Geometric and Electronic Structure of the Aqueous Al(H2O)63+ Complex

Synthesis and crystal structures of [Al(H2O)6](SO4)NO3·2H2O and [Al(H2O)6](SO4)Cl·H2O

Common features in the crystal structures of [Al(H₂O)₆](SO₄)NO₃·2H₂O and [Al(H₂O)₆](SO₄)Cl·H₂O are [Al(H₂O)₆]³⁺ octa­hedra and sulfate tetra­hedra. These components, the remaining anion (NO₃⁻ and Cl⁻, respectively) and lattice water mol­ecules are separated from each other. Inter­actions are mediated via medium–strong hydrogen bonding.

Two novel aluminium double salts, [Al(H₂O)₆](SO₄)NO₃·2H₂O, hexa­qua­alumin­ium sulfate nitrate dihydrate, (1), and [Al(H₂O)₆](SO₄)Cl·H₂O, hexaqua­aluminium sulfate chloride hydrate, (2), were obtained in the form of single crystals. Their crystal structures are each based on an octa­hedral [Al(H₂O)₆]³⁺ unit and both structures have in common one charge-balancing SO₄²⁻ anion. The final positive charge from the aluminium(III) cation is balanced by an NO₃⁻ or a Cl⁻ anion for (1) and (2), respectively. Compound (1) further contains two unligated water mol­ecules while compound (2) only contains one unligated water mol­ecule. In the crystal structures, all components are spatially separated and inter­actions are mediated via medium–strong hydrogen bonding, compared to many other reported aluminium sulfates where corner-sharing of the building units is common. The two compounds represent rare cases where one aluminium(III) cation is charge-balanced by two different anions.

Aluminum-Based Promotion of Nucleation of Carbon Dioxide Hydrates

Gas hydrate formation has several applications in CO₂ sequestration, flow assurance, and desalination. Nucleation of hydrates is constrained by very high induction (wait) times, which necessitates the use of complex nucleation promotion techniques to form hydrates. Presently, we report the discovery of a simple, passive nucleation promotion technique, wherein an aluminum surface significantly accelerates nucleation of CO₂hydrates. Statistically meaningful measurements of induction times for CO₂ hydrate nucleation were undertaken using water droplets as individual microsystems for hydrate formation. The influence of various metal surfaces, droplet size, CO₂ dissolution time, and the presence of salts in water on nucleation kinetics was characterized. Interestingly, we observe nucleation initiation only on aluminum surfaces, the influence of which cannot be replicated by salts of aluminum. We discover that the aluminum-water interface is responsible for nucleation promotion. We hypothesize that hydrogen bubbles generated at the aluminum-water interface are responsible for nucleation promotion.

Dihydroxyacetone conversion into lactic acid in an aqueous medium in the presence of metal salts: influence of the ionic thermodynamic equilibrium on the reaction performance

Different Lewis acid aluminium complexes catalyse the successive reactions to convert dihydroxyacetone into lactic acid in an aqueous medium.

Metal-Foam-Based Ultrafast Electronucleation of Hydrates at Low Voltages

The induction time for the nucleation of hydrates can be significantly reduced by electronucleation, which consists of applying an electrical potential across the hydrate precursor solution. This study reveals that open-cell aluminum foam electrodes can reduce the electronucleation induction time by 150× when compared to nonfoam electrodes. Experiments with tetrahydrofuran hydrates show that aluminum foam electrodes trigger near-instantaneous nucleation (in only tens of seconds) at low voltages. Furthermore, this study suggests that two distinct interfacial mechanisms influence electronucleation, namely, electrolytic bubble generation and the formation of metal ion complex-based coordination compounds. These mechanisms (which depend on the electrode material and polarity) affect the induction time to vastly different extents. Coordination compound formation (verified via detection of metal ions in solution) exerts a much greater influence on electronucleation than the mechanistic effects associated with bubble generation. This work uncovers the benefits of using foams to promote electronucleation and shows that foams lead to more deterministic (as opposed to stochastic) nucleation when compared with nonfoam electrodes.

Phosphorylation promotes Al(iii) binding to proteins: GEGEGSGG as a case study

Aluminum, the third most abundant element in the Earth's crust and one of the key industrial components of our everyday life, has been associated with several neurodegenerative diseases due to its ability to promote neurofilament tangles and β-amyloid peptide aggregation.

Aluminum interaction with 2,3-diphosphoglyceric acid. A computational study

Favorable formation of aluminum–2,3-DPG complexes in a variety of forms: 1 : 1, 1 : 2 and ternary complexes with citrate.

A comparison of 4f vs 5f metal-metal bonds in (CpSiMe3)3M-ECp* (M = Nd, U; E = Al, Ga; Cp* = C5Me5): synthesis, thermodynamics, magnetism, and electronic structure

Reaction of (CpSiMe(3))(3)U or (CpSiMe(3))(3)Nd with (Cp*Al)(4) or Cp*Ga (Cp* = C(5)Me(5)) afforded the isostructural complexes (CpSiMe(3))(3)M-ECp* (M = U, E = Al (1); M = U, E = Ga (2); M = Nd, E = Al (3); M = Nd, E = Ga (4)). In the case of 1 and 2 the complexes were isolated in 39 and 90% yields, respectively, as crystalline solids and were characterized by single-crystal X-ray diffraction, variable-temperature (1)H NMR spectroscopy, elemental analysis, variable-temperature magnetic susceptibility, and UV-visible-NIR spectroscopy. In the case of 3 and 4, the complexes were observed by variable-temperature (1)H NMR spectroscopy but were not isolated as pure materials. Comparison of the equilibrium constants and thermodynamic parameters DeltaH and DeltaS obtained by (1)H NMR titration methods revealed a much stronger U-Ga interaction in 2 than the Nd-Ga interaction in 4. Competition reactions between (CpSiMe(3))(3)U and (CpSiMe(3))(3)Nd indicate that Cp*Ga selectively binds U over Nd in a 93:7 ratio at 19 degrees C and 96:4 at -33 degrees C. For 1 and 3, comparison of (1)H NMR peak intensities suggests that Cp*Al also achieves excellent U(III)/Nd(III) selectivity at 21 degrees C. The solution electronic spectra and solid-state temperature-dependent magnetic susceptibilities of 1 and 2, in addition to X-ray absorption near-edge structure (XANES) measurements from scanning transmission X-ray microscopy (STXM) of 1, are consistent with those observed for other U(III) coordination complexes. DFT calculations using five different functionals were performed on the model complexes Cp(3)M-ECp (M = Nd, U; E = Al, Ga), and empirical fitting of the values for Cp(3)M-ECp allowed the prediction of binding energy estimates for Cp*Al compounds 1 and 3. NBO/NLMO bonding analyses on Cp(3)U-ECp indicate that the bonding consists predominantly of a E-->U sigma-interaction arising from favorable overlap between the diffuse ligand lone pair and the primarily 7s/6d acceptor orbitals on U(III), with negligible U-->E pi-donation. The overall experimental and computational bonding analysis suggests that Cp*Al and Cp*Ga behave as good sigma-donors in these systems.