Syntheses, crystal structures, weak interaction, magnetic and luminescent properties of two new organic–inorganic molecular solids with substituted chlorobenzyl triphenylphosphinium and tetra(isothiocyanate)cobalt(II) anion

Two new organic–inorganic molecular solids of tetra(isothiocyanate)cobalt(II) dianion and meta-substituted benzyl triphenylphosphinium, [2ClBzTPP]2[Co(NCS)4] (1) and [4ClBzTPP]2[Co(NCS)4] (2) ([2ClBzTPP]+ = 1-(2′-chlorobenzyltriphenylphosphonium) and [4ClBzTPP]+ = 1-(4′-chlorobenzyltriphenylphosphonium), were prepared and characterized by elemental analysis, FT-IR, UV–vis spectra, ESI-MS and single crystal X-ray diffraction method. Both 1 and 2 crystallize in monoclinic, and the Co(II) ion of the [Co(NCS)4]2− anion shows a distorted tetrahedral coordination geometry. The CH⋯Cl, CH⋯S hydrogen bonds were found in 1 while CH⋯S, CH⋯Co, p⋯π, CH⋯π interactions were found in 2 consolidating the stacking of the crystal. Magnetic susceptibility measurement in the temperature range 2–300 K shows that 1 and 2 exhibit a weak antiferromagnetic coupling behavior. Upon excitation at 268 nm, two molecular solids show the luminescent emission peak in the UV-light region in the solid state at room temperature.