMO Orbitals of the two forms HOMO Of Protonated form
Compare HOMO and LUMO Orbitals of the two forms LUMO Of Protonated form
Compare HOMO and LUMO Orbitals of the two forms HOMO Of Dianion form
Compare HOMO and LUMO Orbitals of the two forms LUMO Of Dianion form
Example: Heat of Solution Students can use a primitive device to measure the temperature change when a solid is added to water. potassium nitrate endothermic DH=+35 kJ potassium acetate exothermic DH=-15 kJ Why? What factors are involved?
Example: Heat of Solution www.gaussian.com
Example: Comparing Azulene and Naphthalene Students can measure heats of combustion. Also they can compare IR, uv-VIS, and NMR spectra of these two isomers. What electronic details account for the differences that are observed?
Example: Comparing Azulene and Naphthalene www.webmo.net
Example: Comparing Azulene and Naphthalene azulene naphthalene Heats of Combustion [kJ/mol] -5291 -5156 DHiso = -135 kJ/mol
DHiso Theoretical and Experimental Estimates Huckel -46 kJ/mol AM1 -177 HF/6-31G(d) -181 B3LYP/6-31G(d) -141 CBS-Q -147
DHiso Theoretical and Experimental Estimates Huckel -46 kJ/mol AM1 -177 HF/6-31G(d) -181 B3LYP/6-31G(d) -141 CBS-Q -147 Gas phase Expt-148
Example: Electronic Spectrum of a Vanadium Complex Students prepare and obtain the uv-VIS spectrum of vanadyl acetylacetonate and attempt to classify the transitions as: d-d d-ligand ligand-ligand ligand-metal
Example: Electronic Spectrum of a Vanadium Complex www.serenasoft.com
Example: Electronic Spectrum of a Vanadium Complex www.gaussian.com
Example: Electronic Spectrum of a Vanadium Complex www.cscs.ch/molekel/
load gaussian output file into Molekel and examine optimized B3LYP LANL2DZ distances ...
load gaussian cubes into Molekel, subtract ground from excited state for this d-d transition