2009-04-09 JMFrost - Fullerene Talk to Chemistry

An early version of the data on PCBM adducts (just Bis I think at this stage?). This was put together very quickly, for a talk over in Chemistry.

The results that followed from this were the key ones of my PhD.

To form the SMILES strings for PCBM with arbitrary attachment points, I borrowed a PhD friend's indoor Football (which is the same shape) and used post-it notes to locate the sidechains, while I rotated in in front of my eyes + checked that it agreed with the hand-annotated Schlegel diagrams in my lab book that I had built for each adduct.

I had evidently already started a combinatory sift, and found the CPDT fullerene, though hadn't yet managed to calculate Tris adducts.

Transcript

1. HOMO/LUMO of
   Fullerene Adducts
   A Quantum
   Chemical Study
   Jarvist Frost, James Kirkpatrick, Jenny Nelson
   Physics Department, Imperial College London
   

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2. Schlegel Diagram
   

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3. SMILES (Simplified molecular input line entry specification)
   (C1%61%98C2%99C3C4C5C61C7C8C9%61C%10C%11C%122C%13C%143C%15C%16C%174C
   %18%96C%195C%20C%217C%22C%23C%248C%25C%26%10C%27C%28%11C%29C%30%13C%31C
   %32%15C%33C%34%16C%35C%36%97%18C%37C%38%20C%39%22C%40C%41C%42%23C
   %43%25C%44C%45%27C%46C%47%29C%48%31C%49C%50%33C%51C%52%35C%53%37C
   %54%40C%55C%56%51C%57%49C%58%46C%59%44C%60%41%55)
   [C1 Isomer]
   (c1(h)c(h)c(h)c(h)c(h)c1C%X%Y(C(h)(h)C(h)(h)C(h)(h)C(O)OC(h)(h)(h)))
   [PBM Tail]
   (c1(h)c(h)c(h)c(h)c(h)c1C%98%99(C(h)
   (h)C(h)(h)C(h)(h)C(O)OC(h)(h)(h)))(hC
   %96%97(h))
   (C1%61%98C2%99C3C4C5%96C6%971
   C7C8C9%61C%10C%11C%122C%13C
   %143C%15C%16C%174C%18C%195C
   %20C%217C%22C%23C%248C%25C
   %26%10C%27C%28%11C%29C
   %30%13C%31C%32%15C%33C
   %34%16C%35C%36%18C%37C
   %38%20C%39%22C%40C%41C
   %42%23C%43%25C%44C%45%27C
   %46C%47%29C%48%31C%49C
   %50%33C%51C%52%35C%53%37C
   %54%40C%55C%56%51C%57%49C
   %58%46C%59%44C%60%41%55)
   (smi23d) (UFF,
   AM1,
   DFT)
   HOMO: Highest Occupied KS
   Energy Level (well defined)
   HOMO+1: First virt KS orbital
   (badly defined, but free)
   E(Anion)-E(Neutral): Further
   SCF calculation of charged
   molecule without nuclear
   coordinated relaxation
   HOMO+TD-DFT(1st Singlet):
   TD-DFT 'spectroscopic'
   calculation
   L
   U
   M
   O
   {
   

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4. View Slide

5. View Slide

6. View Slide

7. Bis-Cyclopentadithiophene-PBM
   HOMO LUMO (eV)
   C1: -5.22893 -3.46713
   C2: -5.30618 -3.34498
   C3: -5.30590 -3.4574
   E': -5.28632 -3.34532
   T1: -5.27054 -3.44314
   T2: -5.29720 -3.4211
   T3: -5.37526 -3.47596
   T4: -5.32576 -3.43576
   Mono-PCBM: -3.74881
   Lifted HOMO (effect on working cell?)
   Lifted LUMO (~300meV c.f. Mono-pcbm)
   Homo spin density on Thiophene unit
   Thiophene unit fairly compact (effect on packing)
   Further Work: Different adducts, higher order adducts
   Understanding effect of varying Lumo of isomers on performance (fill factor?)
   Combine with simplistic MD to generate amorphous films + charge transport studies
   

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8. Comparison of DFT Methods for Molecular Orbital Eigenvalue Calculations –
   Gang Zhang et al. J. Phys. Chem. A 2007, 111, 1554-1561
   Principles of Fullerene Reactivity – Andreas Hirsch. Topics in Current Chemistry, Vol.
   199
   Fullerene Chemistry in Three Dimensions – Andreas Hirsch et al. Angew. Chem. Int.
   Ed. Engl. 1994, 33, No. 4
   The Addition Patterns of C60 Trisadducts – Francis Djojo et al. Eur. J. Org. Chem.
   1999, 3027-3039
   Lecture Notes on Fullerene Chemistry – Roger Taylor, Imperial College Press 1999
   Pi-Conjugated Fullerene Adducts – Floris Berend Kooistra, PhD Thesis 2007,
   University of Groningen
   Acknowledgments and References
   Jenny Nelson (Supervisor)
   James Kirkpatrick (Gaussian Assistance + awk scripts)
   Kevin Gilbert, Rajarshi Guha - Indiana University (smi23d coordinate generation)
   Other Software: Openbabel, Gaussian 03, PyMol
   High Performance Computing facility, Imperial College London (2.5 CPU-Years)
   

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