1. Transition metal chemistry Coordination compounds – ligands and things Coordinate covalent bonds and ligands Coordinate covalent bonds and ligands Nomenclature Nomenclature Isomerism Isomerism Spectroscopy Spectroscopy Electronic structure Electronic structure

2. Coordinate covalent bond  Lewis acid/base chemistry  Lone pair on water (base)  Vacancy on Fe 2+ (acid)

3. Positive, neutral, negative  The complex can be an ion that forms part of a neutral compound - square brackets delineate the complex  Or may exist as a standalone neutral compound (no square brackets)

4. Things to consider  Coordination number – the number of ligands around the central ion  Geometry – the shape of the complex  Much greater variety and complexity compared with the geometry of covalent molecules of the representative elements

5. Coordination number Complex 2 [Ag(NH 3 ) 2 ] +, [CuCl 2 ] - 3 [HgI 3 ] - 4 [Zn(NH 3 ) 4 ] 2+, [Ni(CN) 4 ] 2- 5 [Ni(CN) 5 ] -, Fe(CO) 5 6 [Cr(H 2 O) 6 ] 3+, [Fe(CN) 6 ] 3- 7 [ZrF 7 ] 3- 8 [Mo(CN) 8 ] 4- Examples of complexes with different coordination numbers

6. Geometry - prelude  Rules for determining geometry are more involved than the simple VSEPR approach that works well with covalent compounds  Note: same composition may adopt different geometries  Will be dealt with using ligand-field theory

7. Things to know  Writing the correct formula  Determining oxidation state on the central atom Complex charge - Sum of anion charges = o.s. Complex charge - Sum of anion charges = o.s. Square bracket Number of neutral ligands Number of anion ligands Overall charge

8. Ligands – entities with teeth  Must contain a lone electron pair  Classify the ligands according to the number of available pairs Monodentate – one pair Monodentate – one pair Bidentate – two pairs Bidentate – two pairs Polydentate – many pairs Polydentate – many pairs

9. Anion ligand Name Neutral ligand Name BromideBromoAmmoniaAmmine CarbonateCarbonatoWaterAqua ChlorideChloro Carbon monoxide Carbonyl CyanideCyano Ethylene diamine FluorideFluoro HydroxideHydroxo OxalateOxalato Thiocyanate Thiocyanato/Iso thiocyanato Common ligands and names in complex ions

11. Chelating – ligands with claws  Ligands with greater than one lone pair can form more than one bond to a single metal ion  Ethylene diamine (en)– tridentate en  EDTA - hexadentate EDTA

12. Important biological entities  (a) The structure of the porphine molecule. Loss of the two NH protons gives a planar, tetradentate 2– ligand that can bond to a metal cation. The porphyrins are derivatives of porphine in which the peripheral H atoms are replaced by various substituent groups. (b) Schematic of the planar heme group, the attached protein chain, and the bound O 2 molecule in oxyhemoglobin and oxymyoglobin. The Fe(II) ion has a six-coordinate, octahedral environment, and the O 2 acts as a monodentate ligand.

13. What’s in a name

14. Rules, rules, rules 1. If the compound is a salt, naming is as for common salts: cation first and then anion Potassium hexacyanoferrate(III)

15. Complex ion or neutral complex 2. Ligands first then metal  Endings are the thing Anionic ligands end in –o Anionic ligands end in –o -ide → -o; -ate → -ato -ide → -o; -ate → -ato Neutral ligands have normal names except… Neutral ligands have normal names except… H 2 O (aqua), NH 3 (ammine), CO (carbonyl) H 2 O (aqua), NH 3 (ammine), CO (carbonyl)  One word: nospacebetweenligandandmetal Diamminedichloroplatinum(II)

16. More than one ligand 3. Indicate number of ligands by prefixes: di-, tri-, etc.  Ligands are listed in alphabetical order Tetraaquadichlorochromium(III) chloride

17. It’s all Greek to me 4. If the ligand name contains a Greek prefix (ethylenediamine), the ligand name is in parantheses and use an alternative prefix: bis- (2), tris-(3), tetrakis(4) Tris(ethylenediamine)cobalt(III) chloride

18. Roman numerals 5. Roman numeral in parantheses to indicate oxidation state of metal in situation where the o.s. is variable

19. -ate crimes 6. -ate is the conventional ending for the metal in an anionic complex  Check table for exact wording Metal Anion Name Metal AluminiumAluminateIronFerrate ChromiumChromateManganeseManganate CobaltCobaltateNickelNickelate CopperCupratePlatinumPlatinate GoldAurateZincZincate