New strong organic acceptors by cycloaddition of TCNE and TCNQ to donor-substituted cyanoalkynes

Abstract

Donor-substituted 1,1,2,4,4-pentacyanobuta-1,3-dienes and a cyclohexa-2,5-diene-1,4-diylidene-expanded derivative were prepared by a [2 + 2] cycloaddition of tetracyanoethene (TCNE) or 7,7,8,8-tetracyanoquinodimethane (TCNQ) to anilino-substituted cyanoalkynes, followed by retro-electrocyclisation; they feature intense bathochromically-shifted intramolecular charge-transfer bands and undergo their first one-electron reductions at potentials similar to those reported for TCNE and TCNQ.

Postfunctionalization of aromatic polyamine by [2+2] cycloaddition of 7,7,8,8-tetracyanoquinodimethane with side chain alkynes

“…A similar result was observed for the postfunctionalization of polythiophene derivatives [25]. This study also suggested that the use of stronger acceptor molecules, such as 7,7,8,8-tetracyanoquinodimethane (TCNQ) and its derivatives [26][27][28][29][30][31][32][33][34], is effective for the dramatic lowering of the LUMO levels or the enhancement of the n-type characteristics.…”

Click synthesis of donor–acceptor-type aromatic polymers

“…2). As reported for the other TCBD derivatives [10,11,27,34], significant twisting of the two dicyanovinyl subunits was observed in the TCBD moiety. Thus, the torsion angle θ[C(1)-C(2)-C(3)-C(4)] is -122.8(5)º, which is comparable to that reported previously [22].…”

“…The currently available donor groups for almost quantitative yields include aromatic amines [18][19][20][21], ferrocene [22,23], and azulene derivatives [24,25]. Diederich and others are now extensively expanding this chemistry by applying it to other acceptor molecules, such as 7,7,8,8-tetracyanoquinodimethane (TCNQ) and the derivatives [26][27][28][29] as well as the dicyanovinyl and tricyanovinyl derivatives [30,31]. They also succeeded in the syntheses of dendritic donor-acceptor molecules [32], the linear donoracceptor oligomers by the sequential addition of TCNE and tetrathiafulvalene (TTF) to polyynes [33], and chiral induction in the TCBD moieties [34][35][36].…”

Isolation of p-tricyanovinylphenyldicyanomethide ion via a [2+2] cycloaddition of 7,7,8,8-tetracyanoquinodimethane (TCNQ) molecules

“…However, while the reactivity of TCNQ has been explored [20,21], some of the structural features of this molecule have obviously been ignored. Namely, it possesses two types of strongly electrondeficient CC double bonds that could, in analogy to tetracyanoethylene (TCNE) [22,23] undergo thermal [2+2] cycloaddition with electron-rich alkynes.…”