Показано ефективну методику для отримання кристалів окисненої форми, проаналізовано вплив розчинників, температури та підтримуючого електроліту на перебіг процесу. Показано, що сполука дитієно-ТТФ кристалізується у формі солі катіон-радикалу, на відмінувід очікуваного дикатіона.
Исследован эффективный метод получения кристаллов окисленной формы, проанализировано влияние на ход процесса растворителей, температуры и поддерживающего электролита. Показано, что соединение дитиено-ТТФ кристаллизируется вформе соли радикал-катиона, в отличии от ожидаемого дикатиона.
General principles of the electrocrystallization technique in application to organic molecules are shown, as some historical background. Based on this, we were able to rationalize main variables in the experiment which are needed in order to get crystals of the oxidized form, that are suitable for further applications such as for example single crystal x-ray diffraction analysis or conductivity measurements. The biggest impact comes fromsuch factors as choice of solvent and supporting electrolyte, which influence directly the solubility of both the starting compound and its oxidized form. Purity of all components is also paramount. In order to avoid formation of by-products, experim&ent is usually performed in a sealed U-shaped electrochemical cell with a glass filter between the anodic and cathodic compartments and under inert atmosphere such as argon or nitrogen. Other parameters considered here, such as temperature of the sol&ution and intensity of the current, help to fine-tune the result, but have less impact on whether the crystallization will occur at all. It is also critical to maintain both parameters at constant values in order to obtain high quality single crystal&s. Galvanostatic oxidation mode is more favourable comparing to the potentiostatic as it allows steady rate of oxidation by providing fixed intensity of the electrical current and subsequently more stable rate of crystal grows, although potentiostati&c mode or alternating current can be used to grow bigger amounts when quality of the single crystal is less important. Further we used this approach to electrocrystalize previously obtained by our group dithieno-TTF, based on the exTTF scaffold. Acco&rding to the literature cyclic voltammetry data, dithieno-TTF undergoes reversible single-wave two electron oxidation to form bis-cation similar to classic exTTF, but in our case only radical-cation salt was obtained in a form of shiny, dark-red, nee&dle-like single crystals. This could be attributed to its extremely low solubility and corresponding formation of the kinetic product, which correlate well with relatively fast crystallization just within 3 days. Another possibility is a comproportio&nation reaction involving the starting neutral molecule and oxidized dication
