Polymeric Manganese(II) Acetate Derivatives: Syntheses, Crystal Structures and Magnetic Properties

Abstract Three novel polymeric Mn(II) acetate derivatives, identified as {[Mn 2.5 (OH)(CH 3 COO) 4 ] ⋅ 0.5CH 3 OH ⋅ 0.5CH 3 CN} n ( 1 ), {[Mn 3 (CH 3 CO O) 6 ] ⋅ 0.5CH 3 CN} n ( 2 ) and {Mn 1.5 K(CH 3 COO) 4 } n ( 3 ), have been successfully prepared by systematically adjusting the ratio of reactants and using the 2‐mercapto‐5‐methyl‐1,3,4‐thiadiazole (Hmmt) as the template agent. These three complexes can be regarded as the different crystalline forms of Mn(CH 3 COO) 2 under different reaction conditions. Single‐crystal X‐ray diffraction analyses revealed that 1 and 2 feature the unique three‐dimensional (3D) framework. For 3 , it displays a 2D structure, which is further assembled to form a 3D extended network via the weak hydrogen bond interactions. Magnetic studies confirmed that 1 and 2 show antiferromagnetic interactions, and 1 displays a long‐range ordering phase below the critical temperature ( T c ) of 7.8 K. In addition, magnetisation data collected for 1 – 2 yield low magnetic entropy changes, which can be attributed to the strong antiferromagnetic interactions among the Mn(II) centres.