Thioharnstoff-Derivate als Liganden in Eisen-Komplexen: Synthese und Kristallstrukturen von [FeI2L2], [Fe2I4L3], (L -L)2+[FeI4 -]2 (L = (Me2N )2CS) und [Fe2I4(C6H10(NH-CS -NHMe)2)2] mit einer Notiz zu [FeIL3]+[Fe4S4I3L]-/Thiourea Derivatives as Ligands in Iron Complexes: Syntheses and Crystal Structures of [FeI2L2], [Fe2I4L3], (L -L)2+[FeI4 -]2 (L = (Me2N )2CS) and [Fe2I4(C6H10(NH-CS -NHMe)2)2] and a Note on[FeIL3]+[Fe4S4I3L]-

Abstract

Abstract [FeI2L2] (1) and [Fe2I4L3] (2) are obtained from the reaction o f FeI2 and 1,1,3,3-tetramethylthiourea (L) in tetrahydrofuran solution. The Fe(III) complex [FeI3L] (3) and iodine react in dichloromethane to give (L-L )2+[FeI4-]2 (4). The bidentate thiourea derivative C6H10(NH - CS -NHMe)2 (5) reacts in acetonitrile solution with Fel2 producing the dinuclear complex [Fe2I4(C6H10(NH - CS -NHMe)2)2] (6). 1 and 2 were obtained in nearly quantitative, 4 and 6 in good (ca. 87%) yield. The structures of 1, 2 ,4 and 6 were determined from single crystal X-ray diffraction data. 1 crystallizes in the monoclinic space group C 2/c with a = 1862.5(1), b = 1084.0(1), c = 1433.4(1) pm, β = 134.01(1)°. V = 1994.69 x 106 pm3, Z = 4, conventional R 0.055. The complex exhibits a two-fold symmetry and a distorted tetrahedral coordination of Fe(II). 2: monoclinic, C 2/c, a = 1968.9(2), b = 902.8(1), c = 2222.4(2) pm, β = 123.35(1)°, V = 3299.91 x 106 pm3, Z = 4, conventional R 0.036. The metals of the dinuclear complex of 2 are sulfur-bridged with distorted tetrahedral coordination of Fe(II). The bridging sulfur lies on a two-fold axis. 4: monoclinic, P21/c, a = 1135.3(2), b = 1791.9(5), c = 1642.1(4) pm, β = 93.53°, V = 3334.00 x 106 pm3, Z = 4, conventional R 0.044. The mean Fe -I bond length within the tetrahedral Fel4 - anions is 254.1 pm. The (Me2N)2CS - S(NMe2)2 2+ cation exhibits a CS - SC dihedral angle of 75.9° and an S - S bond length o f 205.2(4) pm. In the dinuclear complex of 6 two bidentate ligands coordinate two FeI2 units in such a way that a central eighteen-membered ring is formed. The complex shows a two-fold symmetry. Angles at the (pseudotetrahedral) metal range from 102.1(1) to 118.2(1)°. The reported synthetic and structural studies and the isolation of [FeIL3]+[Fe4S4I3L]- (7) indicate that thiourea derivatives seem to be useful ligands for the stabilization o f neutral Fe -S clusters.