UNIT 10: Organometallic Chemistry

Question 1

Study of organometallic compounds, their reaction and chemical composition.

Answer 1

ORGNOMETALLIC CHEMISTRY

Question 2

• Contain at least one (1) chemical bond between a carbon atom and a metal.
• Most medicinal organometallic compounds are bounded to transition metals (d-block).

Answer 2

Organometallic Compounds

Question 3

lons or neutral molecules that bond to a central metal atom or ion.

Answer 3

Ligands

Question 4

The total number of atoms, ions, or molecules bonded to the atom in question.

Answer 4

Coordination Number/Ligancy

Question 5

It pertains to the number of atoms involved in the metal bonding with ligands. It describes how many contiguous (connected) atoms within a single ligand interact with the metal center.

Answer 5

Hapticity (n)

Question 6

The process of isolating and purifying the product of a chemical reaction

Answer 6

Work up

Question 7

• No pharmaceutical applications due to high reactivity and are pyophoric
• Mostly stored in hydrocarbons
• Synthesis of modern medicine (e.g. NaCp and BuLi Compounds)

Examples:
a. ________
b. ________
C. ________

Answer 7

1. Main Group Metals/S or P- block

Examples:
a. Organolithium
b. Organomagnesium (Grignard reagent)
C. Organoaluminum

Question 8

• Stable complexes
• “Hapticity” can be further increased

Examples:
a. ________
b. ________

Answer 8

2. Transition Metals/D-block

Question 9

• Catalysis
• MRI
• Radiotherapy

Example:
a. technetium-99m sestamibi (Cardiolite)

Answer 9

3. Lanthanides and Actinides/F-block

Question 10

• Organometallic compounds where the metal and carbon are directly bonded through a single sigma bond.

Example:
a. __________
b. __________
c. __________

Answer 10

1. Sigma (a) Bond

Example:
a. Grignard Reagent (RMgX)
b. Diethyl Zinc (ZnEt2)
c. Trimethyl aluminum (Al(CH3)3)

Question 11

Organometallic compounds where the metal and carbon are bonded through pi interactions, often involving unsaturated ligands like alkenes or alkynes.

Example:
a. _______________
b. _______________

Answer 11

2. Рi (л) Bond

a. Cyclooctatetraene Complexes
b. Bis(benzene)chromium

Question 12

• Organometallic compounds that exhibit both sigma and pi bond.

Example:
a. _________
b. _________
c. _________

Answer 12

3. Mixed Sigma and Pi Bond

Example:
a. Ferrocene
b. Zeise Salt
c. Metal Carbonyls

Question 13

C. LIGAND TYPE

1. Sigma (o) Donors
   a. _______
   b. _______
   c. _______
2. Pi (n) Donors
   a. _______
   b. _______
   c. _______

Answer 13

C. LIGAND TYPE

1. Sigma (o) Donors
   a. Alkyls
   b. Hydrides
   c. Halides
2. Pi (n) Donors
   a. Alkenes
   b. Alkynes
   c. Dienes

Question 14

3. ______________
   a. Isocyanides
   b. Alkynes
4. ______________
   b. Ethers
   a. Amines
   c. Anionic atoms like Chloride, Fluoride, Alkoxides

Answer 14

3. Pi (n) Acceptors
   a. Isocyanides
   b. Alkynes
4. Neutral and Anionic Ligands
   b. Ethers
   a. Amines
   c. Anionic atoms like Chloride, Fluoride, Alkoxides

Question 15

5. ____________
   * Have multiple donor atoms in a single molecule, resulting to a ring structure around a metal center
   Example:
   a. ____________
   b. ____________
   c. ____________
6. ____________
   Common ligands with P-atom bonded to one or more organic groups.
   a. ____________

Answer 15

5. ____________
   * Have multiple donor atoms in a single molecule, resulting to a ring structure around a metal center
   Example:
   a. Ethylenediamine
   b. Diethylamine
   c. Bipyridine
6. Phosphine
   Common ligands with P-atom bonded to one or more organic groups.
   a. Triphenylphosphine

Question 16

7. ___________
   *CO as a donor group.
   a. ________
   b. ________
8. ___________
   - Create metallocenes by sandwiching a metal between two (2) Cyclopentadienyl rings.
   a. ________

Answer 16

7. Carbonyl Ligands
   *CO as a donor group.
   a. Fe(CO)3
   b. Ni(CO)4
8. Cyclopentadienyl ligands *
   - Create metallocenes by sandwiching a metal between two (2) Cyclopentadienyl rings.
   a. Ferrocene

Question 17

C. BASED ON ORGANIC GROUPS ATTACHED

1. ________
2. ________
3. ________

Answer 17

1. Aliphatic
2. Aromatic
3. Polycylic

Question 18

• Addition of an __________ to a ketone or aldehyde
• ________ –> Tertiary Alcohol
• ________ –> Secondary Alcohol
• Grignard Reagent + Primary Alcohol → _________

Mechanism Of Reaction
* RMgX –> Grignard Reagent
*R-Alkyl or Aryl Group
*X -Halogen

Answer 18

A. GRIGNARD REACTION
- organomagnesium halide (Grignard reagent)

• Ketone
• Aldehyde
• Formaldehyde

Question 19

• Process where there is palladium-catalyzed C-C coupling between aryl halides or vinyl halides and activated alkenes in the presence of a base
• Provides outstanding trans selectivity

Answer 19

B. HECK REACTION/COUPLING

Question 20

• Is a metal catalyzed reaction, typically with Pd, between an alkenyl (vinyl), aryl, or alkynyl organoborane (boronic acid or boronic ester, or special cases with aryl trifluoroborane) and halide or triflate under basic conditions

Answer 20

C. SUZUKI REACTION/COUPLING

Question 21

• Involves two olefin substrates which form a four-membered ring intermediate and then rearrange the substituents to form two new carbon-carbon double bonds

Answer 21

D. OLEFIN METATHESIS

Question 22

• Organometallics that is also known as “sandwich complexes” due to its structure where a metal is in between two (2) cyclopentadienyl ring ligands

Answer 22

METALLOCENES?

Question 23

• Cobalt containing inks + Arsenic-containing cobalt salts

→ Cacodyl oxide + Tetramethyldiarsine

Answer 23

1760: Louis Cadet

Question 24

• First Pi-Complex
  → Zeise Salt

Answer 24

1827: William Zeise

Question 25

* Discovery →Diethylzinc (ZnEt2)

Answer 25

1849: Edward Frankland

Question 26

→ Diethyl Mercury (HgEt2)

Answer 26

1852: Edward Frankland

Question 27

* Discovery →Tetraethyltin (SnEt4) →Trimethylborane (BMe)

Answer 27

1860: Edward Frankland

Question 28

* Substitution of metals salts by electronegative elements

Answer 28

1870s: Paul Schützenberger

Question 29

* Discovery →Tetracarbonylnickel (Ni(CO)4) →Pentacarbonyliron (Fe(CO)5)

Answer 29

1852: Ludwig Mond & Pierre-Eugène-Marcellin Berthelot

Question 30

* Developed → Friedel-Crafts alkylation and acylation

Answer 30

1900: Charles Friedel & James Crafts

Question 31

* Developed →Grignard Reagent

Answer 31

1900: Victor Grignard

Question 32

* First Sigma alkyl-metal complex →lodotrimethylplatinum (CH3),Pt

Answer 32

1909: William John Pope

Question 33

* First Diene-complex → Fe(n-butadiene)(CO)3

Answer 33

1930s: Reilhen

Question 34

* First metal-hydride complex →Iron tetracarbonyl dihydride (Fe(CO)4H2)

Answer 34

1930s: Walter Hieber

Question 35

* Catalysis of substitution reactions by electron transfer * Distinction between outer and inner sphere electron transfer

Answer 35

1950s: Henry Taube

Question 36

* Discovery →Ferrocene (wrong structure)

Answer 36

1950s: Kealy, Pauson, & Miller

Question 37

* Developed →Electronic theory of valency

Answer 37

1950s: Nevil Vincent Sidgwick

Question 38

* Finalization of Ferrocene (bis- cyclopentadienyl-iron)

Answer 38

1950s: Robert Woodward, Geoffrey Wilkinson, & Ernst Fischer

Question 39

* Discovery →Cobaltocenium and Fluxional molecules

Answer 39

1950s: Cotton & Wilkinson

Question 40

* Developed → Ziegler-Natta polymerization

Answer 40

1960s: Ziegler & Natta

Question 41

→ Wittig reaction

Answer 41

1960s: George Wittig Developed

Question 42

*Developed →Hydroboration of Olefins

Answer 42

1960s: Herbert Brown

Question 43

* Discovery → Uranocene and its derivatives

Answer 43

1960s:

Question 44

* Developed →Metathesis of Olefins

Answer 44

1970s: Yves Chauvin

Question 45

* Discovered first triple-decker sandwich complex →tris(cyclopentadienyl)dinickel cation

Answer 45

1970s: H. Werner & A. Salzer

Question 46

* Additional research of Biferrocene and its derivatives

Answer 46

1990s and beyond:

Question 47

APPLICATION OF METALLOCENES

Answer 47

A. CATALYSIS B. ORGANIC SYNTHESIS AND NEW MATERIALS C. BIOMEDICAL APPLICATIONS

Question 48

* Provides an environment that lowers activation energy of reactions * Metal influences reactivity of substrates making it susceptible to reactions * Widely used as a catalyst in Plastic Production

Answer 48

A. CATALYSIS

Question 49

B. ORGANIC SYNTHESIS AND NEW MATERIALS

Answer 49

* Contributes to the creation of new materials and compounds

Question 50

C. BIOMEDICAL APPLICATIONS

Answer 50

* Development of anticancer drugs and antimalarial agents * Development of radiopharmaceuticals and biosensors for DNA detection