katalis homogen.pdf
TRANSCRIPT
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Katalis Homogen
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Katalis
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Jenis katalis
Katalis homogen adalah senyawa yang ada dalam fase yang sama (gas atau cair) sebagai reaktan,
sedangkan katalis heterogen
- Katalisis asam, katalis organologam, dan katalisis enzima
- Keuntungan dari katalis homogen adalah bahwa katalis lebih cepat bercampur ke dalam campuran reaksi, yang memungkinkan
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Organometallic
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According to RSC
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According to ACS
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Noble-Prize Winners in Works Related to OM
Grignard & Saba
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Trans Eect
In inorganic chemistry, the trans eect is the labiliza
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ELECTRON COUNTING
- Basis of Electron Coun
- Importance of Electron Coun
- Coun
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Method 1: The ionic (charged) model
Pada metode ini melibatkan ligan sebagai pendonor pasangan electron ke logam. Untuk menentukan jumlah total electron, kita harus menghitung juga muatan se
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Method 2: The covalent (neutral) model
Pada metode ini kita akan menggunakan jumlah electron yang akan didonasikan oleh ligand tetapi dalam keadaan netral. Pada ligan anorganik sederhana, jumlah electron yang didonasikan sama dengan muatan nega
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Ligan dengan donasi elektronnya
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TRANSITION METALS ORGANOMETALLICS
A transi:on metal is one which forms one or more stable ions which have incompletely
lled d orbitals.
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Transition vs Main Elements The physical and chemical properties of transition metals differ from main group metals (s-block) by the following: are hard and have high densities. have high melting and boiling points. form compounds which are often paramagnetic. show variable oxidation states. form coloured ions and compounds. form compounds with profound catalytic activity. form stable complexes.
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Transi:on Metals Overview
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Early Transi:on Metals Groups 3, 4
Strongly electrophilic (Strongly bounds to high electronega
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Early Transi:on Metals Groups 3,4
Typical catalysis in Polymerization
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"Middle" Transi:on Metals Groups 5-7
Many accessible oxida
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"Middle" Transi:on Metals Groups 5-7 Typical catalysis: Alkene and alkyne metathesis
- Late Transi
- Late Transi
- Transi
- 1st row: o`en unpaired electrons (High spin state). dierent spin states (HS/LS) accessible highest oxida
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Nomenclature
The mode of aRachment of the donor ligand is described by deno
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Metal Carbonyls (Bonding)
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Evidence of Back-bonding
Note that an empty orbital in the ligand (LUMO) is used in the bonding (an an
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Metal Phosphines
Ter
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Bonding in Metal Phosphines
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Electronic Eects of Phosphines
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Controlling The Space Around The Metal
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Correla:on of Cone Angles & Reac:on
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Mono-dentate Phosphines
- We can increase the bulkness around the metal by replacing the phosphine ligand without aec
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Tolman plot of Electronic Parameter and Cone Angle
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Hydrido Complexes
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METAL AMINE
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Metal Alkenes (Bonding)
- Ligand Assosia
- Dissocia
- Commonly observed mechanis
- An Example of an Oxida
- Oxida
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Commonly used sources of Pd0 include:
Tris(dibenzylideneacetone)dipalladium (0) Pd2(dba)3
Tetrakis(triphenylphosphine)palladium (0)
Pd(PPh3)4
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Also, Pd(II) is very readily reduced to Pd(0):
Thus, it is o`en more convenient to use Pd(II) complexes, which are more air-stable than commercial Pd(0) complexes.
- 2) Reduc
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Complex Rate Constant (s-1) T(oC)
PdCH3Ph3P
Ph3P CH3
PdCH3MePh2P
MePh2P CH3
PdCH3P
P CH3
PhPh
PhPh
1.04 x 10-3 60
60
80
9.62 x 10-5
4.78 x 10-7
Relative rates of reductive elimination
Most crowded is the fastest reaction
PdCH3L
L CH3+ solv
-L
PdCH3L
solv CH3
RELPd(solv) + CH3 CH3
- Transmetalla
- Now we will put the three reac
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SUZUKI-MIYAURA CROSS COUPLING REACTION
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Bagaimana Mekanismenya??
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MECHANISM OF SUZUKI-MIYAURA CROSS COUPLING REACTION
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Selected examples of the Suzuki-Miyaura coupling in organic synthesis
- When a reac
- Negishi Cross-Coupling Reac
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I OR + ZnCl ORTHF, 60o C
[Pd(PPh3)2Cl2]
L = (PPh3)2
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Predict the main products, include the mechanism
- To understand the Heck Reac
- The inser
- The -hydride Elimina
- Heck Reac
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I +Pd-Cat
n-Bu3N, DMF
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Br +THF, 60o C
Pd-Cat
O
O
O
O
- The Heck reac