Temperature-dependent effective magnetic moment of compound 6 in toluene solution, recorded between T= 4 and 300 K with an applied magnetic field of 0H= 1 kG. Symbols: corrected experimental data. Solid line: fit with a regular solution model without cooperativity.(65) The fit was applied to the data above T= 180 K (in the liquid phase of the solvent). Parameters of the fit: LS= 1.7 B(fixed in the fit), HS= 3.9 B(fixed in the fit), H= 14.42(76) kcal mol1, and S= 35(2) cal mol1K1(T0.5= 412 K for a 1:1 ratio of high-spin (HS) to low-spin (LS) states).
