Photo-catalysis of red wine stains using titanium dioxide sol-gel coatings on wool fabrics

This paper investigated the use of titanium dioxide sol-gel coatings to photo-catalyse red wine stains on wool fabrics. Coatings were produced by the hydrolysis and condensation of titanium butoxide (Ti(OC4H9)4) on the surface of wool fabrics after pad application. Coatings were partially converted to the anatase form of titanium dioxide by prolonged immersion in boiling water. The coating presence was confirmed using scanning electron microscopy, UVspectrophotometry and atomic force microscopy. Coated samples were measured for photo-catalytic activity by degrading red wine stains from the surface of the coated fabric. The level of photocatalysis was determined for each of the coating systems after 168 hours. Red wine stains were photo-catalysed and level of staining was reduced from the UV exposed surface of the coated wool fabric.

Non-covalent surface modification of boron nitride nanotubes for enhanced catalysis

Boron nitride nanotubes were functionalized with microperoxidase-11 in aqueous media, showing improved catalytic performance due to a strong electron coupling between the active centre of microperoxidase-11 and boron nitride nanotubes.

Photoredox catalysis of intramolecular cyclizations with a reusable silica-bound ruthenium complex

Photoredox catalysis with the use of a stable, reusable silica-bound chromophore was applied to the intramolecular cyclization of a series of 2-benzylidenehydrazinecarbothioamides to give 5-phenyl-1,3,4-thiadiazol-2-amines. The catalyst was readily prepared by carbodiimide-mediated coupling of commercially available amine-functionalized silica beads to a carboxylic acid functionalized ruthenium complex. The immobilized catalyst was readily removed from the reaction product by filtration and was used eight times without loss of catalytic activity. This simple, safe, and practical method is an attractive alternative to conventional procedures.

Flexible and rigid amine-functionalized microporous frameworks based on different secondary building units: supramolecular isomerism, selective CO₂ capture, and catalysis

We report the synthesis, structural characterization, and porous properties of two isomeric supramolecular complexes of ([Cd(NH₂—bdc)(bphz)_0.5 ]⋅DMF⋅H₂O}_n (NH₂ —bdc=2-aminobenzenedicarboxylic acid, bphz=1,2-bis(4-pyridylmethylene)hydrazine) composed of a mixed-ligand system. The first isomer, with a paddle-wheel-type Cd₂ (COO)₄ secondary building unit (SBU), is flexible in nature, whereas the other isomer has a rigid framework based on a μ-oxo-bridged Cd₂(μ-OCO)₂ SBU. Both frameworks are two-fold interpenetrated and the pore surface is decorated with pendant -NH₂ and =N—N= functional groups. Both the frameworks are nonporous to N₂ , revealed by the type II adsorption profiles. However, at 195 K, the first isomer shows an unusual double-step hysteretic CO₂ adsorption profile, whereas the second isomer shows a typical type I CO₂ profile. Moreover, at 195 K, both frameworks show excellent selectivity for CO₂ among other gases (N₂ , O₂ , H₂ , and Ar), which has been correlated to the specific interaction of CO₂ with the -NH₂ and =N—N= functionalized pore surface. DFT calculations for the oxo-bridged isomer unveiled that the -NH₂ group is the primary binding site for CO₂ . The high heat of CO₂ adsorption (ΔH_ads =37.7 kJ mol^-1) in the oxo-bridged isomer is realized by NH₂ ⋅⋅⋅CO₂ /aromatic π⋅⋅⋅CO₂ and cooperative CO₂ ⋅⋅⋅CO₂ interactions. Further, postsynthetic modification of the -NH₂ group into -NHCOCH₃ in the second isomer leads to a reduced CO₂ uptake with lower binding energy, which establishes the critical role of the -NH₂ group for CO₂ capture. The presence of basic -NH₂ sites in the oxo-bridged isomer was further exploited for efficient catalytic activity in a Knoevenagel condensation reaction.