One‐Dimensional End‐To‐End Azide‐Bridged Mn III Complexes Incorporating Alkali Metal Ions: Slow Magnetic Relaxations and Metamagnetism

Three azide‐bridged Mn III chains [Mn(3‐MeOsalpn)(N 3 )] ⋅ 0.5 AClO 4 (A=Na ( 1 ), K ( 2 ), Rb ( 3 ); 3‐MeOsalpn= N , N ′‐propylenebis(3‐methoxysalicylideneiminato) dianion) incorporating alkali metal ions and perchlorate anions were systematically synthesized. The overall structure can be described as a one‐dimensional chain bridged by end‐to‐end azide ligands, although spatial arrangements of Jahn–Teller axes of Mn in 1 and 2 are different from that in 3 . Relying on the alkali metal ions, magnetic properties are varied from a two‐step phase transition ( 1 ) to metamagnetic transitions ( 2 and 3 ). In this system, spin canting definitely plays a central role in giving rise to the apparent slow magnetic relaxations in 1 and 2 because application of a high external magnetic field tends to destroy single‐chain magnet (SCM) properties. Despite the existence of a long‐range antiferromagnetic order at T N , slow magnetic relaxation is notably observed in 2 , which likely emanates from the operative spin canting below T N .