View
136
Download
2
Tags:
Embed Size (px)
Citation preview
By- Mr.Dinkar Kamkhede
M.Sc CHE 2014
Coordination chemistry is the branch of chemistry, which lets us know how
metal complexes are built. A complex is a cluster of ions and molecules, which
can exists independently but prefers to join together in a structurally well
defined manner. A metal complex consists of a metal ion, often structurally
well-defined manner. A metal complex consists of a metal ion, often referred to
as the central metal atom or ion, which binds a number of ions and or
molecules, called ligand.
The reorganization of true nature of complexes began with
Alfred Warner, who in 1893 proposed what is now commonly referred to as
Warner’s coordination theory He prepared an characterized hundreds of
coordination compounds. For this major contribution, Warner awarded the
noble prize in chemistry in 1913.
The interaction of transition metal ions with biological molecules provides one of
the fascinating areas of coordination chemistry.
The application has been grown readily due to their wide range in household,
industry, medicine, chemical and biological system. Some of the important once
are
Plant growth:
Plants need various nutrients for healthy growth. Essential nutrients
include number of mental such as iron, copper and zinc etc. Iron in the +3 state
the soil is mostly hydrolyzed to from insoluble iron hydroxide, which cannot be
taken up by plants. Deficient in iron are likely to develop a disorder known as
iron chlorosis, evidenced by yellowing leaves.
• Therapeutic chelating agents:
The coordination complex of platinum effectively inhibit the growth of cancerous cells.
It has long been suspected that chelation processes are associated both with the
development of cancer and with antitumor actively
Important of cefadroxil
Cefadroxil is a broad – spectrum antibiotic of the cephalic sporum HPE Effectixe in
gram positive and gram negative bacterial infection. It is a bactericidal
antibiotic.Cefadroxil is a first generation cephalosporin antibacterial ative of cefadraxil.It
has been effectiom of the skin and urinary fract.
Pharmacakinetics:-cefadroxil is almost completely absorded from gastrointestinal
tract after does of 500 mg and 19 by mouth, peak plasma doncetration of about 16 and
30 micrograms/ ml are bastioned after 1.5 to 2 hours.
It is widely distributed to body tissue and fluid it crosses the placentas and appears in
breast milk.
Side effect :- toast common side effect cefadroxil is diarrhea, nausea,
upset stomach and vomiting other rahshes hixes, itching .
Dental use :- is used as antibiotic prophylaxis dental pracedare fpr patiens
allergic to penicillin.
Veterinary use :- Canbe used for treating interacted woinds on animals
usuallyin powder from mixied with water has a colorand smell similar amount
dependent on their we igth and severity of intercting.
General Methods to Study Metal Complexes:
The numbers of methods deal with the study of metal –ligand complexes in
solution are
,
pH Metric Technique-
Metal complex formation may be taken place due to the displacement of
proton from ligand causing a drop in the pH- metric value of the solution. Irving and Rossotti
61 have given a method for calculation of stability constants of complexes by pH-metric
technique. This general technique has been followed by Calvin and bjerrum.
Co-relation between the basicity of the ligand and stability of complexes: The complex formation is a complexation between metal ions and protons in
most cases. Therefore, it is reasonable to expect that there is some correlation between the
stability constant of the complex and the acidic dissociation constant of conjugate acid of the
ligand.Larsson" finds linear relationships between the corresponding constants for the
complexes of silver ion with organic amines. Subsequently similar correlations were found in
many complex systems". The ligand may affect the chelating tendency in two possible ways.
•It may influence of basicity of donor group by inductive and resonance effect.
•The addition of groups on the ligand may be purely statistical. Sterical effects prevent the
ligand ions or molecules from acquiring the orientation about the central metal ion most
favourable for chelation.
Determination of the stability constants from the experimental data consist
of three steps:-
The determination of the formation curve of the system expressed as a Plot
•The calculation of values of log K1 and log 2 by solving the formation
of the system.
n-n-n-
-------------- (16)against log K = log 1
[L]
•The calculation of values of log K1 and log K2 by solving the formation
of the system.
• The conversion of stoichiomctric constants into the thermodynamic
functions
The experimental procedure involves titration of:
•Nitric Acid (A)
•Nitric Acid -1- Ligand Acid (A + L)
•Nitric Acid * Ligand Acid + Metal Salt (A — L + hi)
With standard solution of sodium hydroxide. The ionic strength of each
solution is kept constant at 0.01 M by addition of 1.00 potassium nitrate
solution
Calculation of A, n and pL
n-
A= y -
(V2 - V1) (N + E0)
(V0+ V1 ) T
0 L
1)The experimental data obtained from the titration curves helps in calculation of nA n
and pL.i) Proton ligand formation number nA for different pH values can be obtained from
expression.
2)The metal ligand formation number n can be calculated from the expression:-
=
Chapter – III
EXPERIMENTAL, RESULTS AND DISCUSSION
ExperimentalSolvents
Distilled Water:
Distilled water prepared may contain small quantities of dissolved ammonia and carbon
dioxide.Distilled water used investigation was obtained by redistilling twice the distilled water
prepared from alkaline potassium permanganate: the head and tail fractions were rejected to
remove the dissolved ammonia'`. The dissolution of carbondioxide was prevented during
distillation by connecting a potassium hydroxide trap in the receiver of distillate. The resulting
distillate was boiled to expel oxygen and then it was cooled in a well-stoppered glass bottle
(Distilled water free from ammonia and carbondioxide had pH 7.00)
Sodium Hydroxide:
The solution of sodium hydroxide {E. Merck} was prepared carbonate by allowing the
solution to stand for along time till any if present precipitated. The solution was filtered
through a sintered glass crucible and kept in a pyrex veasel free from carbondioxide and
was used as the titrant for the pH-metric titrations. Titrating against standard oxalic acid
solution before starting an experiment standardized the solution of sodium hydroxid.
Formation Curves –
The formation curves were constructed by plotting the values of
Aagainst pH of solution and are presented in Fig. 19 to 34. The dissociation constant pk of
ligands are calculated from formation curves. The values of pk obtained are represented in Table
34(a). The dissociation constants (pk values) for substituted ligands are found to be above pH
10.00 for all the systems.
Meta I-Ligand Stability Constants –
The metal Ligand stability constant is the association or formation constant. For the conversion of
any Calvin-Bjerrum titrations data -into stability constants, following conditions should hold
good for the system under investigation.
•Formation of complex or chelate under the experimental conditions Employed.
•Absence of metal ion hydrolysis, polynuclear hydrogen and hydroxyl complexes and anion of
complexing metal ions.
System log log
Cu (II) ligand 1.29 0.386
Metal-Ligand stability constant
Conclusion
•The departure between acid curve and ligand curve indicated the dissociation of phenolic. -OH
group.
•The departure between ligand curve and metal curve indicated the commencement of complex
formation.
•The change in colour during pH-metric titration also indicated the fomution of complexes
between ligands and metal ions.
The values of pK and log K arc increased with increasing the mixture of water which is attributed
due to the effect of bulky solvent.
•The non-linear relationship for the graphs I:D versus pK/log K but linear relation
relationship for the graphs between mole fraction versus pK/log K is observed.
Volume of Alkali added Titration free acid Titration of free acid + Ligand Titration of free acid +ligand + Metal
Cu II
0.00 1.5 1.5 1.5
0.5 1.7 1.7 1.7
1.0 1.9 1.9 1.9
1.5 2.1 2.1 2.1
2 2.1 2.1 2.1
2.5 2.3 2.3 2.3
3 2.5 2.5 2.5
3.5 3 3 3
4 3.5 4 3.7
4.5 4.6 4.7 4.3
5 5.4 5.5 4.7
5.5 6.3 6.4 5.3
6 7.5 7.3 5.8
6.5 8.7 8.2 6.7
Table 1: pH – Metric Titration Data
0
2
4
6
8
10
12
14
1 2 3 4 5 6 7 8 9 10 11 12
pH
Volume of NaOH
Ligand
Metal
Table2: Determination of A Values
pH V1(ml) V2 (ml) V2 - (ml) A
4 4.8 4.90 0.10 0.8087
4.5 4.9 5.00 0.10 0.8087
5 5.10 5.20 0.10 0.8094
5.5 5.5 5.70 0.20 0.6216
6 5.80 6.00 0.20 0.6236
6.5 6.00 6.20 0.20 0.625
7 6.20 6.45 0.25 0.477
7.5 6.19 7.20 0.25 0.539
8 7.45 7.70 0.25 0.542
8.5 7.45 7.75 0.30 0.451
9 7.65 8.30 0.30 0.099
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1 2 3,5 4 4,5 5 5,5 6 6,5 7 7,5 8 8,5 9 9,5
pH
pH V2(ml) V3 (ml) V3 – V2 (ml)
4 4 3.7 0.3 2.91
4.5 4.7 4.3 0.4 8.83
5 5.5 4.7 0.8 7.56
5.5 6.4 5.3 1.1 10.2
6 7.3 5.8 1.5 13.74
6.5 8.2 6.7 1.6 14.52
7 9.2 7.6 1.6 14.98
7.5 10 8.3 1.7 17.60
8 10.2 8.4 1.8 16.83
8.5 10.4 8.5 1.9 16.68
9 10.7 8.7 2.0 17.90
9.5 11.1 9.00 2.1 18.04
10 11.8 10.1
Table2: Determination of
0
0,5
1
1,5
2
2,5
3
3,5
4
4,5
1 2 3 3,5 4 4,5 5 5,5 6 6,5 7 7,5 8 8,5 9 9,5pH
n
Reference:
• http:// www.tku-e.com/assets/MIC/cefadroxil.pdf
• cefadroxil side effect,” Drugs
• begrouthy R, Robin, F, Dabboussi, F, Mallat, H, Hamze , M, Bonnet, R.
• Pristinnamyun :- old drug, new tricks?
Cooper, E. C Curtis, N, Cranswick, N Gwee, A.
• Isolation of ciprofloxacin – resistant legionella pneumophila in a patient with severe pneumonia. Bruin, J.P.,
koshkolda, Ijzerm an, E.P.F Luck, C Diederen, B.M.W. den boer, J.W, Mouton, J.W.
• Genomic identification of ahovel cotrimoxazole resistance genotype and its prevalence amongst streptococeus
pneumonia in malawin
Author: - Cornick J.E. Etal: Source- joirna antimicrobial chemotherapy.
• Game changex – antibiotic and other in works for superbug
Author: - Dolgin E
Source: - Nature Taedicine
• Towards new business model for R and D for novel antibiotics.
Author: - So A.D. Etal:
Source: - Drug Resistance update
• Psychology, Health and medicines
Author: - Bell B.G. Etal :
• BMC infectious Diseases
Author:- Bell Bg Etal :
• Kinetic and mechanism of oxidation of giutamio Acid by N- Bromoph – thalimide in Aqueous Acidc. Medium
N. M. I. Alhaji , S. Sofiya Lawre
Thank You....