lect17_ch24b_3pg

lect17_ch24b_3pg - Polydentate Ligands& Nomenclature...

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Unformatted text preview: Polydentate Ligands & Nomenclature Chapter 24 – Lecture 2 Chemistry 123 Spring 2008 Dr. Woodward Chelating (Polydentate) Ligands (Polydentate) Porphyrins Porphine (C20H14N4) Myoglobin & Hemoglobin 1 Chlorophyll Rules for Naming Coordination Compounds 1. For ionic compounds the cation comes before the anion. 2. For the complex ion part (within brackets) the ligands are listed in alphabetical order before the metal. 3. Anionic ligands end in the letter o, neutral ligands retain their names (NH3 = ammine, H2O = aqua). Cl− = chloro Br− = bromo I− = iodo O2− = oxo OH− = hydroxo CN− = cyano 4. Greek prefixes are used to indicate the number of ligands (different prefixes are used if the ligand itself has one of these prefixes). 2 = di 3 = tri 4 = tetra 5 = penta 6 = hexa 2 = bis 3 = tris 4 = tetrakis (alternate prefixes) 5. If the complex ion has a negative charge it ends in ate. 6. The oxidation number of the metal is given in parentheses in roman numerals. Color: CrO4- & Chromate Salts 1.2 5 conc. 2CrO4 solution SrCrO4 1.0 PbCrO4 0.8 2- dilute CrO4 solution 3 0.6 2 0.4 absorbance (SrCrO4, PbCrO4) 2- absorbance (CrO4 ) 4 1 0.2 0.0 250 300 350 400 450 500 550 600 650 0 700 wavelength (nm) SrCrO4 behaves much like a concentrated CrO42- solution. Sr2+ ions have little effect on the electronic absorption, whereas Pb2+ ions shift the absorption edge to lower energy (longer wavelengths). 2 ...
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This note was uploaded on 06/03/2011 for the course CHM 123 taught by Professor Woodward during the Spring '08 term at Ohio State.

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