Crystal and molecular structure of the new anion-radical salts—(N-Me-2-NH2-Pz)(TCNQ)2 and (N-Me-Tetra-Me-Pz)(TCNQ)2 (Pz is pyrazine)

Two anion-radical salts (ARS) of 7,7′,8,8′-tetracyanoquinodimethane (TCNQ) – (N-Me-2-NH2-Pz)(TCNQ)2 and (N-Me-Tetra-Me-Pz)(TCNQ)2 (N-Me-2-NH2-Pz, N-methyl-2-amino-pyrazinium-; N-Me-Tetra-Me-Pz, N-methyl-tetra-methyl-pyrazinium-ions) – were synthesized and characterized. Both salts (ARS) were found to be semiconductors with a room-temperature conductivity of 3.8 × 10−5 and 1.93 × 10−2 Ω−1 cm−1, respectively. For both salts a layered structure of cations and anion-radicals was discovered, where layers composed of cations alternate along the b-axis with the layers containing TCNQ anion-radicals. The cations in the (N-Me-2-NH2-Pz)(TCNQ)2 form pairs bonded by strongly shortened 1.97 (2) Å intermolecular hydrogen N(1)…H(3a) links.