Organometallic Chemistry of the f-block

Question 1

geometry of 3-coord Ln(N’‘)3 complex

Answer 1

should be trigonal planar but actually trigonal pyramidal

Question 2

Ln alkoxides

Answer 2

size of R determines nuclearity of complex, bulkier R = homonuclear, linear to maximise e- donation

Question 3

uranium amides

Answer 3

U3+, needs steric bulk protection for stabilisation

Question 4

why use Cp*

Answer 4

sterically bulkier, increases solubility in organic solvents

Question 5

Ln hydrides synthesis

Answer 5

via hydrogenolysis, hard to stabilise due to small H ligand

Question 6

bonding in COT

Answer 6

8pi, antiaromatic

Question 7

aromatic

Answer 7

4N+2

Question 8

antiaromatic

Answer 8

4n

Question 9

formation of inverse arene complexes

Answer 9

UX(N’‘)3 with KC8 and toluene gives arene sandwiched between 2xU groups, don’t need KC8 if you start with U3+

Question 10

role of KC8

Answer 10

reductant

Question 11

consequences of formation of inverse arene complexes

Answer 11

arene is reduced, now very e- rich, can react with boranes

Question 12

Uranium CO complex formation

Answer 12

Uatoms + CO, unstable but can measure decrease in vibrational freq of CO to demonstrate binding

Question 13

why no Ln CO complexes

Answer 13

Ln have purely ionic bonding, not possible with CO due to its synergistic bonding effects

Question 14

U N2 complex types

Answer 14

end on
side on seen with less sterically hindered complexes