Resonance Practice PDF

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practice for orgo quiz 1 and 2...

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UML Organic I

21

Resonance Select the pairs of molecules that represent resonance structures. i)

CH 3C P O

S C ii)

and

S NH 3

O CHCl2CH

and

iv)

O CH 2 N O

and

H NH 2

and

iii)

and

CH 3C P O

OH Cl2C CH

O H 2C N O

Draw one resonance form of the following molecules. O

B OH

OH

O

F H3C

N

CH3

CH3

O

O H

O

UML Organic I

22

Resonance Provide a resonance structure for the following molecule in which all the atoms have a full octet. O

Provide the set of curved arrows that converts structure A to the resonance form B. Indicate the major contributor.

H R

H N

N

R

C C

N

N

C

C

C C

C

C

C N

N

C N

N

A

B

Determine the hybridization of the oxygen atom (O) in each of the following molecules using resonance structures for delocalized electrons to explain your reasoning. Be sure to include curved arrows in all resonance structures presented.

O

O

O

Write the resonance structure that would result from moving the electrons in the way indicated by the curved arrows.

O

H 2N

O

UML Organic I

23

Provide one possible resonance structure for the following molecule. NH 2

Provide two major resonance contributors for the following molecule.

H

O C N O H

H

Use curved arrows on each structure to show electron flow to obtain two resonance forms for the indicated molecule. Be sure to include all lone pairs and formal charges on the molecules.

O

ii) State the molecular formula of the compound: iii) Select from your molecules in part 1ci) and draw the most stable resonance form in the space below.

Provide the resonance contributor that would result from the arrow movement on the molecule shown below.

O H O

OH OH

UML Organic I

24

Resonance and Hybridization O I

O

N H

H N

O

O Redox Probe for Bacteria

The molecule shown above is used to sense metabolic activity in blue-green microbes. Please answer the following questions about the molecule. a) What is the molecular formula of the compound? b) How many sp3-hybridized carbon atoms are present in the molecule? c) How many sp2-hybridized carbon atoms are present in the molecule? d) How many sp-hybridized carbon atoms are present in the molecule? e) Draw in all the missing lone pairs in the structure above. f) Indicate the molecular geometry (shape) around each of the atoms indicated by the arrow. (Hint: use the hybridization of the atom to help you)

O I

N H

O

H N

O

O

Give the hybridization and the approximate bond angle for the indicated atoms in structure of the antibiotic Puromycin, shown below.

Hybridization

A

Bond angle

A

N

B

N B

D

C

N

HO

D

O O NH 2 NH O

C

OH

N N

UML Organic I

25

Amotosalen has a planar structural core and is used reduce the risk of transfusion-transmitted infections. The molecule fits in the grooves of DNA and destroys DNA structure when illuminated with UV light. Use your knowledge of resonance and hybridization to determine the hybridization of all the ring atoms of Amotosalen and show the ring structure is planar. H 2N O

O

O

O

Amotosalen

Resonance and Hybridization Determine the hybridization of all the heteroatoms in the following molecules. N N

N N

O

N OH O

HO

S

O

O

OH B OH

H N

O

HN

N H H 2N O

Determine the number of pi-bonds in the drug molecules Zorcor and Lipitor, respectively. HO

O O

O

O O

N H

H

N

OH OH O OH

F Lipitor

Zorcor

The molecule shown below is a current drug for Parkinson’s disease. Clearly state the hybridization of the atoms indicated by each arrow in the structure. Drug for Parkinson's disease O HO

N C N

HO O

N

O

O...