Back to Animations.
| ===> |
In this simulation, lasting 1.02ps, cyclobutene ring-opens to form
1,3-butadiene. At room temperature, this reaction would not occur
spontaneously, so the initial conditions included enough energy to allow the
reaction to proceed. At the
transition state, all normal modes are
unpopulated except the transition mode, which has an energy of 0.3kcal/mol. This is a dynamic reaction coordinate calculation,
modeling the isolated system in a vacuum, so energy is conserved.
This means that although butadiene is formed, there is enough energy in the
system that it would eventually go back to cyclobutene, however the wait might
be very long! Under normal conditions, the excess energy would be carried away
into the surroundings. For reference: DHf(cyclobutene)
= 37.5 kcal/mol |
Data set used by MOPAC:
irc=-1* drc t-priority=0.4 cycles=4000 gnorm=0.1 Cyclobutene -> butadiene C 0.00000000 +0 0.0000000 +0 0.0000000 +0 -0.2711 C 2.09542702 +1 0.0000000 +0 0.0000000 +0 -0.2711 C 1.41235903 +1 74.6911459 +1 0.0000000 +0 2 1 0 -0.1643 C 1.39536653 +1 102.9147444 +1 14.9750623 +1 3 2 1 -0.1645 H 1.07961066 +1 121.5806832 +1 141.5488537 +1 1 4 3 0.1329 H 1.08188876 +1 122.7322763 +1 -58.8561305 +1 1 4 3 0.1527 H 1.07962359 +1 121.5787713 +1 141.5886061 +1 2 3 4 0.1329 H 1.08192201 +1 122.7666089 +1 -58.7492900 +1 2 3 4 0.1527 H 1.07183872 +1 129.4772894 +1 150.2423278 +1 3 4 1 0.1498 H 1.07184180 +1 129.4782103 +1 150.2141939 +1 4 3 2 0.1498