Compounds with intermediate spin. 3. Structure of tris[N,N-bis(2-hydroxyethyl)dithiocarbamato]iron(III) at 150 and 295 K

Abstract

Abstract. Fe[S2CN(C2H4OH)

Iron(III) Spin Crossover Compounds

“…This compound crystallises in the space group P3 1 /c revealing two crystallographically independent Fe(III) entities, each with C 3 symmetry. The difference between the Fe-S bond lengths in the high spin and low spin states is about 0.15 , which is also in line with the Fe-S bond lengths for the low spin tris(1-pyrrole-dithiocarbamato)iron(III) hemikis(dichloro- [7] N,N-Di(2-hydroxyethyl)-295 P-1 2.39 [8] 4.2 [8] 150 P-1 2.33 [8] 2.4 [8] N,N-Dipropionitrile-210 P-1 2.308 [9] 3.19 [9] 295 P-1 2.324 [9] 3.94 d [9] N,N-Di-n-butyl 298 C2/c 2.416 72.8 [10] 5.32 [7,11] N,N-Di-n-butyl- [14] 3.0 [14] N,N-Dibenzyl-295 P2 1 2.34 [15] 3.45 [ [20] 3.80 [20] This compournd remains in the low spin state at all temperatures Table 1 (continued) methane) (Fe-S=2.297 (298 K)) [23] and the high spin tris(1-pyrrolidinedithiocarbamato)iron(III) (Fe-S=2.45 (295 K)) [16]. The contraction in the Fe-S distance accompanying the HS!LS change results from the complete transfer of electrons in the antibonding e g orbitals to the (almost) nonbonding t 2g orbitals.…”

“…Their study may be regarded as an attempt to relate the differences in capability for hydrogenbonding formation of the two ligands to the magnetic data for these compounds. As expected, the 2-hydroxyethyl-substituted ligand sets up an extensive hydrogen-bonding network [8], whereas the dimethyl-substituted derivative does not. However, the magnetic data recorded over the temperature range 80-300 K are about the same for both compounds.…”

“…Benzene [21] and nitrobenzene [22] do not appear to be involved in any hydrogen-bonding interactions, and in this instance, the existing low spin$high spin equilibria have been found to be markedly shifted towards the low spin side [32]. Although this explanation appears to be reasonable in this case, the investigation of Albertsson and Os-karsson, who compared tris(N,N-di(2-hydroxyethyl)-dithiocarbamato) iron(III) [8] with tris(N,N-dimethyl-dithiocarbamato)iron(III) [5] indicates that the expected effects may not always be observed. Their study may be regarded as an attempt to relate the differences in capability for hydrogenbonding formation of the two ligands to the magnetic data for these compounds.…”