COMPLEX COMPOUNDS.
THE NATURE OF CHEMICAL
GARDENS IN COMPLEX
COMPOUNDS

By the end of the 19th century, he had divided all
chemical compounds into atomic, first-order, and high-
molecular-weight compounds. Over time, high-order
stable substances began to be called coordination
compounds.

Coordination compounds are very
common in nature
Malaxite Cu2 (OH) 2CO3,
 Izumrud Be 3Al [Si6O18]
Porphyrins are vital products for the human body
 Mg is green chlorophyll, Fe (II) is red hemoglobin,
and Cu (II) is blue hemocyanin (blood pigment).

 Initially, a high-order compound or complex
compound was understood to be a substance
whose connections could not be explained on
the basis of valence theory.
 The first complex compound was obtained in
1704 by Disbach
 K4 [Fe (CN) 6].

 But since he could not explain its structure and
valences, he considered the compound to be a
double salt. 4KCN * Fe (CN) 2.
 In 1798, Tasser synthesized [Co (NH3) 6 CI3,
which he synthesized in the laboratory, luteo-
yellow, depending on its color, and called the
second salt CoCl3 3NH3 prazeo-green salt.

 Many authors began to call the complex compounds
they synthesized, that is, complex compounds, by the
names of the authors.
 Kosse salt K [Pt (NH3) 6] Cl3 was synthesized. It's like
ammonia, he wrote.
 CoCl3 * 6NH3 Seyse salt was synthesized.

The term "complex compound"
was first coined by Ostwald.
 The term complex means complex
 For example C6H4O2 * C6H4 (OH) 2 - xingidron

Academician Yu.N. Kukushkin
"A complex compound is a
compound that contains a central
atom surrounded by ligands,
whether in the crystalline state or
in solution," he said.
 [SoF8] 5-

“As coordination compounds
compounds that can exist both in the crystalline
state and in solution, as well as complex ions
composed of a central atom (electron acceptor)
and orbiting ligands (electron donors). ”
[Co3 + (En) 4] 3+

Basic cases of Werner's
theory :
 1) Most elements have additional valences in
addition to their basic valences.
 2) Each element tends to saturate its primary and
secondary valences
 Co3 + + 6 NH3  [Co (NH3) 6] 3+
 Co3 + + 6 CN–  [Co (CN) 6] 3–
 [Co (NH3) 6] 3+ + 6 CN–  [Co (CN) 6] 3– + 6
NH3
Alfred Verner (1866-1919)

 Acidocomplexes. Complex compounds whose
ligands consist of acid residues are called acid
complexes (eg K2 [Pt (NO2) 4Br2])
[Fe(NCS)6]3− + 4F− = [FeF4]− + 6NCS−
K4[Fe(CN)6]
K3[Fe(CN)6]

 Polyhalogenides. Complex compounds whose
central ions and ligands are composed of halogens
are called polyhalogenides. For example: K [I3], K
[ICl4] and so on.
KI + I2 = K[I(I)2]
CsCl + IBr = Cs[I(Br)(Cl)]
K[I(I)2] + t° = KI + I2
Cs[I(Br)(Cl)] + t° = CsCl + IBr

 Complex hydrides. When acidic and
amphoteric hydrides react with basic hydrides
in solvents other than water, a complex
hydride is formed.
 For example
 K [AlH4], Al [BH4] 3.
 LiH BH3 Li [BH4],
Li[AlH4] Na[BH4]

 Complexes similar to metallic organic compounds.
 For example: ferrocene Fe (C5H5) 2, dibenzene
chromium Cr (C6H6) 2, lithium hexaphenyl
chromium Li [Cr (C6H5) 6] and so on.
[Fe(C5H5)2]

 Metal carbonyls. Compounds of metals formed with
carbon monoxide CO are called carbonyls.
 Examples: nickel tetracarbonyl Ni (CO) 4, iron
pentacarbonyl Fe (CO) 5, decacarbonidium
manganese Mn2 (CO) 10 and so on.
[Ni(CO)4]

4. When naming groups that act as a "bridge" connecting
one coordination center with another, the letter m is
placed in front of them. For example: -di - -
gidroksooktaakvoditemir (III) -sulfate, -kaliy di - -
hydroxotetra-oxalatodichrome (III).
K4 (C2O4)2Cr
OH
OH
Cr(C2O4)2

A) Neutral complexes
[MLn] n L M (in a word)
Examples:
[Ni (CO) 4] - tetracarbonyl nickel;
[Co2 (CO) 8] - octacarbonyldicobalt;
[Al2Cl6] - hexachlorodialuminum;
[Co + III (NH3) 3Cl3] - trichlorotriamminkobalt (III)
[Co + II (H2O) 4 (NO2) 2] - dinitrotetraacvacobalt
(II)
Name of complex compounds

1. Peyrone's rule. When acid complexes react with
ammonia, products of the cis-isomeric state are formed.
For example, if we add 2 moles of ammonia to 1 mole of
potassium tetrachloroplatin (II) -K2 [PtCl4] in solution, cis-
dichlorodiamminplatina is formed and KCl is released.
Effect of ammonia on acid complexes

2. Iorgensen's rule. When ammonia decomposes under
the action of acids, it often forms trans-isomeric acid
compounds. For example, when tetramminplatin (II)
chloride [Pt (NH3) 4] decomposes Cl2 with HCl,
trans-dichlorodiamminplatin (II) is formed.
Effect of acids on ammonia

4. N.S. Kurnakov's rule. It is important to separate the
coordination compounds in the trans- and cis-forms.
Studies have shown that the trans-form of the same
coordination compound is less soluble than its cis-form.
N. Kurnakov's rule helps to differentiate trans - and fog
- forms. N.S. Kurnakov examined the reaction of cis-
and trans-diamines with thiourea SC (NH2) 2, which
revealed a complete exchange of ligands in the cis-
isomer for thiourea:
Separation of trans and fog
complexes

5. II Chernyaev's rule of trans-influence. In 1926, II
Chernyaev described a very important rule for the
chemistry of coordination compounds by
examining the isomers of flat square compounds of
2-valent platinum.
The relative strength of a bond between a ligand
and a central ion in coordination compounds
depends on the nature of the other ligand in the
trans state relative to that ligand..
The rule of thumb

The ligand, which enhances the covalent nature of the
bond between the central atom and the ligand, enhances
the ionic level of the ligand-bonded atomic bond in its
trans (state) and facilitates its exchange with other
ligands (only in octahedral and flat square geometric
coordination compounds). . The nature of the bond must
be ionic for the exchange to take place in the solution.
For example, the reaction activity of Cl increases due to
the stronger trans-action of the NO2 group on Cl.

This law explains why some mixed ligand complexes do not
form. For example, it is not known whether PtCl2 (Thio) 2 is
formed in solution when thiourea is added to a solution of
[PtCl4] 2, because no substance containing the Thio molecule is
formed in the cis state, and the trans-effect of Thio is strong. the
presence of Cl leads to an increase in the ionic level when it
binds to the central atom and is therefore excitable. This law
states that when one of the three chloride ions of a substance
containing [PdCl3 (NO2)] 2 participates in an exchange reaction,
the exchange process in a molecule containing only Cl -, as
opposed to trans - active NO2, [PdCl3 (NH3)] - (one mole when
a mole complex of ions is present with the incoming substance)
allows us to predict the presence of a Cl - ion in the trans state
relative to NH3.