数码比色法测定环境及生物样品中的氰化物浓度

在传统氰化物检测方法的基础上,提出了一种新的方法—数码比色法。在一定条件下,苦味酸与氰化物生成黄色化合物,用数码相机对显色溶液拍照,通过数码比色,进行灰度处理,照片的三原色值与氰化物的浓度成线性关系,可以直接分析出其氰化物的浓度。对唾液样品测定,其回收率为98.18%,对照品测定的相对标准偏差RSD为1.5%。研究结果表明,数码比色法具有准确度和精密度都比较理想,方便快速、环境友好等特点。     

Theoretical study of the helio hydrogen cyanide dication HeCNH2+

The structure and stability of the helio hydrogen cyanide molecular ion, HeCNH²⁺, is investigated by standard quantum chemical methods. Single reference calculations are carried out using second-order perturbation theory (MP2), the coupled cluster expansion in the CCSD approximation, and the hybrid approach using a perturbative estimate of the triple excitation energy component designated CCSD(T). Multireference calculations using a complete active space (CASSCF) and a second-order perturbation theory estimate of correlation effects (CASPT2) are reported.     

双金属氰化物催化二氧化碳与环氧丙烷聚合

研究了双金属氰化配合物(DMC)催化剂催化二氧化碳(CO2)与环氧丙烷(PO)的共聚及PO的均聚反应,考察了DMC催化剂的诱导现象。结果表明,共聚时DMC催化的诱导期比均聚短,尤其是在低CO2压力(1.0MPa)下更明显,诱导期由均聚时的45min缩短为共聚时的15min。共聚时诱导期随CO2压力升高而增加,当反应压力由1.0MPa升高至7.0MPa时,诱导期由15min增至40min。PO与CO2共聚时的引发现象不同于PO均聚:共聚引发时温度和压力突然异常升高并迅速降低至引发前的状态,而均聚引发时温度突然升高后逐渐下降。由此可知CO2能促进DMC催化剂的活化。     

High‐pressure studies of the micro‐Raman spectra of iron cyanide complexes: Prussian blue (Fe4[Fe(CN)6]3), potassium ferricyanide (K3[Fe(CN)6]), and sodium nitroprusside (Na2[Fe(CN)5(NO)]·2H2O)

The pressure dependences of the peaks observed in the micro‐Raman spectra of Prussian blue (Fe₄[Fe(CN)₆]₃), potassium ferricyanide (K₃[Fe(CN)₆]), and sodium nitroprusside (Na₂[Fe(CN)₅(NO)]·2H₂O) have been measured up to 5.0 GPa. The vibrational modes of Prussian blue appearing at 201 and 365 cm⁻¹ show negative dν/dP values and Grüneisen parameters and are assigned to the transverse bending modes of the Fe C N Fe linkage which can contribute to a negative thermal expansion behavior. A phase transition occurring between 2.0 and 2.8 GPa in potassium ferricyanide is shown by changes in the spectral region 150–700 cm⁻¹. In the spectra of the nitroprusside ion, there are strong interactions between the FeN stretching mode and the FeNO bending and the axial CN stretching modes. The pressure dependence of the NO stretching vibration is positive, 5.6 cm⁻¹ GPa⁻¹, in contrast to the negative behavior in the iron(II)‐meso‐tetraphenyl porphyrinate complex. Copyright © 2011 John Wiley & Sons, Ltd.     

Rapid measurements of hydrogen cyanide concentration in combustion gas via terahertz spectroscopy

The development of a real-time measurement system to determine the concentrations of combustion gases mixed with smoke particles in fire environments is an essential technical issue in the fire safety field. In this study, the absorption line for the J = 8–7 rotational transition at 708.9 GHz of hydrogen cyanide (HCN) produced by the combustion of silk is rapidly measured in a 1 m cell during repeat scans (seven times a minute) via terahertz spectroscopy. The obtained time profile of HCN concentrations agrees well with the time profile obtained via Fourier transform infrared (FT-IR) spectroscopy. The maximum concentrations derived via terahertz spectroscopy are consistent with those derived via FT-IR within an accuracy of 10%. The minimum sensitivity of HCN is 100 ppm as detected via terahertz spectroscopy. The repetition rate, the accuracy, and the sensitivity for the scans demonstrate the potential of terahertz spectroscopy to rapidly diagnose combustion gas flow concentrations in fire environments.     

Effect of ultrasonic pretreatment on eliminating cyanogenic glycosides and hydrogen cyanide in cassava

Traditional soaking method takes days to remove cassava cyanide. Ten minutes of ultrasonic pretreatment (UPT) was found to be a new effective method to eliminate both cyanogenic glycosides and hydrogen cyanide in cassava. Here, the parameters of UPT were optimized and the underlying mechanisms were investigated. 40.36% and 24.95% of hydrogen cyanide and cyanogenic glycosides in cassava juice were eliminated under 10 min of UPT (45℃, 81 W). UPT before boiling enhanced the total cyanide elimination to 41.94%. The degradation patterns of hydrogen cyanide and cyanogenic glycosides were different. Ultrasound directly eliminated hydrogen cyanide and indirectly degraded cyanogenic glycosides through promoting enzymatic hydrolysis. The β-glucosidase activity was increased by 17.99% induced by ultrasound. This was supported by the movement of hydrophobic residual and the rearrangement of the secondary structure of the molecular as found in fluorescence, CD, FTIR, DSC and TG analysis. This study revealed that UPT acted as a fast and simple technical way in improving cassava safety.     

Bithiophene triarylborane dyad: An efficient material for the selective detection of CN− and F− ions

A new fluorescent chemosensor based on bithiophene coupled dimesitylborane (BMB-1) was synthesized and characterized. BMB-1 was used for colorimetric and turn-on fluorescent sensing of cyanide (CN⁻) and fluoride (F⁻) ions, in the presence of other competitive anions in an aqueous (CH₃CN–H₂O) medium. BMB-1 showed a hypsochromic shift (blue shift) with addition of CN⁻ and F⁻ ions in absorption studies. The lower detection level of CN⁻ and F⁻ ions is 1.37 × 10⁻⁹ and 1.75 × 10⁻⁹ M, respectively. The BMB-1 binding mechanism is based on the nucleophilic addition of CN⁻ and F⁻ ions in the internal charge transfer transition of bithio moiety to the boranylmesitylene unit, and the color changes were observed under UV light. This result is further confirmed by Fourier transform infrared spectroscopy, mass spectrometry and density functional theory calculations. Also, the BMB-1 probe is found to be a good adsorbent for the removal of F⁻ ions in real water samples using the adsorption technique.     

机械球磨共聚络合剂法制备Zn-Ni双金属催化剂催化环氧丙烷和领苯二甲酸酐共聚

机械化学是一种快速且环境友好,具有巨大潜力的无溶剂合成双金属氰化物催化剂(DMC)的合成方法。共聚络合剂辅助机械球磨法成功制备出了Zn-Ni双金属催化剂。经元素分析和红外光谱表明双金属催化剂中掺入了各种共聚络合剂。扫描电镜表明,由此产生的双金属催化剂是纳米级的。双金属催化剂在无溶剂、反应时间为6h、反应温度为110°C的条件下对环氧丙烷(PO)与邻苯二甲酸酐(PA)的开环聚合是高效催化的。红外光谱、 1H-NMR 和 13C-NMR图谱均证明有聚酯(PO-co-PA)的结构。在共聚反应中,双金属催化剂显示相对较高的活性,得到了高产率、高分子量和窄分子量分布的聚酯(PO-co-PA）。     

Cyanides and Isocyanides of Zinc,Cadmium and Mercury: Matrix Infrared Spectra and Electronic Structure Calculations for the Linear MNC,NCMCN, CNMNC,NCMMCN, and CNMMNC Molecules

Cadmium atoms from laser ablation react with cyanogen, NC=CN, in excess argon during co-deposition at 4 K, and even more on UV irradiation of the cold samples. Final annealing to 35 K increases bands at 2187.3 and 2089.2 cm⁻¹ at the expense of weaker bands at 2194.6 and 2092.2 cm⁻¹ through addition of another cadmium atom. Reaction products were identified by comparison with B3LYP and CCSD(T) computed frequencies and energies, through frequency differences between Zn and Cd products, and by cyanogen isotopic substitution. The CN radical, ZnNC, and CdNC were observed on sample deposition. Hg arc ultraviolet (UV) irradiation activates the insertion of Cd and Zn to form the NCCdCN, CNCdNC, NCZnCN and CNZnNC molecules. Next annealing increased the dimetal products NCCdCdCN, CNCdCdNC, NCZnZnCN, and CNZnZnNC at the expense of their single metal analogs. Laser ablated mercury amalgam also produced NCHgCN, NCHg−HgCN, CNHgNC and CNHg−HgNC. The Group12 metals form both cyanide and isocyanide products, and the argon matrix also traps the higher energy but much more intensely absorbing isocyanides. In the isocyanide case bond polarity results in very intense infrared absorptions. Group 12 metals produce shorter M−M bonds in the dimetal cyanides NCM−MCN and isocyanides CNM−MNC than in the M−M itself, and their computed M−M bond lengths compare favorably with those measured for dimetal complexes stabilized by large ring containing molecular ligands.     

Complex Formation Between Hydroxy Naphthol Blue and First Row Transition Metal Cyanide Complexes

Abstract

It has been found that cyanide complexes of first row transition metal elements exhibit enhanced binding to hydroxy naphthol blue (HNB) relative to the binding of corresponding aquo-ions. HNB forms a 2:1 complex with Fe³⁺ and Cu²⁺ cyanides, and 1:1 complexes with all other transition metal cyanide complexes studied; formation constants have been calculated from the spectrophotometric data in each case. It is possible to use HNB as a spectrophotometric reagent for transition metal cyanide complexes, lower limits of detection being determined for each complex.