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Ag6(VIVO)2(PO4)2(P27) was obtained by reaction of Ag3PO4 and (VO)2P2O7 (sealed ampoule, 550 °C, 3 d). The crystal structure of the new mixed ortho-pyrophosphate was determined from X-ray single-crystal data [Pnma, Z = 4, a = 12.759(3) Å, b = 17.340(4) Å, c = 6.418(1) Å, R1 = 0.071, wR2 = 0.184 for 3174 unique reflections with F0 > 4σ(F0), 141 variables]. Ag+ ions are located in between layers [(VIVO)2(PO4)2(P2O7)]6-. Equilibrium relations of the new phosphate to neighboring phases were determined. The electronic structure of the (VIV≡O)2+ group was investigated by polarized electronic absorption spectroscopy (ν1a = 9450 cm-1, ν1b = 9950 cm-1, ν2 = 14750 cm-1), EPR spectroscopy [X- and Q-band, powder and single crystal, orthorhombic crystal g-tensor with g1 = 1.9445(3), g2 = 1.9521(3), g3 = 1.9695(3)] and magnetic measurements (powder, μexp/μB = 1.71, Θp = -1.7 K). [ABSTRACT FROM AUTHOR]

Flow systems, either stopped or continuous, have long been at the core of kinetic studies of chemical reactions. Such flow systems need to be coupled with appropriate spectroscopic or otherwise techniques for the detection of the chemical species studied. If paramagnetic species are formed or consumed during the investigated reaction, electron paramagnetic resonance (EPR) with its nanomolar sensitivity can be the spectroscopic method of choice. However, not much literature is available on the application of EPR to quantitatively study kinetics of chemical reactions in the liquid state. Herein, we report the characterisation of the commercially available mixing resonator ER 4117 MX from B ruker using the TEMPO-dithionite reaction as a standard. Furthermore, this setup was used to study the kinetics of the Fenton-like system of TiCl 3 /H 2 O 2 and ethanol forming the α-hydroxyethyl radical. Potential contributions of reactions with O 2 , H 2 O 2 , Ti 3+/4+ , and self-recombination in the decay of the α-hydroxyethyl radical were investigated and the bimolecular decay was shown to be the dominant decay pathway, with a decay rate constant of 6.6 × 10 8 M −1 s −1 . This study shows the effectiveness and capabilities of EPR as a direct, sensitive and in-situ method in kinetic studies. [ABSTRACT FROM AUTHOR]