Complexation of trivalent metal cations (Al³⁺, Ga³⁺, In³⁺, La³⁺, Lu³⁺) to cucurbiturils: a DFT/SMD evaluation of the key factors governing the host–guest recognition

Abstract

Cucurbiturils (CBs), the pumpkin-shaped macrocycles, are suitable hosts for an array of neutral and cationic species. A plethora of host-guest complexes between CBs and a variety of guest molecules has...

Metal-Assisted Complexation of Fluorogenic Dyes by Cucurbit[7]uril and Cucurbit[8]uril: A DFT Evaluation of the Key Factors Governing the Host–Guest Recognition

“…Our previous studies provided evidence that among biologically essential mono- and divalent metal cations, the magnesium ion binds to CBs in the strongest fashion [ 51 ], whereas the non-biogenic trivalent metal cations (e.g., gallium(III)) form even stronger complexes with the host cavitands [ 52 ]. In light of these findings, in the present research, we modelled Mg 2+ and Ga 3+ as competitors of the fluorogenic dyes.…”

“…M062X functional has been shown to be efficient in main group thermochemistry, kinetics, and non-covalent interactions calculations. Furthermore, our previous studies [ 51 , 52 ], exploring the metal-assisted cucurbituril chemistry, as well as calculations regarding other macrocyclic structures, such as cyclodextrins [ 57 ] and calixarenes [ 58 ], proved this particular combination of method and basis set reliable when the aim is obtaining a general perspective of controlling key factors. The Gaussian 09 program [ 59 ] was employed in performing the calculations.…”

“…Herewith, we endeavor to continue our previous work [ 51 , 52 ] exploring key factors governing metal-assisted cucurbituril–guest complexation activity by applying reliable DFT/SMD methodology. Metal cations play a crucial role in host–guest recognition but are known to exert a dual effect by either competitively binding [ 53 ] or cooperatively associating [ 54 ] with the CB@dye structures.…”

Computation of entropy values for non-electrolyte solute molecules in solution based on semi-empirical corrections to a polarized continuum model

“…It should be noted that eqn (9) can be approximately derived from eqn (8) (Please see ESI †). This implies that the simple lattice model presented herein will be valid so long as is N solute oo N cell true.…”

“…Consequently, this model has been widely used and accepted by researchers in various fields. [5][6][7][8][9] Even so, it should be noted that the commonly used QM/PCM technique combined with the quasi-ideal gas treatment (IGT) comprising calculations involving ideal gas/rigid rotor/harmonic oscillator models can lead to significant errors when deriving thermodynamic parameters for liquid-phase molecules. The contribution of solvent effects as obtained using a self-consistent reaction field is normally added to the electronic energy, and other contributions to H and S are corrected via the same formalism employed in the case of ideal gas-phase molecules.…”