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Symmetry of PolyoxometalateBased Late-Transition-MetalOxo Complexes And The “Oxo
Wall”
Mixtli Campos-Pineda
Group Theory. ...
Outline


Introduction
◦ The Oxo Wall
◦ The Vanadyl Ion (C4v)



Late transition metal M=O symmetries
◦ AuO (C2v)
◦ Pt-o...
Introduction


Terminally bound oxo species are
proposed as intermediates of
important catalyzed reactions.



The Oxo W...
Groups 3-6 are stable
 Groups 7-8 are more reactive
 Groups 9-11 are rare (electrons begin
to populate antibonding orbit...
The Vanadyl Ion
 C4v symmetry of VO(H2O)5

s-orbitals transform as A1
 p-orbitals transform as A1+E
 d-orbitals transform as A1+B1+B2+E




a.s.=5

1 1 3 1 = 2A1...


B2 is a non bonding orbital


Transitions (B2 initial state)
◦ B2 (A1+E)=B2 + E
◦ Only 2B2E is symmetry allowed
◦ 2B22B1 and 2B2 2A1 are vibronica...
Late transition metal M=O
symmetries


AuO


C2v symmetry of AuO

s-orbital transforms as A1
 p-orbitals transform as A1+B1+B2
 d-orbitals transform as A1+A2+B1+B...


Transitions (A2 initial)
◦ A2 (A1+B1+B2)= A2+B1+B2
◦ A2A1 transition is a vibronic one


Pt-oxo and Pd-oxo
s-orbitals transform as A1
 p-orbitals transform as A1+E
 d-orbitals transform as A1+B1+B2+E




a.s.=5

1 1 3 1 = 2A1...


Transitions (E initial state)
◦ E (A1+E)=E + A1+A2+B1+B2
◦ All allowed transitions



Transitions (B2 initial state)
◦...


Electronic transitions:
Revisiting the late transition
metal M=O complexes.


The square planar Pd unit (D4h)


D4h symmetry of Pd unit
s-orbital transforms as A1g
 p-orbitals transform as Eu+A2u
 d-orbitals transform as
Eg+B1g+B2g+A1g
 a.s.=4 0 0 2 0 0 0...
Conclusions
Group Theory can help us assign and
describe the symmetry of MOs.
 We can assess the symmetry of
transitions ...
References
C J Ballhausen et al, Inorg. Chem.
1962, 1(1), 111.
 K P Halloran et al, Inorg. Chem.,
2012, 51 (13), 7025–703...
Symmetry of metal-oxo complexes
Symmetry of metal-oxo complexes
Symmetry of metal-oxo complexes
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Symmetry of metal-oxo complexes

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Symmetry of metal-oxo complexes

  1. 1. Symmetry of PolyoxometalateBased Late-Transition-MetalOxo Complexes And The “Oxo Wall” Mixtli Campos-Pineda Group Theory. December 4th, 2013
  2. 2. Outline  Introduction ◦ The Oxo Wall ◦ The Vanadyl Ion (C4v)  Late transition metal M=O symmetries ◦ AuO (C2v) ◦ Pt-oxo and Pd-oxo (C4v)  Revisiting the late transition metal M=O complexes. ◦ The square planar Pd unit (D4h)  Conclusions
  3. 3. Introduction  Terminally bound oxo species are proposed as intermediates of important catalyzed reactions.  The Oxo Wall: ◦ “M=O groups are stabilized at metal centers with an oxidation state of no less than 4+ and no more than four d electrons”
  4. 4. Groups 3-6 are stable  Groups 7-8 are more reactive  Groups 9-11 are rare (electrons begin to populate antibonding orbitals) 
  5. 5. The Vanadyl Ion  C4v symmetry of VO(H2O)5 
  6. 6. s-orbitals transform as A1  p-orbitals transform as A1+E  d-orbitals transform as A1+B1+B2+E   a.s.=5 1 1 3 1 = 2A1+B1+E
  7. 7.  B2 is a non bonding orbital
  8. 8.  Transitions (B2 initial state) ◦ B2 (A1+E)=B2 + E ◦ Only 2B2E is symmetry allowed ◦ 2B22B1 and 2B2 2A1 are vibronically allowed
  9. 9. Late transition metal M=O symmetries  AuO
  10. 10.  C2v symmetry of AuO s-orbital transforms as A1  p-orbitals transform as A1+B1+B2  d-orbitals transform as A1+A2+B1+B2 
  11. 11.  Transitions (A2 initial) ◦ A2 (A1+B1+B2)= A2+B1+B2 ◦ A2A1 transition is a vibronic one
  12. 12.  Pt-oxo and Pd-oxo
  13. 13. s-orbitals transform as A1  p-orbitals transform as A1+E  d-orbitals transform as A1+B1+B2+E   a.s.=5 1 1 3 1 = 2A1+B1+E
  14. 14.  Transitions (E initial state) ◦ E (A1+E)=E + A1+A2+B1+B2 ◦ All allowed transitions  Transitions (B2 initial state) ◦ B2 (A1+E)=E +B2 ◦ Only pure electronic transitions to states with E or B2 symmetry are allowed.
  15. 15.  Electronic transitions:
  16. 16. Revisiting the late transition metal M=O complexes.  The square planar Pd unit (D4h)
  17. 17.  D4h symmetry of Pd unit
  18. 18. s-orbital transforms as A1g  p-orbitals transform as Eu+A2u  d-orbitals transform as Eg+B1g+B2g+A1g  a.s.=4 0 0 2 0 0 0 4 2 0= A1g+B1g+Eu   Transitions (tentatively) ◦ EB1 becomes EgB1g ◦ EA1becomes EgA1g ◦ B2B1 becomes B2gB1g
  19. 19. Conclusions Group Theory can help us assign and describe the symmetry of MOs.  We can assess the symmetry of transitions even if we don’t know their energy.  Group Theory can’t help us in structure determinations, since it requires us to postulate a structure with a point group 
  20. 20. References C J Ballhausen et al, Inorg. Chem. 1962, 1(1), 111.  K P Halloran et al, Inorg. Chem., 2012, 51 (13), 7025–7031.  T M Anderson et al, Science, 2012, 306, 2074 .  T M Anderson et al, J. Am. Chem. Soc., 2005, 127, 11948.  R Cao et al, J. Am. Chem. Soc., 2007, 129, 11118. 

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