Synthesis and structures of 11,11,12,12-tetracyano-2,6-diiodo-9,10-anthraquinodimethane and its 2:1 cocrystals with anthracene, pyrene and tetrathiafulvalene

Yi Ren; Semin Lee; Jeffery Bertke; Danielle L Gray; Jeffrey S Moore

doi:10.1107/S2053229616016387

Synthesis and structures of 11,11,12,12-tetracyano-2,6-diiodo-9,10-anthraquinodimethane and its 2:1 cocrystals with anthracene, pyrene and tetrathiafulvalene

Acta Crystallogr C Struct Chem. 2016 Dec 1;72(Pt 12):923-931. doi: 10.1107/S2053229616016387. Epub 2016 Nov 4.

Authors

Yi Ren¹, Semin Lee², Jeffery Bertke³, Danielle L Gray⁴, Jeffrey S Moore¹

Affiliations

¹ Department of Chemistry, University of Illinois at Urbana-Champaign, 600 S. Mathews Ave, Urbana, IL 61801, USA.
² Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, 405 N. Mathews Ave., Urbana, IL 61801, USA.
³ Department of Chemistry, Georgetown University, 146 Regents Hall, Washington, DC 20057, USA.
⁴ School of Chemical Sciences, University of Illinois at Urbana-Champaign, 505 S. Mathews Ave, Box 59-1, Urbana, IL 61801, USA.

PMID: 27918292
DOI: 10.1107/S2053229616016387

Abstract

Radical salts and charge-transfer complexes (CTCs) containing tetracyanoquinodimethane (TCNQ) display electrical conductivity, which has led to the development of many TCNQ derivatives with enhanced electron-accepting properties that are applicable toward organic electronics. To expand the family of TCNQ derivatives, we report the synthesis and structures of 11,11,12,12-tetracyano-2,6-diiodo-9,10-anthraquinodimethane (abbreviated as DITCAQ), C₂₀H₆I₂N₄, and its charge-transfer complexes with various electron donors, namely DITCAQ-anthracene (2/1), C₂₀H₆I₂N₄·0.5C₁₄H₁₀, (I), DITCAQ-pyrene (2/1), C₂₀H₆I₂N₄·0.5C₁₆H₁₀, (II), and DITCAQ-tetrathiafulvalene (2/1), C₂₀H₆I₂N₄·0.5C₆H₄S₄, (III). The molecular structure of DITCAQ consists of a 2,6-diiodo-9,10-dihydroanthracene moiety with two malononitrile substituents. DITCAQ possesses a saddle shape, since the malononitrile groups bend significantly up out of the plane of the central ring and the two benzene rings bend down out of the same plane. π-π interactions between DITCAQ and the electron-donor molecules control the degree of charge transfer in cocrystals (I), (II), and (III), which is reflected in both the dihedral angles between the terminal benzene ring and the central ring on the DITCAQ motifs, and their corresponding IR spectra.

Keywords: 9,10-anthraquinodimethane; anthracene; charge-transfer interaction; cocrystallization; crystal structure; electrical conductivity; pyrene; tetrathiafulvalene.