Cu(ii)–vitamin C-complex catalyzed photo-induced homocoupling reaction of aryl boronic acid in base-free and visible light conditions

In this work, the photocatalytic efficiency of Cu(ii)–vitamin C complex immobilized on titanium dioxide nanoparticles was exploited in the photo-assisted homocoupling reaction of aryl boronic acids under heterogeneous conditions. The homocoupling reaction affords the corresponding symmetrical biaryls in 50–97% yields at ambient temperature in the air under visible light irradiation without any need for any additive such as base or oxidant. This method tolerates various substituents on the aryl boronic acids such as halogen, carbonyl, and a nitro group. The light-dependent photocatalytic performance of the title catalyst evaluated by action spectra revealed a maximum apparent quantum efficiency (AQYs) at 410 nm demonstrating the visible-light-driven photocatalytic reaction. The as-prepared nano biophotocatalyst proved to be reusable at least six times without losing its activity. Thus this work exhibits a favorable method from the environmental and economic point of view which enables the industrially important reactions such as coupling reactions, to be carried out efficiently under photocatalytic and practically attainable conditions.

TiO₂–ascorbic acid (AA)–Cu(ii), nanohybrid is active in the selective aerobic oxidative homocoupling of aryl boronic acids under heterogeneous conditions in air and visible light conditions.     

Prophylaxis of ophthalmia neonatorum comparison of betadine, erythromycin and no prophylaxis

Ophthalmia neonatorum is a form of bacterial conjunctivitis contracted by newborns during delivery and occurs during the first month of life. Etiologic factors include Neisseria gonorrhoeae, Chlamydia trachomatis, viruses and chemicals. Its prevalence differs in different parts of the world and is dependent mainly upon socioeconomic conditions, level of knowledge about general health, standard of maternal healthcare as well as the type of prophylactic program used. This randomized clinical trial was performed during the years 2004-05 in the Delivery Section of Vali-e-Asr Hospital on 330 neonates who were divided into three equal groups of 110; Group A received betadine eye drops, Group B received Erythromycin eye drops and Group C (control group) received no treatment. Results showed that clinical conjunctivitis occurred in 52 subjects (17%), 58% of whom constituted males. On the whole, 9% of the infected newborns were from group A, 18.4% from group B and 22.4% from group C. It was concluded that 2.5% sterile betadine eye drops had a pronounced effect on ophthalmia neonatorum (p = 0.030).     

Cu(ii) vitamin C tunes photocatalytic activity of TiO2 nanoparticles for visible light-driven aerobic oxidation of benzylic alcohols

The incorporation of Cu(OAc)₂ into ascorbic acid coated TiO₂ nanoparticles easily provided a new heterogeneous visible-light active titania-based photocatalyst (TiO₂-AA-Cu(ii)) which was characterized by different techniques such as FT-IR, XPS, ICP-AES, TGA and TEM. A red-shift of the band-edge and a reduction of the band-gap (2.8 eV vs. 3.08 for TiO₂) were demonstrated by UV-DRS and Tauc plots. The combination of the as-prepared TiO₂-AA-Cu(ii) nanoparticles with TEMPO and molecular oxygen (air) afforded an active catalytic system for the selective oxidation of diverse set of benzylic alcohols under solvent-free conditions. A photoassisted pathway was confirmed for oxidation reactions evidenced by good correlation between apparent quantum yield (AQY) and diffuse reflectance spectra (DRS) of the as-prepared nanohybrid. The spectral data and recycling experiments demonstrated the structural stability of the title copper photocatalyst during oxidation reactions.

The combination of TiO₂-AA-Cu(ii) nanoparticles with TEMPO and molecular oxygen (air) afforded an active catalytic system for the selective oxidation of diverse set of benzylic alcohols under solvent-free condition.