JOURNAL DE PHYSIQUE
CoNoque C1, suppl6rnent au n " 1 , Tome 41, janvier 1980, page (21-293
HYPERFINE IMERACTIONS AND WGNETIC MCFWTS OF S M F~(II) COMPLEXES WITH DIMETHYLFORMAMIDE AND
G. Wiesinger, G. Gritzner and W. Linert
Institut fUr ExperimentaZphysik, 2'. U. Vienna, Austria.
+ Institut fUr Anorganische Chemie, T. U. Vienna, Austria.
The aim of the present investigation w a s to gain
infonation on the different interactions of trans-
ition metal cations with ligands that exhibit their
donor properties via an oxygen and a sulphur atm
respectively. Model substances to study these
interactions have been prepared from Fe( 11) com-
plexes and NN dimethylfomanide (D1vIF) as well as
NN dimethylthiofomide (DIWF). The following
ccmpounds were obtained:
F ~ ( D M F ) ~ ( C ~ O ~ ) ~
Fe (DMF) Br2
Fe (DC4TF) 2Br2
Fe (DLWF )
In the present discussion emphasis is laid on re-
sults fkwn MGssbauer and magnetic measurements.
Additional experiments which have been performed
during this work, i.e. structure determination,
optical spectroscopy, and electrical conductivity
measurement w i l l be published elsewhere /I, 2/.
The 57~e Mijssbauer experiments have been carried
out in the temperature range between 4.2 K and
200 K. It is cmon to all these compounds that
they exhibit a relatively low me1 ting point (-400 K).
A s a consequence they have a low Debye temperature
and therefore the recoil free fraction is vanishing
above-200 K. The spectra were fitted using a
least squares f i t procedure assuming a super-
position of Lorentzian lines /3/. With one ex-
ception only pure doublets were obtained. The re-
sulting hyperfine parameters are listed in table 1:
TABLE 1: Hyperfinc parameters at T = 4.2 K
[m/sec 2 0.023
[m/sec +_ 0.021