Introduction to organosulphur chemistry
The main points about sulphur
A range of oxidation states are available – predominantly 2, 4 and 6.
Quite nucleophilic in its divalent state, even more so as S–.
Hydrogens alpha to sulphur atoms are noticeably more acidic than they would be if the sulphur were absent. The carbocation generated by deprotonation is stabilised inductively by the sulphur, but more important is the fact that the negative charge can induce a dipole in the large, easily polarised charge cloud of sulphur, giving rise to favourable (stabilising) dipole-induced dipole ineractions.
When singly bonded to electronegative elements (including itself), the bonds tend to be weak and the sulphur is electrophilic.
S-S bonds are also weak with respect to homolytic fission into radical species.
Has a great affinity for both phosphorus and mercury (this latter is due to favourable soft-soft interactions between the two soft elements) – mercury spillages are usually cleared up using elemental sulphur.
A reaction to illustrate some of sulphur’s properties:
Points of note
i. The use of Hg2+ to remove sulphur bearing substituents is quite common in organosulphur chemistry.
ii. Overall a useful oxidation has been carried out α to a ketone. (see a similar reaction here)