Half-sandwich lanthanide crown ether complexes with the slow relaxation of magnetization and photoluminescence behaviors.

Four half-sandwich type mononuclear lanthanide crown ether complexes with the formula [Ln(12-crown-4)(NO3 )3 ] (Ln3+ = Dy3+ (1), Tb3+ (2), Ho3+ (3), and Er3+ (4); 12-crown-4 = 1,4,7,10-tetraoxacyclododecane) were successfully synthesized and structurally characterized. Ac magnetic susceptibility measurements reveal that dysprosium complex 1 behaves as a typical single-ion magnet, while solid state photoluminescence studies show that complexes 1 and 2 have the respective lanthanide(iii) luminescence characteristics.