Gas-Phase and Condensed-Phase Studies on the Reactivity of the Azido(2,2':6',2''-terpyridine)platinum(II) Cation

Abstract

The recent report of the gas-phase loss of nitrogen from [Pt(dien)N₃]⁺ (dien = diethylenetriamine) under collisioninduced dissociation conditions has prompted us to investigate whether the analogous fragmentation of [Pt(tpy)N₃]⁺ (tpy = 2,2′: 6′,2″-terpyridine) occurs in the gaseous and condensed phase as well as in the solid state. While such a process occurs in the gaseous phase, attempts to fragment [Pt(tpy)N₃]⁺ by refluxing it in MeCN yielded the tetrazolato complex [Pt(tpy)(N₄CMe)]⁺, and solid state thermolysis resulted in decomposition. In order to examine the mode of binding of the tetrazole to platinum, the related complex [Pt(tpy)(N₄CPh)]BF₄ was synthesized via a similar route. X-ray crystallography revealed that the tetrazolate ligand in this complex binds through the N 2 position. In addition, the gas-phase reactivity of these complexes has been investigated using electrosprayionization tandem mass spectrometry (ESI-MS/MS). [Pt(tpy)N₃]⁺ fragments to form [Pt(tpy)N]⁺, which readily reacts with alcohols, CH₃CN and (CH₃)₂CO, to form adducts. The [Pt(tpy)N+R′OH]⁺ adduct ions (R′ = CH₃, CH₃CH₂ and (CH₃)₂CH) fragment to yield [Pt(tpy)N+H₂]⁺ ions with concomitant oxidation of the alcohols.