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A molecular precursor approach to titania (anatase) nanopowders modified with different amounts of rare-earth elements (REEs: Eu, Sm, and Y) was developed using the interaction of REE nitrates with titanium alkoxides by a two-step solvothermal–combustion method. The nature of an emerging intermetallic intermediate was revealed unexpectedly for the applied conditions via a single-crystal study of the isolated bimetallic isopropoxide nitrate complex [Ti2Y(iPrO)9(NO3)2], a nonoxo-substituted compound. Powders of the final reaction products were characterized by powder X-ray diffraction, scanning electron microscopy–energy-dispersive spectroscopy, Fourier transform infrared, X-ray photoelectron spectroscopy, Raman spectroscopy, and photoluminescence (PL). The addition of REEs stabilized the anatase phase up to ca. 700 °C before phase transformation into rutile became evident. The photocatalytic activity of titania modified with Eu3+ and Sm3+ was compared with that of Degussa P25 titania as the control. PL studies indicated the incorporation of Eu and Sm cations into titania (anatase) at lower annealing temperatures (500 °C), but an exclusion to the surface occurred when the annealing temperature was increased to 700 °C. The efficiency of the modified titania was inferior to the control titania while illuminated within narrow wavelength intervals (445–465 and 510–530 nm), but when subjected to a wide range of visible radiation, the Eu3+- and Sm3+-modified titania outperformed the control, which was attributed both to doping of the band structure of TiO2 with additional energy levels and to the surface chemistry of the REE-modified titania., Molecular insight into the mechanism of solution−combustion synthesis provided clues to understanding the photocatalytic properties of rare-earth-doped nanotitania.

Titania nanoparticles surface-functionalized with sulfate were prepared by thermal degradation of titanyl sulfate. At 600 degrees C pure anatase phase is obtained. X-ray photoelectron spectroscopy (XPS) showed 1.4 at.% sulfur in the +6 oxidation state. At 700 degrees C anatase was still present, which is attributed to the presence of small amounts of stabilizing sulfate groups only detectable by high-resolution XPS, segregating to the nanoparticle interfaces. Adsorption and photocatalytic degradation of acetaldehyde reactions were studied by in situ diffuse reflectance Fourier transform spectroscopy and 2D correlation spectroscopy, and compared with pure anatase nanoparticles. Aldol condensation of acetaldehyde and subsequent accumulation of crotonaldehyde was lower on sulfate-modified titania. Butanoate was identified as an intermediate, which forms after dimerization and aldol condensation. Much more carboxylates and carbonates accumulated on pure anatase catalysts compared with sulfate-modified anatase during photocatalysis. It is conjectured that surface acidic photocatalysts could be beneficial for achieving sustained activity for photodegradation of organic pollutants.

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 SO4 2− 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.

Herein we report the asymmetric syntheses of a number of oxygenated terpenoids that are of importance in the chemical ecology of bark beetles. These are pinocamphones, isopinocamphones, pinocarvones, and 4-thujanols (= sabinene hydrates). The camphones were synthesized from isopinocampheol, the pinocarvones from beta-pinene, and the thujanols from sabinene. The NMR spectroscopic data, specific rotations, and elution orders of their stereoisomers on a chiral GC-phase (beta-cyclodextrin) are also reported. This enables facile synthesis of pure compounds for biological activity studies and identification of stereoisomers in mixed natural samples.

Since the discovery of its photocatalytic properties, titanium dioxide has remained one of the most popular and widely used metal oxide photocatalysts. Its major drawback, however, lies in the narrow region (UV) of sunlight necessary to produce reactive oxygen species. This have been countered by sensitizing with organic dyes to red-shift the absorption spectrum but also with doping of other metals and non-metals. Volume doping or surface modification have demonstrated improved photocatalytic efficiency, mainly via red-shifted absorption by introduction of intermediate energy states between the valence band (VB) and conduction band (CB) and increased number of surface hydroxyl groups (which can form reactive hydroxyl radicals) from charge compensation, and in some cases by improved surface-adsorption of organic molecules. Doped titania and complex titanates have traditionally been produced via, for instance, co-precipitation of mixed metal salts or via solid-state synthesis. While these methods usually are simple, they offer limited control over size, shape, and phase composition. An alternative is the use of single-source precursors (SSPs), i.e., molecules already containing the desired metal ratio in a homogenous distribution. The last one or two decades have seen an increased number of reported transition metal-doped titanium oxo-alkoxides (TOA), particularly for the first-row transition metals as potential single-source precursors (SSP) for doped titania and complex titanates. This review aims at providing an overview of TM-doped TOAs, focusing on first and second row TM elements, with special emphasis on their synthesis, photochemical properties, and their applications as SSPs.

A novel nanoceria-nanocellulose hybrid material has been developed and evaluated as a potential drug delivery system. Crystalline nanoceria was synthesized in situ in the nanocellulose to obtain a homogenous distribution without extensive particle aggregation. The hybrid materials were loaded with two antibiotic drugs, triclosan and ampicillin, and one anti-inflammatory drug, diclofenac. The bacteriostatic effect on the gram-negative bacteria Escherichia coli was evaluated for the hybrid materials containing triclosan and ampicillin. The nanoceria-nanocellulose hybrid displayed a better retention of ampicillin than triclosan in the disc diffusion test, which is likely due to the presence of the carboxylic acid group in ampicillin that has better affinity for ceria compared to the phenolic group in triclosan. However, drug release studies in solution revealed rapid release of ampicillin and diclofenac, indicative of outer-sphere complexes between ceria and the drugs.

In order to develop a new type of improved wound dressing, we combined the wound healing properties of nanotitania with the advantageous dressing properties of nanocellulose to create three different hybrid materials. The hemocompatibility of the synthesized hybrid materials was evaluated in an in vitro human whole blood model. To our knowledge, this is the first study of the molecular interaction between hybrid nanotitania and blood proteins. Two of the hybrid materials prepared with 3 nm colloidal titania and 10 nm hydrothermally synthesized titania induced strong coagulation and platelet activation but negligible complement activation. Hence, they have great potential as a new dressing for promoting wound healing. Unlike the other two, the third hybrid material using molecular ammonium oxo-lactato titanate as a titania source inhibited platelet consumption, TAT generation, and complement activation, apparently via lowered pH at the surface interface. It is therefore suitable for applications where a passivating surface is desired, such as drug delivery systems and extracorporeal circuits. This opens the possibility for a tailored blood response through the surface functionalization of titania.

Titania (anatase) nanoparticles were anisotropically functionalized in water-toluene Pickering emulsions to self-assemble into nanoshells with diameters from 500 nm to 3 μm as candidates for encapsulation of drugs and other compounds. The water-phase contained a hydrophilic ligand, glucose-6-phosphate, while the toluene-phase contained a hydrophobic ligand, n-dodecylphosphonic acid. The addition of a dilute sodium alginate suspension that provided electrostatic charge was essential for the self-limited assembly of the nanoshells. The self-assembled spheres were characterized by scanning electron microscopy, elemental mapping, and atomic force microscopy. Drug release studies using tetracycline suggest a rapid release dominated by surface desorption.

Titanium (oxo-) alkoxide phosphonate complexes were synthesized using different titanium precursors and

Phosphotungstic acid (POM) was crystallized together with the neurotransmitter γ-aminobutyric acid (GABA) in acidic medium to form [(HGABA)3PW12O40], compound 1. The latter would only crystalize in the presence of dopamine, while dopamine itself did not become a part of the complex, but crystallized separately as [(Hdopamine)2HPW12O40], compound 2, as previously reported. GABA interacts with POM via hydrogen bonding between the protonated amino group and a terminal oxygen on POM and also via protonated carboxylic acid group. Based on structural information from the crystal structures of 1 and 2 together with complementary studies using other catechols we attempted to provide molecular insight into the well-known structure-directing effect of dopamine. Strong hydrogen bonding between dopamine and POM, together with formation of “dopamine dimers” in the packed structure by interactions between the aromatic rings and intermolecular hydrogen bonding might be important factors for them in directing the self-assembly of polyoxometalates into complex hierarchal structures. Interaction between dopamine and GABA in solution was investigated by diffusion ordered spectrometry (DOSY) NMR in MilliQ-water and in 0.1 M HCl.

We present the structure of a new tetranuclear titanium oxo complex containing the antibacterial agent triclosan. This provides a good model for the interaction between triclosan and titania, which may be used for drug-delivery applications. The antibacterial activity of the hydrolyzed complex against Staphylococcus aureus is investigated. Thereafter, we use the obtained titanium oxo complex to demonstrate its susceptibility towards hydrolysis, contrary to the widespread belief that titanium oxo complexes are water-stable, and demonstrate that it transforms into titania (anatase) on contact with water. Both hydrolysis and thermolysis of the complex yield titania particles, of very uniform size and shape, that connect into 3D nanostructures; this is of interest for practical applications.

A novel complex between the [HPW12O40]2− Keggin ion and the biomolecule dopamine (C8H11NO2), [HPW12O40(dop)2] • 4H2O (1) was crystallized and structurally characterized by single crystal X-ray diffraction and infrared spectrometry. Dopamine interacts via hydrogen bonding between its ammonium group and a W O oxygen atom in [HPW12O40]2−. NMR analyses (1H DOSY) suggests that the [HPW12O40(dop)2] complex dissociates in D2O.

A novel titanium phenylphosphonate alkoxide complex, [Ti6(µ3-O)2(µ-OEt)6(µ2-OEt)6(µ3-PPA)4]·0.5C7H8 (1) was synthesized by solvothermal processing and its structure was determined by single crystal X-ray diffraction. The solution stability was characterized in solution by 1H NMR, 13C NMR and 31P NMR and 1H DOSY NMR and compared with a previously reported titanium phenylphosphonate alkoxide complex [(Ti4O(OEt)12PPA] (2) of similar size. According to the NMR analyses, the solid-state structure is predominantly retained in solution for both 1 and 2. 31P NMR and 1H DOSY NMR of the mother liquor from the synthesis of 2 indicated presence of traces of at least two other complexes which could not be isolated in pure form.

Spherical cellulose nanocrystal-based hybrids grafted with titania nanoparticles were successfully produced for topical drug delivery. The conventional analytical filter paper was used as a precursor material for cellulose nanocrystals (CNC) production. Cellulose nanocrystals were extracted via a simple and quick two-step process based on first the complexation with Cu(II) solution in aqueous ammonia followed by acid hydrolysis with diluted H2SO4. Triclosan was selected as a model drug for complexation with titania and further introduction into the nanocellulose based composite. Obtained materials were characterized by a broad variety of microscopic, spectroscopic, and thermal analysis methods. The drug release studies showed long-term release profiles of triclosan from the titania based nanocomposite that agreed with Higuchi model. The bacterial susceptibility tests demonstrated that released triclosan retained its antibacterial activity against Escherichia coli and Staphylococcus aureus. It was found that a small amount of titania significantly improved the antibacterial activity of obtained nanocomposites, even without immobilization of model drug. Thus, the developed hybrid patches are highly promising candidates for potential application as antibacterial agents.