Ludv. Koch.

FeBr2 has reacted with an equivalent of mnt(2-) (mnt = cis-1,2-dicyanoethylene-1,2-dithiolate) and the alpha-diimine L (L = 1,10'-phenantroline, 2,2'-bipyridine) in THF solution, and followed by adding of t-butyl-isocyanide to give [Fe(mnt)(L)(t-BuNC)(2)] neutral compound. The products were characterized by infrared, UV-visible and Mossbauer spectroscopy, besides thermogravimetric and conductivity data. The geometry in the equilibrium was calculated by the density functional theory and the electronic spectrum by the time-dependent. The experimental and theoretical results in good agreement have defined an octahedral geometry with two isocyanide neighbours. The pi ->pi* intraligand electronic transition was not observed for cis-isomers in the near-IR spectral region