Theoretical and Quantitative Structural Relationships of the Electron Transfer and Electrochemical Properties of Cis-Unsaturated Thiocrown Ethers and Supramolecular Complexes [X-UT-Y]@[La2@C72(Adamantylidene Mono-Adducts)n] (n=0,1)

Abstract

Endohedral fullerenes belong to a new class of compounds that are technologically and scientifically important owing to their unique structures and optoelectronic properties. The isolated pentagon rule (IPR) states that all pentagonal carbon rings are isolated in the most stable fullerene. Metallofullerenes M@Cn, are a class of spherical carbon allotrope group with unique properties. Electron transfer between metallofullerenes and other molecules is thought to involve the transfer of electrons between molecules surrounding the fullerene cage. One class of electron-transfer molecules is the [La2@C72(Adamantylidene Mono-Adducts)n] (n = 0,1) 10–13. The supramolecular complexes 1–9 and 10–13 are shown to possess a previously unreported host-guest interaction for electron transfer processes. The unsaturated, cis-geometry, thiocrown ethers, (1–9), (described as [X-UT-Y], where X and Y indicate the numbers of carbon and sulfur atoms, respectively), are a group of crown ethers that display interesting physiochemical properties in light of their conformational restriction compared to a corresponding saturated system, as well as the sizes of their cavities. Topological indices have been successfully used to construct mathematical methods that relate structural data to various chemical and physical properties. To establish a good relationship between the structures of 1–9 with derivatives of 10–13, an index is utilized, μ cs . This index is the ratio of the sum of the number of carbon atoms (nc ) and the number of sulfur atoms (ns ) with the product of these two numbers for 1–9. In this study, the relationships between this index and oxidation potential ( ox E 1 ) of 1–9, as well as the first and second free energies of electron transfer (ΔGet(n) , for n = 1, 2, which is given by the Rehm-Weller equation) between 1–9 and [La2@C72(Adamantylidene Mono-Adducts)n] (n = 0,1; n = 0 for “a”, n = 1 for “b-g”) 10–13 and their derivatives as [X-UT-Y]@[La2@C72(Adamantylidene Mono-Adducts)n] (n = 0,1; n = 0 for “a”, n = 1 for “b-g”) (groups 14–17 and their derivatives) supramolecular complexes are presented and investigated.