This Part 2 of p acids and bases illustrates the implementation of the

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This Part 2 of p acids and bases illustrates the
implementation of the Research for the
Classroom program in this 4610/5560 course

• Research for the Classroom is a program I am
  currently implementing as proposed in the
  Educational Component of my active NSF-CAREER
  proposal.
• Some classroom students perform a small research
  project instead of writing a term paper.
• The classroom students findings are incorporated
  into research papers that relate the findings to
  experimental and computational data in my and my
  collaborators labs or from the literature.
• Three success stories are illustrated here by
  students in this 4610/5560 class.

2

• R e-withdrawing (e.g., CF3)
• Should make it a p acid

R e-releasing (e.g., Me i-Pr t-Bu) ? should
make it a p base
M Cu Ag Au Metal effect??
3
Project given as a classroom assignment to Alex
Gonser Chem 5560 student in Fall 2003 (in
collaboration with his advisor, Dr. Cundari)
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DFT-calculated electrostatic potentials mapped
on the electron density surfaces of M3Pz3
complexes. Color code bluemost positive p
acid redmost negative p base Yellow weak p
base Green very weak p base
Cu3Pz3 Ag3Pz3 Au3Pz3
Pz have Me groups on the Pz rings (inductive
effect of Me renders all trimers basic)
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Positive charge
These triangles are unsubstituted M3Pz3 trimers
with M Cu, Ag, Au
PzAu3
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All strong p acids The inductive effect of CF3
renders all trimers acidic, even the Au trimer.
Contrast the following
3,5-(CF3)2PzAu3
PzAu3
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• These findings by Alex combined with other
  experimental data led to a paper just published
  in Inorganic Chemistry (the premier journal in
  inorganic chemistry) that was selected to be
  featured on the JOURNAL COVER

Trinuclear pyrazolate ring complexes of coinage
metals exhibit startling luminescence
thermochromism due to intertrimer M-M excimeric
bonding in their supamolecular stacks. Though
unsubstituted PzM3 trimers are bases (Augt Cu
gtgt Ag), fluorination renders even the Au trimer
acidic, leading to the isolation of the first
acid-base adduct in which a trinuclear AuI
complex acts as an acid. See M. A. Omary, M. A.
Rawashdeh-Omary, M. W. A. Gonser, O. Elbjeirami,
T. Grimes, T. R. Cundari, H, V. K. Diyabalanage,
C. S. Palehepitiya Gamage, and H. V. R. Dias, p
8200.
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SUMMARY

• Substituent effect
• R e-withdrawing (e.g., CF3)
• makes it more of a p acid
• R e-releasing (e.g., Me i-Pr t-Bu)
• ? makes it more of a p base

Metal effect Relative p basicity
AugtCugtAg Relative p acidity AggtCugtAu
M Cu Ag Au
If you want to react with naphthalene (p base),
what would you choose for R and M to form an
acid-base adduct?
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Maha Eldabaja (4610 student here doing research
in the Omary group).just got crystals of an
adduct for Ag(3,5-(CF3)2Pz)3 with naphthalene
and found that it has green emission, consistent
with naphthalene phosphorescence
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Maha Eldabaja (4610 student here doing research
in the Omary group).just got crystals of an
adduct for Ag(3,5-(CF3)2Pz)3 with naphthalene
and found that it has green emission, consistent
with naphthalene phosphorescence (lets hear it
for Maha!!)
Chi2 1.032 Durbin Watson 1.85 Z
374.2 Pre-exp. 1 825.2 1.638E001 Lifetime
1 1.575E004 ms 6.652E002 Offset 26.5
t 15.8 0.7 ms
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OK so we studied substituent and M effects, how
about the effect of the bridging ligand itself?

• Project THIS SEMESTER for Samer Tekarli

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(carb)Au3
(im)Au3
(C6H4)Hg3
TzAu3
PzAu3
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Neutral Anion dH Neutral Anion dH
Carbeniate -33.2603 -32.6385 0.6218 -20871.1756 -20480.9782 390.1973
Imidazolate -39.0693 -38.4402 0.6291 -24516.3538 -24121.5806 394.7731
Pyrazolate -39.0512 -38.4814 0.5698 -24505.0272 -24147.4673 357.5599
Tyrazolate -42.7174 -42.1766 0.5408 -26805.5693 -26466.2027 339.3666
Triphenyl (-1) -37.3825 -36.7372 0.6453 -23457.8726 -23052.9376 404.9350
Triphenyl (-2) -36.7372 -35.8858 0.8514 -23052.9376 -22518.6597 534.2779
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Ag
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Ag
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Au
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Au
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Cu
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Cu
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HOMO_1 (5453)
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HOMO_2 (5354)
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LUMO (55)