Divide and Protect: Passivating Cu(111) by Cu-(benzotriazole)2

Binding of benzotriazolate anion (BTA) to copper complexes and Cu(111) surface was investigated by density functional theory calculations. [BTACuBTA](1-) was found to be a very stable complex that BTAH molecules and copper atoms can form and [BTACuBTA] is energetically preferred over intact BTAH molecule and other BTA-Cu complexes on the Cu(111) surface. At the [BTACuBTA]/Cu(111) interface, all nitrogen atoms can bind to copper, which stabilizes the interface considerably. In this way, [BTACuBTA] can be densely packed on Cu(111). Our study opens new views on the atomic structure of the copper-BTAH interface that is widely used to protect copper and its alloys from corrosion.