2018 Volume 61 Issue 2 Pages 140-149
Multifunctional phthalocyanine metal complexes are very useful for many applications, such as electroconductivity, electrochromism and liquid crystalline formation, so the syntheses of phthalocyanine derivatives have attracted much interest in recent years. Previously, we noticed that no template effect was observed for the microwave-assisted synthesis of phthalocyanine copper complex, which we thought might be due to dielectric loss coefficient of the added metal salt. However, the dielectric loss coefficient of metal salt in a dilute solution is very difficult to directly measure. Since the heat quantity is proportional to the dielectric loss coefficient from basic microwave theory, the maximum temperature of a solution containing a metal salt heated by microwave irradiation can be an indirect index of the dielectric loss coefficient. In this study, glycerin solutions containing one of twelve different metal salts (MCl2, MSO4, M(OAc)2: M = Co, Ni, Cu, Zn) were heated by microwave irradiation. The maximum temperature of the solution reached was measured for each of the metal salts. Then, the corresponding phthalocyanine metal complexes (C8S)8PcM (M = Co, Ni, Cu, Zn) were prepared using these twelve different metal salts by microwave heating. The findings showed a proportional relationship between the yields and the maximum temperatures reached by microwave irradiation. This relationship may provide a useful guideline in microwave-assisted synthesis of organic metal complexes.
