Module 4

Question 1

Sigma-bond Metathesis

Answer 1

Common for early transition metal complexes where there are not enough electrons on the metal atom for it to participate in oxidative addition.

Question 2

1,1-Migratory Insertion Reaction

Answer 2

1,1: X-group was one bond away from the metal atom ends up on atom that is one bond away from the metal atom.

Question 3

1,2 Insertions/Beta-hydride Elimination

Answer 3

1,2: X-group was one bond away from the metal atom ends up on atom that is two bonds away from the metal atom.

Question 4

Cyclometallation

Answer 4

Metal inserts into the remote C-H bond

Question 5

Catalyst

Answer 5

A substance that increases the rate of a reaction but is not itself consumed. This is done by introducing new pathways with lower Gibbs energy of activation.

Question 6

Catalytic Cycle

Answer 6

A sequence of reactions that consumes the reactants and forms products, with catalytic species being regenerated after the cycle.

Question 7

Selectivity

Answer 7

A selective catalyst yields a high proportion of the desired product with minimum amounts of side products.

Question 8

Homogenous Catalyst

Answer 8

Present in the same phase as reagents, often well defined.

Question 9

Heterogeneous Catalyst

Answer 9

Present in different phases.

Question 10

Alkene Metathesis

Answer 10

Redistribution of C – C double bonds.

Question 11

Hydrogenation of Alkenes

Answer 11

Addition of hydrogen to an alkene

Question 12

Wilkinson’s Catalyst

Answer 12

[RhCl(PPh3)3] Rh(I) Complex

Question 13

Hydroformylation

Answer 13

A reaction of alkene, CO, and H2 to form an aldehyde that contains one more C than the original alkene.

Question 14

Wacker Oxidation of Alkenes

Answer 14

Primarily production of ethanal (acetaldehyde) from ethene and oxygen.

Question 15

Pd-catalyzed C – C Bond-forming Reaction

Answer 15

Heck, Stille, Suzuki “coupling reaction”. Ex: coupling of Grignard reagents with an alkyl halide.

Question 16

Oligomerization/Polymerization

Answer 16

Ethene into linear alkenes: homogenous catalysis with Ni catalyst. Alkene polymerization: heterogeneous Ziegler-Natta catalysts.

Question 17

Facts about d-Block Elements

Answer 17

(1) All metallic
(2) High density, high melting/boiling points
(3) Form colorful compounds (d-d transitions, charge-transfer transitions)
(4) Form compounds in many oxidation states
(5) Form paramagnetic compounds (unpaired electrons) (6) Show homo- and heterogeneous catalytic activity

Question 18

The occurrence of d-Block elements

Answer 18

Early 3d metals occur in nature (oxides, metal cations in combination with oxoanions)

Question 19

Which compound is most difficult to reduce?

Answer 19

TiO2

Question 20

Which 3 ions oxidizes reduced with carbon?

Answer 20

Cr-, Mn-, and Fe

Question 21

Which metals occur mainly as sulfides and arsenides?

Answer 21

Co, Ni, Cu, Zn

Question 22

Which rows transition to mostly sulfides sooner?

Answer 22

Row 2 and 3.