Zur strukturellen Verzerrung von Fe4S4I4 2- -Clustern durch Iod-Iod-Kon Die Kristallstrukturen von (Ph4P)2Fe4S4I4 und (Me3NCH2Ph)2Fe4S4I4 / Structural Distortion of Fe4S4I2 2- Clusters through Iodine-Iodine Contacts: Crystal Structures of (Ph4P)2Fe4S4I4 and (Me3NCH2Ph)2Fe4S4I4

Abstract

Abstract The structures of (Ph4P)2Fe4S4I4 (1) and (Me3NCH2Ph)2Fe4S4I4 (2) were determined from single crystal X-ray diffraction data. 1 crystallizes in the tetragonal space group I41/a with a = 1088.3(1) and c = 4540.3(2) pm. Z = 4. 2: Monoclinic, space group Cc. a = 1332.0(2), b = 1513.8(3), c = 1755.1(3) pm, β = 96.69(1)°, Z = 4. In 1 the anion Fe4S4I4 2- has imposed S4 symmetry with four short (226.2 pm) and eight long (228.1 and 228.4 pm) Fe-S distances parallel and perpendicular, respectively, to the crystallo­graphic 4̃ axis. The Fe-Fe distances were found to be 274.3 and 275.5 pm (Fe-I 254.1 p0m). In (Me3NCH2Ph)2Fe4S4I4 the [Fe4S4]2+ cluster also exhibits a slightly compressed tetragonal core structure but the core distortions are larger and less regular than in 1 (Fe-S distances from 224.6 to 232.9 pm, Fe-Fe distances from 269.6 to 275.9 pm, Fe-I distances from 249.5 to 255.7 pm). In addition there are in 2 iodine-iodine interactions between the anions with an I-I distance of 391.7 pm. These weak attractive forces seem to be the reason for the rather large and hitherto in [Fe4S4] clusters with four identical ligands unobserved distortion of the Fe4S4 core.