Construct the Hückel determinants for cyclobutadiene and cyclopentadiene. In what ways are they alike? In what ways are they different?
Interpretation:
The Hückel determinants for cyclobutadiene and cyclopentadiene are to be constructed. The similarities and differences between the two are to be stated.
Concept introduction:
Hückel theory deals with the conjugated systems. In this theory, the
Answer to Problem 15.48E
The Hückel determinant for cyclobutadiene is shown below.
The Hückel determinant for cyclopentadiene is shown below.
The value of overlap integral and the
Explanation of Solution
The structure of the cyclobutadiene is given in figure 1.
Figure 1
The secular determinant for the cyclobutadiene can be written as shown below.
In the above determinant, the overlap integrals
Substitute the value of
The above determinant represents the Hückel determinant for cyclobutadiene.
The structure of the cyclopentadiene is given in figure 2.
Figure 2
The secular determinant for the cyclopentadiene can be written as shown below.
In the above determinant, the overlap integrals
Substitute the value of
The above determinant represents the Hückel determinant for cyclopentadiene.
The value of overlap integral and the
The Hückel determinant for cyclobutadiene is shown below.
The Hückel determinant for cyclopentadiene is shown below.
The value of overlap integral and the
Want to see more full solutions like this?
Chapter 15 Solutions
Bundle: Physical Chemistry, 2nd + Student Solutions Manual
- a.) Write down for yourself the secular determinant for the hypothetical molecule linear H3 making the Huckel approximation, using the 1s atomic orbitals from each atom as the basis set. Given that α=-2.00 eV and β= -3 eV, what is the total electronic energy in eV? b.) Write down the secular determinant for the hypothetical molecule cyclic H3 making the Huckel approximation, using the 1s atomic orbitals from each atom as the basis set. Given that α=-2.00 eV and β= -2 eV, what is the total electronic energy in eV?arrow_forwardDetermine the number of canonical or resonant forms of 1,2-diphenylethylene, the trans isomer of which is shown in images. Explain the order of stability of canonical forms. (canonical or resonant forms are not cis / trans forms)arrow_forwardHow do you write the Huckel determinant for the pi electrons of butadiene? How would you find the energies of the molecular orbitals?arrow_forward
- 1. Escriba el producto de la reacción Diels - Alder, muestre la estereoquímica del producto.arrow_forward7. For naphthalene, (a) set up the Hückel determinant (without solving). (b) Calculate the energy of the following MO (find the value of a if necessary.) 0 -a -a a a 0 -a aarrow_forwardWhen using the Hartree-Fock approximation with the 6-31G* basis set to optimise the geometry of the water molecule, how do your results compared with the experimental values reported in experimental values (bond distance 0.95718 Angstroms and bond angle 104.474 degrees)? Calculation slightly underestimates distance and slightly overestimate angle; Calculation underestimates both distance and angle; Calculation slightly overestimates distance and slightly underestimate angle; Calculation overestimates both distance and angle.arrow_forward
- An electron in the 7 orbital of ethylene (C,H,) is excited by a photon to the * orbital. Do you expect the equilib- rium bond length in the excited ethene molecule to be greater or less than that in ground-state ethene? Will the vibrational frequency in the excited state be higher or lower than in the ground state? Explain your reasoning.arrow_forwardTOPIC: QUANTUM, ATOMIC AND MOLECULAR PHYSICIS (a) Using Hückel's method, describe the energy of the molecular orbitals T of cyclobutadiene C4H4, which is a flat molecule made up of a square ring of carbons, as shown in the figure; (b) Do the same for 1,3-butadiene C4H6, which is an elongated planar molecule, as shown in the figure. (c) In both cases, draw an energy diagram indicating the filling of the orbitals and identifying the HOMO and the LUMO. Sketch by hand schematically (using two colors to distinguish the lobes from the 2pz orbitals) the result obtained for the orbitals, identifying them with the corresponding energy. If possible, you can use the Orbital Viewer program to plot the orbitals.arrow_forwardDraw the structure of 1-methoxy-1,3-butadiene, construct the diagram energy for molecular orbitals, identify the boundary orbitals and indicate the most favorable HOMO-LUMO transition (s).arrow_forward
- Set up the secular determinants for (i) linear H3, (ii) cyclic H3 within the Hückel approximation.arrow_forwardIf [CH4}) = 0.1M; [O2] = 0.25M\[CO2 ]= 0.35M and [H2O] = 0.15M what is the value of Qc?arrow_forward1. For the molecules hexatriene (A) and cyclopentadienyl radical (B) shown below, use the Hückel approximation to obtain the following: (a) Secular determinant (b) Energy levels (c) Molecular orbitals (d) Delocalization energy (A) (B)arrow_forward
- Physical ChemistryChemistryISBN:9781133958437Author:Ball, David W. (david Warren), BAER, TomasPublisher:Wadsworth Cengage Learning,Organic Chemistry: A Guided InquiryChemistryISBN:9780618974122Author:Andrei StraumanisPublisher:Cengage LearningPrinciples of Modern ChemistryChemistryISBN:9781305079113Author:David W. Oxtoby, H. Pat Gillis, Laurie J. ButlerPublisher:Cengage Learning