Bi(III) halometallate ionic liquids: Interactions and speciation

Abstract

Bismuth containing compounds are of particular interest for optical or photo-luminescent applications in sensing, bio-imaging, telecommunications, and opto-electronics and as components in non-toxic extremely dense liquids. Bismuth(III) halometallates form highly colored novel ionic liquid based solvents for which experimental characterization and fundamental understanding are limited. In this work, Bismuth(III) halometallates incorporating chloride, bromide, and iodide have been studied via density functional theory employing B3LYP-D3BJ/aug-cc-pVDZ. Lone anions, and anions in clusters with sufficient 1-ethyl-3-methyl-imidazolium [C2C1Im]+ counter-cations to balance the charge, have been investigated in the gas- phase, and with polarizable continuum solvation. Evaluation of speciation profiles indicates that dimeric or trimeric anions are prevalent. In contrast to analogous Al systems, anions of higher charge (−2, −3) are present. Speciation profiles are similar, but not identical with respect to the halide. The Bi based anions [BimXn]x− in the gas phase and generalized solvation environment produce multiple low energy conformers; moreover, key structural interaction patterns emerge from an analysis of ion-pair and neutral-cluster structures (BimXn)x−(C2C1Im)x+ for x = 1, 2, and 3. Cation–anion interactions are weak; with Coulombic and dispersion forces predominating, anion–π structures are favored, while significant hydrogen bonding does not occur. Anion to cation charge transfer is minimal, but mutual polarization is significant, leading to local positive regions in the anion electrostatic potential surface. The key features of experimental x-ray photoelectron, UV–Vis spectra, and Raman spectra are reproduced, validating the computational results and facilitating rationalization of key features.

Synthetic Application of Bismuth LMCT Photocatalysis in Radical Coupling Reactions

“…These show that Bi 3+ ions favor square pyramidal coordination in excess of chloride over other structures. 30 The synthetic scope of this photocatalytic bismuth-mediated Giese-type coupling was explored to showcase its generality (Scheme 1). Differently substituted electron-deficient alkenes bearing nitrile, carboxyl, and sulfone groups were viable coupling partners (2−8b).…”

Molecular Modelling of Ionic Liquids: Situations When Charge Scaling Seems Insufficient

“…The ESP relative root-mean-squared error (RRMSE) is often computed with reference to the target of the regularized charge fitting, i.e., the HF/6-31G* ESP in the current case. It is often argued that this ab initio level would produce low-quality (inaccurate) results and shifting to higher-level Hamiltonians is preferred [ 73 , 74 , 75 , 76 , 77 , 78 , 79 ]. However, the necessity of replacing the traditional cheap choice HF/6-31G* with higher-level techniques is not really justified by the numerical data in practical ILs species.…”

Ionic liquid based dopant-free band edge shift in BiVO4 particles for photocatalysis under simulated sunlight irradiation

“…2a), this sample presents higher relative intensity peaks of V 2 O 5 . The internal anion interaction between Bi and Cl is less polar and more covalent which may be the reason for the lower reactivity between Bi and V. 44 Therefore, we may suggest that adding the IL on the Bi side decreases the interaction between Bi and V to form BiVO 4 , and as a result the reaction is stabilized to obtain an additional unwanted phase of V 2 O 5 under calcination conditions. 45,46 The Scherrer formula was used to estimate the crystal size: 47 where D represents the crystal size in nanometers, K is the shape factor, λ is the X-ray wavelength (0.15418 nm), and β is the peak width at half maximum.…”