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 14 th
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
The biological nitrogen cycle
Nitrogenase Nitrogenase consists of 2 proteins: dinitrogenase reductase and dinitrogenase Overall reaction dinitrogenase reductase dinitrogenase 16 ATP required for each reduction of N 2 -> 2 NH 3
Some bacteria fix nitrogen only when involved in a symbiotic relationship with plants
Leghemoglobin protects nitrogenase by binding oxygen A true cross-species collaboration: Plant makes the globin protein and bacterium makes the heme cofactor
Industrial Haber process (N 2 -> NH 3 ) T = °C p = atm
Dinitrogenase model compound
Oxygen binding in body
You will make model compound, Co(salen) Co(salen) can bind oxygen, just like the biological heme molecule
Oxygen binding depends on Co environment Co(salen) exists with Co in a 4, 5, or 6 coordinate site Solvated Co(salen) only binds O 2 when it is 5 or 6 coordinate In crystals: Solvated:
Experimental apparatus for measuring O 2 binding