Preparation of Bis Acetylacetonao Copper 2
Experiment 6
Title: Preparation of bis(acetylacetonato)copper(II) complex
Objective: To synthesize the bis(acetyacetonato) copper(II) complex
Theory/Background:
All metal ions in solution are 'associated' with water. The water molecules can also be weakly bonded or more strongly as a ligand to form a complex ion, and these can also present in solid 'hydrated' salts of crystallization. E.g Copper(II) nitrate (Cu(NO3) 2.3H2O).
A complex ion has a metal ion at its centre with a number of other molecules or ions surrounding it. These can be considered to be attached to the central ion by co-ordinate (dative covalent) bonds. The molecules or ions surrounding the central metal ion are called ligands. Simple ligands include water, ammonia, acetyl acetone and chloride ions.
Ligand has active lone pairs of electrons in the outer energy level. These are used to form co-ordinate bonds with the metal ion. All ligands are lone pair donors. In other words, all ligands function as Lewis bases.
Lewis acid-base theory reminders:
A base is an electron pair donor and an acid is an electron pair acceptor.
Ligands like water, can donate a pair of non-bonding electrons (lone pair) into a vacant orbital of a central metal ion and so dative covalent (co-ordinate) bonds hold a complex together.
The central metal ion with vacant bonding orbitals can act as a Lewis acid.
Ligands act as Lewis bases by electron pair donation to form the metal-ligand bond.
Bronsted-Lowry acid-base theory reminders (essentially a sub-set of Lewis Theory)
A base is a proton acceptor.
This is via an electron lone pair on the base (a Lewis base is a lone pair donor).
e.g. NH3, HCO3-, OH- etc.
An acid is proton donor.
This involves a heterolytic breakage of an X-H bond (a Lewis acid is an electron pair acceptor).
e.g. HCl, HCO3-, H2SO4, CH3COOH etc. • Many hexa-aqa complex ions can undergo acid-base reactions with water to produce solutions of pH less than 7. o Usually
Title: Preparation of bis(acetylacetonato)copper(II) complex
Objective: To synthesize the bis(acetyacetonato) copper(II) complex
Theory/Background:
All metal ions in solution are 'associated' with water. The water molecules can also be weakly bonded or more strongly as a ligand to form a complex ion, and these can also present in solid 'hydrated' salts of crystallization. E.g Copper(II) nitrate (Cu(NO3) 2.3H2O).
A complex ion has a metal ion at its centre with a number of other molecules or ions surrounding it. These can be considered to be attached to the central ion by co-ordinate (dative covalent) bonds. The molecules or ions surrounding the central metal ion are called ligands. Simple ligands include water, ammonia, acetyl acetone and chloride ions.
Ligand has active lone pairs of electrons in the outer energy level. These are used to form co-ordinate bonds with the metal ion. All ligands are lone pair donors. In other words, all ligands function as Lewis bases.
Lewis acid-base theory reminders:
A base is an electron pair donor and an acid is an electron pair acceptor.
Ligands like water, can donate a pair of non-bonding electrons (lone pair) into a vacant orbital of a central metal ion and so dative covalent (co-ordinate) bonds hold a complex together.
The central metal ion with vacant bonding orbitals can act as a Lewis acid.
Ligands act as Lewis bases by electron pair donation to form the metal-ligand bond.
Bronsted-Lowry acid-base theory reminders (essentially a sub-set of Lewis Theory)
A base is a proton acceptor.
This is via an electron lone pair on the base (a Lewis base is a lone pair donor).
e.g. NH3, HCO3-, OH- etc.
An acid is proton donor.
This involves a heterolytic breakage of an X-H bond (a Lewis acid is an electron pair acceptor).
e.g. HCl, HCO3-, H2SO4, CH3COOH etc. • Many hexa-aqa complex ions can undergo acid-base reactions with water to produce solutions of pH less than 7. o Usually