Single pot synthesis of pyridine-N-oxide based polymeric complexes of cadmium and manganese: Crystal structure and luminescence property

Two new polymeric complexes of cadmium(II) and manganese(II) with Pyridine-N-oxide (pyo) mediated by thiocyanate and dicyanamide (dca) anions have been synthesized and characterized by X-ray single crystal structure analysis. The structural analyses reveal that complexes [Cd(pyo)2(SCN)2]n (1) and [Mn(pyo)2(dca)2]n (2) [where, pyo = pyridine-N-oxide; dca = dicyanamide] are 2D coordination polymers. In complex 1 hexa-coordinated Cd(II) centers posses distorted octahedral coordination environments. Each Cd(II) is coordinated by four SCN- in end to end fashion forming a zigzag chain and two pyo monodentate ligands bridge two adjacent Cd(II) centers leading to a two-dimensional sheet structure. In complex 2 hexa-coordinated Mn(II) centers posses octahedral coordination environments. The coordination polymer constitute a 2D polymeric sheet and has a (4, 4) grid network architecture Successive stacking of coordination polymeric sheets are enforced by inter layer OH⋯O and OH⋯N hydrogen bonding. The luminescence properties of these two polynuclear complexes in solid state were studied and complex 1 exhibits higher luminescence intensity than 2.

► Two polymeric CdII and MnII with pyridine-N-oxide have been synthesized.
► Structural characterization reveals both complexes have 2D layer structure.
► Fluorescence study and thermal analysis has been performed.
► The observed luminescence is a consequence of LMCT.