NMR Study of CO Capture by Butylamine and Oligopeptide KDDE in Aqueous Solution: Capture Efficiency and Gibbs Free Energy of the Capture Reaction as a Function of pH.

We have been interested in the development of rubisco-based biomimetic systems for reversible CO capture from air. Our design of the chemical CO capture and release (CCR) system is informed by the understanding of the binding of the activator CO ( CO ) in rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase). The active site consists of the tetrapeptide sequence Lys-Asp-Asp-Glu (or KDDE) and the Lys sidechain amine is responsible for the CO capture reaction.

Solution structure of zinc-seamed -alkylpyrogallol[4]arene dimeric nanocapsules.

The structural stability and solution geometry of zinc-seamed--propylpyrogallol[4]arene dimers has been studied in solution using neutron scattering and 2D-DOSY NMR methods. In comparison with the structures of the analogous copper-/nickel-seamed dimeric entities, the spherical geometry of the PgCZn species ( = 9.4 Å; diffusion coefficient = 1.

Pertechnetate-Induced Addition of Sulfide in Small Olefinic Acids: Formation of [TcO(dimercaptosuccinate)] and [TcO(mercaptosuccinate)] Analogues.

Technetium-99 (Tc) is important to the nuclear fuel cycle as a long-lived radionuclide produced in ∼6% fission yield from U or Pu. In its most common chemical form, namely, pertechnetate (TcO), it is environmentally mobile. In situ hydrogen sulfide reduction of pertechnetate has been proposed as a potential method to immobilize environmental TcO that has entered the environment.

Conversion of Pregabalin to 4-Isobutylpyrrolidone-2.

Solid-state studies of C-butyl-resorcin[4]arene with pregabalin (Lyrica, Nervalin) in nitrobenzene yielded a cocrystal of C-butyl-resorcin[4]arene with 4-isobutylpyrrolidone-2. A combined experimental and quantum chemical investigation was implemented to further our understanding of the factors affecting the conversion process.

Near-silence of isothiocyanate carbon in (13)C NMR spectra: a case study of allyl isothiocyanate.

(1)H and (13)C NMR spectra of allyl isothiocyanate (AITC) were measured, and the exchange dynamics were studied to explain the near-silence of the ITC carbon in (13)C NMR spectra. The dihedral angles α = ∠(C1-C2-C3-N4) and β = ∠(C2-C3-N4-C5) describe the conformational dynamics (conformation change), and the bond angles γ = ∠(C3-N4-C5) and ε = ∠(N4-C5-S6) dominate the molecular dynamics (conformer flexibility). The conformation space of AITC contains three minima, Cs-M1 and enantiomers M2 and M2'; the exchange between conformers is very fast, and conformational effects on (13)C chemical shifts are small (νM1 - νM2 < 3 ppm).

Isolation and identification of an allelopathic phenylethylamine in rice.

Allelopathy is the process whereby an organic chemical (allelochemical) released from one plant influences the growth and development of other plants. Allelochemicals produced by specific rice (Oryza sativa L.) cultivars have potential to manage barnyard grass (Echinochloa crus-galli L.

Solution structures of polcalcin Phl p 7 in three ligation states: Apo-, hemi-Mg2+-bound, and fully Ca2+-bound.

Polcalcins are small EF-hand proteins believed to assist in regulating pollen-tube growth. Phl p 7, from timothy grass (Phleum pratense), crystallizes as a domain-swapped dimer at low pH. This study describes the solution structures of the recombinant protein in buffered saline at pH 6.

Investigating structural alterations in pyrogallol[4]arene-pyrene nanotubular frameworks.

Small-angle neutron scattering (SANS) and diffusion NMR studies are performed to investigate the stability and geometry of hydrogen-bonded pyrene-guest-containing C-hexylpyrogallol[4]arene (PgC(6) -pyrene) nanotubular frameworks in solution. In the solid state, hydrogen-bonded pyrogallol[4]arene tubes are formed; however, the scattering data for PgC(6) -pyrene assemblies in acetone are best modeled as dimeric spheres of PgC(6) with no pyrene guest. The result of diffusion NMR study also indicates the rearrangement of tubular entity into spherical framework in acetone.

Solution-phase structures of gallium-containing pyrogallol[4]arene scaffolds.

The variations in architecture of gallium-seamed (PgCGa) and gallium-zinc-seamed (PgCGaZn) C-butylpyrogallol[4]arene nanoassemblies in solution (SANS/NMR) versus the solid state (XRD) have been investigated. Rearrangement from the solid-state spheroidal to the solution-phase toroidal shape differentiates the gallium-containing pyrogallol[4]arene nanoassemblies from all other PgCM nanocapsules studied thus far. Different structural arrangements of the metals and arenes of PgCGa versus PgCGaZn have been deduced from the different toroidal dimensions, C–H proton environments and guest encapsulation of the two toroids.

15N nuclear magnetic resonance relaxation studies on rat beta-parvalbumin and the pentacarboxylate variants, S55D and G98D.

15N relaxation data for Ca(2+)-bound rat beta-parvalbumin (a.k.a.