Spectator ligands in RM chemistry

Question 1

What are L type ligands?

Answer 1

Natural charge ligands

Question 2

What are X type ligands?

Answer 2

1e radical donors when considered neutral (neutral electron counting)
or 2e donors (oxidative state method)

Question 3

Do L type ligands have an odd or even numbers of electrons?

Answer 3

Even

Question 4

Do X type ligands have an odd or even number of electrons?

Answer 4

Odd

Question 5

What type of ligand is carbonyl CO?

Answer 5

L

2e-

Question 6

What type of ligand is phosphine PR3?

Answer 6

L

2e-

Question 7

What type of ligand is hydride H?

Answer 7

X

1e-

Question 8

What type of ligand is chloride Cl?

Answer 8

X

1e-

Question 9

What type of ligand is alkyl/aryl?

Answer 9

X

1e-

Question 10

What type of ligand is alkene?

Answer 10

L

2e-

Question 11

What type of ligand is alkyne?

Answer 11

L

2e-

Question 12

What type of ligand is cytopentadiene C5H5?

Answer 12

X

5e-

Question 13

What type of ligand is butadiene?

Answer 13

L

4e-

Question 14

What type of ligand is benzene?

Answer 14

L

6e-

Question 15

What type of ligand is alkoxide?

Answer 15

X

1e-

Question 16

What type of ligand is amide?

Answer 16

X

1e-

Question 17

How do spectator ligands interact during a chemical transformation?

Answer 17

They remain unchanged

Question 18

What is the role of spectator ligands and how do they achieve this?

Answer 18

Control the physical properties as well reactivity of an RM compound.
They modify the electronic and steric properties

Question 19

How do phosphines and neutral nitrogen complexes interact as donors and acceptors?

Answer 19

They are σ-donors and π-acceptors

Question 20

How do amides interact as donors?

Answer 20

They are σ(sp2)-π(p) donors
2e-4e
They donate electrons into the d orbitals to stabilise the compounds

Question 21

How do bulky alkoxides interact as donors?

Answer 21

σ(sp2)-2π(p) donors

2e-6e

Question 22

What is the maximum donation a spectator ligand can give?

Answer 22

2e-6e

Question 23

What is hapticity ηⁿ?

Answer 23

n = the number of carbon atoms bonded directly to the metal centre as a single group
Coordination via a continuous series of atoms

Question 24

In hapticity, what does it mean if the n is even? Why?

Answer 24

The hydrocarbon is considered to be a neutral donor

The organic fragment is an electron pair donor from a filled π-orbital

Question 25

What is facial coordination?

Answer 25

Each π bond donates 2e and all 6 carbon atoms bond equally to M as a 6e donor, forming a η6 complex

Question 26

In hapticity, what does it mean if the n is odd?

Answer 26

The hydrocarbon must be considered to be an anion so that the fragment donates electrons in pairs