CHM1022 Week 9 Workshop 1 & 2 Ligands & Nomenclature PDF

Week 9/Workshop 1: Ligands v 1.0 Objectives for Week 9 Workshop 1 Identify ligands and their donor atoms Demonstrate knowledge of abbreviations and structures of common ligands Classify ligand using the concept of denticity Describe the origin of acidity of metal aqua complexes...

Week 9/Workshop 1: Ligands v 1.0 Objectives for Week 9 Workshop 1 Identify ligands and their donor atoms Demonstrate knowledge of abbreviations and structures of common ligands Classify ligand using the concept of denticity Describe the origin of acidity of metal aqua complexes Describe the relationship between thermodynamic stability and ligand exchange Derive equilibrium constants for ligand exchange Workshop 2 Apply conventions to accurately name and give formula for coordination compounds Convert between chemical name, chemical structure and formula for coordination compounds  Recap from pre-workshop material Ligands, donor atom(s), denticity Atoms/molecules that can act as ligands: water, NH3, carbon monoxide F-, chloride ion, OH-, ethylenediamine (en), bis(ethylene)triamine (trien) cyanide ion, SCN-, nitrite ion, NO3-  Feed Code: V6SPFH Examples Identify the ligands (number) and donor atoms. Ligands = water (6); donor atoms = oxygen There are three bidentate ligands (bipyridine); donor atoms = nitrogen There is only one ligand (EDTA), which is hexadentate with both N and O donor atoms  Feed Code: V6SPFH Bonus Example – Bridging Ligands 4- colourless solution + FeIII (yellow solution) Bridging cyanide ligands Prussian Blue Activity 1: Ligands Case Study Identify the ligands and donor atoms in these complexes. 2. CuSarTATE Can be used as a 64Cu radiotracer for imaging using positron emission tomography. Dalton Trans., 2014, 43, 1386-1396. 1. Ru complex of clotrimazole Antiparasitic (also as the free ligand) against Trypanosoma cruzi. Inorg. Chem., 2001, 40, 6879–6884. 3. Amavadin A compound that is found in toadstools. Thought to act as a peroxidase, but it’s role has not been fully explored. J. Inorg. Biochem., 2005, 99, 1264–1267.  Recap from pre-workshop material Brønsted Acidity of Metal Aqua Complexes - All metal ions are Lewis acids (electron pair acceptors) but their strength varies. - In general Lewis acidity increases (i) across the periodic table (left to right) and (ii) with increasing positive charge (3+ > 2+) - The net results is the formation of a Brønsted acid (H3O+) solution. - The pKa of the final solution will depend on the Lewis acidity of the metal i.e. greater Lewis acidity yields solutions of lower pKa value (i.e. results in a stronger Brønsted acid) Activity 2: Brønsted Acidity of Metal Aqua Complexes Rank the four metal complexes (in aqueous solution) in order of increasing Brønsted acidity Explain why you have ranked them this way Recap from pre-workshop material Chelating ligands and chelating effect When a multidentate ligand coordinate to a metal ion using more than one donor atom (forming a ring with the metal), the ligand is said to be a chelating ligand and the resulting compound is said to be a chelate complex.  Recap from pre-workshop material ΔG = ΔH - TΔS - As we go from reaction (I) to (II) to (III) the entropy of the reaction increases because the number of particles (molecules) increases with the reaction. - Therefore, reaction (III) forms the most stable product. - This is also known as chelating effect. Activity 3: Ligand Exchange and Complex Stability You will be shown a number of animations, showing chemicals A, B, and C mixed in different orders and combinations. You should: Observe the colour changes of the reactions Using the order in which things displace, determine what each chemical is from a given list of chemicals Explain how you determined the contents of the jars  Activity 3: Ligand Exchange and Complex Stability Ammonia +C +A +B [Cu(OH2)6] Ethylenediamine +B +C +A [Cu(OH2)6] Disodium EDTA Match the chemical to the correct jar Activity 4: Equilibrium demonstration 2[CrO4]2- + 2H+ [Cr2O7]2- + H2O Add acid to [CrO4]2- and equilibrium will move to the right Add base to [Cr2O7]2- (i.e. lower [H+]) and equilibrium will move to the left [products] [Cr2O72-] Equilibrium constant K = = [reactants] [CrO42-]2[H+]2 Activity 5: Ligand Exchange Equilibrium Constants Examine the reaction that is shown below. For this reaction derive: Equations for the stepwise equilibrium constants An equation for the overall equilibrium constant Summary Today we have: Identified ligands and their donor atoms. Classified ligand using the concept of denticity. Discussed the origin of acidity of metal aqua complexes. Described the relationship between thermodynamic stability and ligand exchange. Derived equilibrium constants for ligand exchange. Week 9/Workshop 2: Nomenclature v 1.0 Objectives for Week 9 Workshop 1 Identify ligands and their donor atoms Demonstrate knowledge of abbreviations and structures of common ligands Classify ligand using the concept of denticity Describe the origin of acidity of metal aqua complexes Describe the relationship between thermodynamic stability and ligand exchange Derive equilibrium constants for ligand exchange Workshop 2 Apply conventions to accurately name and give formula for coordination compounds Convert between chemical name, chemical structure and formula for coordination compounds Recap from pre-workshop material Recap from pre-workshop material Activity 1: Naming and Formula Conventions for Coordination Compounds Pt. 1 You will be given parts of chemical names, and a picture of a coordination compound. You will then need to: Examine the molecule being shown and use the provided name fragments to create a name for the molecule Not all fragments will need to be used How many can you get right? Example 1 Activity 1: Naming and Formula Conventions for Coordination Compounds Pt. 1 Using only the relevant options provided, determine the full systematic name for the following compound: AQUA (I) BROMIDE (II) BROMIDO (III) CHLORIDO (IV) COBALTATE MONO COBALT DI WATER TRI TETRA NICKEL HEXA Start by identifying the main components of the compound... Example 2 Activity 1: Naming and Formula Conventions for Coordination Compounds Pt. 1 Using only the relevant options provided, determine the full systematic name for the following compound: SODIUM (I) BROMIDE (II) CHLORIDE (III) CHLORIDO (IV) ZINCATE MONO ZINC DI Zn TRI TETRA POTASSIUM HEXA Example 3 Activity 1: Naming and Formula Conventions for Coordination Compounds Pt. 1 Using only the relevant options provided, determine the full systematic name for the following compound: AMINE κ AMMINE (II) AMINO (III) NITRATE (IV) COBALTATE O COBALT N NITRITE MONO TETRA NITRITO PENTA Example 4 Activity 1: Naming and Formula Conventions for Coordination Compounds Pt. 1 Using only the relevant options provided, determine the full systematic name for the following compound: SODIUM (I) POTASSIUM (II) SCN (III) THIOCYANATE (IV) THIOCYANATO κ IRON DI IRONATE HEXAKIS TETRA FERRATE HEXA S N Example 5 Activity 1: Naming and Formula Conventions for Coordination Compounds Pt. 1 Using only the relevant options provided, determine the full systematic name for the following compound: NITRITE (I) NITRITO (II) NITRATE (III) NITRATO (IV) COPPER BIS CUPRATE DI ETHYLENEDIAMINE TETRA ( TETRAKIS ) Activity 2: Naming and Formula Conventions for Coordination Compounds Pt. 2 - This activity has 9 different questions in which either (i) chemical formula, (ii) chemical structure or (iii) chemical name is given. - You are asked to complete the other two missing information about a complex. - The question are divided into easy (3), medium (3) and hard (3).  M en u Questions Activity 2: Naming and Formula Conventions for Coordination Compounds Pt. 2 Easy #1 Medium #1 Hard #1 Easy #2 Medium #2 Hard #2 Easy #3 Medium #3 Hard #3 Question: Easy 1 Activity 2: Naming and Formula Conventions for Coordination Compounds Pt. 2 In groups, provide the name/formula/diagram (whichever two are missing) for the compounds shown. ? Chemical Structure ? Answer ? Chemical Name ? Question: Easy 2 Activity 2: Naming and Formula Conventions for Coordination Compounds Pt. 2 ? Chemical Formula ? In groups, provide the name/formula/diagram (whichever two are missing) for the compounds shown. ? Chemical Structure ? Answer Question: Easy 3 Activity 2: Naming and Formula Conventions for Coordination Compounds Pt. 2 ? Chemical Formula ? 3- O In groups, provide the name/formula/diagram O (whichever two are missing) for the compounds O shown. O O O V O O O O O O Answer ? Chemical Name ? Question: Medium 1 Activity 2: Naming and Formula Conventions for Coordination Compounds Pt. 2 In groups, provide the name/formula/diagram (whichever two are missing) for the compounds shown. ? Chemical Structure ? Answer ? Chemical Name ? Question: Medium 2 Activity 2: Naming and Formula Conventions for Coordination Compounds Pt. 2 ? Chemical Formula ? In groups, provide the name/formula/diagram (whichever two are missing) for the compounds shown. ? Chemical Structure ? Answer Question: Medium 3 Activity 2: Naming and Formula Conventions for Coordination Compounds Pt. 2 ? Chemical Formula ? In groups, provide the name/formula/diagram (whichever two are missing) for the compounds shown. Answer ? Chemical Name ? Question: Hard 1 Activity 2: Naming and Formula Conventions for Coordination Compounds Pt. 2 In groups, provide the name/formula/diagram (whichever two are missing) for the compounds shown. ? Chemical Structure ? Answer ? Chemical Name ? Question: Hard 2 Activity 2: Naming and Formula Conventions for Coordination Compounds Pt. 2 ? Chemical Formula ? In groups, provide the name/formula/diagram (whichever two are missing) for the compounds shown. ? Chemical Structure ? Answer Question: Hard 3 Activity 2: Naming and Formula Conventions for Coordination Compounds Pt. 2 ? Chemical Formula ? In groups, provide the name/formula/diagram (whichever two are missing) for the compounds shown. Answer ? Chemical Name ? Summary Today we have: Discussed the conventions to accurately name and give formula for coordination compounds. Practiced the conversion between chemical name, chemical structure and formula for coordination compounds.