Lecture 24 Outline of Last Lecture I. Coordination Numbers and Geometry II. Chelates and Kinetic Lability III.Nomenclature IV.Isomerism Outline of Current Lecture I. Isomers cont. (mainly optical) II. d-Orbital Energies a. Crystal Field Theory b. d-Orbital Splitting Current Lecture I. To review, optical isomers are mirror images, but cannot be superimposed. Remember, isomers that are mirror images, but can rotate on top of one another are solely the same compound, not optical isomers. Only if you cannot get them to line up by drawing from another angle are they optical isomers. The first two examples below on the left are not optical isomers, but the next set are: ! Chem 1120 1st Edition!!!These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best !used as a supplement to your own notes, not as a substitute. !!The cis platinum complex below can be drawn 12 different ways, all of which are the same molecule: *Convince yourself that this complex is not chiral Question: What is the similarity and what is the difference between the d and l isomers of a compound? Answer: A !!Answer: A Question: What is the electron configuration for Cobalt? For Cobalt 3+? Answer: Cobalt ——> [Ar]4s23d7 Cobalt 3+ ——> [Ar]3d6 A. d-orbitals in a “ligand field” experience repulsion by the ligand electrons differently, based on their respective symmetries relative to the ligand axes Crystal Field Theory:!-The five d orbitals in an uncomplexed metal have the same energy B. Magnitude of d-orbital splitting: The energy gap between the two sets of orbitals depends on metal and, to a larger extent, on the ligand The spectrochemical series: ligands can be arranged in an order based on ligand field strength; this series was empirically derived using visible light absorption spectroscopy!Weak field ligand = low energy difference = high spin Strong field ligand = high energy difference = low
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