Langmuir Films of Calix[8]arene/Fullerene Complexes

Abstract

We present the pressure area isotherms for Langmuir films made of calix[8]arene, the calix[8]arene/C60 complex, and the calix[8]arene/C70 complex, all of them measured at 306.1 K. A Brewster angle microscope was used to observe the phases shown by the π−A isotherms. In these three cases, we found a solid phase and its solid−gas coexistence but no expanded liquid phases. The Langmuir films made of calix[8]arene and the calix[8]arene/C60 complex are very similar. The experimental information is consistent with the assumption that C60 is situated inside the cavity of calix[8]arene. The Langmuir films of calix[8]arene and the calix[8]arene/C70 complex are not very similar; we present a discussion to explain the origin of this difference.

Synthesis, Langmuir and Langmuir–Blodgett films of a calix[7]arene ethyl ester

“…However, if ions place in the cavity of the calixarene ring, the complex ion-calixarene will behave similar to the calixarene molecule in the process of film formation. This behaviour has been observed for other calixarene-metal complexes and even for a calixarene-C 60 complex [30]. Nevertheless, the isotherm obtained in ions subphase is steeper than in water subphase, and thus with slightly lower compressibility coefficients, indicating that the ions placed in the calixarene cavity impart more rigidity to the molecule.…”

“…The nanometric size domain observed by AFM ( Figure 5) is out of the resolution of the used BAM. This multilayer formation has also been observed in BAM images for a calix [8]arene [30] but yet at low surface pressure values; for this system the authors stated that the film is in a solid phase and that a transition from gas to solid phase occurs. In our case the appearance and behaviour of the film on zone II, with a value of the Young modulus around 200 mN/m for the p-tert-butylcalix [7]arene ethyl ester, points to a liquid condensed (LC) phase, and multilayering occurs at higher surface pressure values.…”

“…The Langmuir technique has been used to study the response of calixarene derivative monolayers at metal ions present in the subphase [20][21][22][23][24][25][26][27], to amino acids [28] or for the molecular recognition of nucleosides [29]. Studies on Langmuir and Langmuir-Blodgett (LB) films of calix [4]arenes are more abundant than on calix [6]arenes [22,23,26] or calix [8]arenes [21,25,30,31]. Vollhardt et al [27] studied the influence of diverse cations (Na + , Cd 2+ , Eu 3+ , Th 4+ ) on amphiphilic Pfunctionalized calix [4]arene monolayers, concluding that the features of the isotherms are not influenced by the cations in the subphase, although Brewster Angle Microscopy (BAM) images show 2D condensed phase domains with a shape modified by the cation 3 valency.…”

“…This process has been recently used to obtain a calixarenic modified electrode for the determination of lead and cadmium [7] or thallium and cadmium [32]. De Miguel et al [31] have studied the organization of a calix [8]arene derivative at the air-water interface and Castillo et al [30] the structure of Langmuir films of calix [8]arene/fullerene complexes. Recently, Roales et al [33] investigated the optimization of mixed LB films of porphyrin in a calix [8]arene matrix for gas sensing application.…”

Electrochemical Behavior of C60−p-Tert-butylcalix[8]arene Inclusion Complex Film in Mixed Acetonitrile and Water

“…The interaction between C 60 and L has been confirmed by CP-MAS 13 C NMR, IR spectroscopy and UV-visible spectroscopy [16][17][18][19]. Castillo et al [20] made the Langmuir film of fullerene/calix [8]arene complex. Chen et al [21] studied the effects of calixarenes on the electrochemical reduction of C 60 in toluene, mixed toluene and acetonitrile and mixed toluene and DMSO, and found that p-tert-butylcalixarenes could interact or react with C n¹ 60 anions; the products of these reactions were insoluble or poorly soluble in the solvent mixture and adsorbed or precipitated onto the electrode surface.…”