用户:DoroWolf/沙盒/试亚铁灵
| DoroWolf/沙盒/试亚铁灵 | |
|---|---|
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| 识别 | |
| CAS号 | 14634-91-4 
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| PubChem | 84567 |
| ChemSpider | 76289 |
| SMILES |
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| InChI |
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| InChIKey | CIWXFRVOSDNDJZ-NUQVWONBAU |
| 性质 | |
| 化学式 | C36H24FeN62+ |
| 摩尔质量 | 596.27 g·mol⁻¹ |
| 若非注明，所有数据均出自标准状态（25 ℃，100 kPa）下。 | |
试亚铁灵（英语：Ferroin）是一种配位化合物，化学式为[Fe(o-phen)3]SO4，其中o-phen为1,10-菲啰啉的缩写，是一种双齿配体。
氧化还原指示剂
这种配位化合物在分析化学中用作指示剂。[1]活性成分是[Fe(o-phen)3]2+离子，它是一种发色团，可以被氧化成铁衍生物[Fe(o-phen)3]3+。 在1M H2SO4中，此氧化还原变化的电位为+1.06 V。 它是一种受欢迎的氧化还原指示剂，用于可视化振荡B-Z反应。
试亚铁灵适合作为氧化还原指示剂，因为颜色变化是可逆、非常明显且快速的，并且试亚铁灵溶液在高达60 °C的温度下是稳定的。它是陶瓷测量法中使用的主要指示剂。[2]
Nitroferroin, the complex of iron(II) with 5-nitro-1,10-phenanthroline, has transition potential of +1.25 volts. It is more stable than ferroin, but in sulfuric acid with Ce4+ ion it requires significant excess of the titrant. It is however useful for titration in perchloric acid or nitric acid solution, where cerium redox potential is higher.[2]
通过调整邻二氮菲核上甲基的位置和数量，铁-邻二氮菲络合物的氧化还原电位可以在 +0.84 V 和 +1.10 V 之间变化。[2]
制备
- 3 phen + Fe2+ → [Fe(phen)3]2+
铁是低自旋和具有 D 3对称性的八面体。这种亚铁络合物的强烈颜色来自金属到配体的电荷转移转变。
Reaction kinetics
When sulfuric acid (H2SO4) is added to a solution of [Fe(phen)3]2+, it causes the iron complex to decompose as described by the following reaction:
- [Fe(phen)3]2+(aq) + 3 H3O+(l) → Fe2+(aq) + 3 phenH+(aq) + 3 H2O(l)
Thanks to the high molar absorptivity of ferroin (a measure of how much the molecule interacts with light), this decomposition can be observed measuring the solution absorbance over time.
The rate of decomposition is first order in [Fe(phen)3]2+, and zeroth order in 3 H3O+. That means the rate law is:
- Decrease in ferroin over Time = k [Ferroin]
where k is the reaction constant, and [Ferroin] is the concentration of ferroin. [H3O+] does not show up in the rate law. The concentration of ferroin over time decreases with exponential decay.
References
- ^ Harris, D. C. Quantitative Chemical Analysis
4th. New York, NY: W. H. Freeman. 1995. ISBN 978-0-7167-2508-4.
- ^ 2.0 2.1 2.2 Handbook on the Physics and Chemistry of Rare Earths. Elsevier. 2006: 289–. ISBN 978-0-08-046672-9.
