Synthesis, Crystal Structure, Cryomagnetic Properties and Catalytic Activity for H 2 O 2 Disproportionation of New Dinuclear and Polynuclear Bis(2,4‐pentanedionate)manganese(II) Complexes with Diazine Ligands

The structures, magnetic properties, and catalytic activity for H 2 O 2 disproportionation are reported for three new complexes [Mn 2 (acac),(pydz)] ( 1 ), [Mn(acac) 2 (pym)] ( 2 ), and (Mn(acac) 2 (pyz)] ( 3 ) (acac = 2,4‐pentanedionate, pydz = pyridazine, pym = pyrimidine, pyz = pyrazine). The X‐ray crystal structures of 1 and 3 have been determined. Complex 1 crystallizes as a binuclear complex with η 2 ‐pyridazine and acac bridging ligands 3 crystallizes as a linear polymeric chain with bridging pyrazine molecule. Cryomagnetic investigations (4‐300 K) reveal a weak intramolecular antiferromagnetic spin exchange with J = −2.05, −0.04, and −0.05 cm −1 for the complexes of 1, 2 , and 3 , respectively. The complexes 1–3 showed two‐step catalytic activity for H 2 O 2 disproportionation in pyridine solution at 0 °C.