Extra credit

1
Extra credit

• Extra credit 1 ionic radii trends
• Extra credit 2 solving MIMT single crystal
  structures
• Work on these must be completed individually.
• Due date May 14th

2
Exploring biological functionality

• Enzymes
• Complex systems that often contain metals at
  active site
• Metals are particularly import for redox enzymes
• Bio-inorganic chemistry
• Synthesis of model compounds

3
The biological nitrogen cycle
4
Nitrogenase
Nitrogenase consists of 2 proteins dinitrogenase
reductase and dinitrogenase
Overall reaction
dinitrogenase reductase
dinitrogenase
16 ATP required for each reduction of N2 -gt 2 NH3
5
Some bacteria fix nitrogen only when involved in
a symbiotic relationship with plants
6
Leghemoglobin protects nitrogenase by binding
oxygen
A true cross-species collaboration Plant makes
the globin protein and bacterium makes the heme
cofactor
7
Industrial Haber process (N2 -gt NH3)
T 400-500 C p 300-1000 atm
8
Dinitrogenase model compound
9
Oxygen binding in body
10
You will make model compound, Co(salen)

• Co(salen) can bind oxygen, just like the
  biological heme molecule

11
Oxygen binding depends on Co environment

• In crystals
• Solvated

• Co(salen) exists with Co in a 4, 5, or 6
  coordinate site
• Solvated Co(salen) only binds O2 when it is 5 or
  6 coordinate

12
Experimental apparatus for measuring O2 binding