Slow Magnetic Relaxation in Silver(II) Macrocyclic Systems.

The spin-lattice relaxation time has been studied trough alternating-current susceptometry and ultralow-frequency Raman spectroscopy in a family of silver(II)-derived molecular systems with spin 1 / 2 and formulas [Ag II ( m -CTH)(NO 3 ) 2 ] ( 1 ) and [Ag II ( m -CTH)(ClO 4 ) 2 ] ( 2 ), where CTH = meso -5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane. The combination of both techniques demonstrates the occurrence of slow spin magnetic relaxation induced by spin-phonon interaction. The magnetic behavior of these silver(II)-derived systems opens the door to a new cation in the scarce family of S = 1 / 2 systems with slow relaxation of magnetization.