Byla připravena série komplexů kobaltu s ligandy obsahující triazén-1-oxid [Co(LX)2] a [Co(LX2)2] (HLX = 3-fenyl-1-methyltriazén-1-oxid, X = o-F, o-Cl, o-Br, o-OMe, o-OEt, o-OPh, X2 = o-, m-Cl) za účelem studia jejich magnetických vlastností. Sloučeniny [Co(LF)2], [Co(LCl)2], [Co(LBr)2], [Co(LOMe)2] a [Co(LOEt)2] již byly dříve syntetizovány, avšak struktura byla vyřešena jen pro [Co(LCl)2] a magnetické vlastnosti také nebyly studovány. Podařilo se strukturně charakterizovat další tři komplexy ([Co(LBr)2], [Co(LOMe)2] a [Co(LCl2)2]) a studovaly se jejich magnetické vlastnosti. [Co(LCl)2], [Co(LBr)2] a [Co(LOMe)2] jsou polem indukované jednoiontové magnety a [Co(LF)2] a [Co(LCl2)2] se chovají jako jednoiontové magnety bez vnějšího magnetického pole.A series of cobalt complexes containing triazene-1-oxide [Co(LX)2] and [Co(LX2)2] (HLX = 3-phenyl-1-methyltriazene-1-oxide, X = o-F, o-Cl, o-Br, o-OMe, o-OEt, o-OPh, X2 = o-, m-Cl) has been synthetized in order to study their magnetic properties. Compounds [Co(LF)2], [Co(LCl)2], [Co(LBr)2], [Co(LOMe)2] and [Co(LOEt)2] have been already prepared but their structure has been solved only for [Co(LCl)2] and magnetic properties hasn't been studied. We managed to characterize structures of another three complexes ([Co(LBr)2], [Co(LOMe)2] and [Co(LCl2)2]) and we studied their magnetic properties. [Co(LCl)2], [Co(LBr)2] and [Co(LOMe)2] are field-induced single-ion magnets and [Co(LF)2] and [Co(LCl2)2] act as single-ion magnets in absence of magnetic field.