An organogel library for solution NMR analysis of nanoparticle suspensions in non-aqueous samples

Non-Innocent Role of the Ceria Support in Pd-Catalyzed Halophenol Hydrodehalogenation

“…To this end, we determined how the 13 C transverse relaxation rates (Δ R 2 ) of the substrate signals change when the catalyst is added to the solution. The value of Δ R 2 is proportional to the fraction of molecules that bind the catalyst surface and lose magnetization because of the slower molecular tumbling of adsorbed species. ,, Although we observed a large increase in transverse relaxation rate (average Δ R 2 7.0 ± 0.3 s –1 ) when setting 4-Cl-PhOH in the presence of the catalyst, no significant changes (Δ R 2 ∼ 0 s –1 ) were observed when the catalyst was added to solutions of Cl-Ph or 4-Cl-PhOMe (Figure S10). These results indicate that while 4-Cl-PhOH interacts strongly with the catalyst, the non-hydroxylated haloaromatics have a weaker affinity for Pd/CeO 2 .…”

“…The value of ΔR 2 is proportional to the fraction of molecules that bind the catalyst surface and lose magnetization because of the slower molecular tumbling of adsorbed species. 9,10,28 Although we observed a large increase in transverse relaxation rate (average ΔR 2 7.0 ± 0.3 s −1 ) when setting 4-Cl-PhOH in the presence of the catalyst, no significant changes (ΔR 2 ∼ 0 s −1 ) were observed when the catalyst was added to solutions of Cl-Ph or 4-Cl-PhOMe (Figure S10). These results indicate that while 4- Cl-PhOH interacts strongly with the catalyst, the nonhydroxylated haloaromatics have a weaker affinity for Pd/ CeO 2 .…”

“…Pd/CeO2 was degassed at 100 °C under vacuum for 24 h. The pre-dried catalyst was then introduced into NMR tubes containing 4-Cl-PhOH solution (1 mL, 100 mM, benzene-d6) or only benzene-d6 as a control. 13 C transverse relaxation rate (R2) measurement were acquired on gel-stabilized NMR samples 27 prepared by following previously described procedures 28 . Briefly, the appropriate amount of the nanoparticle and 12-Hydroxyoctadecanamide gelator was weighed directly into an NMR tube followed by the addition of 10 mM substrate solution in cyclohexane-d12 to produce 0.5 wt % nanoparticle and 0.5 wt % gelator sample.…”

“…13 C transverse relaxation rate (R 2 ) measurements were acquired on gel-stabilized NMR samples 27 prepared by following previously described procedures. 28 Briefly, the appropriate amount of the nanoparticle and the 12hydroxyoctadecanamide gelator was weighed directly into an NMR tube followed by the addition of 10 mM substrate solution in cyclohexane-d 12 to produce a 0.5 wt % nanoparticle and a 0.5 wt % gelator sample. The capped NMR tube was placed into a sonic bath (Branson 1800) and heated to a temperature of ∼70 °C.…”

Solution NMR methods for structural and thermodynamic investigation of nanoparticle adsorption equilibria

“…A library of small molecule gelators that satisfy these requirements was recently developed to stabilize NP suspensions in a number of NMR-friendly aqueous 155 and organic solvents. 156 …”