Week 8: Coordination Chemistry 4 Overview Getting Started Techniques Procedure FAQ Full Lab Manual Introduction & Goals Chemistry & Background Key Questions Prelab Problems Safety Procedure In Your Write-up Experiments Index ChemLab Home		Goals This week, you will further investigate the ligand exchange reaction between NO2- and [Co(NH3)5(H2O)]3+. You will monitor the two steps of the reaction and determine the reaction rate constants and the order of both steps with respect to [Co(NH3)5(H2O)]3+. To Learn or Review Transition Metal Complexes Zumdahl, pp. 910-917 Rate Laws Zumdahl pp. 690-708 Reaction Mechanisms Zumdahl, pp. 708-714 Color of Complex Ions Zumdahl pp. 940-941 Introduction The reaction mechanism for the substitution of a nitrite ion, NO2-, for the water ligand of [Co(NH3)5(H2O)]3+ is more complicated than it first appears. Your results from last week should have shown that the reaction occurs in two steps, an initial ligand attachment followed by an isomerization to a final product. Your data should have shown which linkage isomer, the nitro or nitrito, is formed first and which is formed second. The isomer formed initially is considered to be kinetically favored, since it can form quickly. The isomer that is the final product is the thermodynamically favored isomer, since it is energetically more stable, although it is not formed initially for kinetic reasons.
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