Syntheses, crystal structures, luminescent properties of two new molecular solids with tetra(isothiocyanate)zinc(II) and substituted benzyl triphenylphosphonium cations

The self-assembly of [Zn(NCS)4]2− (NCS− = isothiocyanate) anion and substituted benzyl triphenylphosphonium cations [4RBzTPP]+ (R = H(1), NO2(2); BzTPP = benzyl triphenylphosphonium) results in the forming of two new molecular solids, [BzTPP]2[Zn(NCS)4] (1) and [4NO2BzTPP]2[Zn(NCS)4] (2), which have been characterized by elemental analyses, UV, IR, ESI-MS and single-crystal X-ray diffraction. The Zn(II) ion of the [Zn(NCS)4]2− anion both 1 and 2 has a distorted tetrahedral environment with four N atoms of four NCS− anions. The anions form a 1D chain through S⋯S interactions with the distances of 3.470 Å for 1 and 4.067 Å for 2, while the combination of the CH⋯S and CH⋯O hydrogen bonds as well as p⋯π interaction in 2 make the cations form a 1D column. The title molecular solids show fluorescence emission in the solid state at room temperature.