A dirhodium(II,II) complex as a highly selective molecular material for ammonia detection: QCM studies

摘要: The well known axial coordination capabilities of dirhodium(II,II) complexes towards Lewis bases have been exploited for the development functional molecular materials selective ammonia monitoring. On basis literature data and experimental evidence, [Rh2(form)4] (1) (form = N,N′-di-p-tolylformamidinate anion) complex has selected, among a series derivatives, as most suitable this aim. By exposure to gaseous ammonia, 1 readily reacts, both in solution solid state, with gas afford corresponding ammonia-axial adduct. reaction is reversible accompanied by significant color change from dark yellow-green red-brown due adduct formation, confirmed RGB, UV-vis FT-IR spectroscopic investigations. Solid state UV/vis spectra reveal that while occurs steadily, judged blue shift observed λmax (470 1vs. 430 nm adduct), its complete release, free air, takes more than week. potentiality detection headspace aqueous solutions examined QCM dynamic response obtained such studies consistent binding process occurring at layer surface, which operating once fraction analyte “irreversibly” bound sensor layer. shows an excellent linearity wide concentration range (1–30 wt%) without any saturation effect up high levels selectivity interfering gases.