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After exposure to micron-sized TiO 2 particles, anatase and/or rutile, Rhodococcus ruber GIN-1 accumulates an increased concentration (2.2 ± 0.2 mg kg −1 ) of mobilized Ti into its biomass with concomitant decreases in cellular biometals Fe, Zn, and possibly Mn, while levels of Cu and Al are unaffected. 

The photochemistry of a plasmonic biomaterial that consisted of gold nanoparticles (AuNP) on the exterior of the iron sequestration protein, ferritin (Ftn), was investigated. The light driven photochemistry of the hybrid system was studied mechanistically and for the reduction of the high priority pollutant, chromate, Cr( vi ) as CrO 4 2− . In the absence of aqueous Cr( vi ), but in the presence of a sacrificial electron donor, the Fe( iii ) oxyhydroxide semiconducting core of Ftn underwent a photoreaction to release Fe( ii ) when exposed to light having wavelengths, λ < 475 nm. AuNP grown on the exterior of the Ftn produced plasmonic heterostructures (Au/Ftn) that allowed similar photochemistry to occur at longer wavelengths of light ( i.e. , λ > 475 nm). Au/Ftn also facilitated the reduction of Cr( vi ) to Cr( iii ) in the presence of visible light ( λ > 475 nm), a reaction that was not observed if AuNP were not attached to the Ftn cage. Results also indicated that AuNP need to be intimately bound to Ftn to extend the photochemistry of Au/Ftn to longer light wavelengths, relative to Au-free Ftn. 

The solid-state structures of the Na + , Li + , and NH 4 + salts of the 4,5-dihydroxybenzene-1,3-disulfonate (tiron) dianion are reported, namely disodium 4,5-dihydroxybenzene-1,3-disulfonate, 2Na + ·C 6 H 4 O 8 S 2 2− , μ-4,5-dihydroxybenzene-1,3-disulfonato-bis[aqualithium(I)] hemihydrate, [Li 2 (C 6 H 4 O 8 S 2 )(H 2 O) 2 ]·0.5H 2 O, and diammonium 4,5-dihydroxybenzene-1,3-disulfonate monohydrate, 2NH 4 + ·C 6 H 4 O 8 S 2 2− ·H 2 O. Intermolecular interactions vary with the size of the cation, and the asymmetric unit cell, and the macromolecular features are also affected. The sodium in Na 2 (tiron) is coordinated in a distorted octahedral environment through the sulfonate oxygen and hydroxyl oxygen donors on tiron, as well as an interstitial water molecule. Lithium, with its smaller ionic radius, is coordinated in a distorted tetrahedral environment by sulfonic and phenolic O atoms, as well as water in Li 2 (tiron). The surrounding tiron anions coordinating to sodium or lithium in Na 2 (tiron) and Li 2 (tiron), respectively, result in a three-dimensional network held together by the coordinate bonds to the alkali metal cations. The formation of such a three-dimensional network for tiron salts is relatively rare and has not been observed with monovalent cations. Finally, (NH 4 ) 2 (tiron) exhibits extensive hydrogen-bonding arrays between NH 4 + and the surrounding tiron anions and interstitial water molecules. This series of structures may be valuable for understanding charge transfer in a putative solid-state fuel cell utilizing tiron.