Syntheses, Crystal Structures, and Magnetic Properties of Two Meta-Substituted Benzyl Triphenylphosphinium Tetra(isothiocyanate)cobaltate(II) Complexes

Two new complexes of tetra(isothiocyanate)cobalt(II) dianion and meta-substituted benzyl triphenylphosphinium, [3BrBzTPP](2)[Co(NCS)(4)] (1) and [3CNBzTPP](2)[Co(NCS)(4)] (2) ([3BrBzTPP](+) = 1-(3 '-bromobenzyltriphenylphosphonium and [3CNBzTPP](+) = 1-(3 '-cyanobenzyltriphenylphosphonium), 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 P2(1)/c, and the Co(II) ion of the [Co(NCS)(4)](2-) anion shows a distorted tetrahedral coordination geometry. The C-H center dot center dot center dot S hydrogen bonds and p center dot center dot center dot pi interaction found in 1 and 2 consolidate the stacking of the crystal. Magnetic susceptibility measurement in the temperature range 2-300K shows that 1 and 2 exhibit a weak antiferromagnetic coupling behavior.