Synthesis and molecular structure of carbonyl derivatives of iron(II) thiolates containing nitrogen-donor ligands

Abstract

Several carbonyl derivatives of iron(II) thiolates containing N-donor ligands with the general formula FeS 2N 2(CO) 2 were prepared in methanol solution starting from FeSO 4·7H 2O, the appropriate thiol (S) and nitrogen-donor ligand (N), carbon monoxide and a base. The structures of two representatives Fe(SC 6H 4- NH 2- o) 2(CO) 2 ( 1) and Fe(SPh) 2(H 2NC 2H 4NH 2)- (CO) 2 ( 2) were determined. Complex 1 crystallizes with one molecule of THF in the triclinic space group P1, a=5.659(3), b=8.960(6), c=10.624(6) Å, α= 105.15(5), β=103.23(5), γ=94.35(5)°, V=500.86 Å 3, Z=1, D calc=1.43 g cm −3. Complex 2 crystallizes in the monoclinic space group P2 1/ c, a=11.739(2), b=9.725(2), c=15.868(2) Å, β=101.583(8)°, V= 1774.6 Å 3, Z=4, D calc=1.44 g cm −3. Final agreement factors, R=0.0300, R w=0.0304 (1787 reflections) for 1; R=0.0368, R w=0.0369 (2147 reflections) for 2; the absolute configuration of 1 was determined. The octahedral complexes contain the two CO ligands in cis position and the coordinated N atoms are trans to the CO groups. A necessary condition for the stability of such complexes is the presence of at least one chelating ligand; all complexes lose CO on heating and this reaction is (in part) reversible.