Single-crystal X-ray diffraction me

Single-crystal X-ray diffraction measurement shows that complex 1 crystallizes in the triclinic P-1 space group, and the asymmetric unit of 1 contains one NiII atom, one CH3O-BDC anion, and 1,4-bimb ligand. Ni1 is also six-coordinated by four carboxylate oxygen atoms from three different CH3O-BDC ligands, and two nitrogen atoms from two different 1,4-bimb ligands, adopting a distorted octahedral coordination geometry (Fig. 2a). The Ni-O, Ni-N bond distances and O-Ni-O, O-Ni-N, N-Ni-N bond angles ranging from 2.046(3) Å to 2.197(3) Å and from 60.52(11)° to 176.59(13)°, respectively. The values are in agreement with those found in other Ni(II) complexes with oxygen and nitrogen donating ligands [26]. In the crystal structure of 1, the CH3O-BDC ligand act as bridging/chleating-μ3 mode to link three metal ions, whereas 1,4-bimb ligand acts as a trans-bidentate bridging ligand to link two Ni(II) ions. In this manner, the dinuclear nickel units are connected by μ3-CH3O-BDC ligands to generate a linear chain of [Ni2(CH3O-BDC)2N4]n with dinuclear nickel cores separated by 10.072 Å (Fig. 2b), in which the chains are further connected into a (4,4) layered structure through μ2-1,4-bimb ligands when the dinuclear nickel units and CH3O-BDC ligands are regarded as nodes and linkers, respectively (Fig. 2c and 2d).