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Polyynes

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Application of revised isodesmic equations to polyynes.

Application of revised isodesmic equations to polyynes.

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    Polyynes Polyynes Presentation Transcript

    • Thermodynamic Properties of the Polyynes! Dr. Peter D. Jarowski!
    • Graduate  Research  in  Applied  Computa(onal  Chemistry:  Thermochemistry  of  Polyynes   Conjuga(on  and  Hyperconjuga(on   Impact   Applica(on  Conjuga(on   Hyperconjuga(on   Strain  Energies   Aroma(c   Stabiliza(on   Expanded   Radical   Polyhedranes   Stabiliza(on   Low-­‐barrier  Rota(on   in  Cumulenes    
    • Graduate  Research  in  Applied  Computa(onal  Chemistry:  Thermochemistry  of  Polyynes   Conjuga(on  and  Hyperconjuga(on   Impact   Applica(on   From  a  new  way  of   looking  at  some   fundamental  concepts  in   thermochemistry.  Conjuga(on   Hyperconjuga(on   Strain  Energies   Aroma(c   Stabiliza(on   Expanded   Radical   Polyhedranes   Stabiliza(on   Low-­‐barrier  Rota(on   in  Cumulenes    
    • Graduate  Research  in  Applied  Computa(onal  Chemistry:  Thermochemistry  of  Polyynes   Conjuga(on  and  Hyperconjuga(on   Impact   Applica(on  Conjuga(on   Hyperconjuga(on   Strain  Energies   To  some  intui(ve   and  direct   examples.   Aroma(c   Stabiliza(on   Expanded   Radical   Polyhedranes   Stabiliza(on   Low-­‐barrier  Rota(on   in  Cumulenes    
    • Graduate  Research  in  Applied  Computa(onal  Chemistry:  Thermochemistry  of  Polyynes   Conjuga(on  and  Hyperconjuga(on   Impact   Applica(on  Conjuga(on   Hyperconjuga(on   Strain  Energies   Aroma(c   Stabiliza(on   Finally,  their  use  Expanded   Radical   Polyhedranes   in  some  topical   applica(ons.   Stabiliza(on   Low-­‐barrier  Rota(on   in  Cumulenes    
    • Conjuga(ve  Stabiliza(on  as  a  Theore(cal  Construct:  1,3-­‐Butadiene   33%  H2SO4   1h  100  oC   Conjuga(ve   Stabiliza(on   (3.4  kcal/mol)   (Terpineol)   (α-­‐Terpinene)   (γ-­‐Terpinene)   29%   15%   Pauling,  1933   Dewar,  1960   Bartell,  1978  Smith, M.; March, J. Marchʼs Advanced Organic Chemistry, 5th ed.; John Wiley & Sons: New York, 2001.!
    • Conjuga(ve  Stabiliza(on  as  a  Theore(cal  Construct:  1,3-­‐Butadiene   33%  H2SO4   Standard  conjuga(ve   1h  100  oC   Conjuga(ve   stabiliza(on  in   Stabiliza(on   butadiene  generalized   (3.4  kcal/mol)   for  all  double  bonds.     (Terpineol)   (α-­‐Terpinene)   (γ-­‐Terpinene)   29%   15%   Pauling,  1933   Dewar,  1960   Bartell,  1978  Smith, M.; March, J. Marchʼs Advanced Organic Chemistry, 5th ed.; John Wiley & Sons: New York, 2001.!
    • Conjuga(ve  Stabiliza(on  as  a  Theore(cal  Construct:  1,3-­‐Butadiene   33%  H2SO4   1h  100  oC   Conjuga(ve   An  experimentally   Stabiliza(on   important  concept.     (3.4  kcal/mol)   (Terpineol)   (α-­‐Terpinene)   (γ-­‐Terpinene)   29%   15%   Pauling,  1933   Dewar,  1960   Bartell,  1978  Smith, M.; March, J. Marchʼs Advanced Organic Chemistry, 5th ed.; John Wiley & Sons: New York, 2001.!
    • Conjuga(ve  Stabiliza(on  as  a  Theore(cal  Construct:  1,3-­‐Butadiene   33%  H2SO4   1h  100  oC   Conjuga(ve   Stabiliza(on   (3.4  kcal/mol)   (Terpineol)   (α-­‐Terpinene)   (γ-­‐Terpinene)   29%   15%   Readily  explained  by  a  combina(on   of  three  oO  used  concepts  in   organic  chemistry,  resonance,   Pauling,  1933   Dewar,  1960   hybridiza(on  and  steric  strain.     Bartell,  1978  Smith, M.; March, J. Marchʼs Advanced Organic Chemistry, 5th ed.; John Wiley & Sons: New York, 2001.!
    • Conjuga(ve  Stabiliza(on  as  a  Theore(cal  Construct:  1,3-­‐Butadiyne   Conjuga(ve   NaOH   Stabiliza(on   (???  kcal/mol)   Two  Planes  of   sp-­‐sp  C-­‐C  Bond   Resonance   No  Repulsive   1,3-­‐interac(ons  
    • Conjuga(ve  Stabiliza(on  as  a  Theore(cal  Construct:  1,3-­‐Butadiyne   Can  the  same   Conjuga(ve   NaOH   arguments  be  made   Stabiliza(on   for  the  conjuga(on   (???  kcal/mol)   of  two  triple  bonds?   Two  Planes  of   sp-­‐sp  C-­‐C  Bond   Resonance   No  Repulsive   1,3-­‐interac(ons  
    • Conjuga(ve  Stabiliza(on  as  a  Theore(cal  Construct:  1,3-­‐Butadiyne   There  are  many   Conjuga(ve   NaOH   experimental   Stabiliza(on   examples  here   (???  kcal/mol)   too.   Two  Planes  of   sp-­‐sp  C-­‐C  Bond   Resonance   No  Repulsive   1,3-­‐interac(ons  
    • Conjuga(ve  Stabiliza(on  as  a  Theore(cal  Construct:  1,3-­‐Butadiyne   Conjuga(ve   NaOH   Stabiliza(on   (???  kcal/mol)   Also,  the   thermodynamics   argumnts  work  even   beQer  for  1,3-­‐butadiyne!   Two  Planes  of   sp-­‐sp  C-­‐C  Bond   Resonance   No  Repulsive   1,3-­‐interac(ons  
    • Hyperconjuga(on  Masks  Conjuga(on  in  1,3-­‐Butadiyne  (G3  Energies)   Energy (kcal/mol) 26.7 70.6 70.4 30.4 Conjuga(ve   !!Hhydr: Stabiliza(on   -­‐0.2   -0.2 3.7   3.7 (0  kcal/mol!)   ΔH  in  Kcal/mol  Rogers, D. W.; Matsunaga, N.; Zavitsas, A. A.; McLafferty, F. J.; Liebman, J. F.; Org. Lett. 2003, 5, 2373-2375. Jarowski, P. D.;Wodrich, M. D.; Wannere, C. S.; Schleyer, P. v. R.; Houk, K. N., J. Am. Chem. Soc. 2004, 126, 15036.; Kistiakowsky, G. B.; Smith, E.A., J. Am. Chem. Soc. 1939, 61, 1868.; Muller, N.; Mulliken, R. S., J. Am. Chem. Soc. 1958, 80, 3489. !
    • Hyperconjuga(on  Masks  Conjuga(on  in  1,3-­‐Butadiyne  (G3  Energies)   Energy (kcal/mol) 70.6 26.7 Comparing  heats   of  hydrogena(on   gives  the  standard   value  of  1,3-­‐ butadiene  for   conjuga(on   stabiliza(on.   70.4 30.4 Conjuga(ve   !!Hhydr: Stabiliza(on   -­‐0.2   -0.2 3.7   3.7 (0  kcal/mol!)   ΔH  in  Kcal/mol  Rogers, D. W.; Matsunaga, N.; Zavitsas, A. A.; McLafferty, F. J.; Liebman, J. F.; Org. Lett. 2003, 5, 2373-2375. Jarowski, P. D.;Wodrich, M. D.; Wannere, C. S.; Schleyer, P. v. R.; Houk, K. N., J. Am. Chem. Soc. 2004, 126, 15036.; Kistiakowsky, G. B.; Smith, E.A., J. Am. Chem. Soc. 1939, 61, 1868.; Muller, N.; Mulliken, R. S., J. Am. Chem. Soc. 1958, 80, 3489. !
    • Hyperconjuga(on  Masks  Conjuga(on  in  1,3-­‐Butadiyne  (G3  Energies)   For  1,3-­‐ butadiyne  this   Energy (kcal/mol) 26.7 70.6 model  predicts   zero   stabiliza(on.   Could  this  be   true?   70.4 30.4 Π σ*   Conjuga(ve   !!Hhydr: Stabiliza(on   -­‐0.2   -0.2 3.7   3.7 (0  kcal/mol!)   ΔH  in  Kcal/mol  Rogers, D. W.; Matsunaga, N.; Zavitsas, A. A.; McLafferty, F. J.; Liebman, J. F.; Org. Lett. 2003, 5, 2373-2375. Jarowski, P. D.;Wodrich, M. D.; Wannere, C. S.; Schleyer, P. v. R.; Houk, K. N., J. Am. Chem. Soc. 2004, 126, 15036.; Kistiakowsky, G. B.; Smith, E.A., J. Am. Chem. Soc. 1939, 61, 1868.; Muller, N.; Mulliken, R. S., J. Am. Chem. Soc. 1958, 80, 3489. !
    • Hyperconjuga(on  Masks  Conjuga(on  in  1,3-­‐Butadiyne  (G3  Energies)   Energy (kcal/mol) 26.7 70.6 No,  not  really.   It’s  a  limita(on   of  the  model.   70.4 30.4 Π σ*   Conjuga(ve   !!Hhydr: Stabiliza(on   -­‐0.2   -0.2 3.7   3.7 (0  kcal/mol!)   ΔH  in  Kcal/mol  Rogers, D. W.; Matsunaga, N.; Zavitsas, A. A.; McLafferty, F. J.; Liebman, J. F.; Org. Lett. 2003, 5, 2373-2375. Jarowski, P. D.;Wodrich, M. D.; Wannere, C. S.; Schleyer, P. v. R.; Houk, K. N., J. Am. Chem. Soc. 2004, 126, 15036.; Kistiakowsky, G. B.; Smith, E.A., J. Am. Chem. Soc. 1939, 61, 1868.; Muller, N.; Mulliken, R. S., J. Am. Chem. Soc. 1958, 80, 3489. !
    • Hyperconjuga(on  Masks  Conjuga(on  in  1,3-­‐Butadiyne  (G3  Energies)   Energy (kcal/mol) 26.7 70.6 This  problem   arises  from   hyperconjuga(on,   30.4 70.4 which  is  also   being  evaluated.   Π σ*   Conjuga(ve   !!Hhydr: Stabiliza(on   -­‐0.2   -0.2 3.7   3.7 (0  kcal/mol!)   ΔH  in  Kcal/mol  Rogers, D. W.; Matsunaga, N.; Zavitsas, A. A.; McLafferty, F. J.; Liebman, J. F.; Org. Lett. 2003, 5, 2373-2375. Jarowski, P. D.;Wodrich, M. D.; Wannere, C. S.; Schleyer, P. v. R.; Houk, K. N., J. Am. Chem. Soc. 2004, 126, 15036.; Kistiakowsky, G. B.; Smith, E.A., J. Am. Chem. Soc. 1939, 61, 1868.; Muller, N.; Mulliken, R. S., J. Am. Chem. Soc. 1958, 80, 3489. !
    • Hyperconjuga(on  Masks  Conjuga(on  in  1,3-­‐Butadiyne  (G3  Energies)   24.3 Energy (kcal/mol) 26.7 70.6 + 2.4 CH4+ 32.8 70.4 30.4 Π σ*   Conjuga(ve   !!Hhydr: Stabiliza(on   -­‐0.2   -0.2 3.7   3.7 8.5   8.5 (0  kcal/mol!)   ΔH  in  Kcal/mol  Rogers, D. W.; Matsunaga, N.; Zavitsas, A. A.; McLafferty, F. J.; Liebman, J. F.; Org. Lett. 2003, 5, 2373-2375. Jarowski, P. D.;Wodrich, M. D.; Wannere, C. S.; Schleyer, P. v. R.; Houk, K. N., J. Am. Chem. Soc. 2004, 126, 15036.; Kistiakowsky, G. B.; Smith, E.A., J. Am. Chem. Soc. 1939, 61, 1868.; Muller, N.; Mulliken, R. S., J. Am. Chem. Soc. 1958, 80, 3489. !
    • Hyperconjuga(on  Masks  Conjuga(on  in  1,3-­‐Butadiyne  (G3  Energies)   24.3 Energy (kcal/mol) 26.7 70.6 + 2.4 CH4+ The  larger   hyperconjuga(ve   32.8 stabiliza(on  of   1,3-­‐butadiyne   70.4 30.4 fully  obscures  the   conjuga(ve   stabiliza(on  here.   Π σ*   Conjuga(ve   !!Hhydr: Stabiliza(on   -­‐0.2   -0.2 3.7   3.7 8.5   8.5 (0  kcal/mol!)   ΔH  in  Kcal/mol  Rogers, D. W.; Matsunaga, N.; Zavitsas, A. A.; McLafferty, F. J.; Liebman, J. F.; Org. Lett. 2003, 5, 2373-2375. Jarowski, P. D.;Wodrich, M. D.; Wannere, C. S.; Schleyer, P. v. R.; Houk, K. N., J. Am. Chem. Soc. 2004, 126, 15036.; Kistiakowsky, G. B.; Smith, E.A., J. Am. Chem. Soc. 1939, 61, 1868.; Muller, N.; Mulliken, R. S., J. Am. Chem. Soc. 1958, 80, 3489. !
    • Hyperconjuga(on  Masks  Conjuga(on  in  1,3-­‐Butadiyne  (G3  Energies)   24.3 65.7 Energy (kcal/mol) 26.7 70.6 + + 2.4 4.9 CH4+ + CH4 32.8 75.3 70.4 30.4 Π σ*   Conjuga(ve   9.6   !!Hhydr: 9.6 Stabiliza(on   -­‐0.2   -0.2 3.7   3.7 8.5   8.5 (0  kcal/mol!)   ΔH  in  Kcal/mol  Rogers, D. W.; Matsunaga, N.; Zavitsas, A. A.; McLafferty, F. J.; Liebman, J. F.; Org. Lett. 2003, 5, 2373-2375. Jarowski, P. D.;Wodrich, M. D.; Wannere, C. S.; Schleyer, P. v. R.; Houk, K. N., J. Am. Chem. Soc. 2004, 126, 15036.; Kistiakowsky, G. B.; Smith, E.A., J. Am. Chem. Soc. 1939, 61, 1868.; Muller, N.; Mulliken, R. S., J. Am. Chem. Soc. 1958, 80, 3489. !
    • Hyperconjuga(on  Masks  Conjuga(on  in  1,3-­‐Butadiyne  (G3  Energies)   24.3 65.7 Energy (kcal/mol) 26.7 When  we   70.6 + + numerical  remove   2.4 4.9 hyperconjuga(on,   the  world  is  back   CH4+ + CH4 in  focus  and  1,3-­‐ butadiyne  is  more   32.8 75.3 stabilized  by   conjuga(on  than   70.4 30.4 1,3-­‐butdiene   Π σ*   Conjuga(ve   9.6   !!Hhydr: 9.6 Stabiliza(on   -­‐0.2   -0.2 3.7   3.7 8.5   8.5 (0  kcal/mol!)   ΔH  in  Kcal/mol  Rogers, D. W.; Matsunaga, N.; Zavitsas, A. A.; McLafferty, F. J.; Liebman, J. F.; Org. Lett. 2003, 5, 2373-2375. Jarowski, P. D.;Wodrich, M. D.; Wannere, C. S.; Schleyer, P. v. R.; Houk, K. N., J. Am. Chem. Soc. 2004, 126, 15036.; Kistiakowsky, G. B.; Smith, E.A., J. Am. Chem. Soc. 1939, 61, 1868.; Muller, N.; Mulliken, R. S., J. Am. Chem. Soc. 1958, 80, 3489. !
    • The  Conjuga(ve  Stabiliza(on  of  1,3-­‐Butadiyne  by  Isodesmic  Reac(ons  and  Heats  of  Isomeriza(on  (G3  Energies)   Conven(onal  Conjuga(ve  Stabiliza(on   -­‐0.2   + 2 + 3.7   2 New  Conjuga(ve  Stabiliza(on   9.6   + 2 CH4 2 + CH3CH3 8.5   + 2 CH4 2 + CH3CH3 Isomeriza(on  Energies   9.0   8.1   ΔH  in  Kcal/mol  
    • The  Conjuga(ve  Stabiliza(on  of  1,3-­‐Butadiyne  by  Isodesmic  Reac(ons  and  Heats  of  Isomeriza(on  (G3  Energies)   Conven(onal  Conjuga(ve  Stabiliza(on   -­‐0.2   + An  iden(cal  way  to  look  at  it  is  to   2 compare  the  conven(onal   isodesmic  equa(on  at  top  here.   3.7   + 2 New  Conjuga(ve  Stabiliza(on   9.6   + 2 CH4 2 + CH3CH3 8.5   + 2 CH4 2 + CH3CH3 Isomeriza(on  Energies   9.0   8.1   ΔH  in  Kcal/mol  
    • The  Conjuga(ve  Stabiliza(on  of  1,3-­‐Butadiyne  by  Isodesmic  Reac(ons  and  Heats  of  Isomeriza(on  (G3  Energies)   Conven(onal  Conjuga(ve  Stabiliza(on   -­‐0.2   + 2 + 3.7   2 New  Conjuga(ve  Stabiliza(on   9.6   + 2 CHt4 new  equa(ons  that  have   To   he   2 + CH3CH3 removed  hyperconjuga(ve  effects.   8.5   + 2 CH4 2 + CH3CH3 Isomeriza(on  Energies   9.0   8.1   ΔH  in  Kcal/mol  
    • The  Conjuga(ve  Stabiliza(on  of  1,3-­‐Butadiyne  by  Isodesmic  Reac(ons  and  Heats  of  Isomeriza(on  (G3  Energies)   Conven(onal  Conjuga(ve  Stabiliza(on   -­‐0.2   + 2 + 3.7   2 New  Conjuga(ve  Stabiliza(on   9.6   + 2 CH4 2 + CH3CH3 8.5   + 2 CH4 2 + CH3CH3 Isomeriza(on  Energies   9.0   The  new  schemes  compare  well  to   experimentally  verifiable  heats  of   isomeriza(on,  where  hyperconjuga(on   8.1   effects  are  naturally  balanced  and   cancel  out.   ΔH  in  Kcal/mol  
    • Reception and Impact   “Once  Kis(akowsky’s  path  is  abandoned,  one  is  on  a   slippery  slope.”   Donald  W.  Rogers,  2005.     “there  is  so  much  overwhelming  experimental   evidence  for  stabiliza(on  arising  from  conjuga(on,   [for  polyynes].”   François  Diederich,  2004.     “It’s  not  an  experimental  ques(on;  it’s  a  ques(on  of   interpreta(on.”   Wes  Borden,  2004.     Aroma(c   Strain   Stabiliza(on   Energies  C&EN News, December 20, 2004; C&EN News February 25, 2008.; Wodrich, M. D.; Wannere, C. S.; Jarowski, P. D.; Mo, Y.; Schleyer,P. v. R.; Houk, K. N. Chem. Eur. J., 2007, 13, 7731-7744.!
    • Impact on Radical Stabilization Energies, Yet Another TheoreticalConstruct (CBS-RAD Energies)   Conven(onal  Radical  Stabiliza(on   XmCH3-m + CH4 XmCH4-m + CH3 New  Radical  Stabiliza(on   XmCH3-m + 2m CH4 m CH3CH3 + m XH + CH3 p   π 16.8   29.8   (0.88)   35.0   (0.69)   22.3   43.6   (0.98)   58.6   (0.88)   Agrees  with  HMO  Theory     12.3   26.1   (1.06)   33.4   (0.90)   21.9   43.5   (0.99)   58.7   (0.89)   ΔH  in  Kcal/mol  Jarowski,  P.  D.;  Mo,  Y.;  Schleyer,  P.  v.  R.;  Houk,  K.  N.  J.  Am.  Chem.  Soc.  2006,  submiked;  Crans,  D.;  Clark,  T.;  Schleyer,  P.  v.  R.  Tetrahedron  Le4.  1980,  21,  3681.  7.    
    • Impact on Radical Stabilization Energies, Yet Another TheoreticalConstruct (CBS-RAD Energies)   Conven(onal  Radical  Stabiliza(on   XmCH3-m + CH4 XmCH4-m + CH3 Similar  equa(ons  can  be   New  Radical  Stabiliza(on   applied  to  the  concept  of   radical  stabiliza(on.   + 2m CH4 XmCH3-m m CH3CH3 + m XH + CH3 p   π 16.8   29.8   (0.88)   35.0   (0.69)   22.3   43.6   (0.98)   58.6   (0.88)   Agrees  with  HMO  Theory     12.3   26.1   (1.06)   33.4   (0.90)   21.9   43.5   (0.99)   58.7   (0.89)   ΔH  in  Kcal/mol  Jarowski,  P.  D.;  Mo,  Y.;  Schleyer,  P.  v.  R.;  Houk,  K.  N.  J.  Am.  Chem.  Soc.  2006,  submiked;  Crans,  D.;  Clark,  T.;  Schleyer,  P.  v.  R.  Tetrahedron  Le4.  1980,  21,  3681.  7.    
    • Impact on Radical Stabilization Energies, Yet Another TheoreticalConstruct (CBS-RAD Energies)   Conven(onal  Radical  Stabiliza(on   XmCH3-m + CH4 XmCH4-m + CH3 New  Radical  Stabiliza(on   XmCH3-m + 2m CH4 m CH3CH3 + m XH + CH3 p   π Propargyl  and  allylic  radicals   have  different  trends   16.8   29.8   (0.88)   35.0   (0.69)   according  to  the   22.3   43.6   (0.98)   58.6   (0.88)   conven(onal  equa(ons   (red).   Agrees  with  HMO  Theory     12.3   26.1   (1.06)   33.4   (0.90)   21.9   43.5   (0.99)   58.7   (0.89)   ΔH  in  Kcal/mol  Jarowski,  P.  D.;  Mo,  Y.;  Schleyer,  P.  v.  R.;  Houk,  K.  N.  J.  Am.  Chem.  Soc.  2006,  submiked;  Crans,  D.;  Clark,  T.;  Schleyer,  P.  v.  R.  Tetrahedron  Le4.  1980,  21,  3681.  7.    
    • Impact on Radical Stabilization Energies, Yet Another TheoreticalConstruct (CBS-RAD Energies)   Conven(onal  Radical  Stabiliza(on   XmCH3-m + CH4 XmCH4-m + CH3 New  Radical  Stabiliza(on   They  should  both   XmCH3-m + 2m CH4 m CH3CH3 + m XH + CH3 saturate,  according   p   to  perturba(on   theory.   π 16.8   29.8   (0.88)   35.0   (0.69)   22.3   43.6   (0.98)   58.6   (0.88)   Agrees  with  HMO  Theory     12.3   26.1   (1.06)   33.4   (0.90)   21.9   43.5   (0.99)   58.7   (0.89)   ΔH  in  Kcal/mol  Jarowski,  P.  D.;  Mo,  Y.;  Schleyer,  P.  v.  R.;  Houk,  K.  N.  J.  Am.  Chem.  Soc.  2006,  submiked;  Crans,  D.;  Clark,  T.;  Schleyer,  P.  v.  R.  Tetrahedron  Le4.  1980,  21,  3681.  7.    
    • Impact on Radical Stabilization Energies, Yet Another TheoreticalConstruct (CBS-RAD Energies)   Conven(onal  Radical  Stabiliza(on   XmCH3-m + CH4 XmCH4-m + CH3 New  Radical  Stabiliza(on   XmCH3-m + 2m CH4 m CH3CH3 + m XH + CH3 p   π 16.8   29.8   (0.88)   35.0   (0.69)   22.3   43.6   (0.98)   58.6   (0.88)   The  revised  schemes  lead   Agrees  with  HMO  Theory     to  an  equalizing  of  the   qualita(ve  and   12.3   26.1   (1.06)   33.4   (0.90)   21.9   43.5   (0.99)   58.7   (0.89)   trends  for   quan(ta(ve   both  series.   ΔH  in  Kcal/mol  Jarowski,  P.  D.;  Mo,  Y.;  Schleyer,  P.  v.  R.;  Houk,  K.  N.  J.  Am.  Chem.  Soc.  2006,  submiked;  Crans,  D.;  Clark,  T.;  Schleyer,  P.  v.  R.  Tetrahedron  Le4.  1980,  21,  3681.  7.    
    • Application to the Rotational Barrier of Alkynylcumulenes!
    • Applica(on  of  Conjuga(ve  Stabiliza(on  and  Radical  Stabiliza(on  to  the  Analysis  of  the  Low  Rota(onal  Barrier  of  Alkynylbutatrienes   31.9   20.3   26.9   Conjuga(ve   Radical   Rota(onal   +   Stabiliza(on   Stabiliza(on   Barrier   ΔG≠  in  Kcal/mol  Auffrant, A.; Jaun, B.; Jarowski, P. D.; Houk, K. N.; Diederich, F. Chem. Eur. J. 2004, 10, 2906-2911; Jarowski, P. D.; Diederich, F.;Houk, K. N., J. Phys.Chem. A 2006, 110, 7237; Chynwat, V. Ph.D. Thesis, Worcester Polytechnic Institute, 1992; Bertsch, K.; Karich,G.; Jochims, J. C. Chem. Ber. 1977, 110, 3304; Roth, W. R.; Exner, H.-D. Chem. Ber. 1976, 109, 1158-1162; Kuhn, R.; Schulz, B.;Jochims, J. C. Angew. Chem. Int. Ed. Engl. 1966, 5, 420.
    • Applica(on  of  Conjuga(ve  Stabiliza(on  and  Radical  Stabiliza(on  to  the  Analysis  of  the  Low  Rota(onal  Barrier  of  Alkynylbutatrienes   We  can  use  the  concepts  of   conjuga(ve  and  radical   31.9   stabiliza(on  to  predict  useful   informa(on  about  real   chemical  problems.   20.3   26.9   Conjuga(ve   Radical   Rota(onal   +   Stabiliza(on   Stabiliza(on   Barrier   ΔG≠  in  Kcal/mol  Auffrant, A.; Jaun, B.; Jarowski, P. D.; Houk, K. N.; Diederich, F. Chem. Eur. J. 2004, 10, 2906-2911; Jarowski, P. D.; Diederich, F.;Houk, K. N., J. Phys.Chem. A 2006, 110, 7237; Chynwat, V. Ph.D. Thesis, Worcester Polytechnic Institute, 1992; Bertsch, K.; Karich,G.; Jochims, J. C. Chem. Ber. 1977, 110, 3304; Roth, W. R.; Exner, H.-D. Chem. Ber. 1976, 109, 1158-1162; Kuhn, R.; Schulz, B.;Jochims, J. C. Angew. Chem. Int. Ed. Engl. 1966, 5, 420.
    • Self-­‐consistent  Rota(onal  Model  and  Energy  Evalua(on  ΔH≠core     ΔHTSS     TS   ΔHGSS     +   ΔH≠   GS  
    • Self-­‐consistent  Rota(onal  Model  and  Energy  Evalua(on  ΔH≠core     ΔHTSS     The  radical  stabiliza(on  in   the  transi(on-­‐state  to   rota(on  and  the  conjuga(ve   TS   stabiliza(on  in  the  ground-­‐ state  can  be  es(mated  using   a  self-­‐consistent  set  of   isodesmic  equa(ons.   ΔHGSS     +   ΔH≠   GS  
    • Rota(onal  Barrier  is  Controlled  by  the  Radical  Stabiliza(on  of  the  Transi(on  State  (CASPT2/6-­‐31G(d)//B3LYP/6-­‐31G(d)   90   GSS   TSS   Barrier   60   ΔH  in  Kcal/mol   30   0  
    • Rota(onal  Barrier  is  Controlled  by  the  Radical  Stabiliza(on  of  the  Transi(on  State  (CASPT2/6-­‐31G(d)//B3LYP/6-­‐31G(d)   90   GSS   TSS   Barrier   60   ΔH  in  Kcal/mol   The  lowering  of  the  barrier   height  in  the  ethynyl  series  is   due  to  increasing  radical   stabiliza(on  in  the  transis(on   state!  A  statement  only  possible   to  make  with  the  proper   30   equa(ons  set  up.     0  
    • Extended  Cumulenes  Will  have  Near-­‐zero  Rota(onal  Barriers;  Thermal  Energies  will  Favor  a  Ground-­‐State  Diradical   1 ‡ Cl H 1 H H ‡ Me Ar Cl Ar N Me H H Ar Ar Cl Me Cl !G‡ = 65 kcal/mol !G‡ < 0 kcal/mol !G‡ = 16.4 kcal/mol R1 R2 R1 R2 m m R3 R4 R3 R4 R = H, AlkynylDouglas, J. E.; Rabinovitch, B. S.; Looney, F. S. J. Chem. Phys. 1955, 23, 315-323; Rabinovitch, B. S.; Michel, K. –W. J. Am. Chem.Soc. 1959, 81, 5065-5071; Müller, Eu.; Neuhoff, H. Ber. Deut. Chem. Ges. 1939, 72, 2063; Müller, Eu.; Tietz, E. Ber. Deut. Chem. Ges.1941, 74, 807; Kalinowski, H.; Kessler, H. Top. Stereochem 1973, 7, 295; Nagase, S.; Morokuma, K. J. Am. Chem. Soc. 1978, 100,1661-1666.
    • Applica(on  to  the  Thermochemistry  of  Expanded   Polyhedranes    
    • Applica(on  to  Octamethoxy  Expanded  Cubane:  A  Highly  Explosive  Exo(c  Molecule   Radical/Anionic/ Ca(onic   Stabiliza(on   Strained  Diyne   Conjuga(on  Manini, P.; Amrein, W.; Gramlich, V.; Diederich, F. Angew. Chem. Int. Ed. 2002, 41, 4339.
    • Applica(on  to  Octamethoxy  Expanded  Cubane:  A  Highly  Explosive  Exo(c  Molecule   Radical/Anionic/ Ca(onic   Stabiliza(on   Now  lets  apply  some  of   these  concepts  to   exo(c  materials.   Strained  Diyne   Conjuga(on  Manini, P.; Amrein, W.; Gramlich, V.; Diederich, F. Angew. Chem. Int. Ed. 2002, 41, 4339.
    • Thermal  Instability  of  Octamethoxy-­‐Expanded-­‐Cubane  Is  Related  to  Its  Bending  Strain   !1 = 107° Bending  Strain  of  the  Corner  Unit  Facilitates  Heteroly(c   Bond  Dissocia(on   !2 OMe MeO OMe MeO OMe MeO OMe Bending  Strain  of  the  Diyne  Unit  Facilitates   MeO OMe Polymeriza(on   !1 = 174° 174°! 177°! 176°! 173°! ∠CCC ≈ 166°! Not Isolabile,! Explosive! !2 = 177° Polymerizes! Decomposition! Stable, mp.≈160 °C !Jarowski, P. D. Diederich, F.; Houk, K. N., J. Org. Chem. 2005, 70, 1671.; Manini, P.; Amrein, W.; Gramlich, V.; Diederich, F., Angew.Chem. Int. Ed. 2002, 41, 4339. Gleiter, R.; Merger, R.; Chavez, J.; Oeser, T.; Irngartinger, H.; Pritzkow, H.; Nuber, B. Eur. J. Org.Chem. 1999, 2841-2843; Scott, L. T.; DeCicco, G. J. Tet. Lett. 1976, 31, 2663-2666; Pilling, G. M.; Sondheimer, F. J. Am. Chem. Soc.1971, 93, 1970-1977; Sondheimer, F.; Amiel, Y.; Wolovsky, R. J. Am. Chem. Soc. 1957, 79, 62636267; Sondheimer, F.; Amiel, Y. J.Am. Chem. Soc. 1957, 79, 5817-5820. !
    • Thermal  Instability  of  Octamethoxy-­‐Expanded-­‐Cubane  Is  Related  to  Its  Bending  Strain   !1 = 107° Bending  Strain  of  the  Corner  Unit  Facilitates  Heteroly(c   Bond  Dissocia(on   !2 OMe MeO OMe MeO OMe Octamethoxy  Expanded  Cubane   here  is  explosive.  Its  instability  is   MeO OMe somehow  related  to  its  strained   and  bent  structure  that  manifest  in  Diyne  Unit  Facilitates   Bending  Strain  of  the   MeO OMe Polymeriza(on   facile  bond  cleavage  and/or  radical   !1 = 174° decomposi(on.   174°! 177°! 176°! 173°! ∠CCC ≈ 166°! Not Isolabile,! Explosive! !2 = 177° Polymerizes! Decomposition! Stable, mp.≈160 °C !Jarowski, P. D. Diederich, F.; Houk, K. N., J. Org. Chem. 2005, 70, 1671.; Manini, P.; Amrein, W.; Gramlich, V.; Diederich, F., Angew.Chem. Int. Ed. 2002, 41, 4339. Gleiter, R.; Merger, R.; Chavez, J.; Oeser, T.; Irngartinger, H.; Pritzkow, H.; Nuber, B. Eur. J. Org.Chem. 1999, 2841-2843; Scott, L. T.; DeCicco, G. J. Tet. Lett. 1976, 31, 2663-2666; Pilling, G. M.; Sondheimer, F. J. Am. Chem. Soc.1971, 93, 1970-1977; Sondheimer, F.; Amiel, Y.; Wolovsky, R. J. Am. Chem. Soc. 1957, 79, 62636267; Sondheimer, F.; Amiel, Y. J.Am. Chem. Soc. 1957, 79, 5817-5820. !
    • Method  of  Evalua(on  for  Strain  Energies   ΔH riso €
    • Method  of  Evalua(on  for  Strain  Energies   ΔH riso € Which  equa(on  would  you   choose?  Let  pick  the  one  that   only  evaluates  strain,  not   conjuga(on  (top)  and   hyperconjuga(on  (middle).   So  the  boQom  then.  
    • Expanded  Polyhedranes  Are  Less  Strained  Than  Expected   106º 173º Strain Energy (kcal/mol) 108º 1 66º 168º 163º 173º 113.1! 111.8! 107.8! 70.7! 167º 168º 162º 165º 108º 105º 170º 176º 57.7! 168º 169º 106º 46.3! 175º 32.7! 175º 108º 22.4! Wiberg, K. B. Angew. Chem. Int. Ed. Engl. 1986, 65, 312. ! Level: HF/6-31G(d)!
    • Expanded  Polyhedranes  Are  Less  Strained  Than  Expected   154.7! 150.0! 136.6! 106º 173º Strain Energy (kcal/mol) 108º 1 66º 168º 163º 173º 113.1! 111.8! 107.8! 70.7! 167º 168º 162º 165º 108º 170º 176º 105º 63.9! 57.7! 54.7! 168º 169º 51.8! 106º 46.3! 175º 32.7! 175º 108º 27.5! 26.5! 22.4! Wiberg, K. B. Angew. Chem. Int. Ed. Engl. 1986, 65, 312. ! Level: HF/6-31G(d)!
    • Expanded  Polyhedranes  Are  Less  Strained  Than  Expected   159.0   154.7! 150.0! 136.6! 106º 134.5   173º Strain Energy (kcal/mol) 108º 1 110.0   66º 168º 163º 173º 113.1! 111.8! 107.8! 70.7! 167º 168º 162º 165º 108º 170º 176º 105º 63.9! 57.7! 54.7! 168º 169º 51.8! 106º 46.3! 175º 32.7! 175º 108º 27.5! 26.5! 22.4! Wiberg, K. B. Angew. Chem. Int. Ed. Engl. 1986, 65, 312. ! Level: HF/6-31G(d)!
    • Expanded  Polyhedranes  Are  Less  Strained  Than  Expected   159.0   154.7! 134.4! 150.0! 132.6! 136.6! = = 130.8! = 26.6! 19.5! 19.0! ΔE ΔE ΔE 106º 134.5   173º Strain Energy (kcal/mol) 108º 1 110.0   66º 168º 163º 173º 113.1! 111.8! 107.8! 70.7! 167º 168º 162º 165º 108º 170º 176º 105º 63.9! 57.7! 54.7! 168º 169º 51.8! 106º 46.3! 175º 32.7! 175º 108º 27.5! 26.5! 22.4! Wiberg, K. B. Angew. Chem. Int. Ed. Engl. 1986, 65, 312. ! Level: HF/6-31G(d)!
    • Expanded  Polyhedranes  Are  Less  Strained  Than  Expected   159.0   154.7! 134.4! 150.0! 132.6! 136.6! = = 130.8! = 26.6! 19.5! 19.0! ΔE ΔE ΔE 106º 134.5   173º Strain Energy (kcal/mol) 108º 1 110.0   66º 168º The  strain  evaluated  for  expanded   163º polyhedranes  is  113.1! less  than  for   173º actually   111.8! 107.8! the  unexpanded  classical  molecules   like  cubane.  For  cubane,  the  strain  is   addi(ve  (6  x  26.5).  For  expanded   polyhedranes  7 he  final  strain  energy  is   70.7! 16 tº 168º 162º 165º less  than  addi(ve.  This  is  due  to  the   108º 105º 63.9! 170º 176º bending  ability  of  the  acetylenes.   57.7! 54.7! 168º 169º 51.8! 106º 46.3! 175º 32.7! 175º 108º 27.5! 26.5! 22.4! Wiberg, K. B. Angew. Chem. Int. Ed. Engl. 1986, 65, 312. ! Level: HF/6-31G(d)!
    • Distribu(on  of  the  Strain  Energy  from  Molecular  Mechanics   ϕ2 ϕ1 ϕ3 Undistorted   Average   %  Bend  Energy   Distor(on   (kcal/mol)   ϕ1 113o   108o   13   ϕ2 180o   170o   46   ϕ3 180o   172o   41  
    • Distribu(on  of  the  Strain  Energy  from  Molecular  Mechanics   ϕ2 ϕ1 ϕ3 Undistorted   Average   %  Bend  Energy   We  can  see  from  Molecular   Distor(on   (kcal/mol)   Mechanics  analysis  that  most   of  the  strain  energy  is   ϕ1 113o   108o   localized  on  the  diyne  units.   13   ϕ2 180o   170o   46   ϕ3 180o   172o   41  
    • Internal  Volumes  and  Host-­‐guest  Supramolecular  Chemistry  of  Large  Expanded  Polyhedranes  from  Molecular  Mechanics   3 12 33 15,358 117,984 Li+ Na+ K+ CH4 H2S CO2 NH3 PH3 1.8 4.4 11.0 28 30 33 23 33 Bondi, A. J. Phys. Chem. 1964, 68, 441-451 ! Volume (Å3)
    • Internal  Volumes  and  Host-­‐guest  Supramolecular  Chemistry  of  Large  Expanded  Polyhedranes  from  Molecular  Mechanics   3 12 33 Some  truly  impossible   molecules  with  large  interior   spaces.   15,358 117,984 Li+ Na+ K+ CH4 H2S CO2 NH3 PH3 1.8 4.4 11.0 28 30 33 23 33 Bondi, A. J. Phys. Chem. 1964, 68, 441-451 ! Volume (Å3)
    • Impact:  Further  Proper(es,  Con(nuing  Synthe(c  Efforts   Bond  dissocia(on  energies   Ongoing  work  towards  the  asymmetric    of   synthesis  octaphenyl  expanded  cubane   297.0 399.8 Ca(on  affini(es   ∠CCC ≈ 166°! ∠CCC ≈ 166°! not isolable,! mp. = 150° C! unstable to polymerization Jarowski, P. D. Diederich, F.; Houk, K. N., J. Org. Chem. 2005, 70, 1671-1678. Manini, P.; Amrein, W.; Gramlich, V.; Diederich, F.Angew. Chem. Int. Ed. 2002, 41, 4339-4343. Bachrach, S. M. J. Phys. Chem. 2003, 107, 4957-4961.; Demoin, D. W.; Bachrach, S.M. J. Org. Chem. 2006, 71, 5105!
    • Impact:  Further  Proper(es,  Con(nuing  Synthe(c  Efforts   Bond  dissocia(on  energies   Ongoing  work  towards  the  asymmetric    of   synthesis  octaphenyl  expanded  cubane   Current  work  is  on  stabilizing   297.0 these  structures  by  changing   399.8 the  corner  groups.  They  make   intriguing  supramolecular   hosts  for  ca(ons.   Ca(on  affini(es   ∠CCC ≈ 166°! ∠CCC ≈ 166°! not isolable,! mp. = 150° C! unstable to polymerization Jarowski, P. D. Diederich, F.; Houk, K. N., J. Org. Chem. 2005, 70, 1671-1678. Manini, P.; Amrein, W.; Gramlich, V.; Diederich, F.Angew. Chem. Int. Ed. 2002, 41, 4339-4343. Bachrach, S. M. J. Phys. Chem. 2003, 107, 4957-4961.; Demoin, D. W.; Bachrach, S.M. J. Org. Chem. 2006, 71, 5105!
    • Summary!  Reevaluating Theoretical Energy Constructs.! !Graduate Research at UCLA with Prof. K. N. Houk. !   The conjugative stabilization of 1,3-butadiyne is NOT ZERO.!   Propargylic and allylic radicals are stabilized to the same extent.!   Self-consistent approach to the rotational energetic barriers of cumulenes.!   Expanded polyhedranes are LESS strained than their unexpanded analogues.!
    • Acknowledgment and Thank You! François Diederich! Ken Houk! Yi-Lin Wu (Special Thanks)! Electrochemistry! Computing:! Maurice Gross, Jean-Paul Gisselbrecht,! ATS Beowulf Cluster! Corinne Boudon (Univ. Louis Pasteur,! Pittsburgh Supercomputing Center! Strasbourg)! FUNDING:! X-ray:! NSF! Dr. Bernd Schweizer, Paul Seiler (ETHZ)! ACS Organic Division! (Organic Reaction Inc.)! Computing:! Competence Center for Computational! Chemistry! (C4) ETHZ.! FUNDING:! ETH Research Council! Fonds der Chemischen Industrie!