Rep:Mod:fs1309moeule 3

3rd year computational lab Module 3 Transition states and reactivity.

Abstract:

This module aims to characterize the transition structures on potential energy surfaces for the Cope rearrangement and Diels Alder cycloaddition reactions. These can be achieved by using molecular orbital based method, solving Schrodinger equation numerically and locating the transition structures based on the local shape of a potential energy surface. Also calculating the structure of transition state, reaction paths and barrier heights.

Part 1 The Cope Rearrangement tutorial

Marks will be given for correct answers, the documentation showing how you got these, discussion, and how you went about solving any problems you encountered.

Table showing final energy and symmetry

Conformers	Total energy /a.u.(literature vale)	Point group	Structure	Structure in Appendix 1	Summary
Anti 1	-231.69260220 (-231.69260)	C2	Optimized structure	File:Filename Structure in appendix 1	Summary table
Anti 2	-231.69253494 (231.69254)	Ci	Optimized structure	File:Filename Structure in appendix 1	Summary table
Anti 3	-231.68907066 (-231.68907)	C2h	Optimized structure	File:Filename Structure in appendix 1	Summary table
Anti 4	-231.69097054 (-231.69097)	C1	Optimized structure	File:Filename Structure in appendix 1	Summary table
Gauche 1	-231.68771613 (-231.68772)	C2	Optimized structure	File:Filename Structure in appendix 1	Summary table
Gauche 2	-231.69166702 (-231.69167)	C2	Optimized structure	File:Filename Structure in appendix 1	Summary table
Gauche 3	-231.69266120 (-231.69266)	C1	Optimized structure	File:Filename Structure in appendix 1	Summary table
Gauche 4	-231.69153032 (-231.69153)	C2	Optimized structure	File:Filename Structure in appendix 1	Summary table
Gauche 5	-231.68961572 (-231.68962)	C1	Optimized structure	File:Filename Structure in appendix 1	Summary table
Gauche 6	-231.68916017 (-231.68916)	C1	Optimized structure	File:Filename Structure in appendix 1	Summary table

Comparison of results using HF/3-21G and B3LYP/6-31G

Geometry (comparison with geometric parameter?) Energy -234.61169881 vs -231.69253494 change in energy.

Frequency calculation (unit???????)

IR spectrum of anti2 1,5 hexadiene

Sum of electronic and zero-point Energies=           -234.469231
Sum of electronic and thermal Energies=              -234.461865
Sum of electronic and thermal Enthalpies=            -234.460920
Sum of electronic and thermal Free Energies=         -234.500877

Optimizing the Chair and Boat Transition structures.

In this section you will learn how to set up a transition structure optimization (i) by computing the force constants at the beginning of the calculation, (ii) using the redundant coordinate editor, and (iii) using QST2. You will also visualize the reaction coordinate and run the IRC (Intrinisic Reaction Coordinate) and calculate the activation energies for the Cope rearrangement via the "chair" and "boat" transition structures.