Synthesis, crystal structure and magnetic properties of diaquabis(2,6‐diamino‐7 H ‐purin‐1‐ium‐κ N 9 )bis(4,4′‐oxydibenzoato‐κ O )cobalt(II) dihydrate

The title mononuclear Co II complex, [Co(C 5 H 7 N 6 ) 2 (C 14 H 8 O 5 ) 2 (H 2 O) 2 ]·2H 2 O, has been synthesized and its crystal structure determined by X‐ray diffraction. The complex crystallizes in the triclinic space group P , with one formula unit per cell ( Z = 1 and Z ′ = ). It consists of a mononuclear unit with the Co II ion on an inversion centre coordinated by two 2,6‐diamino‐7 H ‐purin‐1‐ium cations, two 4,4′‐oxydibenzoate anions (in a nonbridging κ O ‐monodentate coordination mode, which is less common for the anion in its Co II complexes) and two water molecules, defining an octahedral environment around the metal atom. There is a rich assortment of nonbonding interactions, among which a strong N + —H…O − bridge, with a short N…O distance of 2.5272 (18) Å, stands out, with the H atom ostensibly displaced away from its expected position at the donor side, towards the acceptor. The complex molecules assemble into a three‐dimensional hydrogen‐bonded network. A variable‐temperature magnetic study between 2 and 300 K reveals an orbital contribution to the magnetic moment and a weak antiferromagnetic interaction between Co II centres as the temperature decreases. The model leads to the following values: A (crystal field strength) = 1.81, λ (spin‐orbit coupling) = −59.9 cm −1 , g (Landé factor) = 2.58 and zJ (exchange coupling) = −0.5 cm −1 .