Mixed valence radical cations and intermolecular complexes derived from indenofluorene-extended tetrathiafulvalenes

Tuning crystal polymorphs of a π-extended tetrathiafulvalene-based cruciform molecule towards high-performance organic field-effect transistors

“…It also should be stated that a stronger electron-weight is distributed along the direction of DTF-substituted vertical conjugation backbones, indicating the ability of losing electrons of IF-TTF molecules to the electrodes for the formation of efficient hole charge transport channels in organic electronic devices. The calculated HOMO and LUMO energy levels are −4.79 eV and −1.62 eV, respectively, with the corresponding experimental values of −4.64 eV for HOMO and −2.09 eV for LUMO obtained through the cyclic voltammetry curves [23]. Additionally, a good thermal stability with the decomposition at around 310°C for IF-TTF was observed by thermo-gravimetric analysis (TGA) (see Fig.…”

“…However, using toluene as the solvent promoted the platelet/block-shaped β-phase, and IF-TTF single crystals were formed generally with length of tens micrometers and width of several micrometers (Fig. 2b), indicating the strong solvent effect on molecular aggregation [23] and further assembly for IF-TTF, which is very popular for TTF-derived molecules [31][32][33] and other organic systems [34][35][36]. Fortunately, by carefully controlling the slow solvent evaporation from their corresponding saturated chloroform or toluene solution for crystal growth, enough large ribbon (named as α-phase) and block (named as β-phase) single crystals of IF-TTF were successfully obtained separately for single crystal data analysis.…”

“…Different from the one-dimensional TTF-based molecules widely investigated in the past, we focused on combining dithiafulvene (DTF; "TTF half unit") and other functional molecular units to design cruciform-like molecular structures (that is, two orthogonally oriented π-systems). One aim was to achieve good and tunable conducting properties by virtue of the different conjugation pathways that exist between the individual parts of the molecule [17][18][19][20][21][22][23]. These DTF-based cruciform molecular wires have demonstrated potential promising applications in molecular electronics and also provided a good platform for the investigation of the dependence of conducting properties on their molecular structures [24][25][26].…”

“…As a continuation of our work on such extended TTF compounds, it is interesting to further investigate their applications in organic electronic devices, such as OFETs, the basic component of organic circuits. Here, we present a comprehensive study on an indenfluorene-extended TTF recently reported [23] (IF-TTF; Fig. 1a), tuning its crystal polymorphs, analyzing their molecular structures and measuring their electrical transport properties.…”

Expanded Indacene–Tetrathiafulvalene Scaffolds: Structural Implications for Redox Properties and Association Behavior

“…Extended tetrathiafulvalenes (TTFs) have attracted wide interest in supramolecular and materials chemistry on account of their redox properties . One recent class of such compounds is the indenofluorene‐extended TTFs ( IF‐TTF s; Figure ), for which we have developed a convenient synthetic protocol . These compounds are chromophores that exhibit high molar absorptivities in the visible region.…”