resumo
Buckybowls have risen as appealing fullerene fragment derivatives. Their intrinsic curvature has been exploited in the generation of host-guest supramolecular assemblies, not only through concave-convex complementarily but also through less-known concave-concave staggered arrangements. Whereas the stabilization of bowl-in-bowl dispositions has been ascribed to efficient pi-pi forces together with favorable dipole-dipole interactions, a detailed analysis on the forces guiding the formation of the staggered arrangements is missing so far. Herein, we present a thorough theoretical characterization of bowl-in-bowl vs staggered hemifullerene-based homodimers and heterodimers with the electron-donor truxTTF molecule, as test cases, under the density functional theory and by means of chemical bonding techniques. Our results dearly reveal strong and localized noncovalent signatures, together with an enhanced orbital interaction, associated with CH-pi and sulfur-mediated interactions governing the staggered formation. Bending the fullerene fragment is demonstrated to favor the stabilization in both homo- and heterodimers, in good accord with the depletion in the pi-electron density calculated upon increasing the buckybowl curvature. The optimal buckybowl curvature for the highest interaction energy is, however, dependent on the type of supramolecular assembly (bowl-in-bowl vs staggered) and the concave region to which hemifullerene approaches truxTTE. Interestingly, two regimes are found as a function of buckybowl curvature for hemifullerene homodimers: bowl-in-bowl dispositions are calculated more stable at low curvatures whereas staggered dimers prevail for highly curved buckybowls. Our results highlight the potential of discrete CH-pi and sulfur-mediated interactions to generate unconventional staggered supramolecular arrangements toward the development of a new and unexplored host-guest chemistry.
palavras-chave
HETEROJUNCTION SOLAR-CELLS; DISPERSION-CORRECTED DFT; ELECTRONIC COMMUNICATION; STRUCTURAL-ANALYSIS; FULLERENE FRAGMENT; PI-STACKING; CORANNULENE; BUCKYBOWLS; HYDROCARBON; SYSTEMS
categoria
Chemistry; Physics
autores
Calbo, J; Arago, J; Boto, RA; Sanchez-Marin, J; Orti, E; Contreras-Garcia, J
nossos autores
Roberto Álvarez Boto
Bolseiro de pós-DoutoramentoGrupos
agradecimentos
Financial support from MINECO of Spain (CTQ2015-71154-P, CTQ2015-71936-REDT, and Unidad de Excelencia Maria de Maeztu MDM-2015-0538), Generalitat Valenciana (PROM-ETEO/2016/135), and European FEDER funds (CTQ2015-71154-P) is acknowledged. J.C. is grateful to the Generalitat Valenciana for a postdoctoral fellowship (AFOSTD/2017/081). J.A. is acknowledged to the MINECO for a "JdC-Incorporacion" Fellowship (IJCI-2015-26154),