Synthesis,X-ray Structures,and Photoluminescence of the Octahedral Cu4I4 Cluster with Bulky Bidentate Bis(phosphanyl)amine Ligand

The reaction of C₁₀H₇-1-N(PPh₂)₂ ( 1 ) with two equivalents of CuI in acetonitrile resulted in the formation of octahedron Cu₄I₄[ 1 ]₂ complex ( 2 ). The crystal structure of 2 showed it adopted a rare octahedral arrangement. The rectangular Cu₄ plane is μ⁴-capped by two of the iodides and is placed in axial positions above and below the Cu₄-plane form an octahedron, whereas the other two iodides are bonded to two copper atoms in a μ²-fashion. The luminescence of complex 2 arises from a triplet halide-to-ligand charge transfer (³XLCT) excited state and ³CC (Cu₄I₄ cluster-centered) excited state are not involved in the luminescence by the rigid bidentate ligand 1 in spite of the short Cu^I–Cu^I bond length. Complex 2 was identified and characterized by multinuclear NMR (¹H, ¹³C, ³¹P NMR) and IR spectroscopy. Crystal structure determinations of 1 and 2 were carried out.     

A comparison of two nuclear analytical techniques for determination of 210Pb-specific activity in solid environmental samples

Two nuclear analytical techniques for determination of ²¹⁰Pb-specific activity in solid environmental samples have been validated and compared. The first technique depends on determination of ²¹⁰Pb via its alpha emitting daughter ²¹⁰Po using alpha-particle spectrometry, while the second technique is based on direct determination of ²¹⁰Pb by measuring its activity at the 46-keV gamma line by low-energy gamma-ray spectrometry. Detection limits, repeatability, reproducibility, and surrogate recovery were the main validation parameters. Measurement uncertainties were estimated and compared for both techniques. Results of this study have shown that the expected activity of ²¹⁰Pb in the environmental samples and the required measurement uncertainty are the main factors influencing a selection of the appropriate method for the application.     

Preparation of produced water reference material for analyzing 226Ra by gamma spectrometry

Journal of Radioanalytical and Nuclear Chemistry - Produced water reference material containing high concentration of 226Ra activity was prepared in 2009 and used for ALMERA worldwide proficiency...     

New polymer syntheses 84. Synthesis of functional polyethers by alkylation of silylated diphenols

4,4′-Bistrimethylsiloxy diphenylsulfone was polycondensed with six different alkylating agents in N-Methylpyrrolidone/K₂CO₃ mixtures and polyethers were isolated from all experiments. The best results were obtained with the mesylate of bis(2-hydroxyethyl)hydroquinone, BHEH. Similar results were found when silylated n-butyl-3,5-dihydroxybenzoate was used. A comparison of five different reaction media revealed that NMP gives the highest molecular weights. Finally, various silylated diphenols containing functional groups were polycondensed with the mesylate of BHEH. In this way polyethers with pending ester, aldehyde, keto, and amide groups were obtained. © 1996 John Wiley & Sons, Inc.     

Fallout of7Be in Damascus City

Atmospheric fallout of⁷Be was measured over a 2 year period (January 1995–January 1997) at Damascus city (33 N^o, 727 m above sea level). The annual total deposition of⁷Be was found to be 420 and 634 Bq·m⁻² for 1995 and 1996, respectively, reflecting a Mediterranean climate where two well recognized periods are dominant (wet and dry). The depositions in the wet periods were 303 Bq·m⁻² and 517 Bq·m⁻² for 1995 and 1996, respectively, while unexpected equal deposition rates in the two dry periods were found to be about 117 Bq·m⁻². In addition, monthly deposition rate of⁷Be showed a maxima in February in 1995 and January for 1996. Moreover, a comparison has been set for our measurements and other data obtained at different locations in the world.     

Synthesis, characterization, and crystal structures of novel intramolecularly base-stabilized borane derivatives with six- and seven-membered chelate rings

The reaction of (2-dimethylaminophenyl)alcohols 1-HOX-2-NMe(2)C(6)H(4) [X = CPh(2) (1), X = CCy(2) (2), X = CPh(2)CH(2) (4)] and 1-phenylaminoalkyl-2-dimethylaminobenzene 1-HN(Ph)X-2-NMe(2)C(6)H(4) [X = C(H)Ph (3), C(H)PhCH(2) (5)] with BH(3)(THF) yielded the BH(2) derivatives 1-H(2)BOX-2-NMe(2)C(6)H(4) [X = CPh(2) (6), CCy(2) (7), CPh(2)CH(2) (9)] and 1-H(2)BN(Ph)X-2-NMe(2)C(6)H(4) [X = C(H)Ph (8), C(H)PhCH(2) (10)]. Treatment of 1-H(2)BOCPh(2)-2-NMe(2)C(6)H(4) (6) with acetic acid gave 1-(CH(3)COO)HBOCPh(2)-2-NMe(2)C(6)H(4) (11). Compounds 6-11 were characterized spectroscopically (NMR, IR, MS). Crystal structure determinations were carried out on 6-11, which are novel examples of structurally characterized BH(2) derivatives containing six- or seven-membered chelate rings. For the chiral compounds 8, 10, and 11, both enantiomers are present in the unit cell.     

Polonium-210 distribution in Syrian phosphogypsum

Polonium-210 distributions in Syrian phosphogypsum and its leaching mechanisms have been evaluated. Radiochemical analyses have shown that ²¹⁰Po concentration in Syrian phosphogypsum is always higher than ²²⁶Ra concentration. ²¹⁰Po concentrations were found to vary between 373 and 589 Bq^.kg^–1 with an average value of 471 Bq^.kg^–1, which is lower than values reported in other countries. ²¹⁰Po was found to be more concentrated in smaller particles; a specific activity of 827 Bq^.kg^–1 in particles less than 250 mesh was observed. Leaching experiments using distilled water have shown that ²¹⁰Po are strongly bounded to phosphogypsum particles. The amount of ²¹⁰Po transferred to aqueous media does not exceed 5.6% and 8.4% for batch wise and continuous leaching, respectively; lowering the pH has increased this percentage to 20%. In addition, leaching with diluted sulfuric acid indicated that 80% of polonium is present as water insoluble quadrivalent polonium sulfate while 20% as soluble simple polonium sulfate. However, the obtained data could be used to explain environmental pathways of ²¹⁰Po from phosphogypsum.     

Synthesis and Characterization of New N-(Diphenylphosphino)-Naphthylamine Chalcogenides: X-Ray Structures of (1-NHC10H7)P(Se)Ph2 and Ph2P(S)OP(S)Ph2

Abstract

The reaction of 1-naphthylamine with one equivalent of chlorodiphenylphosphine in the presence of triethylamine gave the (1-NHC₁₀H₇)PPh₂ (1) ligand. Refluxing of 1 with elemental sulfur or grey selenium in toluene (1:1 molar ratio) afforded (1-NHC₁₀H₇)P(S)Ph₂ (2) and (1-NHC₁₀H₇)P(Se)Ph₂ (3), respectively. Moreover, the byproduct {Ph₂P(S)}₂O (4) was isolated from the reaction of 1 with elemental sulfur. Compounds 1–3 were identified and characterized by multinuclear (¹H, ¹³C, ³¹P, ⁷⁷Se) NMR spectroscopy, mass spectrometry, and elemental analysis. Crystal structure determinations of 3 and 4 were carried out.     

Natural radiation background in the ancient city of Palmyra

Natural radiation background has been determined for the Ancient City of Palmyra and its surrounding areas. Car-borne gamma spectrometry, indoor radon gas concentration and natural radionuclides levels in environmental samples (soil, water and plants) have been determined. Two types of dwelling were involved in this study, one with cancer cases, and the others without. The results showed that indoor radon gas concentrations and radiation exposure rates are within reported mean background levels in Syria (45 Bq m^?3 and less than 0.1 μSv h^?1, respectively); no differences were noticed between the dwelling groups. In addition, the results did not indicate any relation between recorded cancers and measured natural radioactivity.