Lasri Mohammed, El Alami Abouelhaoul, Idlahoussaine Noureddine, Ait-Karra Aziz, Zakir Othmane, Maatallah Mohamed, Idouhli Rachid, Fdil Rabiaa, Khadiri Mohy Eddine, Abouelfida Abdesselam
Laboratory of Physical Chemistry of Materials and Environment, Department of Chemistry, Faculty of Sciences Semlalia, University Cadi Ayyad, BP 2390, Marrakech, Morocco.
Bioorganic Chemistry Team, Faculty of Science, University Chouaïb Doukkali, Jabran Khalil Jabran Avenue, PO Box: 299, El Jadida, 24000, Morocco.
Phys Chem Chem Phys. 2025 Sep 10;27(35):18710-18722. doi: 10.1039/d5cp01114k.
This study reports the synthesis and characterization of a new Schiff base derivative, 2-(5-methyl-1-pyrazol-3-yl)-'-(2-(5-methyl-1-pyrazol-3-yl)acetyl)acetohydrazide (AA3). The molecular structure of AA3 was confirmed using H and C nuclear magnetic resonance (NMR) spectroscopy. The corrosion inhibition performance of AA3 on copper in a 3.5 wt% NaCl solution was evaluated through electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP) techniques, and theoretical chemical studies, particularly density functional theory (DFT) calculations. Experimental data demonstrated that AA3 is an effective corrosion inhibitor, with its inhibition efficiency increasing in correlation with concentration. At a concentration of 5 × 10 M, AA3 achieved a notable inhibition efficiency of 79.66%. Scanning electron microscopy (SEM) analysis of copper surfaces treated with 10 M AA3 confirmed the formation of an adsorbed protective film, suggesting surface coverage. The adsorption characteristics of AA3 molecules aligned well with the Langmuir isotherm model. The value of AA3 is -38.83 kJ mol, demonstrating that it acts on the metal/solution interface through physical adsorption and chemisorption. Theoretical calculations at the molecular scale illustrated that the nitrogen and oxygen atoms in the AA3 molecule play a key role in the inhibition process by interacting with copper atoms and blocking active sites. This was supported by the calculated quantum chemical descriptors. The highest occupied molecular orbital ( = -5.73 eV) and the lowest unoccupied molecular orbital ( = -0.17 eV) indicated a favorable electronic structure for adsorption and inhibition, similar to the energy gap (Δ = 5.56 eV). These findings are further supported by Monte Carlo simulations, which revealed various probable interactions between the AA3 inhibitor and copper surface. The strong agreement between the theoretical predictions and experimental results provides significant insights into the mechanism of corrosion inhibition by AA3.
本研究报道了一种新型席夫碱衍生物2-(5-甲基-1-吡唑-3-基)-N-(2-(5-甲基-1-吡唑-3-基)乙酰基)乙酰肼(AA3)的合成与表征。使用氢和碳核磁共振(NMR)光谱确认了AA3的分子结构。通过电化学阻抗谱(EIS)、动电位极化(PDP)技术以及理论化学研究，特别是密度泛函理论(DFT)计算，评估了AA3在3.5 wt% NaCl溶液中对铜的缓蚀性能。实验数据表明，AA3是一种有效的缓蚀剂，其缓蚀效率随浓度增加而提高。在浓度为5×10⁻⁴ M时，AA3的缓蚀效率达到了显著的79.66%。对用10⁻³ M AA3处理的铜表面进行扫描电子显微镜(SEM)分析，证实形成了吸附保护膜，表明有表面覆盖。AA3分子的吸附特性与朗缪尔等温线模型吻合良好。AA3的吸附热为-38.83 kJ/mol，表明它通过物理吸附和化学吸附作用于金属/溶液界面。分子尺度的理论计算表明，AA3分子中的氮和氧原子通过与铜原子相互作用并阻断活性位点，在缓蚀过程中起关键作用。这得到了计算出的量子化学描述符的支持。最高占据分子轨道( = -5.73 eV)和最低未占据分子轨道( = -0.17 eV)表明其具有有利于吸附和缓蚀的电子结构，类似于能隙(Δ = 5.56 eV)。蒙特卡罗模拟进一步支持了这些发现，该模拟揭示了AA3缓蚀剂与铜表面之间的各种可能相互作用。理论预测与实验结果之间的高度一致性为AA3的缓蚀机理提供了重要见解。
