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 molecular solids containing [Co(NCS)4]2− dianion were prepared and characterized.
• There are CH⋯Cl, CH⋯S, CH⋯S, CH⋯Co, p⋯π, CH⋯π and interactions in 1 and 2.
• Two molecular solids show a broad fluorescence emission at room temperature.
• Two molecular solids show weak antiferromagnetic coupling behavior.

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.

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