A New Type of Two-Dimensional Organic Conductors: Alkylammonium Bis[1,2,5]thiadiazolotetracyanoquinodimethanides

Abstract

Anion radical salts of bis[1,2,5]thiadiazolotetracyanoquinodimethan (BTDA) containing forty kinds of alkylammonium ions were prepared whose molar ratios are unique for each cation and changed from 1:1 (2A–2L) to 2:3 (2M–2Z), 1:2 (2a–2m), and 2:5 (2n) with elongation of the side chains. The electrical conductivities of the salts are largely affected by the molar ratio and the spatial requirement of cations (ρRT 3.1 Ω cm for 2a and 4.2×106 Ω cm for 2L), and some of the salts exhibit high electrical conductivities (ρRT 3.1–8.3 Ω cm for 2a–2e) with small anisotropy (ρ⁄⁄ 1.7 Ω cm, ρ⊥ 21.6 Ω cm for a single crystal of 2g). Three salts (2A, 2M, and 2g) showed semiconducting temperature dependence of electrical conductivity with the activation energies of 0.12–0.20 eV. The X-ray study of three kinds of the salts (2A, 2g, and 2m) revealed that two-dimensional networks are formed by S–N≡C interactions (3.12–3.33 Å) of BTDA anion radicals. The crystals of 2A and 2g showing higher conductivities consist of two-dimensionally expanded “ribbon” networks accompanied with equally spaced columnar stackings while molecules are pairing to form dyads in 2m which exhibits lower conductivity.

An Electron‐Transfer Ferromagnet with Tc=107 K Based on a Three‐Dimensional [Ru2]2/TCNQ System

“…In this arrangement, two axial coordination sites of respective [Ru 2 ] units are used to provide the links to form the neutral network. [13,14,15,16] As was observed in previously studied compounds, the difference in bond lengths for BTDA-TCNQ (from 0 to À1) are very small, but a rough trend can still be observed, as in the case of TCNQ: b and d are shortened and meanwhile c and e (b-d are defined in Figure 2 a and Table S1, Supporting Information) are lengthened on increasing the charge from 0 to À1; in Figure 2. The bond lengths in the BTDA-TCNQ moiety of 3 are listed in Table S1 (Supporting Information) together with those of BTDA-TCNQ salts reported previously.…”

“…While 1 and 2 exhibit a 2D hexagonal network, [10,11] 3 is an infinite 3D network structure ( ] states. Therefore, the oxidation state of BTDA-TCNQ was evaluated by three relationships based on c: [17] on the basis of neutral BTDA-TCNQ (1 = 0) [13] and [NEt(-Me) 3 ]BTDA-TCNQ (1 = À1) [16] with A 1 = À25.64, B 1 = 34.64, A 2 = À22.73, B 2 = 20.98, A 3 = À50.00, and B 3 = 23.25. [13,14,15,16] As was observed in previously studied compounds, the difference in bond lengths for BTDA-TCNQ (from 0 to À1) are very small, but a rough trend can still be observed, as in the case of TCNQ: b and d are shortened and meanwhile c and e (b-d are defined in Figure 2 a and Table S1, Supporting Information) are lengthened on increasing the charge from 0 to À1; in Figure 2.…”

An Electron‐Transfer Ferromagnet with Tc=107 K Based on a Three‐Dimensional [Ru2]2/TCNQ System

“…Chemie particular, the distance c is characteristic. Therefore, the oxidation state of BTDA-TCNQ was evaluated by three relationships based on c: [17] on the basis of neutral BTDA-TCNQ (1 = 0) [13] and [NEt(-Me) 3 ]BTDA-TCNQ (1 = À1) [16] with A 1 = À25.64, B 1 = 34.64, A 2 = À22.73, B 2 = 20.98, A 3 = À50.00, and B 3 = 23.25. The estimated values for 3 are 1 c = À1.435, and 1 c/d = À1.463, and 1 c/(b+d) = À1.512 (Table S1, Supporting Information).…”

“…The bond lengths in the BTDA-TCNQ moiety of 3 are listed in Table S1 (Supporting Information) together with those of BTDA-TCNQ salts reported previously. [13,14,15,16] As was observed in previously studied compounds, the difference in bond lengths for BTDA-TCNQ (from 0 to À1) are very small, but a rough trend can still be observed, as in the case of TCNQ: b and d are shortened and meanwhile c and e (b-d are defined in Figure 2 a and Table S1, Supporting Information) are lengthened on increasing the charge from 0 to À1; in Solvent molecules and m-FPhCO 2 ligands are omitted for clarity. Symmetry operations (*) Àx + 3/2, Ày + 3/2, Àz + 1; (#) Àx + 1, y, Àz + 1/2; (**) Àx + 2, Ày + 1, Àz + 1.…”

Breathing Some New Life into an Old Topic: Chalcogen-Nitrogen π-Heterocycles as Electron Acceptors

“…, radical anions—RAs), though observed by EPR (S and Se derivatives) in the mid-1960s [18,56,57,58,59,60,61,62,63,64,65], were not used until recently in the design and synthesis of potentional functional materials because of the lack of methods for their isolation. The only related species were RAs of TCNQ-fused 1,2,5-thia(selena)diazoles isolated in the form of salts [66,67,68,69]. However these RAs are normally considered as derivatives of TCNQ, i.e., the well-known precursor of numerous RA salts and charge-transfer (CT) complexes.…”