A New Complex as a Dimer of a Silver Ion with AMTTO and Phosphane Ligands. The Crystal Structure of {[(AMTTO)Ag(PPh3)2]NO3}2·0.5CH3OH·0.5H2O

Reaction of 4‐amino‐6‐methyl‐1,2,4‐triazine‐3‐thione‐5‐on (AMTTO) as a bidentate ligand with silver nitrate and triphenyl phosphine as the co‐ligand make the centrosymmetric dimeric complex {[(AMTTO)Ag(PPh₃)₂]NO₃}₂·0.5CH₃OH·0.5H₂O ( 1 ). 1 was characterized by elemental analyses, IR‐ and NMR spectroscopy as well as X‐ray diffraction studies. The silver atom in 1 has distorted tetrahedral coordination. 1 crystallizes in triclinic space group . Crystal data for 1 at −80 °C: a = 1185.8(1), b = 1314.6(1), c = 1385.3(1) pm, α = 97.78(1)°, β = 111.38(1)°, γ = 92.41(1)°, Z = 2, R₁ = 0.0377.     

Investigation of Aqueous Diethanolamine Performance in Prediction of Hydrogen Sulfide and Carbonyl Sulfide Removal from Liquefied Propane

Journal of Solution Chemistry - Hydrogen sulfide and carbonyl sulfide represent undesirable impurities in a variety of industrial gas streams such as natural gas, liquefied natural gas and...     

Syntheses of substituted pyrrolo[2,3‐d]imidazole‐5‐carboxylates and substitued pyrrolo[3,2‐d]imidazole‐5‐carboxylates

Starting from readily available p‐substituted‐benzylamines a series of ethyl 2‐alkylthio‐1‐substituted‐ben‐zylpyrrolo[2,3‐d]imidazole‐5‐carboxylates was prepared. In addition, starting from 2‐alkyl‐4(or 5)‐formylimidazoles and methyl 4′‐bromomethylbiphenyl‐2‐carboxylate a series of methyl substituted‐pyrrolo[2,3‐d]imidazole‐5‐carboxylates and methyl substituted‐pyrrolo[3,2‐d]imidazole‐5‐carboxylates was prepared.     

A Coordination Polymer from HAMTTO with Silver(I) (HAMTTO = 4‐Amino‐6‐methyl‐1,2,4‐triazine‐3‐thione‐5‐one)

The reaction of 4‐amino‐6‐methyl‐1,2,4‐triazine‐3‐thione‐5‐one, HAMTTO, with silver (I) nitrate in methanol led under deprotonation to the polymeric compound [(AMTTO)Ag]_n. The coordination polymer {[Ag(HAMTTO)]ClO₄}_n ( 1 ) is synthesized from the reaction of the latter polymeric compound with perchloric acid. Both compounds were characterized by elemental analysis and IR spectroscopy. Single‐crystal X‐ray diffraction studies on compound 1 showed that HAMTTO acts as a bidentate ligand and chelates the silver atom via its hydrazine nitrogen atom and its sulfur atom. Crystal data for 1 at ?90 °C: space group P2₁, Z = 2, a = 629.3(1), b = 748.7(1), c = 1071.7(1) pm, β = 98.28(1)°, R₁ = 0.0533.     

Phytochemicals for prevention of solar ultraviolet radiation-induced damages

While solar light is indispensable for sustenance of life, excessive exposure can cause several skin-related disorders. The UV part of solar radiation, in particular, is linked to disorders ranging from mild inflammatory effects of the skin to as serious as causing several different types of cancers. Changes in lifestyle together with depletion in the atmospheric ozone layer during the last few decades have led to an increase in the incidence of skin cancer. Skin cancers consisting of basal and squamous cell carcinomas are especially linked to the UVB part of solar radiation. Reducing excessive exposure to solar radiation is desirable; however, as this approach is unavoidable, it is suggested that other novel strategies be developed to reduce the effects of solar radiation to skin. One approach to reduce the harmful effects of solar radiation is through the use of phytochemicals, an approach that is popularly known as "Photochemoprotection." In recent years many phytochemicals with potential antioxidant properties have been identified and found to be photoprotective in nature. We describe here some of the most popular phytochemicals being studied that have the potential to reduce the harmful effects associated with solar UV radiation.     

Naked magnetite nanoparticles for both clean-up and solid-phase extraction-trace determination of mercury

A new solid-phase extraction method was developed for trace determination of Hg(II) by using a small amount of naked magnetite nanoparticles as an adsorbent. The magnetite nanoparticles were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The adsorbed Hg(II)-dithizone complex was eluted with 1.0 mL aliquot of an acidic 1-propanol solution prior to electrothermal atomic absorption spectrometry. A huge positive effect was found on the mercury adsorption by ionic strength. Under optimized condition, a linear calibration curve was obtained for mercury in the range of 0.2–50 ng mL^?1 with relative standard deviation in the range of 0.5–2.0%. The limit of detection and enrichment factor were 0.01 ng mL^?1 and 98.3, respectively. The effects of coexisting ions were studied extensively, and a new clean-up procedure was used to remove the matrix effects by using a simple sample pretreatment step using a little amount of magnetite nanoparticles. The method was successfully applied to the determination of Hg(II) in different water and human urine samples and a commercial sodium nitrate.     

Comparison of quasi-steady-state and unsteady-state formulations in a freeze dryer modeling

An unsteady-state model is developed for primary and secondary stages of freeze drying process of skim milk. The results are compared with those obtained from a quasi-steady-state (QSS) formulation. The QSS formulation is not valid where the applied heat load is high. The applied heat load affects on the drying time the most compared to other parameters like chamber pressure and the radiation surface temperature.