Vinamidinium–tetracyanoquinodimethane salt with two different, one-dimensional tetracyanoquinodimethane stacking axes

Abstract

Three possible methods of synthesis of the VINϕ₂–TCNQ₂ 1 : 2 salt have been compared. Single crystals show two columnar stackings which differ in their orientation (114°). TCNQ molecules of both stacks have different ionicity (1/3 e^– and 2/3 e^–) linked to the presence of hydrogen bonding between the cations on one type of TCNQ. Intrinsic magnetic and electrical properties of both chains are governed by the opening in the band structure of a narrow gap owing to dials formation in both stacks. The highly charged one is semiconducting (gap = 70 meV) whereas the other one is probably metallic. The typical quasi-one-dimensional magnetic behaviour of both stacks demonstrates that the chains are uncoupled in the temperature range studied.