Concept explainers
Interpretation:
The molecular orbital diagram for ground state of cyclopentadiene is to be completed; appropriate lobes are to be shaded to indicate the phase signs. HOMO and LUMO orbitals are to be labeled. Appropriate number of electrons, using straight single-barbed arrows in each level, is to be represented.
Concept introduction:
舧 Molecular orbital diagrams are used to explain the linear combination of atomic orbitals.
舧 HOMO and LUMO are types of molecular orbitals and are abbreviations for highest occupied molecular orbital and lowest unoccupied molecular orbital, respectively.
舧 Each lobe is a representation of p-orbital and each lobe has two poles, that is, shaded and non-shaded regions.
舧 The orbitals are aligned in such a way that each double bond in cyclopentadiene has the same orbitals.
舧 The lowest energy position is where all orbitals are shaded on top and clear on bottom.
舧 The second energy level has one orbital overlap.
舧 Third energy level has no orbital overlap but the two orbitals in the same alignment create similar signs through-space conjugation.
舧 Fourth energy level has no orbital overlaps or no sign changes and hence, it is the most unstable.
舧 There are two pi-bonds in cyclopentadiene, meaning 4 pi-electrons present in the system.
舧 The pi-electrons fill the lowest energy level.
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Organic Chemistry
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- Organic Chemistry: A Guided InquiryChemistryISBN:9780618974122Author:Andrei StraumanisPublisher:Cengage Learning