CHEM10006 Study Guide - Final Guide: Chelation Therapy, Toxic Heavy Metal, Nitric Oxide
12 Jun 2018
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denticity, stronger complex: binds to metal ion more strongly
Coordination number: The number of donor atoms bound to
the metal ion in a coordination complex, usually between 2-10
If ligands are all neutral,
charge on complex will
equal charge on metal ion
If total charge equals the
charge on the metal ion, the
complex is neutral
If total charge exceeds
charge on metal ion,
complex is anionic
If one catecholate
dissociates it is lost, not as
stable
Catechol: Upon
deprotonation, capable of
chelating metal ions such
as Fe(III): Catecholate
2-
:
dianionic chelating ligand
Bidentate, 6 coordination
points, octahedral,
association constant: 10
33
,
not as strong as
enterobactin
Optical isomers: Stereoisomerism: Chiral
Saturated solution: A solution in which no more solute will
dissolve; rate of dissolving = rate of precipitation
Ferric ion is soluble and available under acidic conditions, but
no oceans have a pH of approximately 2
Freshwater: acidic because of dissolved CO
2
(pH = 5.5), iron
enters food chain as ferrous through deep waters, no oxygen,
via metabolisms of anaerobic bacteria
Oceans: pH = 8.2, carbonate minerals makes sea more basic,
iron available in deep sea waters but not at surface of sea
EDTA
4-
: Ethylenediaminetetraacetate, hexadentate ligand,
tetravalent, can wrap strongly around a metal ion, can remove
Ca
2+
from wate r, act as a water softener, and of use in
c helation therapy
Chelation therapy: Used to treat heavy metal poisoning by
using chelate ligands e.g. EDTA which binds to toxic heavy
metals e.g mercury, to remove them from the body
Coordination isomerism: Same formula, but formula in
complex ion is different
➔Water, OH
2
, aqua
➔Ammonia, NH
3
, ammine
➔Carbon monoxide, CO, carbonyl
➔Nitric oxide, NO
2
, nitrosyl
➔Hydroxide, OH
-
, hydroxido
➔Oxide, O
2-
, oxido
➔Cyanide, CN
-
, cyanido
➔Carbonate, CO
3
2-
, carbonato
(Ide) replaced with (ido)
(Ate) replaced with (ato)
Coordination compound nomenclature
1. Cation named before anion
2. Ligands named before metal ion
3. (Ido) added to root anem if it’s anionic
4. Di, tri, tetra etc. prefixes indicate number of simple
ligands
5. Bis, tris, tetrakis etc. prefixes indicate number of
complicated ligands or ligands that contain di, tri etc.
6. Oxidation state indicated by roman numerals
7. Ligands in alphabetical order
8. If complex is negatively charged, -ate added to metal
name
9. Latin name sometimes used for metal in an anionic
complex
Fe: ferrate
Cu: cuprate
Pb: plumbate
Ag: argentate
Au: aurate
Sn: stannate
Human Iron Nutrition
In stomach Fe released by digestion of food proteins
●Haem (from meat, blood), absorbed faster
●Non-haem e.g. [Fe
III
(H
2
O)
4
(HP
V
O
4
)]
+
; hydrogen
phosphate is a bidentate ligand stable at low
stomach pH, involved in supply of Fe to transferrin
Proteins are constructed from alpha-amino acids
Under acidic conditions, cation favoured, and anion in basic
conditions
Side chain:
Document Summary
Denticity, stronger complex: binds to metal ion more strongly. Coordination number: the number of donor atoms bound to the metal ion in a coordination complex, usually between 2-10. If ligands are all neutral, charge on complex will equal charge on metal ion. If total charge equals the charge on the metal ion, the complex is neutral. If total charge exceeds charge on metal ion, complex is anionic. Saturated solution: a solution in which no more solute will dissolve; rate of dissolving = rate of precipitation. Ferric ion is soluble and available under acidic conditions, but no oceans have a ph of approximately 2. Freshwater: acidic because of dissolved co 2 (ph = . ), iron enters food chain as ferrous through deep waters, no oxygen, via metabolisms of anaerobic bacteria. Oceans: ph = 8. 2, carbonate minerals makes sea more basic, iron available in deep sea waters but not at surface of sea.
