Iron tris(diethyldithiocarbamate) explained

Iron tris(diethyldithiocarbamate) is the coordination complex of iron with diethyldithiocarbamate with the formula Fe(S₂CNEt₂)₃ (Et = ethyl). It is a black solid that is soluble in organic solvents.

Synthesis, structure, bonding

Iron tris(dithiocarbamate)s are typically are prepared by salt metathesis reactions.^[1]

Iron tris(diethyldithiocarbamate) is an octahedral coordination complex of iron(III) with idealized D₃ symmetry.^[2]

The phenomenon of spin crossover (SCO) was first reported in 1931 by Cambi et al. who observed anomalous magnetic behavior for the tris(N,N-dialkyldithiocarbamatoiron(III) complexes.^[3] The magnetism of these complexes are sensitive to the nature of the amine substituents as well as to temperature. This behavior is consistent with an equilibrium between two or more spin states.^[4] In the case of Fe(Et₂dtc)₃, X-ray crystallography reveals that the Fe-S bonds are 231 pm at 79K but 356 pm at 297 K. These data indicate a low-spin configuration at low temperatures and a high spin configuration near room temperature.^[2]

Iron tris(dithiocarbamate)s characteristically react with nitric oxide to give Fe(dtc)₂NO. This efficient chemical trapping reaction provides a means to detect NO.^[5]

Reflecting the strongly donating properties of dithiocarbamate ligands, iron tris(dithiocarbamate)s oxidize at relatively mild potentials to give isolable iron(IV) derivatives [Fe(S₂CNR₂)₃]⁺.^[6]

Safety

Iron tris(dimethyldithiocarbamate) is the herbicide ferbam, which is poisonous.

See also

• Iron tris(dimethyldithiocarbamate) - a related dimethyldithiocarbamate complex of iron
• Iron bis(diethyldithiocarbamate)
• Cobalt tris(diethyldithiocarbamate)

Notes and References

1. The Chemistry of the Dithioacid and 1,1-Dithiolate Complexes. Progress in Inorganic Chemistry. 11. D. Coucouvanis. 2007. 233–371. 10.1002/9780470166123.ch4. 9780470166123.
2. 10.1021/ic50128a012. Correlation between structure- and temperature-dependent magnetic behavior of iron dithiocarbamate complexes. Crystal Structure of Tris(N,N diethyldithiocarbamato)iron(III) at 297.deg. and 79.deg.K. 1973. Leipoldt. J. G.. Coppens. P.. Inorganic Chemistry. 12. 10. 2269–2274.
3. L. Cambi . L and L. Szego . Chem. Ber. Dtsch. Ges.. 1931. 64. 2591. 10.1002/cber.19310641002. Über die magnetische Susceptibilität der komplexen Verbindungen. 10.
4. Book: P. Gütlich . H.A. Goodwin . Spin Crossover in Transition Metal Compounds I. Springer Berlin. 2004. 978-3-540-40396-8.
5. Fujii, S. . Yoshimura, T. . A new trend in iron–dithiocarbamate complexes: as an endogenous NO trapping agent. Coordination Chemistry Reviews. 2000. 198. 89–99. 10.1016/S0010-8545(99)00196-4.
6. Pasek, E. A. . Straub, D. K. . Tris(N,N-disubstituted Dithiocarbamato)iron(IV) Tetrafluoroborates. Inorganic Chemistry. 1972. 11. 2. 259–263. 10.1021/ic50108a012.