Synthesis of MetalPorphyrinFrameworks

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Synthesis of Metal-Porphyrin-Frameworks
Michelle Minton Department of Materials Science
and Engineering
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Introduction

• In July 2008 NSF awarded an Integrative Graduate
  Education and Research Traineeship (IGERT) grant
  to UT funding the Sustainable Technology through
  Advanced Interdisciplinary Research (STAIR)
  program
• The focus of the STAIR program is energy
  sustainability and the RD component focuses on
  hydrogen as a fuel source

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STAIR RD program tasks

• Task 1
• Hydrogen Production through biological pathways
• Task 2
• Discovery of nanoporous materials for hydrogen
  storage
• Task 3
• Structure/property relations in hydrogen fuel
  cells

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Hydrogen Storage

• Good energy density by weight
• Compared to hydrocarbons
• Poor energy density by volume
• By a factor of about 4
• Current storage methods
• High Pressure Vessels
• Cryogenics

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DOE Standards

• In January 2002 the FreedomCAR partnership
  between USCAR and DOE set standards

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Candidates for Hydrogen Storage

• Chemical Storage
• Hydrocarbons
• Metal Hydrides
• Amonia
• Physical Storage
• Carbon Nanotubes
• Doped Polymers
• Glass Capillary Arrays
• Glass Microspheres
• Metal-Organic-Frameworks (MOFs)

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Metal-Organic-Framework (MOF) Structures

• Structures developed by Omar Yaghi and his group
• 2D Arrays
• Nanoporous

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Metal-Porphyrin-Framework (MPF)

• Porphyrin replaces the organic molecule
• 3D arrays
• Adsorption

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3D Arrays offer large volumes for H2 storage
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Crystal Growth

• Based on preliminary attempts by Zhang and Knight
• DMF and CHCl3
• Porphyrin and Zn(NO2)3 6H2O

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Crystals from Solvothermal Synthesis

• After numerous attempts to recreate - basic
  crystallization
• Too small for characterization

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Using the Seed Crystals

• Fragile
• Plate Like

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X-Ray Diffraction Pattern
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Pressure Vessel
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Crystals
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X-Ray Single Crystal Diffraction Pattern
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Results

• Crystal structure determined yesterday
• Zn oxo polymer
• Zn bridged
• by oxygen

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Conclusion

• Trial and error
• In the first case we learned we needed a better
  crystallization method
• In the second case we learned there was too much
  oxygen
• Keep trying
• Synthesize
• XRD
• H2 adsorption

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Acknowledgements
Dr. Claudia J. Rawn
Dr. David J. Keffer
Brenda Dougan, Juia Abbott, and Elizabeth Jacobs
Department of Chemistry, UT