Phase Transitions in Mesogenic Third Generation Poly(Propyleneimine) Dendrimer and Its Iron(II) Complex

Two third generation liquid-crystalline dendrimers, poly(propyleneimine) derivatives with 3,4-bis(decyloxy)benzoic moieties at the periphery, were prepared, and their thermodynamic properties were studied. The formation of a columnar mesophase was verified by differential scanning calorimetry (DSC) and polarizing optical microscopy. It was for the first time that the specific heat capacity and magnetocaloric effect (MCE) of the iron complex G3-K2.10 center dot (FeCl2)(15)in the temperature 288-350 K in magnetic fields varying from 0 to 1.0 T were determined. The temperature-dependent specific heat capacity of the complexes in the range 210-460 K was measured on a differential scanning calorimeter and an original design microcalorimeter. The temperature-dependent heat capacity and magnetocaloric effect are extreme functions.