In observation of slow magnetic relaxation in triple-stranded lanthanide helicates Terbium(III) perchlorate is substituted for dysprosium(III) perchlorate hexahydrate. By reacting 3-formylchromone and hydrated terbium (III) perchlorate in isopropanol, 3-hydroxymethylchromone [icm], bis(3-chromonyl)methanol [dcm] and the novel complex Tb(imc)3(ClO4)3.5H2O are obtained.