Supramolecular systems built from phenylcyanamido ligands. Syntheses, crystal structures and magnetic properties

Abstract

Several new Mn^II compounds with X-phenylcyanamido (Xpcyd) and 2,2′-bipyrimidine (2,2′-bpm) bridging ligands of formula [Mn(pcyd)(MeOH)(μ-pcyd)(μ-2,2′-bpm)_0.5]_n (1), [Mn(3-Clpcyd)(MeOH)(μ-3-Clpcyd)(μ-2,2′-bpm)_0.5]_n (2), (μ-4-Clpcyd)₂[Mn(4-Clpcyd)(H₂O)(2,2′-bpm)]₂ (3) and [Mn(3-Fpcyd)(MeOH)(μ-3-Fpcyd)(μ-2,2′-bpm)_0.5]_n (4) have been synthesised and characterised. The one-dimensional compound [Mn(pcyd)(MeOH)(μ-pcyd)(μ-2,2′-bpm)_0.5]_n (1) crystallises in the triclinic system, P space group and the dinuclear compound (μ-4-Clpcyd)₂[Mn(4-Clpcyd)(H₂O)(2,2′-bpm)]₂ (3) crystallises in the orthorhombic system, P2₁2₁2₁ space group. The two compounds contain the unusual end-to-end cyanamide bridge and give supramolecular 2-D networks by means of H-bonds. Susceptibility measurements on compounds 1–4 reveal moderate antiferromagnetic coupling in all cases. Coupling constants related to the phenylcyanamido bridges are compared with the superexchange model recently proposed for ligands of this kind.