Be—姜黄素—β—环糊精—Triton X—100体系的研究及应用

本文采用姜黄素为显色剂研究了此试剂在β-环糊精和Triton X-100存在下与铍形成配合物的最佳条件:在pH 10.4～11.0的NH_4Cl-NH_3·H_2O介质中,配合物的最大吸收波长为520nm,显色时间快且可稳定3h,表观摩尔吸光系数为4.73×10~4L·mol~(-1)·cm~(-1),铍含量在0～5μg/25mL范围内符合比尔定律,可用于地矿试样中微量铍的测定。     

Theoretical study of beryllium (II) complexes using CATIVIC: New parametric method

Calculations of several beryllium complexes {[Be(H₂O)_n]²⁺ (n = 1–4), [BeOH(H₂O)_n]⁺ (n = 1–3), and [Be(OH)₂(H₂O)_n] (n = 1, 2)} were carried out to compare different ab initio (density functional theory, MP2) and parametric (PM3(tm), CATIVIC) methods. Results show that the parametric method CATIVIC gives geometries and energies closer to the ab initio geometries than the PM3(tm) method due to the inclusion of the atomic excitation energies of the neutral atoms as well as the ions and to the dependence of the molecular parameters on the system charge. The molecular electronic density analysis of the Be? O bonds shows that the Be–water interaction in the [Be(H₂O)_n]²⁺ complexes can be considered as a closed‐shell interaction with a σ character in the bond while in the [Be(OH)₂(H₂O)_n] complexes the Be? water bond have π character. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004     

Chromotropic acid as fluorogenic reagent. I. Fluorimetric determination of beryllium

A highly sensitive and almost specific fluorimetric method has been developed for rapid determination of beryllium at ng/ml and sub-ng/ml levels with chromotropic acid as reagent at pH 4.8–6.0. The fluorescence intensity _ex = 362 nm, _em = 387 nm) is stable for 24 h. The calibration graph is linear over the range 0.1–60 ng/ml beryllium; a 1 1 complex is formed. Over sixty anions and cations, and some complexing agents such as EDTA, oxalate, tartrate, ascorbic acid, thiourea, phthalate, citrate, S₂O ₃ ^2– , SCN^– and salicylate do not interfere even when present in large excess. The method has been applied successfully for the determination of beryllium in ores, alloys, steels, environmental waters and in biological samples. The method is virtually specific and requires no preconcentration or clean-up steps.     

Interatomic potential for the X1Σ state of Be2, revisited

An extended geminal model has been applied to determine the interatomic potential for the X¹Σ state of Be₂. By adopting a (23s, 10p, 8d, 6f, 3g, 2h) uncontracted Gaussian‐type basis, the following spectroscopic parameters are obtained: R_e = 4.633 a.u. (4.63 a.u.), D_e = 945 ± 15 cm (790 ± 30 cm), G(1)–G(0) = 221.7 cm^?1 (223.8 ± 2 cm^?1), G(2)–G(1) = 175.0 cm^?1 (169 ± 3 cm^?1), G(3)–G(2) = 123.1 cm^?1 (122 ± 3 cm^?1), and G(4)–G(3) = 80.8 cm^?1 (79 ± 3 cm^?1), experimental values in parentheses. The calculated binding energy is substantially higher than the accepted experimental value. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2005     

Interrupted super framework of the crystal structure of Cs[Be2(PO4)(PO4H)] cesium diberyllium phosphate hydrophosphate

The crystal structure of cesium diberyllium phosphate hydrophosphate Cs[Be₂(PO₄)(PO₄H)] obtained hydrothermally is analyzed. Unit cell parameters are: a = 4.8860(5) ?, b = 10.7330(11) ?, c = 13.0061(15) ?, α = 92.540(10)°, β = 92.451(9)°, γ = 90.948(9)°, space group P . In the structural motif consisting of PO₄ and BeO₄ tetrahedra, Be,P two-link chains and ribbons are distinguished, typical of a short a-translation of ≈4.9 ?. The presence of ternary and terminal O ligands along with bridging ones determines the term interrupted super framework. The group of two Be tetrahedra with a common edge is detected for beryllium phosphates for the first time. Original Russian Text Copyright ? 2009 by V. V. Bakakin, Yu. V. Seretkin, and S. P. Demin __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 2, pp. 369–373, March–April, 2009.     

A method for the separation of beryllium from spectral interfering elements in inductively coupled plasma-atomic emission spectroscopic analysis

A quick, simple and effective chromatographic method for the separation of beryllium from a wide range of elements is described. The elements selected comprise elements which can interfere with the determination of beryllium by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and elements which commonly occur in environmental and industrial sample matrices. Beryllium is separated from all possible ICP-AES spectral interfering elements using a single extraction chromatographic (EXC) cartridge containing an acidic chelating organophosphorus extractant, Dipex^®, sorbed onto an inert polymeric substrate. The separation method has been evaluated using simulated samples generated using several different digestion methods currently employed in beryllium analyses performed in Department of Energy (DOE) facilities. Incorporating a guard cartridge containing either 2-ethyl-1-hexylphosphonic acid mono 2-ethyl-1-hexyl ester or bis(2,4,4-trimethylpentyl)phosphinic acid to selectively remove U(VI) allows the isolation of beryllium from samples containing over 100 mg of uranium without changing the load, rinse or strip conditions of the method.     

Beryllium Atom Mediated Dinitrogen Activation via Coupling with Carbon Monoxide

The reactions of laser‐ablated beryllium atoms with dinitrogen and carbon monoxide mixtures form the end‐on bonded NNBeCO and side‐on bonded (η²‐N₂)BeCO isomers in solid argon, which are predicted by quantum chemical calculations to be almost isoenergetic. The end‐on bonded complex has a triplet ground state while the side‐on bonded isomer has a singlet electronic ground state. The complexes rearrange to the energetically lowest lying NBeNCO isomer upon visible light excitation, which is characterized to be an isocyanate complex of a nitrene derivative with a triplet electronic ground state. A bonding analysis using a charge‐ and energy decomposition procedure reveals that the electronic reference state of Be in the NNBeCO isomers has an 2s⁰2p² excited configuration and that the metal‐ligand bonds can be described in terms of N₂→Be←CO σ donation and concomitant N₂←Be→CO π backdonation. The results demonstrate that the activation of N₂ with the N?N bond being completely cleaved can be achieved via coupling with carbon monoxide mediated by a main group atom.     

金属铍的压缩变形行为

利用材料试验机及Hopkinson杆装置系统开展热等静压金属铍在不同温度下的静动态压缩力学行为研究,获得了温度、应变率对金属铍屈服强度和加工硬化行为的影响规律。结果表明:金属铍在压缩应力状态下呈现出良好的塑性,同时其力学性能具有显著的应变率敏感性与热软化效应,屈服强度和流动应力随应变率提高呈明显增大趋势,随着温度升高逐渐降低。同时,室温下其加工硬化行为随着应变增大表现为分段硬化特征,随温度升高则趋于理想塑性。最后,采用修正的Johnson-Cook本构模型对实验结果进行了拟合,模型计算结果与实验结果吻合较好。     

ChemInform Abstract: Compounds of Superatom Clusters: Preferred Structures and Significant Nonlinear Optical Properties of the BLi6X (X: F,LiF2, BeF3, BF4) Motifs.

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