
TY  - JOUR
A1  - Abushamleh, AS 
A1  - Goodwin, HA 
T1  - Metal-Complexes of 1,10-Phenanthroline Derivatives. XV. Complexes of 2-(3,5-Dimethylpyrazol-1-yl)-1,10-phenanthroline
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 1988
VL  - 41
IS  - 6
SP  - 873
EP  - 880
KW  - 
UR  - https://doi.org/10.1071/CH9880873 
N2  - Iron(II) and nickel(II) bis ( ligand ) complexes of 2-(3,5-dimethylpyrazol-1-yl)-1,10-phenanthroline (L) have been prepared. The field strength of L as determined from spectral data for the nickel complex is in the range encompassing the critical value at the singlet (1A1) &#8596; quintet (5T2) crossover for iron(II). The magnetic properties of the iron(II) complex both in solution and in the solid state are anomalous, and indicative of the occurrence of a thermally induced spin transition. Mossbauer spectral data confirm this, and reveal separate contributions from the singlet and quintet species with a strong temperature-dependence of their relative intensities. Magnetic data for the complex in solution are consistent with a simple high spin &#8596; low spin equilibrium, and lead to values of &#916;H = 23±0.5 kJ mol-1 and &#916;S = 66±5 J K-1 mol-1 for the low spin &#8594; high spin transformation. 
ER  -

