Electrochemical Crystallization of Organic Molecular Conductors: Electrode Surface Conditions for Crystal Growth

Abstract

An electrochemical cell designed to allow in situ observation of crystal growth of organic conductors was fabricated, and the initial growth process of a partially oxidized salt of bis(ethylenedithio)tetrathiafulvalene (ET) was investigated for different current values. The shape, number, and size of the single crystals grown on the electrode depended on the current. However, our results suggested that the presence of trap sites on the electrode surfaces, which promote crystal nucleation, is more important for crystal growth, since flawless surfaces prepared by melting the electrode gave no crystals. The flawless electrode modified with an alkanethiol self-assembled monolayer (SAM) did not give crystals, while with a terminal carboxylate SAM, it yielded quality crystals over the entire surface, indicating that, when modified by anionic species, the electrode surfaces promote clustering of the oxidized ET radical cations and succeed in nucleating crystal growth of the partially oxidized salt.

Large Counterions Boost the Solubility and Renormalized Charge of Suspended Nanoparticles

“…53,54 In addition, Inabe et al have shown that large hydrated TBA cations are not tightly bound to negatively charged polar heads of mercaptoundecanoic acid (MUA) ligands. 55 This is consistent with the hydrophilic character of charged OH polar heads of MUA ligands 56 and with a weak electrostatic attraction between polar heads and TBA cations due to their large hydrated size. These experimental data suggest that short-range nonelectrostatic attractions between hydrated tetraalkylammonium cations and hydrophilic anionic nanoparticles should be negligible in the absence of specific interactions.…”

“…In particular, Yakamata and Osawa have shown using infrared spectra that the hydration shells are tightly attached to these tetraalkylammonium ions and that large electric fields are required to destroy the corresponding hydration shells. , In addition, Inabe et al . have shown that large hydrated TBA cations are not tightly bound to negatively charged polar heads of mercaptoundecanoic acid (MUA) ligands . This is consistent with the hydrophilic character of charged OH polar heads of MUA ligands and with a weak electrostatic attraction between polar heads and TBA cations due to their large hydrated size.…”

Crystals of 4-(2-benzimidazole)-1,2,4-triazole and its hydrate: preparations, crystal structure and Hirshfeld surfaces analysis

“…Recently, there has been increasing interest in crystal engineered materials because they can be exploited for many purposes such as inorganic nonlinear optical materials [1][2][3], host-guest compounds, biomedical materials, organic conductors and coordination polymers [4][5][6][7]. Polymorphs, co-crystals, solvates, hydrates and salts are different crystal forms, of which hydrates are attracting considerable attention from researchers owing to their activities in monitoring absorption and bioavailability [8][9][10][11].…”