The research on structural and functional biomimics of the active site of [FeFe]-hydrogenases is in an attempt to elucidate the mechanisms of H(2)-evolution and uptake at the [FeFe]-hydrogenase active site, and to learn from Nature how to create highly efficient H(2)-production catalyst systems. Undoubtedly, it is a challenging, arduous, and long-term work. In this perspective, the progresses in approaches to photochemical H(2) production using mimics of the [FeFe]-hydrogenase active site as catalysts in the last three years are reviewed, with emphasis on adjustment of the redox potentials and hydrophilicity of the [FeFe]-hydrogenase active site mimics to make them efficient catalysts for H(2) production. With gradually increasing understanding of the chemistry of the [FeFe]-hydrogenases and their mimics, more bio-inspired proton reduction catalysts with significantly improved efficiency of H(2) production will be realized in the future.

Water-compatible molecularly imprinted polymers (MIPs) for adsorbing bisphenol A (BPA) in aqueous solutions are synthesized using water-soluble monomer as surface hydrophilicity-increasing agent via surface addition−fragmentation chain transfer polymerization. The formation and structure of these hybrid materials are verified by Fourier transform infrared spectroscopy, contact angle studies, thermogravimetric analysis, and scanning electron microscopy. The characterization and adsorption results indicate that the molecularly imprinted polymers prepared with 2-acrylamido-2-methylpropanesulfonic acid (AMPS/MIPs) are water-compatible (the contact angle is 14°). The excellent dispersion of AMPS/MIPs in water provides more opportunity for BPA molecules to access the imprinted cavities and improves their recognition characteristics. The kinetics and isotherm data of AMPS/MIPs can be well described by the pseudo-second-order kinetic model and the Langmuir isotherm, respectively. The thermodynamic studies indicate that the adsorption process is a spontaneous exothermic process.

Oxidation is an important factor for denaturing of whey protein isolate (WPI) during food processing. We studied the effects of chemical oxidation on physicochemical and structural changes along with in vitro digestibility of WPI in this work. Evaluation of physicochemical changes showed that carbonyl level and dityrosine content increased, whereas total and free thiol group levels decreased for oxidized WPI samples. For the structural changes, protein aggregation was measured by surface hydrophobicity, turbidity, and particle diameter, which was increased for oxidized WPI samples. The increase of the secondary structure β-sheets and antiparallel β-sheet also supported the aggregation of oxidized WPI. A direct quantitative relationship between physicochemical and structural changes and protein digestibility indicated that oxidation-related damage restricts the susceptibility of WPI to proteases. In conclusion, WPI had high susceptibility to oxidative stress, and both physicochemical and structural changes caused by severe oxidative stress could decrease the rate of in vitro digestibility of WPI.

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Diiron complexes containing pyridyl-phosphine ligands, that is, (mu-pdt)[Fe(2)(CO)(5)L] (pdt = S(CH(2))(3)S, L = Ph(2)PCH(2)Py, Ph(2)PPy, ) and (micro-pdt)[Fe(CO)(2)(PMe(3))][Fe(CO)(2)L] (L = Ph(2)PCH(2)Py, Ph(2)PPy, ) were prepared as model complexes of the [FeFe]-hydrogenase active site. Protonation of and by HOTf afforded the pyridyl-nitrogen protonated products [H(N)][OTf] and [H(N)][OTf], respectively. The molecular structures of, as well as [H(N)][OTf] and [H(N)][OTf] were confirmed by X-ray diffraction studies, which show that the Ph(2)PCH(2)Py ligand occupies the basal position both in and its protonated species [H(N)][OTf], while the Ph(2)PPy ligand prefers the apical position in and [H(N)][OTf]. The double protonation process of complex was monitored by in situ IR, (1)H and (31)P NMR spectroscopy at low temperature. The spectroscopic evidence indicates that the protonation of occurs first at the Fe-Fe bond and then at the pyridyl-nitrogen atom. Cyclic voltammograms reveal that protonation of and results in a considerable decrease in the overpotential for electrocatalytic proton reduction in the presence of HOTf, while the efficiency is not influenced by protonation. The electrocatalytic efficiency of for proton reduction in the presence of HOAc in CH(3)CN-H(2)O (50 : 1, v/v) is 5 times higher than that in pure CH(3)CN.

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