Simultaneous Spectrophotometric Determination of Iron(II) and Iron(III) in Mixtures Using Di-2-pyridyl Ketone Benzoylhydrazone

A method for simultaneous spectrophotometric determination of total iron, iron(II) and iron(III) in mixtures containing other metal ions has been described. The method is based on the complexation of iron with di-2-pyridyl ketone benzoylhydrazone (DPKBH) in 50% (v/v) ethanolic solution. Iron(II) complex with DPKBH exhibits two absorption maxima at 360 and 650 nm. meanwhile iron(II1) complex with DPKBH exhibits only one maximum at 360nm. Iron(II) and iron(III) complexes with DPKBH have similar behaviour at 360nm. Iron forms 1:2 complexes with the reagent. Beer's laws are obeyed over the ranges 0.1–2 μgml-1 and 0.4–5 μgrn1-l for iron(II) complexes at 360 and 650nm respectively. Iron(III) showed results similar to those obtained for iron(II) at 360nm. The effect of pH, effect of excess reagent. the stability of complexes. and the tolerance limit of many metal ions have been reported. The method is applied to the determination of total iron, iron(I1). and iron(II1) in synthetic solutions.     

Spectrophotometric Determination of Cobalt with Di-2-Pyridyl Ketone Benzoylhydrazone

Abstract

A method for the spectrophotometric determination of cobalt (II) by complexation with di-2-pyridyl ketone benzoylhydrazone (DPKBH) in 50% (v/v) ethanolic solution is described. Cobalt (II) forms a 1:2 complex with DPKBH. The complex has maximum absorbance at 370 nm. Beer's law is obeyed over the range 0.1 – 2.8 μg.ml^?1. The effect of pH, effect of excess reagent, stability of the complex and the tolerance limit of many metal ions have been reported. The method is applied to the determination of cobalt in different alloys containing other metals ions.     

Spectrophotometric Determination of the Stability Constants of Co(II) and DPKBH (DI-2-Pyridyl Ketone Benzoylhydrazone)

Abstract

In order to have more information about the thermodynamic properties of the complexes formed by Cobalt(II) and DPKBH (di-2-pyridyl ketone benzoylhydrazone) and for the development of speciation methods for cobalt, the respective stepwise formation constants were determined in ethanolic solution 50% (V/V), at pH 5.3 and 25.0°C. The spectrophotometric method of corresponding solutions was used and the following overall formation constants were obtained: β₁ = 5.305 × 10⁶ M^?1 and β₂ = 8.476 × 10¹⁰ M^?2. The molar absorptivities of the 1:1 (ε₁) and 1:2 (ε₂) complexes (Co(II):DPKBH) were determined to be 4.475 × 10 and 2.994 × 10 (M^?1cm^?1), respectively. The calculated distribution diagram shows the percentage of the species at equilibrium as a function of the free DPKBH concentration.     

分光光度法测定水中的痕量镍

研究了在非离子表面活性剂 Triton X- 10 0存在下 ,在 p H 10 .5的 Na2 B4 O7- Na OH介质中 ,镍 ( )与显色剂 1- ( 4 -硝基苯 ) - 3- ( 2 -吡啶 ) -三氮烯 ( NPPy T)发生灵敏的显色反应 ,生成 1∶ 2的络合物 ,摩尔吸光系数ε=1.0 2× 10 5L· mol-1· cm-1,在 0— 2 0μg/ 2 5 m L范围内服从比耳定律。方法应用于水中微量镍的测定 ,结果令人满意     

The Low Temperature Polarised Electronic Spectra of Some Tetragonal Nickel(II) Haloacetate Complexes

We have recently reported the single crystal electronic spectra of some substituted ethylenediamine complexes of nickel(II), discussing both cis (1) and trans (2) examples. We have also reported data for their cobalt(II) analogs (3). These were analysed using the Normalised Spherical Harmonic Hamiltonian (NSH) (4) and the Orbital Angular Overlap Model (OAM) (5) approaches. We have     

1-(6-羟基-2-嘌呤基)-3-[4-(苯基偶氮)苯基]- 三氮烯分光光度法测定微量镍

在pH=10.97的NaB4O7-NaOH缓冲溶液中,表面活性剂Tween-80存在下,1-(6-羟基-2-嘌呤基)-3-[4-(苯基偶氮)苯基]-三氮烯(HPAPT)与镍的显色反应,形成一种稳定的1∶2红色配合物,其最大吸收波长位于540nm,表观摩尔吸光系数ε540＝2.06×105L·mol-1·cm-1,Ni(Ⅱ)在0-15μg/25mL范围内符合比耳定律.结合萃取分离,应用于人发、大米和油菜中镍的测定,结果令人满意.     

5-(4-氯苯基偶氮)-8-苯磺酰氨基喹啉分光光度法测定微量镍(Ⅱ)

在 p H10 .5的 Na2 B4O7- Na OH介质及 CS(NH2 ) 2 、氯化十六烷基吡啶 (CPC)存在时 ,室温下镍 ( )与5 - (4 -氯苯基偶氮 ) - 8-苯磺酰氨基喹啉 (CPBSQ)反应 ,生成络合比为 1∶ 4的有色络合物 ,其最大吸收波长位于 6 0 0 nm。研究了反应的最佳条件 ,建立了一个测定 Ni( )的光度分析新方法。 Ni( )的浓度在 0—10 .0 μg/2 5 m L范围内符合比耳定律 ,其摩尔吸光系数为 1.93× 10 5L· mol-1·cm-1。考察了 2 0多种共存离子的影响 ,大多数常见离子在氨水沉淀分离后不干扰测定。方法用于合金钢中镍的测定 ,其相对标准偏差为 1.9%— 2 .1% ,标准加入回收率为 97%— 10 4 %。     

1-偶氮苯-3-(5-氯-2-吡啶)-三氮烯对银的显色反应及研究

合成了1-偶氮苯-3-(5-氯-2-吡啶)-三氮烯(ABCPDT),研究了ABCPDT与银的显色反应。在Na2B4O7-NaOH缓冲溶液(pH9.5)介质中,Triton X-100存在下试剂与Ag生成络合物(1∶1)。络合物在545nm处有最大吸收峰,络合物的表观摩尔吸光系数为1.55×105L·mol-1·cm-1,Ag含量在0—12μg/25mL范围内符合比耳定律。方法已用于回收定影液中银的测定,结果满意。     

2-(2-噻唑偶氮)-对甲苯酚-SCN-体系分光光度法测定微量亚硝酸根

本文研究了在较浓的硫酸介质中2-(2-噻唑偶氮)-对甲苯酚(简称TAC)质子化的酸度条件,及其与硫氰酸根、亚硝酸根离子形成三元离子缔合物的最佳条件,提出了测定微量亚硝酸根的新方法。在(1 1)H2SO4介质中,该三元离子缔合物的最大吸收波长位于380nm处,表观摩尔吸光系数为2.93×104L·mol-1·cm-1,亚硝酸根含量在0—20μg/25mL范围内符合比耳定律。方法应用于环境水样中微量亚硝酸根的测定,回收率达92%—95%。     

Spectrophotometric Determination of Trace Amounts of Mercury with 3-(2-Thiazolylazo)-2, 6-Diaminopyridine and Gelatine

Abstract

A sensitive method for the determination of trace amounts of mercury by complexation with 3-(2-Thiazolylazo)-2, 6-diaminopyridine (2, 6-TADAP) is described. Hg(II) forms a 1:2 complex with the reagent. Beer's law is obeyed over the range 5–40 μg in the total volume of 10 ml. The molar absorptivity was found to be 1.4 × 10⁴ L mol^?1 cm^?1. This method is simple, rapid and involves no extraction steps whereby the use of gelatine as a solubilizing agent is described.     

1-偶氮苯-3-(3-硝基-5-氯-2-吡啶)-三氮烯的合成及其与铜的显色反应

合成了新显色剂1-偶氮苯-3-(3-硝基-5-氯-2-吡啶)-三氮烯(ABNCPDT)。研究了它与铜的显色反应。在pH10.5的Na2B4O7-NaOH缓冲溶液中,Triton X-100表面活性剂存在下,试剂与铜生成4∶1型红色配合物。配合物的最大吸收峰位于540nm,表观摩尔吸光系数为1.48×105L·mol-1·cm-1。Cu2 浓度在0—480μg/L范围内符合比耳定律,用于测定铝合金中微量铜,结果满意。     

Spectrophotometric Determination of Lead with 2-(5-Bromo-2-pyridylazo)-5-diethylaminophenol and Cetyltrimethylammonium Bromide

Abstract

A new spectrophotometric method was employed for the determination of lead (II) based on the ternary complex formation with 2-(5-Bromo-2-Pyridylazo)-5-diethylaminophenol(5-BrPADAP) and cetyltri-methyl-ammonium bromide (CTAB). At pH 7.00 a violet ternary complex, whose molar absorptivity is 5.1×10⁴ 1.mole^?1 cm^?1 at 575 nm, is formed. Beer's law range (0.5 ? 4.9 μg ml^?1 of lead), the apparent stability constant (log β=9.90) and δG° were evaluated. A large number of ions do not interfer at pH 7.00 because they form complexes with 5-Br-PADAP at higher pH's (< 9.40) or at lower pH's (> 4.86). The method offers the advantages of simplicity and requires no extraction.     

2-(2-喹啉偶氮)-5-二甲氨基酚固相萃取光度法测定锌的研究

研究了新试剂2-(2-喹啉偶氮)-5-二甲氨基酚(QADMAP)与锌的显色反应,在pH 8.5的硼酸-氢氧化钠缓冲介质中,Triton X-100存在下,QADMAP与锌反应生成2∶1稳定络合物,体系最大吸收波长λ_max=590 nm,摩尔吸光系数ε=1.22×105 L·moL-1·cm-1,样品中的锌用强阴离子交换固相萃取柱固相萃取预分离和富集后用该方法测定,结果令人满意。     

Spectral and Computational Studies on Benzil Mono-(2-Pyridyl)Hydrazone

In the present study, structural properties of Mono-(2-Pyridyl) Hydrazone were studied extensively utilizing density functional theory (DFT) employing B3LYP exchange correlation. The Fourier transform infrared (solid phase) was recorded. The vibrational frequencies in the ground state were calculated by using density functional method (B3LYP) with 6-31G* and 6-311G** as basis sets. The spectral studies revealed that the title compound exists in Keto form. Spectral techniques that we employed include ¹H and ¹³C NMR, electronic, thermal techniques. Correlation between experimental chemical shifts and GIAO/B3LYP/6-311G**-calculated isotropic shielding constants, δ_exp = a + bσ_calc, are reported. Good linear regressions between experimental and theoretical results for ¹H and ¹³C were obtained.     

2-(2-喹啉偶氮)-1,5-苯二酚分光光度法测定烟草样品中的钙

在 p H为 8.0的柠檬酸钠 -氢氧化钠缓冲介质中 ,Triton X- 10 0存在下 ,2 - (2喹啉偶氮 ) - 1,5苯二酚(QADHB)与钙反应生成 1∶ 1稳定配合物 ,λmax=5 5 5 nm,ε=4 .18× 10 4L· mol-1· cm-1。钙含量在 0 .1—2 5μg/ 2 5 m L的范围内符合比耳定律 ,方法用于烟草中钙含量的测定 ,结果令人满意。     

IR-Spectral Study of 2-Aminopyridine and Aniline Complexes with Palladium (II)

An IR-spectral study of sulphato- and chloro complexes of palladium (II) with 2-aminopyridine and aniline, respectively, is reported. The results obtained confirm the bidentate co-ordination of both 2-aminopyridine and SO₄ group in the case of sulphato-2-aminopyridine-palladium (II) leading to polynuclear structure of the complex in solution. The comparative investigation of sulphato-dianiline-palladium (II) suggests that the self-dependent ability of the SO₄ ^2- ion for bridging co-ordination can stabilize chain-like complexes of palladium (II) only in the solid state.     

Spectrophotometric Determination of Silver (I) Using 3-Methyl-1, 2-Cyclopentanodione Dithiosemicarbazone

The complex of silver (I) with the reagent 3-methyl-1, 2-cyclopentanodione dithiosemicarbazone, 3-Me-CPDT, has been studied spectrophotometrically. Few properties of the complex such as its composition, stability, and free energy of formation have been determined. A sensitive method of analysis for silver in aqueous solutions has been developed based on the spectrophotometric measurement of the absorption of the Ag-3-Me-CPDT complex. The optimum conditions for applying this method for the determination of Ag(I) have been determined. These conditions include the standing time, pH, wavelength, and the effect of interfering ions.     

Solvatochromism of Ternary Iron (II) Diimine Cyanide Complexes in 2-Ethyl-2-(hydroxymethyl) 1,3-Propanediol (Trimethylol Propane)

The solvatochromic behaviour of bis-(2,2′-bipyridyl)-biscyanoiron (II) and 2,2′- bipyridyltetracyanoiron (II) in 2-ethyl-2-(hydroxymethyl)-1,3-propanediol has been established. The significance and sensitivities of the solvatochromic shifts of these charge-transfer bands are outlined for the two iron complexes above.     

Spectrophotometric Determination of Cobalt (II) Using 5,5-Dimethyl-1,2,3- Cyclohexanetrione 1,2-Dioxime 3- Thiosemicarbazone

The reagent 5,5-dimethyl-1,2,3-cyclohexanetrione 1,2-dioxime 3-thiosemicarbazone (DCDT) has been used for the spectrophotometrie determination of cobalt (II). Various factors affecting the sensitivity of this determination have been studied. These factors include wavelength, standing time and pH. The range of applicability of Beer's law on this determination has been concluded and its sensitivity has been calculated and compared with other reagents used for