Ullmann Reaction and Gomberg - Bechmann ReactionEinstein kannan
It contains two naming reactions like Ullmann and Gomberg- Bechmann reaction. Mechanism of Ullmann reaction, exercise problems are included. What is the mechanism behind the Gomberg-Bechmann reaction and its applications and some exercise problems also included from organic naming reaction books. Applications of Ullmann coupling also included. Reference books for this topic is mentioned the last slide.
Protecting group (PG) is a small molecule, to mask temporarily the a specific functional group of a molecule from undergoing reaction, allowing the rest of the functional groups present in the molecule to react without affecting the original reactivity and leave from the host molecule without affecting the rest of the functional groups.
The addition of protecting groups to functional groups is termed ‘protection’ and removal of protecting group is ‘deprotection’.
GRIGNARD REAGENT RMgX.A Grignard reagent is an organomagnesium compound which can be described by the chemical formula 'R-Mg-X' where R refers to an alkyl or aryl group and X refers to a halogen. They are generally produced by reacting an aryl halide or an alkyl halide with magnesium.A Grignard reagent or Grignard compound is a chemical compound with the general formula R−Mg−X, where X is a halogen and R is an organic group, ..
N-BROMOSUCCINAMIDE A REAGENT USED IN THE SYNTHESIS, IT IS ALSO A SYNTETIC REAGENT AND HERE IN THIS PRESENTATION THE MOLECULAR FORMULA ITS ALTERNATE NAME APLLICATION ARE DISCUSSED.
Ullmann Reaction and Gomberg - Bechmann ReactionEinstein kannan
It contains two naming reactions like Ullmann and Gomberg- Bechmann reaction. Mechanism of Ullmann reaction, exercise problems are included. What is the mechanism behind the Gomberg-Bechmann reaction and its applications and some exercise problems also included from organic naming reaction books. Applications of Ullmann coupling also included. Reference books for this topic is mentioned the last slide.
Protecting group (PG) is a small molecule, to mask temporarily the a specific functional group of a molecule from undergoing reaction, allowing the rest of the functional groups present in the molecule to react without affecting the original reactivity and leave from the host molecule without affecting the rest of the functional groups.
The addition of protecting groups to functional groups is termed ‘protection’ and removal of protecting group is ‘deprotection’.
GRIGNARD REAGENT RMgX.A Grignard reagent is an organomagnesium compound which can be described by the chemical formula 'R-Mg-X' where R refers to an alkyl or aryl group and X refers to a halogen. They are generally produced by reacting an aryl halide or an alkyl halide with magnesium.A Grignard reagent or Grignard compound is a chemical compound with the general formula R−Mg−X, where X is a halogen and R is an organic group, ..
N-BROMOSUCCINAMIDE A REAGENT USED IN THE SYNTHESIS, IT IS ALSO A SYNTETIC REAGENT AND HERE IN THIS PRESENTATION THE MOLECULAR FORMULA ITS ALTERNATE NAME APLLICATION ARE DISCUSSED.
2. • There are two limiting mechanisms
for substitution reactions of
coordination complexes,
associative, which corresponds to
the SN2 reaction in organic
chemistry, and
dissociative, which corresponds to
the SN1 reaction in organic
chemistry.
inorganic reaction mechanism
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4. MLnX + Y MLnY + X
Mechanisms of ligand exchange reactions
in octahedral complexes
MLnX MLnY
MLnX Y
Dissociative (D)
MLnX MLnY
MLnXY
Y X
Associative (A)
MLnX MLnY
[MLn]°Y X
X Y
Interchange (I)
Ia if association
is more important
Id if dissociation
is more important
inorganic reaction mechanism
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6. Associative Reactions
• In the limiting case of an associative reaction the entering ligand
begins to interact with the metal as the bond to the departing ligand
(leaving group) lengthens. In order for the entering ligand to bond
to the metal there must be a vacant (preferably) or partially vacant
orbital that is accessible to the entering ligand. In an octahedral
complex only the t2g d orbitals are accessible as the eg orbitals and
the n+1 s and p orbitals are blocked by the presence of the original
six ligands. Associative processes are more likely for larger metal
ions than for smaller so that they are more important early in a
transition series and for heavier members of a family.
inorganic reaction mechanism
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7. Dissociative Reactions
• In the limiting case the dissociative process
involves the formation of a five coordinate
intermediate as a result of complete bond
dissociation to the departing ligand (leaving
group). The five-coordinate intermediate then
reacts with the new ligand (entering group)
to reform a six-coordinate complex.
inorganic reaction mechanism
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8. Principal mechanisms of ligand exchange in octahedral complexes
Dissociative
Associative
inorganic reaction mechanism
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10. Inert and labile complexes
Some common thermodynamic and kinetic profiles
Exothermic
(favored, large K)
Large Ea, slow reaction
Exothermic
(favored, large K)
Large Ea, slow reaction
Stable intermediate
Endothermic
(disfavored, small K)
Small Ea, fast reaction
inorganic reaction mechanism
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11. Experimental evidence for dissociative mechanisms
Rate is independent of the nature of L
inorganic reaction mechanism
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12. Experimental evidence for dissociative mechanisms
Rate is dependent on the nature of Linorganic reaction mechanism
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36. inorganic reaction mechanism USAMA ELAYAAN36
Stereochemistry of base hydrolysis reactions لتفاعالت الفراغية الكيمياءبقاعدة التحلل
N
N
N
N
Co
N
N
N
Co
X
OH
OH
X
N
N
N
N
Co OH
N
1 2
N
N
N
N
Co
OH
OH
N
N
N
Co
OH
OH
N
1
2
7%
93%
• Product distribution is independent of the leaving group and the isomeric form of
the starting material.
• This behavior is not only consistent with the dissociative mechanism, but also
indicative of a trigonal bipyramidal intermediate
38. inorganic reaction mechanism USAMA ELAYAAN38
H+
2+
N
N
N
Co
F
F
N
N
N
N
Co
N
F
FH N
N
N
Co
N
F
OH2
-HF
2+
For X=F , the substitution is strongly acid catalyzed because of much weaker acidity
of HF in water.
فيحالةX = Fيكون االستبدال فإنزَّفمحبحمضبسببللحمض الضعيفة الحمضيةHFالماء في
مجموعة إلى بروتون إضافةالفلوروجسيمات من المغادرة المجموعة طبيعة يغيرأنيونيةجزيء إلىHFالمتعادل
التفكك عملية يسهل مما.
جزئ تفككHFالسلب األيون تفكك من أسهل المتعادل.F-
39. inorganic reaction mechanism USAMA ELAYAAN39
M
L
LL
L O
C
O
OL
M
L
LL
L O
C
O
OL
M
L
LL
L OH
L
H+
- CO2
H
التالي المثال في:سرعةاالستبدالفقط ترجع البسبب أيضا ولكن بروتون إلضافة النظام قابلية بسبب
األكسجين لرابطة انقسام أي يتضمن ال الذي التالي االنقسام خطوة-الكوبالت.
زَّفالمح التفكك هو المغادرة للمجموعة بروتون إلضافة آخر مثالكما العطاء ثنائي للمرتبط بحامض
يلى:
H+
P
P P
P
Fe
Cl
Cl
Cl
Cl
P P
P
Fe
P
Cl
Cl
P P
P
Fe
PH
P
Fe
P
Cl
Cl
حدوث نالحظارتباط قبل التحللالبروتون.أخرى مرة االرتباط في المرتبط يعود البروتون غياب في
أعاله التفاعل يحدث وجودة وفى بالفلز.
40. inorganic reaction mechanism USAMA ELAYAAN40
من أيضاالمتراكب تفاعالت يمثلها بحامض زةَّفالمح التفاعالت
trans-[M(O)(OH)(CN)4]2- (M = Mo,W, Tc or Re)
O
M
OH
CN
CN
NC
NC
2-
O
M
OH2
CN
CN
NC
NC
-
O
M
CN
CN
NC
NC
-
O
M
N
CN
CN
NC
NC
2-
C
S
H
H2O NCS
إضافةللهيدروكسيد بروتونالمرتبطالمائي المرتبط دِّلتوالتفكك سهل.لسرعة المحددة التفكك عملية
المتراكب في التفاعلالمائىسريع ارتباط يصحبهاللمركبالوسيطبأيون التناسق خماسيالثيوسيانات.
41. inorganic reaction mechanism USAMA ELAYAAN41
Protonation of non-labile ligand بطيء المرتبط إلى البروتون إضافةالتفاعل
أن هنا نالحظتسريع إلى يؤدي أن يمكن المرتبطات ألحد البروتون إضافةآخر مرتبط.
في النيتروجين ثنائي مرتبط إلى بروتون إضافةcis-[M(N2)2(PMePh)4] (M = Mo orW)
H
M
N2R3P
R3P PR3
PR3
N
N
2
M
N2R3P
R3P PR3PR3
N
N
HH
M
OMeR3P
R3P PR3
N
N
HH
MeOH
H
M
OMeR3P
R3P PR3OMe
N
N
HH
2+ 2+
2H +
HOMe
البروتونات إضافةالنيتروجين ثنائي مرتبط إلى(مرتبط ليكونالهيدرازيد)الكثافة سحب تأثير له
من اإللكترونيةالفلزالنيتروجين ثنائي مرتبط تفاعل تسرع وبالتالياآلخرN2الفوسفور ومرتبط.PR3
عطاء برابطة الفلز مع يرتبط كالهماعكسىباىمدار خالل منdالمرتبطات في خالية مدارات الى الفلز في
وبالتالىالنقص يكونالبروتون إضافة خالل الفلز على اإللكترونية الكثافة فيلهذه اإلحالل عملية من تسرع
المرتبطات