Abstract
Three TCNQ derivatives carrying nitroxide radicals (3a–3c) were prepared and were found to form single-component charge-transfer (CT) complexes by self-assembly, in which outer nitroxide groups of a couple of different molecules work as donors and the inner TCNQ unit of another molecule as an acceptor. While the CT interactions found for the TEMPO (2,2,6,6-tetramethylpiperidin-1-oxy) derivative 3a and the PROXYL (2,2,5,5-tetramethylpirrolidin-1-oxy) derivative 3b are point-to-face fashion between the oxygen atom of each nitroxide group and the six-membered ring of inner TCNQ unit, the CT interactions found for the PO (2,2,5,5-tetramethyl-3-pyrrolin-1-oxy) derivative 3c are point-to-point contacts between the oxygen atoms of outer nitroxide groups and the carbon atoms of a couple of cyano groups.
Highlights
CT complexes are normally known to consist of two components: a donor molecule and an acceptor molecule, and a wide variety of organic conductors such as TTF-TCNQ (TTF: tetrathiafulvalene, TCNQ: 7,7,8,8-tetracyanoquinodimethane) [1] as a typical example are composed of two-component CT complexes in general
We found recently that some benzoquinone derivatives carrying TEMPO radical (e.g., 1a, 1b in Scheme 1) form single component CT complexes by assembling themselves, where benzoquinone works as an acceptor and the TEMPO group as a donor [8]
Even if a number of TCNQ derivatives have so far been prepared to develop organic conductors or other functional materials by forming respective CT complexes with an appropriate donor molecule, to our knowledge there is no example of a TCNQ derivative carrying a stable radical and a reason will be that a stable radical works as a donor to form the corresponding CT complex [9] with TCNQ or TCNQF4 (2,3,5,6-tetrafluro-7,7,8,8-tetracyanoquinodimethane) and to prevent the introduction of radical substituent on the TCNQ core as a consequence
Summary
CT complexes are normally known to consist of two components: a donor molecule and an acceptor molecule, and a wide variety of organic conductors such as TTF-TCNQ (TTF: tetrathiafulvalene, TCNQ: 7,7,8,8-tetracyanoquinodimethane) [1] as a typical example are composed of two-component CT complexes in general. We found recently that some benzoquinone derivatives carrying TEMPO radical (e.g., 1a, 1b in Scheme 1) form single component CT complexes by assembling themselves, where benzoquinone works as an acceptor and the TEMPO group as a donor [8]. Even if a number of TCNQ derivatives have so far been prepared to develop organic conductors or other functional materials by forming respective CT complexes with an appropriate donor molecule, to our knowledge there is no example of a TCNQ derivative carrying a stable radical and a reason will be that a stable radical works as a donor to form the corresponding CT complex [9] with TCNQ or TCNQF4. We wish to report in this paper the preparation, structures and some properties of the first examples of spin-carrying TCNQ derivatives (3a–3c), starting from the TCNQ derivative 2 with bis-hydroxyethoxy substituents (Scheme 1). Structural formulas of benzoquinone derivatives 1a, 1b and TCNQ derivatives 2, 3a–3c
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call