T. Buchen et P. Gutlich, SUBSTITUENT EFFECTS ON THE SPIN EQUILIBRIUM IN IRON(II) PYRAZOLYLBORATE COMPLEXES, Inorganica Chimica Acta, 231(1-2), 1995, pp. 221-223
Two new complexes of the iron(II) pyrazolylborate system, [Fe(HB(pz)(d
mpz)(2))(2)] and [Fe(HB(pz)(2)(dmpz))(2)] (pz=pyrazole, dmpz=3,5-dimet
hylpyrazole), have been prepared and found to exhibit thermal spin cro
ssover in toluene solutions by means of optical spectroscopy and magne
tic susceptibility measurements. Comparison with the published magneti
c behaviour of the complexes [Fe(HB(dmpz)(3))(2)] and [Fe(HB(pz)(3))(2
)] shows that the high spin state is stabilized with an increasing num
ber of methyl substituents.