Molecular orbitals of acetylene

Use SpartanView to display the two highest-energy occupied molecular orbitals of acetylene. How do they differ ... 

As a first approximation, all this leads to the decrease in energy of low-lying molecular orbitals of acetylene in such a complex as compared to similar orbitals of free acetylene, and, consequently, the triple bond becomes more available for the nucleophilic attack. The nucleophiles themselves in the superbase systems turn to supernucleophiles due to the dramatic increase of their free energy [157,158]. 

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