3.3. Solid state characterisation of 5 and 6
The magnetic profile of complexes 1 and 2 has been previously described [38] and [48]. While complex 1 showed thermal magnetic dependence exhibiting SCO behaviour, complex 2 is stabilised in the HS state over the measured temperature range. The thermal magnetic behaviour of crystalline samples 3–6 was measured by SQUID magnetometry on cooling and warming modes. Results obtained for complexes 3 and 4 are reported elsewhere [40], and indicated that although differently, both complexes exhibited incomplete SCO. Complex 3 showed a gradual SCO on cooling and an abrupt ST on warming with an asymmetric 70 K hysteresis loop. Compound 4 displayed a gradual SCO, and its magnetic behaviour showed to be sensitive to the applied magnetic field and sample thermal history.
Fig. 3 displays the results obtained for samples 5 and 6. At low temperature both compounds are in the LS state with χmT values of 0.59 and 0.37 cm3 mol−1 K, respectively. Complex 6 remains in the LS state up to 150 K, where χmT starts to increase slowly, displaying an incomplete thermal SCO, as indicated by the small value of χmT, 2.4 cm3 mol−1 K, obtained at the highest measured temperature, 370 K. In the case of complex 5χmT values are almost constant (varying between 0.59 and 0.86 cm3 mol−1 K), suggesting that the population of the LS state is essentially maintained up to 300 K.