A new co-crystal dinuclear/trinuclear ZnII–ZnII/ZnII–SmIII–ZnII complex with a salen-type Schiff base ligand

Abstract

In the pentanuclear title complex, [SmZn2(C22H18N2O4)2(NCS)2(C3H7NO)2][Zn2(C22H18N2O4)(NCS)3]·C3H7NO·0.32H2O, namely bis{μ2-6,6′-dimethoxy-2,2′-[phenylene-1,2-diylbis(nitrilomethanylylidene)]diphenolato}-1κ4O,N,N′,O′:2κ3O,O′,O6;2κ3O,O′,O6:3κ4O,N,N′,O′-bis(dimethylformamide-2κO)dithiocyanato-1κN,3κN-2-samarium(III)-1,3-dizinc(II) {μ2-6,6′-dimethoxy-2,2′-[phenylene-1,2-diylbis(nitrilomethanylylidene)]diphenolato-1κ4O,N,N′,O′:2κ2O,O′}trithiocyanato-1κN;2κ2N,N-dizinc(II) dimethylformamide monosolvate 1.32-hydrate, a dinuclear unit and a trinuclear unit co-exist. One of the ZnII centers in the dinuclear unit as well as the two ZnII centers in the trinuclear unit are located in the inner N2O2 cavity of the ligand and are coordinated to the nitrogen atom of one thiocyanate moiety, giving rise to a square-pyramidal geometry. The second ZnII center in the dinuclear unit is coordinated to the two phenolate oxygen atoms of the ligand and to two thiocyanate groups via the nitrogen atom in a tetrahedral geometry. The SmIII ion is eight-coordinated by four phenolate O atoms from the two ligand molecules, two methoxy O atoms from the two ligand molecules and two O atoms from the DFM solvent molecule. In the dinuclear unit, the two methoxy oxygen atoms remain uncoordinated while in the trinuclear unit, for each ligand one methoxy oxygen is coordinated and the other one remains uncoordinated. In the crystal, the trinuclear cationic units and dinuclear anionic units are assembled into infinite layers. These layers are held together via electrostatic interactions, forming a three-dimensional structure. In the dinuclear unit, the C and S atoms of one of the thiocyanate groups are disordered over two sets of sites in a 0.680 (4)(4):0.320 (4) ratio.

Keywords

• crystal structure
• zinc
• samarium
• Schiff base