Synthesis of Supramolecular Self-assembling

Macromolecular Structures Matthew B. Weiss

2006

Chemistry Department Macalester College

Goals

Goals• Improve yields

Goals• Improve yields

• Develop a purification protocol

Goals• Improve yields • Develop a purification protocol• Show successful self-assembly

Oxadiazole Molecule

Background Information

Balsells (2005)

Loye (2003)

Identified Variables

• Problems with protocol

• Low Yield

Potential Self-assembly

N

N

O

NN

N

O

N

P d

N

N

O

N N

N

O

N

P d

P d

P d

C l

C l

C l C l

C l C l

C l

C l

Acylation Reaction

dichloromethane

Acylation Reaction

Diisopropylethylamine

0 °C

dichloromethane

Acylation Reaction

Diisopropylethylamine

0 °C

dichloromethane

Cycloaromatization

H

Cycloaromatization

82 °C Acetonitrile

H

Cycloaromatization

82 °C Acetonitrile

H

Oxadiazole Molecules

2,5-di(thiophen-2-yl)-1,3,4-oxadiazole = dithiophen oxadiazole

2,5-diphenyl-1,3,4-oxadiazole = diphenyl oxadiazole

2-(furan-2-yl)-5-(thiophen-2-yl)-1,3,4-oxadiazole = thiophen/furan oxadiazole

2-phenyl-5-(pyridine-3-yl)-1,3,4-oxadiazole = pyridyl/phenyl oxadiazole

2-phenyl-4-t-butyl-(pyridine-3-yl)-1,3,4-oxadiazole = pyridyl/phenyl-t-butyl oxadiazole

NN

O

N

Oxadiazole Molecules

2,5-di(thiophen-2-yl)-1,3,4-oxadiazole = dithiophen oxadiazole

2,5-diphenyl-1,3,4-oxadiazole = diphenyl oxadiazole

2-(furan-2-yl)-5-(thiophen-2-yl)-1,3,4-oxadiazole = thiophen/furan oxadiazole

2-phenyl-5-(pyridine-3-yl)-1,3,4-oxadiazole = pyridyl/phenyl oxadiazole

2-phenyl-4-t-butyl-(pyridine-3-yl)-1,3,4-oxadiazole = pyridyl/phenyl-t-butyl oxadiazole

NN

O

N

Oxadiazole Molecules

2,5-di(thiophen-2-yl)-1,3,4-oxadiazole = dithiophen oxadiazole

2,5-diphenyl-1,3,4-oxadiazole = diphenyl oxadiazole

2-(furan-2-yl)-5-(thiophen-2-yl)-1,3,4-oxadiazole = thiophen/furan oxadiazole

2-phenyl-5-(pyridine-3-yl)-1,3,4-oxadiazole = pyridyl/phenyl oxadiazole

2-phenyl-4-t-butyl-(pyridine-3-yl)-1,3,4-oxadiazole = pyridyl/phenyl-t-butyl oxadiazole

NN

O

N

Oxadiazole Molecules

2,5-di(thiophen-2-yl)-1,3,4-oxadiazole = dithiophen oxadiazole

2,5-diphenyl-1,3,4-oxadiazole = diphenyl oxadiazole

2-(furan-2-yl)-5-(thiophen-2-yl)-1,3,4-oxadiazole = thiophen/furan oxadiazole

2-phenyl-5-(pyridine-3-yl)-1,3,4-oxadiazole = pyridyl/phenyl oxadiazole

2-phenyl-4-t-butyl-(pyridine-3-yl)-1,3,4-oxadiazole = pyridyl/phenyl-t-butyl oxadiazole

NN

O

N

Oxadiazole Molecules

2,5-di(thiophen-2-yl)-1,3,4-oxadiazole = dithiophen oxadiazole

2,5-diphenyl-1,3,4-oxadiazole = diphenyl oxadiazole

2-(furan-2-yl)-5-(thiophen-2-yl)-1,3,4-oxadiazole = thiophen/furan oxadiazole

2-phenyl-5-(pyridine-3-yl)-1,3,4-oxadiazole = pyridyl/phenyl oxadiazole

2-phenyl-4-t-butyl-(pyridine-3-yl)-1,3,4-oxadiazole = pyridyl/phenyl-t-butyl oxadiazole

NN

O

N

Oxadiazole Molecules

2,5-di(thiophen-2-yl)-1,3,4-oxadiazole = dithiophen oxadiazole

2,5-diphenyl-1,3,4-oxadiazole = diphenyl oxadiazole

2-(furan-2-yl)-5-(thiophen-2-yl)-1,3,4-oxadiazole = thiophen/furan oxadiazole

2-phenyl-5-(pyridine-3-yl)-1,3,4-oxadiazole = pyridyl/phenyl oxadiazole

2-phenyl-4-t-butyl-(pyridine-3-yl)-1,3,4-oxadiazole = pyridyl/phenyl-t-butyl oxadiazole

NN

O

N

1HNMRs of Oxadiazole Derivatives

1HNMRs of Oxadiazole Derivatives

1HNMRs of Oxadiazole Derivatives

1HNMRs of Oxadiazole Derivatives

Results of Synthesis

• The five oxadiazole molecules were successfully synthesized and purified with high yields:– dithiophen– diphenyl– thiophen/furan– pyridyl/phenyl– pyridyl-t-butyl/phenyl

Macromolecular Synthesis

N

N

O

NN

N

O

N

P d

N

N

O

N N

N

O

N

P d

P d

P d

C l

C l

C l C l

C l C l

C l

C l

Self-assembled Tetramer

N

N

O

NN

N

O

N

P d

N

N

O

N N

N

O

N

P d

P d

P d

C l

C l

C l C l

C l C l

C l

C l

Self-assembled Dimer

N

N

O

NN

N

O

N

P d

N

N

O

N N

N

O

N

P d

P d

P d

C l

C l

C l C l

C l C l

C l

C l

N N

O N

NN

ON

P d P dC lC l

C l

C l

Self-assembly Procedure

• Dissolved palladium(II) chloride in acetonitrile at 78 °C

Self-assembly Procedure

• Dissolved palladium(II) chloride in acetonitrile at 78 °C

• Dissolved oxadiazole molecule in acetonitrile at 0 °C

Problems Encountered

• Extracting self-assembled macromolecules using deuterated solvents.

Analysis of Macromolecule

Future Work

• Utilize other components for ligation, such as PtCl2 or ReCl2.

Future Work

• Utilize other components for ligation, such as PtCl2 or ReCl2.

• Assess the fluorescence of modified tetramers.

Acknowledgments• Dr. Ronald Brisbois

• Macalester College

• Minnesota Academy of Science

• Ms. Lois Fruen

• Breck Team Science Research

Synthesis of Oxadiazole Derivatives for Use in

Supramolecular AssemblyMatthew B. Weiss

2006

Analysis

• Electron Impact Mass Spectroscopy (EI-MS)

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Nuclear Magnetic Resonance

• All particles have a property called spin.

• In a magnetic field, particles spin with or against the field.

• When excited with microwave energy, particles become excited and change their spin slightly.