Synthesis, Crystal Structure, DNA Binding, and Hydrolytic Cleavage Activity of a Manganese(II) Complex

A new trinuclear manganese(II) complex {[MnCl(bpma)] 2 [Mn(μ‐Cl) 4 (H 2 O) 2 ]} · CH 3 CN ( 1 ) [bpma = N , N ‐bis(2‐pyridylmethyl)methylamine] has been synthesized and structurally characterized by X‐ray crystallography. The variable temperature‐dependent susceptibility measurement (2–300 K) of 1 reveals a weak antiferromagnetic interaction between the manganese ions through the dichlorido bridging ligands, with J = –0.46 cm –1 , g = 1.99. The electrospray ionization mass spectrum of 1 in solution indicates that the dinuclear [Mn 2 (bpma) 2 Cl 2 (H 2 O)(OH)] + ion is the active species. In the absence of a reducing agent, supercoiled plasmid DNA cleavage by the active species was performed and its hydrolytic mechanism was demonstrated with radical scavengers, anaerobic reaction, and T4 ligase. The pseudo‐Michaelis–Menten kinetic parameters ( k cat. , K M ) were calculated to be 1.11 h –1 and 6.65 × 10 –4 M for the dinuclear species.