Tetrakis(4-amino-1,2,4-triazole)platinum(II) Salts: Syntheses, Crystal Structures, and Properties

Transparent crystals comprising the nitrogen-rich coordination unit [Pt(NH(2)trz)(4)](2+) were synthesized with counterions of various sizes but of the same charge (-1), yielding the compounds [Pt(NH(2)trz)(4)]Cl(2)2H2O, [Pt(NH(2)trz)(4)](NO3)(2) and [Pt(NH(2)trz)(4)](CF3SO3)(2), with NH(2)trz designating 4-amino-1,2,4-triazole. Single-crystal X-ray diffraction analysis showed that NH(2)trz coordinates with only the nitrogen atom in 1-position in all compounds. The [Pt(NH(2)trz)(4)](2+) units are stacked such that the platinum atoms form linear arrays with Pt-Pt spacings mostly uncorrelated to anion size. The compound with the smallest anion (Cl-) has the smallest Pt-Pt spacing (4.72 angstrom) and shows a quasi-one-dimensional structure. Thermal decomposition of the compounds was observed around 200 degrees C. Electrical conductivity of [Pt(NH(2)trz)(4)]Cl-2 and [Pt(NH(2)trz)(4)](SO3CF3)(2) was investigated and found to be humidity-dependent. Finally, [Pt(NH(2)trz)(4)](2+) ions obtained by dissolution of the chloride salt are shown to be useful for the synthesis of new compounds such as the Magnus' salt derivative [Pt(NH(2)trz)(4)][PtCl4].