Nonreactive surfactant molecules have long been used and characterized for a wide range of applications in industries, life science, and everyday life. Recently, new types of functional amphiphilic molecules have emerged that bear another function, for example, a light-absorbing action, or catalytic properties. However, the surfactant properties of these molecules remain to date essentially unknown. In this context, we investigated here the interfacial activity of photocatalytic surfactants based on a ruthenium(II) tris-bipyridine core, functionalized with two alkyl tails. We realized a systematic characterization of the surfactant properties of these molecules at a water–air interface and studied the effect of the alkyl chain length and of the counterions (hexafluorophosphate or chloride) on these properties. Our data demonstrate that ruthenium surfactants with chloride counteranions form a denser layer at the interface, but their surfactant properties can dramatically deteriorate when the chain length of the alkyl tail increases, leading to simple hydrophobic molecules with poor surfactant properties for the longest chains (C17). These findings pave the way for a better use and understanding of photocatalytic soft interfaces.

中文翻译：

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钌基两亲光敏剂的界面表征

长期以来，非反应性表面活性剂分子在工业、生命科学和日常生活中的广泛应用中被使用和表征。最近，出现了具有另一种功能的新型功能性两亲分子，例如光吸收作用或催化特性。然而，迄今为止，这些分子的表面活性剂性质仍然基本未知。在此背景下，我们在此研究了基于钌 (II) 三联吡啶核的光催化表面活性剂的界面活性，该核被两个烷基尾部官能化。我们实现了这些分子在水-空气界面的表面活性剂性质的系统表征，并研究了烷基链长度和反离子（六氟磷酸盐或氯化物）对这些性质的影响。我们的数据表明，具有氯抗衡阴离子的钌表面活性剂在界面处形成更致密的层，但当烷基尾链的链长增加时，它们的表面活性剂性能会显着下降，导致简单的疏水分子对于最长链 (C17) 的表面活性剂性能较差. 这些发现为更好地使用和理解光催化软界面铺平了道路。