title: Evidence of the Disassembly of α-Cyclodextrin-octylamine Inclusion Compounds Conjugated to Gold Nanoparticles via Thermal and Photothermal Effects.
abstract: Cyclodextrin (CD) molecules form inclusion compounds (ICs), generating dimers that are capable of encapsulating molecules derived from long-chain hydrocarbons. The aim of this study is to evaluate the structural changes experienced by ICs in solution with increasing temperatures. For this, a nuclear magnetic resonance (¹H-NMR) titration was performed to determinate the stoichiometric α-cyclodextrin (α-CD):octylamine (OA) 2:1 and binding constant (k= 2.16 M-2) of ICs. Solution samples of α-CD-OA ICs conjugated with gold nanoparticles (AuNPs) were prepared, and ¹H-NMR spectra at different temperatures were recorded. Comparatively, ¹H-NMR spectra of the sample irradiated with a laser with tunable wavelengths, with plasmons of conjugated AuNPs, were recorded. In this work, we present evidence of the disassembly of ICs conjugated with AuNPs. Thermal studies demonstrated that, at 114 °C, there are reversible rearrangements of the host and guests in the ICs in a solid state. Migration movements of the guest molecules from the CD cavity were monitored via temperature-dependent ¹H-NMR, and were verified comparing the chemical shifts of octylamine dissolved in deuterated dimethylsulfoxide (DMSO-d₆) with the OA molecule included in α-CD dissolved in the same solvent. It was observed that, at 117 °C, OA exited the α-CD cavity. CD IC dimer disassembly was also observed when the sample was irradiated with green laser light.
authors: Department of Chemistry, Universidad of Chile, Las Palmeras 3425, Santiago 7800003, Chile. nataly.silva@usach.cl.|Department of Chemistry of Materials, Universidad de Santiago de Chile, Av. Libertador Bernardo O'Higgins 3363, Santiago 9170022, Chile. nataly.silva@usach.cl.
authors: Nataly
authors: N
authors: Silva
authors: Department of Chemistry, Universidad of Chile, Las Palmeras 3425, Santiago 7800003, Chile. sml2910@ug.uchile.cl.
authors: Silvana
authors: S
authors: Moris
authors: Department of Chemistry, Universidad of Chile, Las Palmeras 3425, Santiago 7800003, Chile. mdiazv@ug.uchile.cl.
authors: Maximiliano
authors: M
authors: Díaz
authors: Department of Chemistry, Universidad of Chile, Las Palmeras 3425, Santiago 7800003, Chile. nyutroni@uchile.cl.
authors: Nicolás
authors: N
authors: Yutronic
authors: Department of Biology, CEM, Universidad of Chile, Las Palmeras 3425, Santiago 7800003, Chile. elang@uchile.cl.
authors: Erika
authors: E
authors: Lang
authors: Department of Physics, Universidad de Chile, Beauchef 850, Santiago 8370448, Chile. bchornik@ing.uchile.cl.
authors: Boris
authors: B
authors: Chornik
authors: Department of Pharmacological and Toxicological Chemistry, Universidad of Chile, Sergio Livingston 1007, Santiago 8380492, Chile. mkogan@ciq.uchile.cl.
authors: Marcelo J
authors: MJ
authors: Kogan
authors: Department of Chemistry, Universidad of Chile, Las Palmeras 3425, Santiago 7800003, Chile. pjara@uchile.cl.
authors: Paul
authors: P
authors: Jara
mesh_terms: D000588:Amines / Q000737:chemistry*; D065546:Drug Liberation; D006046:Gold / Q000737:chemistry*; D006358:Hot Temperature; D053768:Metal Nanoparticles / Q000737:chemistry; D018625:Microscopy, Atomic Force; D015394:Molecular Structure; D047391:alpha-Cyclodextrins / Q000737:chemistry*
chemical_list: D000588:Amines; D047391:alpha-Cyclodextrins; D006046:Gold; C008699:octylamine
keywords: cyclodextrin; gold nanoparticles; inclusion compounds; octylamine; photothermal effects