Highly Selective Sequential Addition and Cyclization Reactions Involving Diphenyl Diselenide, an Alkyne, and Alkenes under Visible-Light Irradiation

2003 ◽  
Vol 42 (30) ◽  
pp. 3490-3493 ◽  
Author(s):  
Kaname Tsuchii ◽  
Mikio Doi ◽  
Toshikazu Hirao ◽  
Akiya Ogawa
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Light Irradiation ◽  
Diphenyl Diselenide ◽  
Cyclization Reactions ◽  
Sequential Addition

Alizarin red S–TiO2-catalyzed cascade C(sp3)–H to C(sp2)–H bond formation/cyclization reactions toward tetrahydroquinoline derivatives under visible light irradiation

2018 ◽  
Vol 42 (9) ◽  
pp. 6880-6888 ◽  
Author(s):  
Mona Hosseini-Sarvari ◽  
Mehdi Koohgard ◽  
Somayeh Firoozi ◽  
Afshan Mohajeri ◽  
Hosein Tavakolian
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Bond Formation ◽  
Organic Dye ◽  
Alizarin Red S ◽  
Light Irradiation ◽  
Cyclization Reactions ◽  
Alizarin Red

A very low amount of organic dye (Alizarin red S) sensitized TiO2 and it was successfully used to catalyze cascade C(sp3)–H to C(sp2)–H bond formation/cyclization reactions under visible light irradiation.

Cu Doped TiO2: Visible Light Assisted Photocatalytic Antimicrobial Activity and High Temperature Anatase Stability

2018 ◽  
Author(s):  
Snehamol Mathew ◽  
Priyanka Ganguly ◽  
Stephen Rhatigan ◽  
Vignesh Kumaravel ◽  
Ciara Byrne ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Density Functional ◽  
Anatase Phase ◽  
Sol Gel ◽  
Chemical Properties ◽  
Light Irradiation ◽  
Health Concern ◽  
Bacterial Inactivation ◽  
X Ray

Indoor surface contamination by microbes is a major public health concern. A damp environment is one potential sources for microbe proliferation. Smart photocatalytic coatings on building surfaces using semiconductors like titania (TiO<sub>2</sub>) can effectively curb this growing threat.<b> </b>Metal-doped titania in anatase phase has been proved as a promising candidate for energy and environmental applications. In this present work, the antimicrobial efficacy of copper (Cu) doped TiO<sub>2 </sub>(Cu-TiO<sub>2</sub>) was evaluated against <i>Escherichia coli</i> (Gram-negative) and <i>Staphylococcus aureus</i> (Gram-positive) under visible light irradiation. Doping of a minute fraction of Cu (0.5 mol %) in TiO<sub>2 </sub>was carried out <i>via</i> sol-gel technique. Cu-TiO<sub>2</sub> further calcined at various temperatures (in the range of 500 °C – 700 °C) to evaluate the thermal stability of TiO<sub>2</sub> anatase phase. The physico-chemical properties of the samples were characterised through X-ray diffraction (XRD), Raman spectroscopy, X-ray photo-electron spectroscopy (XPS) and UV-visible spectroscopy techniques. XRD results revealed that the anatase phase of TiO<sub>2</sub> was maintained well, up to 650 °C, by the Cu dopant. UV-DRS results suggested that the visible light absorption property of Cu-TiO<sub>2 </sub>was enhanced and the band gap is reduced to 2.8 eV. Density functional theory (DFT) studies emphasises the introduction of Cu<sup>+</sup> and Cu<sup>2+</sup> ions by replacing Ti<sup>4+</sup> ions in the TiO<sub>2</sub> lattice, creating oxygen vacancies. These further promoted the photocatalytic efficiency. A significantly high bacterial inactivation (99.9%) was attained in 30 mins of visible light irradiation by Cu-TiO<sub>2</sub>.

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