In the present paper, the interaction of three Piperine derivatives namely: 5-(1,3-benzodioxol-5-yl)-1-(piperidin-1-yl) pent-2-en-1-one (S₁), 5-(1,3-benzodioxol-5-yl)-1-(piperidin-1-yl) penta-2,4-dien-1-one (S₂) and 5-(1,3-benzodioxol-5-yl) penta-2,4-dienoic acid (S₃) with iron (Fe) have been investigated theoretically by means of DFT method at the B₃LYP/LANL2DZ high basis set. The interaction with iron surface therefore all possible Fe-inhibitor interaction modes at ―O― and >N― active sites. The preferred complexes are those in which the Fe-atoms is in mono-dentate mode to the studied inhibitors. The quantum chemical properties most relevant to their potential action as corrosion inhibitors have also been calculated in both isolated and Fe-inhibitor (S_i) complex form for comparison. The values of the calculated interaction energy are consistent with the experimentally observed highest corrosion inhibition efficiency trend for the three S₁FeN₂₆, S₂FeN₂₄ & S₃FeO₂₆ complexes. The chemical reactivity and site selectivity of the molecule has been determined with the help of global and local reactivity descriptors of Fe-inhibitor (S_i) complexes. The calculations show that S₁FeN₂₆, S₂FeN₂₄ and S₃FeO₂₆ complexes have thermodynamically favorable binding (ΔG〈0), whereas the other inactive Fe-(S_i)complexes were characterized by slightly positive binding free energy values (ΔG〉0). Furthermore, molecular dynamics simulation was applied to investigate the final and most stable configuration of the inhibitors S_i over Fe (111) in aqueous solution of hydrochloric acid (1.0 M HCl).

在本文中，三种胡椒碱衍生物的相互作用为：5-（1,3-苯并二恶唑-5-基）-1-（哌啶-1-基）戊-2-烯-1-酮（S ₁）， 5-（1,3-苯并二恶唑-5-基）-1-（哌啶-1-基）戊2,4-二烯-1-酮（S ₂）和5-（1,3-苯并二恶唑-5-基d ）在B _3上通过DFT方法对yl）五价2,4-二烯二酸（S ₃）与铁（Fe）进行了研究。LYP / LANL2DZ高基数集。因此，与铁表面的相互作用在“ O”和“ N”活性位点均具有所有可能的铁-抑制剂相互作用模式。优选的配合物是其中所研究的抑制剂的铁原子处于单齿模式的那些配合物。与它们作为缓蚀剂的潜在作用最相关的量子化学性质也已经以分离的和铁缓蚀剂（S _i）复杂的形式进行了计算，以进行比较。计算出的相互作用能的值与实验观察到的三种S ₁ FeN ₂₆，S ₂ FeN ₂₄和S ₃ FeO _26的最高腐蚀抑制效率趋势一致。复合体。借助于Fe-抑制剂（S _i）配合物的整体和局部反应性描述子已经确定了分子的化学反应性和位点选择性。计算表明，S ₁ FeN ₂₆，S ₂ FeN ₂₄和S ₃ FeO ₂₆配合物具有热力学上有利的结合力（ΔG <0），而其他无活性的Fe-（S _i）配合物的特征在于结合自由能值略为正（ΔG＞ 0）。此外，分子动力学模拟被用来研究抑制剂S _i的最终和最稳定的构型。 用Fe（111）在盐酸（1.0M HCl）水溶液中处理。