Carbonyl insertion into a CS bond and complex dimerization during reaction of the dithioesters SC(Me)SEt and SC(Ph)SMe with iron carbonyl complexes

Abstract

Dithioesters react with pentacarbonyliron or nonacarbonyldiiron under UV irradiation to give three classes of compounds. In the metalmetal-bonded complexes [Fe 2(CO) 6{;SC(R 1)SR 2};] (R 1  Me or Ph; R 2  Et or Me) which belong to the first class, the iron atoms are doubly-bridged by a CS unit and the original bicovalent sulphur atom of the intact dithioester unit. Similar metal links also exist in the complex [Fe 2(CO) 6{;μ-η 2-S CS(CH 2) 2S - S,S′};]( Fe-Fe) (I), formed from a trithiocarbonate (R 1R 2  SCH 2CH 2) and [Fe(CO) 5], as confirmed by single-crystal X-ray diffraction. The nature of the bonding in the second class of compounds was established by determining the crystal structure of the dimeric compound [Fe(CO) 3{;SC(Ph)SMe};] 2 (V) in which there is no metal-metal bond but each coordinated ligand forms a non-symmetrical dative sulphur-metal bond to the other iron atom. An X-ray crystal structure of a member of the third type of compound [Fe 2(CO) 6{;SC(R 1)C(O)SR 2};] (R 1  Ph; R 2 7z.dbnd; Me) (VI), shows that it is the result of carbonyl insertion into the C-SR 2 bond of the ligand.