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Preparation and properties of DOET derivatives and their salts
ELSEVIER
Synthetic Metals 102 (1999) 1695
Preparation and properties of DOET derivatives and their salts H. Nishikawa
a*, T. Sato a, T. Kodama a, I. Ikemoto a, K. Kikuchi
a, H. Anzai b, J. Yamada b
a Department of Chemistry Tokyo Metropolitan University, Hachioji, Tokyo192-0397, Japan b Department of Material Science, Himeji Institute of Technology, Himeji, 678-1297, Japan Abstract The selenium containing TTF donors condensed with a 1,4-dioxane or a 1,4-dithiane ring by cis fusion were synthesized as organic donors with a bulky substituent. X-ray diffractional analysis of lc (DOES) revealed that the conformation at the 1,4-dioxane ring fusion site is cis similar to the case of DOET. Several cation-radical salts based on 1 b and lc exhibited metallic conducting behavior. keywords: DOET derivatives,
bulky substituent, electrocrystallization,
1. Introduction It has been considered important to use planar donor for developing organic metals in order to obtain an effective overlap interaction between molecules in donor stacks. In contrast, we have already reported that DOET [( 1,4-dioxanediyl-2,3-dithio)ethylenedithio-TTF] and DOES [( 1,4-dioxanediyl-2,3-dithio)ethylenediselena-TTF] produced metallic salts, although these donors are not planar molecules due to cis fusion of a bulky 1,4dioxane ring [l]. In this paper we describe the synthesis, molecular structure and electrochemical properties of other selenium derivatives of DOET and DTET [(I ,4-dithianediyl-2,3dithio)ethylenedithio-TTF] [2] together with DOES and electrical properties of the radical-cation salts based on these donors.
DoEr:x=o DTEr: x=s
lac:X=O Za-c:X=S
a:R=Me b: R-R = -CHZc: R-R = -(CH*)*-
2. Results and discussion Synthesis of la-c and Za-c was achieved by (Me0)3Ppromoted cross-coupling between the corresponding ketones and thiones or ketone in benzene [3]. The oxidation potentials of la-c and 2a-c were determined by cyclic voltammetry. All donors showed two pairs of reversible redox waves. The value of the first oxidation potential (V vs. SCE) of la-c (la:+0.55, +0.85V; lb:+0.52, +0.8OV; lc:+O.54, +0.84V) were almost same to those of the corresponding 1,4-dithiane derivatives (2a:+0.56, +0.86V; 2b:+0.53, +0.8OV; 2c:+O.56, +0.86V). Both the EI and E2 values of lc are slightly lower than those of the prototype DOET (+0.58, +0.88V). The molecular structure of lc was determined by X-ray diffractional analysis [4]. As shown in Fig. 1, the conformation of the 1,4-dioxane ring fusion site is cis, which makes this molecule non-planar. This molecular structure is same to that of DOET.
Fig. 1. Molecular
structure of DOES (lc)
* The corresponding author’s information telephone; +81 (0)426 77 2530, fax; +81 (0)426 77 2525 e-mail; [email protected]
crystal structure, metal All radical-cation salts of lb except for AsF6 salt exhibited semiconductive behavior, whereas AsF6 salt was metallic down to 15 K. DOES yielded semiconductors with relatively small activation energy and metallic salts with At& and I3-. The crystal structure of AuI2- salt was revealed to be almost isostructural to the metallic (DOET) 2BF4 except for the donor to anion ratio. [l] Table 1. Electrical conductivity of radical-cation salts based on lb and le (DOES) Donor Anion Solvent D:Aa era / Scm-t b lb AsF6‘ TCE 2:l 4.4 (metallic to 20 K) lb PFsTCE 2:l 2.6 X IO-7 (Ea=280meV) 9.4 X 10-5 (Ea=180meV) lb c104TCE 2:l lb BF.q TCE 2:l 9.8 X 10-4 (Ea=180meV) lb TCE 2:l 4.6 X 10-l (Ea=45 meV) Islb TCE 3:2 0.11 @a=110 meV) ____ AuI2___________________-____________________----____________ lc AsFrjPhCl 5~2 5.1 (Ea=52 meV) PFfjPhCl 2:l 0.62 \Ea=74 meV) lc lc c104PhCl 2:l 2.3 (Ea=3.7 meV) IC BFd PhCl 3:2 5.0 @a=74 meV) PhCl 60 (metallic to 250 K) lc 2:l b1.4 (metallic to 55 K) IC AuIzPhCl 2:0.75c aDetermined by elemental analysis, bRoom temperature conductivity measured by a four-probe technique on a single crystal. CDetermined by X-ray analysis. 3. References [l] J. Yamada, et al., J Mater. Chem., 7 (1997) 1311; H. Nishikawa, et al., ibid, 8 (1998) 1321. [2] J. Yamada, et al., Tetrahedron Lett., 36 (1995) 9509 [3] la: 63% yield, ‘H NMR (CDCI,) 8 2.34 (s, 6H), 3.71 (m, 2H), 4.05 (m, 2H), 5.43 (s, 2H). lb: 42% yield, ‘H NMR (CDCI,) 6 3.65 (m. 2H), 4.00 (m, 2H), 4.77 (d, J=7.6 Hz, lH), 5.04 (d, k7.6 Hz, lH), 5.32 (s, 2H). lc: 27% yield, ‘H NMR (CDCI,) 6 3.25 (s, 2H), 3.40 (m, 2H), 3.63 (m, 2H), 3.99 (m, 2H), 5.31 (s, 2H). 2a: 22% yield, ‘H NMR (CDCl,) 6 2.30 (s, 6H), 2.93 (m, 2H), 3.12 (m, 2H), 4.74 (s, 2H). 2b: 54% yield, ‘H NMR (CDCl,) 6 2.94 (m, 2H), 3.11 (m, 2H), 4.73 (s, 2H), 4.83 (d, 5=7.6 Hz, lH), 4.99 (d, J=7.6 Hz, 1H). 2c: 11% yield, ‘H NMR (CDCI,) 6 2.94 (m, 2H), 3.12 (m, 2H), 3.28 (m, 2H), 3.37 (m. 2H), 4.73 (s, 2H). [4] Crystal data for lc: C,,H,,O,S,Se,, M= 536.53, orthorhombic, space group P2,nb; a = 15.098(4) A, b = 30.233(7) .& c = 7.653(2) A, V = 3493.350 A’, Z = 8, R = 0.057, Rw = 0.079 for 1290 independent reflections [I 2 20(I)].
0379-6779/99/$ - see front matter 0 1999 Elsevier Science S.A. All rights reserved. PII: SO379-6779(98)00610-9
Synthetic Metals 102 (1999) 1695
Preparation and properties of DOET derivatives and their salts H. Nishikawa
a*, T. Sato a, T. Kodama a, I. Ikemoto a, K. Kikuchi
a, H. Anzai b, J. Yamada b
a Department of Chemistry Tokyo Metropolitan University, Hachioji, Tokyo192-0397, Japan b Department of Material Science, Himeji Institute of Technology, Himeji, 678-1297, Japan Abstract The selenium containing TTF donors condensed with a 1,4-dioxane or a 1,4-dithiane ring by cis fusion were synthesized as organic donors with a bulky substituent. X-ray diffractional analysis of lc (DOES) revealed that the conformation at the 1,4-dioxane ring fusion site is cis similar to the case of DOET. Several cation-radical salts based on 1 b and lc exhibited metallic conducting behavior. keywords: DOET derivatives,
bulky substituent, electrocrystallization,
1. Introduction It has been considered important to use planar donor for developing organic metals in order to obtain an effective overlap interaction between molecules in donor stacks. In contrast, we have already reported that DOET [( 1,4-dioxanediyl-2,3-dithio)ethylenedithio-TTF] and DOES [( 1,4-dioxanediyl-2,3-dithio)ethylenediselena-TTF] produced metallic salts, although these donors are not planar molecules due to cis fusion of a bulky 1,4dioxane ring [l]. In this paper we describe the synthesis, molecular structure and electrochemical properties of other selenium derivatives of DOET and DTET [(I ,4-dithianediyl-2,3dithio)ethylenedithio-TTF] [2] together with DOES and electrical properties of the radical-cation salts based on these donors.
DoEr:x=o DTEr: x=s
lac:X=O Za-c:X=S
a:R=Me b: R-R = -CHZc: R-R = -(CH*)*-
2. Results and discussion Synthesis of la-c and Za-c was achieved by (Me0)3Ppromoted cross-coupling between the corresponding ketones and thiones or ketone in benzene [3]. The oxidation potentials of la-c and 2a-c were determined by cyclic voltammetry. All donors showed two pairs of reversible redox waves. The value of the first oxidation potential (V vs. SCE) of la-c (la:+0.55, +0.85V; lb:+0.52, +0.8OV; lc:+O.54, +0.84V) were almost same to those of the corresponding 1,4-dithiane derivatives (2a:+0.56, +0.86V; 2b:+0.53, +0.8OV; 2c:+O.56, +0.86V). Both the EI and E2 values of lc are slightly lower than those of the prototype DOET (+0.58, +0.88V). The molecular structure of lc was determined by X-ray diffractional analysis [4]. As shown in Fig. 1, the conformation of the 1,4-dioxane ring fusion site is cis, which makes this molecule non-planar. This molecular structure is same to that of DOET.
Fig. 1. Molecular
structure of DOES (lc)
* The corresponding author’s information telephone; +81 (0)426 77 2530, fax; +81 (0)426 77 2525 e-mail; [email protected]
crystal structure, metal All radical-cation salts of lb except for AsF6 salt exhibited semiconductive behavior, whereas AsF6 salt was metallic down to 15 K. DOES yielded semiconductors with relatively small activation energy and metallic salts with At& and I3-. The crystal structure of AuI2- salt was revealed to be almost isostructural to the metallic (DOET) 2BF4 except for the donor to anion ratio. [l] Table 1. Electrical conductivity of radical-cation salts based on lb and le (DOES) Donor Anion Solvent D:Aa era / Scm-t b lb AsF6‘ TCE 2:l 4.4 (metallic to 20 K) lb PFsTCE 2:l 2.6 X IO-7 (Ea=280meV) 9.4 X 10-5 (Ea=180meV) lb c104TCE 2:l lb BF.q TCE 2:l 9.8 X 10-4 (Ea=180meV) lb TCE 2:l 4.6 X 10-l (Ea=45 meV) Islb TCE 3:2 0.11 @a=110 meV) ____ AuI2___________________-____________________----____________ lc AsFrjPhCl 5~2 5.1 (Ea=52 meV) PFfjPhCl 2:l 0.62 \Ea=74 meV) lc lc c104PhCl 2:l 2.3 (Ea=3.7 meV) IC BFd PhCl 3:2 5.0 @a=74 meV) PhCl 60 (metallic to 250 K) lc 2:l b1.4 (metallic to 55 K) IC AuIzPhCl 2:0.75c aDetermined by elemental analysis, bRoom temperature conductivity measured by a four-probe technique on a single crystal. CDetermined by X-ray analysis. 3. References [l] J. Yamada, et al., J Mater. Chem., 7 (1997) 1311; H. Nishikawa, et al., ibid, 8 (1998) 1321. [2] J. Yamada, et al., Tetrahedron Lett., 36 (1995) 9509 [3] la: 63% yield, ‘H NMR (CDCI,) 8 2.34 (s, 6H), 3.71 (m, 2H), 4.05 (m, 2H), 5.43 (s, 2H). lb: 42% yield, ‘H NMR (CDCI,) 6 3.65 (m. 2H), 4.00 (m, 2H), 4.77 (d, J=7.6 Hz, lH), 5.04 (d, k7.6 Hz, lH), 5.32 (s, 2H). lc: 27% yield, ‘H NMR (CDCI,) 6 3.25 (s, 2H), 3.40 (m, 2H), 3.63 (m, 2H), 3.99 (m, 2H), 5.31 (s, 2H). 2a: 22% yield, ‘H NMR (CDCl,) 6 2.30 (s, 6H), 2.93 (m, 2H), 3.12 (m, 2H), 4.74 (s, 2H). 2b: 54% yield, ‘H NMR (CDCl,) 6 2.94 (m, 2H), 3.11 (m, 2H), 4.73 (s, 2H), 4.83 (d, 5=7.6 Hz, lH), 4.99 (d, J=7.6 Hz, 1H). 2c: 11% yield, ‘H NMR (CDCI,) 6 2.94 (m, 2H), 3.12 (m, 2H), 3.28 (m, 2H), 3.37 (m. 2H), 4.73 (s, 2H). [4] Crystal data for lc: C,,H,,O,S,Se,, M= 536.53, orthorhombic, space group P2,nb; a = 15.098(4) A, b = 30.233(7) .& c = 7.653(2) A, V = 3493.350 A’, Z = 8, R = 0.057, Rw = 0.079 for 1290 independent reflections [I 2 20(I)].
0379-6779/99/$ - see front matter 0 1999 Elsevier Science S.A. All rights reserved. PII: SO379-6779(98)00610-9