Unformatted text preview: Polydentate Ligands &
Chapter 24 – Lecture 2
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.
1.0 PbCrO4 0.8
2- dilute CrO4
solution 3 0.6
0.4 absorbance (SrCrO4, PbCrO4) 2- absorbance (CrO4 ) 4 1
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.
- Spring '08