Unravelling the Interactions of Magnetic Ionic Liquids by Energy Decomposition Schemes: Towards a Transferable Polarizable Force Field.

This work aims at unravelling the interactions in magnetic ionic liquids (MILs) by applying Symmetry-Adapted Perturbation Theory (SAPT) calculations, as well as based on those to set-up a polarisable force field model for these liquids. The targeted MILs comprise two different cations, namely: 1-butyl-3-methylimidazolium ([Bmim]) and 1-ethyl-3-methylimidazolium ([Emim]), along with several metal halides anions such as [FeCl], [FeBr], [ZnCl] and [SnCl] To begin with, DFT geometry optimisations of such MILs were performed, which in turn revealed that the metallic anions prefer to stay close to the region of the carbon atom between the nitrogen atoms in the imidazolium fragment. Then, a SAPT study was carried out to find the optimal separation of the monomers and the different contributions for their interaction energy.

Endohedral alkali cations promote charge transfer transitions in complexes of C with [10]cycloparaphenylenes.

[10]cycloparaphenylene ([10]CPP) effectively encapsulates ionic endofullerenes MC (M = Li, Na, K) as revealed by dispersion-corrected density functional theory methods. The interaction between [10]CPP and these fullerenes is dominated by dispersion, though it is stronger than with pristine C due to a reinforcement of electrostatic and induction contributions to the stability. The C carbon cage effectively shields the cations and distributes the charge among all carbon atoms, so the nature of the endohedral cation has no noticeable effect upon the final stability of the complexes.

Assessment of electronic transitions involving intermolecular charge transfer in complexes formed by fullerenes and donor-acceptor nanohoops.

Complexes formed by fullerenes C60/C70 and substituted cycloparaphenylenes with the capability of acting as donor/acceptor pairs ([10]CPAq and [10]CPTcaq nanohoops) have been studied using density functional theory methods empirically corrected for dispersion. All nanohoops form stable complexes with fullerenes, with complexation energies amounting to around -32 kcal mol-1 with C60 and reaching between -36 and -39 kcal mol-1 in the case of C70. According to DFT calculations, the rings are too large to appropriately accommodate the fullerene, which moves from the centre of the ring to a side region (in most cases located on the side opposite the anthracene unit).

Carbon-nanorings ([10]CPP and [6]CPPA) as fullerene (C and C) receptors: a comprehensive dispersion-corrected DFT study.

A comprehensive computational analysis of all possible complexes between the carbon-nanorings, CNRs, [10]CPP and [6]CPPA with the fullerenes C and C, was carried out. The B97-D2 functional together with the def2-TZVP basis set was used through the work, although comparisons with other different functionals (BLYP-D2, B3LYP-D3(BJ), TPSS-D3(BJ), PBE0-D3(BJ) and M06-2X) were also performed. In order to find all the possible rearrangements of the fullerenes inside the CNRs, two methods of different complexities and computational costs were employed.

Tailoring buckybowls for fullerene recognition. A dispersion-corrected DFT study.

A series of buckybowls with different sizes and structures have been tested as potential receptors of fullerenes C60, C70 and C40. Among these bowls are corannulene (C20H10), sumanene (C21H12), pinakene (C28H14), hemifullerene (C30H12), circumtrindene (C36H12), pentaindenocorannulene (C50H20) and bowl-shaped hexabenzocoronene derivatives. An exhaustive study, taking into account different orientations of fullerenes, was performed in order to obtain the most favourable arrangement for interacting with the bowls.

Interaction of anions with substituted buckybowls. The anion's nature and solvent effects.

Complexes formed by CN-substituted corannulene and sumanene with monovalent anions have been computationally studied to evaluate the effect of anion's nature and solvent upon the interaction. The results indicate that the most stable complex arrangement corresponds in all cases to the anion located by the center of the concave face of the bowl. All complexes are remarkably stable in the gas phase, with interaction energies ranging from -47 to -24 kcal/mol depending on the anion and the bowl considered.