Question #9d3bd

There are four possible products from the acetylation of ferrocene.

Ferrocene

Ferrocene consists of two cyclopentadienide anions coordinated to an #"Fe"^"2+"# cation.

Its IR spectrum shows no carbonyl absorption.

There are 10 equivalent #"H"# atoms, and the NMR spectrum shows a single peak at 4.16 ppm.

This is considerably shielded compared to the normal aromatic range of 6.5 ppm to 9.0 ppm.

However, this is not surprising, given the negative character of the cyclopentadienide rings.

Acetylferrocene

Acetylferrocene has a characteristic carbonyl absorption at #"1615 cm"^"-1"#.

The NMR spectrum shows peaks at 4.19s (#"5H"#, unsubstituted ring) and 2.39s (#"3H, CH"_3#).

The doublet of #"2H"# triplets at 4.5 ppm and 4.8 ppm is an unresolved AA'BB' pattern arising from #"H2"# and #"H3"# on the acetylated ring.

All diacetylferrocenes show strong carbonyl absorption at about #"1615 cm"^"-1"#.

They are distinguished by their NMR splitting patterns.

1,1'-Diacetylferrocene

The compound has 3 proton environments. It shows a #"6H"# singlet and two #"4H"# triplets.

1,2-Diacetylferrocene

This has four proton environments. It shows a #"6H"# singlet, a #"5H"# singlet, a #"2H"# doublet and a #"1H"# triplet.

1,3-Diacetylferrocene

This also has four proton environments. It shows #"6H, 5H, 2H"#, and #"1H"# singlets.