An insight into the beginning stage of the aqueous ring opening metathesis polymerization of exo,exo-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid with RuIII compounds: the consumption of RuIII species in the presence of carboxylic acids monitored by ESR spectroscopy

The presence of paramagnetic species in the aqueous ring opening metathesis polymerizations of the exo,exo-7-oxabicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid monomer with RuCl3 and K-2[RuCl5H2O] compounds was studied using ESR techniques. It was observed that the intensities of the Ru-III signals in the ESR spectra decrease on the time scale of the induction period so that the ROMP can take place. The intensity of the Ru-III signal almost disappeared 50 min after reacting with K-2[RuCl5H2O] and after 100 mm in the case of RuCl3. Reactions of the cis-[Ru(NH3)(4)(H2O)(2)](tfms)(3) and [Ru(NH3)(5)H2O](tfms)(3) complexes with the monomer and different organic compounds representing the organic functions in the monomer (furan, norbornene, but-2-ene-1,4-diol and formic, acetic, oxalic and maleic acids) were also monitored by ESR and UV/vis spectra. It was deduced that the organic acids provide the disappearance of the Ru-III signal. The proton NMR relaxation times of the residual water in D2O for reactions with oxalic acid suggested that the presence of paramagnetic ions in the solution decreases along with