Chelatometry. Introduction of biogenic elements chemistry

1
LECTURE 3
Chelatometry. Introduction of biogenic elements
chemistry
ass. prof. Ye. B. Dmukhalska
2
MINERALS

• Basic functions performed by the minerals are
• 1. As structural components of body tissues.
• 2. In the maintenance of acid-base balance.
• 3. In the regulation of body fluids.
• 4. In transport of gases.
• 5. In muscle contractions.

3

• In the human body and animals are near 70
  chemical elements, but 47 are called biogenic
  elements
• Six elements carbon, hydrogen, oxygen, nitrogen,
  phosphorus, sulfur are on amino acid, basic
  components of albumen, and they are named
  organogenic.
• 94 of all living tissues contain only 4
  elements carbon, hydrogen, oxygen, nitrogen.

4

• Depending on quantitative maintenance all
  elements classified into macro-, micro- and
  ultramicroelements.
• The macroelements are elements which more then
  0,01 of body mass are on organism. It is
  sodium, potassium, calcium, phosphorus, chlorine,
  sulfur, magnesium.
• The microelements 10-310-5 . It is an iodine,
  bromine, fluorine, iron, copper, aluminium,
  magnesium, cobalt, zinc, strontium, lithium,
  selenium, molybdenum.
• The ultramicroelements are elements which lest
  then 10-5 . It is a mercury, gold, chrome,
  silicon, nickel.

5
Complex compounds ?)
Structure CuSO4 4 NH3 Cu (NH3)4 SO4
Cu (NH3)4 SO4 Complex compound

• Cu2 - central atom
• NH3 ligand
• Cu (NH3)42 - complex ion
• SO42- -anion

6

• Coordination compounds are the compounds in which
  the central metal atom is linked to ? number of
  ions or neutral molecules by coordinate bonds
  i.?. by donation of lone pairs of electrons by
  these ions or neutral molecules to the central
  metal atom.
• nickel tetracarbonyl, Ni(CO)4

7

• the species formed by linking of ? number of ions
  or molecules by co-ordinate bonds to the central
  metal atom (or ion) carries positive or negative
  charge, it is called a complex ion. Fe(?N)64-,
  Cu(NH3)42, Ag(CN)2-

8

• The donor atoms, molecules or anions, which
  donate ? pair of electrons to the metal atom and
  form co-ordinate bond with it are called ligands.

9

• If only one donor atom is present in its
  molecule, which can coordinate, then it is called
  as unidentate (monodentate). NH3, ?2? and CN-.
• The ligand may contain two donor atoms
  (coordinating groups) positioned in such ? way
  then it is called bidentate chelating ligand
• The ring is called chelate ring and the resulting
  complex is called ? metal chelate.

10

• The complexes formed by Cu (II) and Pt (II) ions
  with ethylenediamine are metal chelates
  represented as follows

11
(No Transcript)
12

• Some important characteristics of chelates.
• (i) Chelating ligands form more stable complexes
  than the monodentate analogs. This is called
  chelating effect.
• (ii) Chelating ligands, which do not contain
  double bonds e.g. ethylenediamine form five
  membered stable rings. The chelating ligands such
  as acetylacetone form six membered stable ring
  complexes.
• (iii) Ligands with large groups form unstable
  rings than the ligands with smaller groups due to
  steric hindrance.

13

• Coordination number. The total number of
  monodentate ligands (plus double the number of bi
  dentate ligands if any) attached to the central
  metal ion through coordinate bonds is called the
  coordination number of the metal ion.
• Ag(?N)2-, Cu(N?3)42 and Cr(?2?)63

14
Coordination sphere.

• The central atom and the ligands which are
  directly attached to it are enclosed in square
  brackets and are collectively termed as the
  coordination sphere.

15
Oxidation number or oxidation state.

• It is ? number that represents an electric charge
  which an atom or ion actually has or appears to
  have when combined with other atoms,
• oxidation number of copper in Cu(NH3)42 is 2
  but coordination number is 4.
• oxidation number of Fe in Fe(?N)63- is 3 but
  the coordination number is 6.
• (i) Cu (N??)4SO4.
• (ii) Fe in Fe (?N)63-
• (iii)?3Fe(?2?4)3.
• (iv) Ni(CO)4.

16
Charge on the complex ion.

• The charge carried by ? complex ion is the
  algebraic sum of the charges carried by central
  metal ion and the ligands coordinated to the
  central metal ion.
• Ag (CN)2-
• Cu (NH3)42

17
(No Transcript)
18
Co-ordination Werners theory
Charge coordination number
example of the metal
ion 1 2
Ag, Cu 2
4, 6 Cu2, Zn2,
Pd2, Pt2 3 6, 4
Pt4, Cr3, Co3, Fe3 4
8
Sn4
19

• Co(N?3)6 Cl3, hexaamminecobalt (III) chloride.
• K2PtCl6, potassium hexachloroplatinate (IV).
• Co(NO2)(NH3)3, triamminetrinitrocobalt (III)
• PtCl4(NH3)2, diamminetetrachloroplatinum (IV).

20

• (i) Negative ligands end in o
• CN- (cyano), Cl- (chloro), Br- (bromo), F-
  (fluor?), NO2- (nitro), ??- (hydroxo), ?2- (???),
  SO42-(sulphato), ?2?22- (oxalato), N?2- (amido ),
  NH2- (imido), ONO- (nitrito), NO3- (nitrato),
  SCN- (thiocyanato), NCS- (isothiocyanato),
  ??2(N?2)CO?- (glycinato)etc.

21

• (ii) Neutral ligands have no special ending N?3
  (ammine), ?2? (aqua), CO (carbonyl), CS
  (thiocarbonyl) and NO (nitrosyl)

22

• (iii) Positive ligands (which are very few) end
  in -ium, ?.g., N?3 (hydrazinium), NO
  (nitrosonium), N?2 (nitronium).

23

• (iv) Organic ligunds. Organic free radicals are
  given their own names. For example, ??3 (methyl),
  ?2?5 (ethyl), ?6?5 (phenyl), ?5?5
  (cyclopentadienyl).
• For organic neutral molecules, their names are
  used. For example, ?(?6?5)3, triphenylphosphine

24

• (v) Unidentate ligands with more than one
  co-ordinating atoms. It is essential to designate
  the point of attachment of ? ligand by placing
  the symbol of the donor atom attached after that
  name of the groups separated by hyphen. These
  ligands are called ambidentate ligands ?.g., in
  thiocyanate and nitrite ions, we have two options
  each.
• SCN, thiocyanate - N?2- nitro
• NCS, isothiocyanate - ONO, nitrite

25
(No Transcript)
26
Types of complexes.

• (i) ? complex in which the complex ion carries ?
  net positive charge is called cationic complex
  Co(N?3)3, Ni(NH3)62
• (ii) ? complex in which the complex ion carries ?
  net negative charge is called anionic complex
  Ag(CN)2-, Fe (CN)64-
• (iii) ? complex carrying no net charge is called
  ? neutral complex or simply ? complex
• Ni(CO)4, CoCl3 (N?3)3

27
Main types of complex compounds

• 1. With one central atom
• Ammonia complex Cu(NH3)4SO4
• Aqua complexAl(H2O)6Cl3
• acidic complex K2PtCl4
• complex with difference ligands KPt(NH3)Cl3
• cyclic (chelates)
• Polycentral compoynds
• Chain Cr(NH3)5 OH (NH3)CrCl3
• chelaes (CO)5Mn Mn(Co)5

28
(No Transcript)
29
Thank you for attention