Lecture 9-Chemical Bonding II Flashcards
How is a dative covalent bond formed?
Formed by sharing 2 e- with both e- provided by one of the atoms
Where are co-ordinate bonds found?
Transition metal complex ions The Ammonium ion Other nitrogen-containing complexes The Hydroxonium ion Carbon Monoxide Nitric Acid
Who is the donor in a co-ordinate bond?
The atom supplying the shared pair of e-
What is a lone pair of e-?
A pair of e- in the valence shell of the atom that are not involved e.g. nitrogen
What requirement does the acceptor atom in a co-ordinate bond must have and why?
A VACANT bonding orbital to accept the e- pair donated by the donor
How is the ammonium ion formed?
When ammonia reacts with H+
How do complex ions form?
When transition metal ions and Al3+ and dissolved in H20
Why can Al3+ form complex ions?
- All the orbitals in the 3rd shell = vacant + available to accept e-
- Directionality = 2 e- on the oxygen pointing in different directions
What does the function of some biological molecules depends on in dative bonding?
The binding of a metal ion containing cofactor - porphyrins , corrins
Name some of the biological molecules whose function depends on the binding of a metal ion containing cofactor - porphyrins , corrins?
- Haemoglobin
- Myoglobin
- Cytochromes P450
- Vitamin B12
- Chlorophyll
- Photodynamic therapy
In dative covalent bonding, the function of some drugs depend on their ability to what?
- Act as donors in dative covalent bonds -CHELATION THERAPY
- Act as acceptors for biological donors
What element is good at forming dative covalent bonds?
S
What is used for the treatment of copper + arsenic poisoning?
D-penicillamine
What is used for the treatment of mercury , lead + arsenic poisoning?
Dimercaprol
What is used for the treatment of iron overdose?
Desferoxamine
