6533b82afe1ef96bd128c46b

RESEARCH PRODUCT

DLPNO-CCSD(T) scaled methods for the accurate treatment of large supramolecular complexes

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In this work, we present scaled variants of the DLPNO-CCSD(T) method, dubbed as (LS)DLPNO-CCSD(T) and (NS)DLPNO-CCSD(T), to obtain accurate interaction energies in supramolecular complexes governed by noncovalent interactions. The novel scaled schemes are based on the linear combination of the DLPNO-CCSD(T) correlation energies calculated with the standard (LoosePNO and NormalPNO) and modified (Loose2PNO and Normal2PNO) DLPNO-CCSD(T) accuracy levels. The scaled DLPNO-CCSD(T) variants provide nearly TightPNO accuracy, which is essential for the quantification of weak noncovalent interactions, with a noticeable saving in computational cost. Importantly, the accuracy of the proposed schemes is preserved irrespective of the nature and strength of the supramolecular interaction. The (LS)DLPNO-CCSD(T) and (NS)DLPNO-CCSD(T) protocols have been used to study in depth the role of the CH–π versus π–π interactions in the supramolecular complex formed by the electron-donor truxene-tetrathiafulvalene (truxTTF) and the electron-acceptor hemifullerene (C30H12). (NS)DLPNO-CCSD(T)/CBS calculations clearly reveal the higher stability of staggered (dominated by CH–π interactions) versus bowl-in-bowl (dominated by π–π interactions) arrangements in the truxTTF•C30H12 heterodimer. Hemifullerene and similar carbon-based buckybowls are therefore expected to self-assemble with donor compounds in a richer way other than the typical concave–convex π–π arrangement found in fullerene-based aggregates. Contract grant sponsor: Spanish Ministry of Economy and Competitiveness MINECO; Contract grant numbers: CTQ2015-71154-P, CTQ2014-55073-P, CTQ2015-71936-REDT; Contract grant sponsor: Unidad de Excelencia María de Maeztu; Contract grant number: MDM-2015-0538; Contract grant sponsor: Generalitat Valenciana; Contract grant number: PROMETEO/2016/135; Contract grant sponsor: European FEDER; Contract grant number: CTQ2015-71154-P; Contract grant sponsor: MINECO for a “JdC-incorporación”; Contract grant sponsor: Ministerio de Educación y Competitividad, Cultura y Deporte (MECD) of Spain for a predoctoral FPU grant (to J. C.)