Measuring the Intrinsic Dipole Moments of Oligo- ortho -arylamides

1. Measuring the Intrinsic Dipole Moments of Oligo-ortho-arylamides Stephen Bishop Riverside Community College Bioengineering Research Institute for Technical Excellence Advisor: Dr. Valentine I. Vullev Department of Bioengineering, University of California Riverside

2. Outline • Background and Motivation • Goals and Objectives • Methods and Materials • Results • Conclusions • Future Directions

3. Background and Motivation • Photoinduced charge transfer in natural light-harvesting systems • Photosynthetic reaction center (RC) • RC transmembrane proteins is α-helices spanning the electron-transfer pathways • The helix intrinsic dipoles generate the electric field that influence significantly on charge transfer. E. Rabinowitch, Annual Review of Plant Physiology, (1952) 3, 229-264 Norbert Krau, et al. , Nature Structural Biology, (1996) 3, 965 – 973

4. In 2005, the planet’s consumption rate was approximately 16TW Image from www.thinkspace.com The United States consumed approximately 3.4 TW Image from oim.hq.nasa.gov The planet’s primary source of energy is fossil fuels (80%) The practical energy generation rate approximates 600TW Energy Information Administration, US Department of Energy. July 31 2006. Lewis, N.S.,Science 315, 798-801 (2007).

5. Photoinduced charge transfer system --Donor-Bridge-Acceptor (DBA) conjugates • The Biomimic system: • Bridge molecules: polypeptide α-helices • µ= 4-5 D per residue • The Bioinspired system: • Bridge molecules: bioinspired macromolecules • µ= 3-5 D per residue depends on the polymers Fedorova, A., et all. "Photoinduced electron-transfer along a-helical and coiled-coil," Journal of the American Chemical Society 125, 357-362 (2003).

6. Goals and Objectives • Long-term goal: To improve the charge-transfer efficiency of photovoltaic devices in solar energy conversion. • My project objectives: • Engineering design and synthesize macromolecular electrets • Investigate the electric properties of electrets

7. Methods and Materials 1. Engineering design macromolecular electrets

8. 2. Investigate the electric properties of electrets • Theoretical Calculation: Density functional theory (DFT) ab initio calculations • Experimental Validation: Dielectric-constant measurements (impedance spectroscopy) Density measurements Frisch MJ, et al., Gaussian 03, Revision C.02;Wallingford, CT:Gaussian, Inc., 2004.

9. Experimental Validation: Breitung, Vaughan, and McMahon, Rev. Sci. Instrum., (2000) 71, 224-227.

10. n=1 Results 1. Engineering design of macromolecular electrets—aromatic oligo-ortho-arylmides Wet chemistry synthesis General organic chemistry Solid-phase synthesis Polypeptide synthesizer

11. Wet chemistry Synthesis—monomer Synthesis procedure DMAP, DMF + Ice bath, Ar gas BüchiRotovapor R-114 Separation flask

12. 1H-NMR Spectra: N2-hexanoylanthranylamide i g j k b h d a f e c c c a g k j i h b e f d

13. 2. Investigate the electric properties of electrets – monomer & polymer • Theoretical Calculation: Ashraf, M. K; Vullev, V. I. et al. Biotechnology Progres 2009, 25, 915-922

14. 3. Investigate the electric properties of electrets (monomer) • Experimental Validation (in progress)

15. Conclusions • Oligoanthranilamides that have intrinsic dipole moments resultant from the orientation of their amide and hydrogen bonds were designed. • The dipole moments of macromolecules were predicted by density functional theory (DFT) ab initio calculations. • The monomer was synthesized with high yield and the dipole moment measure is in process.

16. Future Directions • Finish the dipole moment measurement of monomer and validate the theoretical calculation. • Synthesize polymers by solid-phase polypeptide synthesizer. • Measure the dipole moments of polymers.

17. Acknowledgements Jun Wang Duoduo Bao Gokul Upadhyayula Robert Bonderer Noah Johnson Dr. Valentine I. Vullev Dr. Sharad Gupta Dr. Daniel Bernier (RCC) Dr. Diane Marsh (RCC)