BET-TTF

Figure 3.21. Scheme of the preparation by MRDT of a conducting surface layer of 0-(BET-TTF)2Br-3H2O nanocrystals on a polycarbonate (PC) substrate. Adapted from Mas-Torrent etal., 2001. 

We have seen in previous sections that doping of insulahng hlms can be achieved through exposure to e.g., iodine gas. This practical and universal method can also be employed for the formahon of conducting layers on transparent and mechanically flexible polymeric substrates as discussed next. The example discussed here refers to conducting layers of 0-(BET-TTF)2Br-3H2O on a polycarbonate matrix (Mas-Torrent et al, 2001). 

Rovira MC, Novoa JJ, Tarres J, Rovira C, Veciana J, Yang S, Cowan DO, Canadell E (1995) Bis(ethylenethio)tetrathiafulvalene (BET-TTF), an organic donor with high electrical conductivity. Adv Mater 7 1023-1027... 

Z /.v(ethylenethio)tetrathiafulvalene (BET-TTF) and related dissymmetrical electron donors 04CRV5289. 

When the BETS donor replaces the BEDT-TTF electron donor molecule during the electrocrystallization process, crystals of KL-(BETS)2Ag(CF3)4(TCE) have been prepared [29] and structurally characterized. Replacement of the inner sulfur atoms of BEDT-TTF with selenium results in a slight expansion of the unit cell and prevents the stabilization of a superconducting state above 1.2 K. Disorder in one of the BETS ethylene endgroups has been offered as a possible explanation. 

Fig. 1 Chemical structures of TTF, BEDT-TTF and BETS electroactive donor molecules...

The synthesis of the mixed sulfur-selenium donor BEDS-TTF (BEST) via the tetralithiation of TTF was mentioned above [53]. Bis(ethylenedithio) tetraselenafulvalene (BEDT-TSF, BETS) is obtained in good yield following the sequence outlined in Scheme 14. The synthesis makes use of a titanium-cyclopentadiene complex to stabilize a problematic, unstable synthetic intermediate (35) [7]. 

As it is well known from recent experiments (1,2), TTF-TCNQ has several subsequent phase transitions at low temperatures. Below 54 K, there is a distortion with wave vector k = L( --[Pg.283]

BET = Brunauer-Emmett-Teller CMON = covalent metal-organic networks CTF = covalent triazine-based framework DCQNI = A,A -dicyanoquinodiimine DEF = A,A-diethylformamide DMA = A,A-dimethyl-acetamide FP-TRMC = flash-photolysis time-resolved microwave conductivity HHT = 2,3,6,7,10,11-hexa-hydroxytriphenylene M-CAT = metal-catecholate PSM = postsynthesis modifications PXRD = powder X-ray diffraction TCNQ = tetracyanoquinodimethane TOF = time-of-flight TTF = tetrathiafulvalene. 

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