engleski

Semiconductive 2D arrays of pancake-bonded oligomers of partially charged TCNQ radicals

Multicentre two-electron (mc/2e or pancake bonding) bonding between 7, 7, 8, 8- tetracyanoquinodimethane (TCNQ) radical anions was studied on its 14 novel salts with planar organic cations. Formal charges of the TCNQδ− moieties are −1/2 and −2/3, and they form mc/2e bonded dimers, trimers and tetramers which are further stacked into extended arrays. Multicentre bonding within these oligomers is characterised by short interplanar separations of 2.9 − 3.2 Å ; distances between the oligomers are larger, typically > 3.3 Å. The stacks are laterally connected by C−H···N hydrogen bonding, forming 2D arrays. The nature of mc/2e bonding is characterised by structural, magnetic and electrical data. The compounds are found to be semiconductors, and high conductivity [10-2 Scm-1] correlates with short interplanar distances between pancake-bonded oligomers.

multicentre two-electron bonding ; TCNQ radical anion ; crystal structure ; crystal engineering ; magnetic properties ; electrical properties

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