Supramolecular complexation is an attractive strategy to modulate the performance of surfactants, e.g., by host-guest interactions. Here, we investigate the interaction of single-chained, di-, tri-, and tetrameric cationic surfactants with cyclodextrins by conductivity and ¹H NMR measurements, exploring the effect of increasing the number of the surfactant hydrophobic tails on the stability of cyclodextrin:surfactant inclusion complexes. The stoichiometry and the binding equilibrium constants of the different inclusion complexes were elucidated. Under the working conditions, the number of hydrophobic chains was found not to affect stoichiometry and 1:1 inclusion complexes were formed for all the surfactants investigated. The stability of the host-guest complexes decreases from single-chained to dimeric (“gemini”) surfactants, the binding following a non-cooperative mechanism. This result may be rationalized by taking into account steric constraints and electrostatic effects as well as the need to overcome the hydrophobic interactions between the chains of the same surfactant molecule. However, a further increase in the number of hydrophobic tails, from two to three to four, results in an increase in the equilibrium binding constant, K₁. In this case, an increment in the number of chains capable of interaction with the cyclodextrin molecules seems to be the main factor responsible for the increase in K₁. ROESY spectra show the coexistence of different types of 1:1 host-guest complexes for tri- and tetrameric surfactants.

超分子络合是例如通过宿主-客体相互作用来调节表面活性剂性能的有吸引力的策略。在这里，我们通过电导率和¹研究单链，二，三和四聚阳离子表面活性剂与环糊精的相互作用。1 H NMR测量，探索增加表面活性剂疏水性尾巴的数目对环糊精：表面活性剂包合物的稳定性的影响。阐明了不同包合物的化学计量和结合平衡常数。在工作条件下，发现疏水链的数量不影响化学计量，并且针对所有研究的表面活性剂形成了1：1的包合物。客体-客体复合物的稳定性从单链表面活性剂到二聚体（“双子座”）表面活性剂降低，其结合遵循非合作机制。通过考虑空间限制和静电效应以及克服相同表面活性剂分子链之间的疏水相互作用的需要，可以使该结果合理化。然而，₁。在这种情况下，能够与环糊精分子相互作用的链数的增加似乎是导致K ₁增加的主要因素。ROESY光谱显示了三聚体和四聚体表面活性剂的不同类型的1：1主客体复合物的共存。