Twenty-one 7,7,8,8-tetracyanoquinodimethanes substituted with Me, Et, i-Pr, F, CI, Br, I, OMe, OEt, 0-i-Pr, 0-i-Bu, O-i-C5H11, -O-CHzOCHr, SMe, and CN groups are reported along with several TCNQ dianion salts.T h e charge transfer complex between tetrathiofulvalene 3i, 3m, and 3n were prepared according to Scheme 11, startand tetracyanoquinodimethane (TTF-TCNQ) 1 shows high ing with p-xylenes 7 or terephthalic acids 8. T h e tere--. phthalic acids were converted first to their acid chlorides, then reduced to glycols, and treated with hydrogen halide [ c f # 3 I" [::m::] t o give p-xylylene dihalides. 1,4-Bis(bromomethyl)-2,5-dimetallic electrical conductivity from room temperature down t o -60 K.14 This chemistry has already been expanded by the preparation of selenium,' tetrathiomethoxy,8 dimethyl,2 t e t r a m e t h~l ,~ benzo,lOJ1 and tetrareported here of a rather complete series of substituted TCNQ's, extended TCNQ's, and related anion salts t h a t may aid in the systematic analysis of charge transfer salt conductivity.'* Substituted 7,7,8,8-tetracyanoquinodimethanes were synthesized according to procedures disclosed or claimed in Du P o n t patents.13 These syntheses most frequently startene dihalides 3b-g, 3j-1, and 3p-s were prepared by direct bischloromethylation of t h e appropriately substituted benzene, as shown in Scheme I. p-Xylylene dihalides, 3a, 3h, 4 ; t 4 * I/@1 c, C1, OMe, OEtb c, OMe, OEt* TCNQ(0Me )(OEt) d, OMe, 0-i-Pr' d, C1, OMe, 0-i-Pr'
