University:
Boston University
Course:
CAS CH 524 | Chemical Biology Laboratory
Academic year:

2024
Views:

163

Pages:

5
Author:

Adriel Kelley

1. Sketch the MO diagram for HCO3− 2. Sketch the MO diagram for C4H6 (1,3-butadiene, CH2=CH–CH=CH2). 2 3. Assume light is absorbed by NO2− to create the excited molecule (NO2−)* in which one electron has shifted from the HOMO to the lowest unoccupied molecular orbital (LUMO), the π antibonding MO. For an excited state, (NO2−)* answer following questions: a. How many electrons are in σ bonding orbitals? 4e− b. How many electrons are in σ nonbonding orbitals? 10e− c. How many electrons are in π bonding orbitals? 2e− d. How many electrons are in π antibonding orbitals? 1e− e. How many electrons are in π nonbonding orbitals? 1e− f. How many electrons are shared between Oleft and N? 3e− g. How many electrons are shared between Oright and N? 3e− h. How many unshared electrons are on Oleft? (4e-)σ-frame+(1/2 e-)π nonbonding+(1/3 e-)π*=4*(5/6)e− i. How many unshared electrons are on Oright? 4*(5/6)e− j. How many unshared electrons are on N? (2e-)σframe + (1/3 e-)π*=2*(1/3) e− k. What is a total number of unshared electrons =2*(1/3) e- + 4*(5/6)e- + 4*(5/6)e- =12 e− 3 l. What has happened to the dipole moment of NO−2 ?( assume the σ framework is unaffected.) Dipole moment will decrease less separation of the charge. 4. Sketch the MO diagram for C4H2, (CAH≡CB–CC≡CDH). Diacetylene a. Determine and draw σ framework: b. How many pairs of electrons are in the σ framework? 10 e− 5. a. How many pairs of electrons are in the π framework? 8 e− b. Draw energy diagram for π framework: c. d. How many pairs of electrons are shared between the middle two carbons in C4H2 1(2/3) pairs or 3(1/3)e− e. How many pairs of electrons are shared between the first two carbons in C4H2, 2(2/3) pairs or 5(1/3) e− 4 6. What is the hybridization of the oxygen atoms in SO2? a. Carbon dioxide, SO2, has a total of 9 pairs of electrons. b. How many pairs of electrons are in the σ framework of SO2? c. How many bonding π electrons are there? 2e- d. How many non-bonding π electrons are there? 2 ee. How many electrons are there on either terminal atom that are not shared with the central atom? 5ef. How many electrons are there on the central atoms that are not shared with the terminal atoms?2eg. How many electrons that are shared with the central and terminal atoms? 6e- π framework diagram  framework 7. What is the hybridization of the oxygen atoms in CO2?( for help go to :http://goo.gl/6hBD8X) a. Carbon dioxide, CO2, has a total of 8 pairs of electrons. How many pairs of electrons are in the σ framework of CO2? 4 pairs b. How many bonding π electrons are there? 4e- c. How many non-bonding π electrons are there?4ed. How many electrons are there on either terminal atom that are not shared with the central atom? 4ee. How many electrons are there on the central atoms that are not shared with the terminal atoms? 0 Additional Examples: Determine σ-framework and corresponding π MO correlation diagram for: H2CO, C3H5−, HCO2−, HOCO2−, N3H 5