pH-Induced switching of metal ion co-ordination: the structure of [Pd([18]aneN2S4·2H+)][BF4]4·2H2O from a twinned crystal ([18]aneN2S4 = 1,4,10,13-tetrathia-7,16-diazacyclooctadecane)

Abstract

Treatment of [Pd([18]aneN₂S₄)][BF₄]₂ ([18]aneN₂S₄ = 1,4,10,13-tetrathia-7,16-diazacyclooctadecane) with HBF₄ led to a marked structural change at Pd(II) from distorted octahedral [N₂S₂ + S₂]-donation to a square-planar S₄-donor co-ordination via protonation of the secondary amine functions; this pH-induced re-arrangement is accompanied by a reversible colour change from purple to yellow in MeCN solution.