The crystal structure of [1,1′‐bis(p‐fluorophenyl)‐4,4′‐bipyridinium]2+(7,7,8,8‐tetracyano‐p‐quinodimethanide) 22−,(FΦBP) (TCNQ)2, its electrical conductivity and the properties of 51 related simple salts are reported. (FΦBP) (TCNQ)2s triclinic, space group PI, with a = 7.112(7), b = = 13.702(11), c = 12.425(9) Å, α = 115.6(1)°, β = 85.6(1)°, γ = 105.3(1)°, U = 1053 Å3Dm = 1.21 Mg m−3, Z = 1, Dc 1.19 Mg m−3. Within the stoichiometric unit the TCNQ's overlap in an exocyclic bond to quinonoid ring manner with a mean intermolecular spacing of 3.14 A. In the direction of stacking the TCNQ diads are separated by the FΦBP dications and consequently the electrical conductivity, Órt = 6 × 10−9 S cm−1, of (FΦBP) (TCNQ)2 is low compared with values obtained for the congeneric pyridinium and bipyridinium TCNQ simple salts. These fall in the range 10−10 to 60 S cm−1 and eight salts have Órt <1 S cm−1.

The crystal structure of [ 1 ,I '-bis-(p-cyanophenyl) -4,4'bipyridinium] + (7,7,8,8-tetracyano-p-quinodimethanide)42-, CPP-TCNQ4, its electrical conductivity, and the properties of the TCNQ salts of five para-substituted dications are reported. CPP-TCNQ4 is triclinic, space group P r , with a = 7.558( 5), b = 13.501 (4), c = 15.1 55(4) 8, M = 102.08(2), p = 100.60(4), y = 98.43(4)", U = 1 458.5 A3, D, = 1.36 M g m-3, Z = 1, D, = 1.34 M g m-3. The structure was solved by direct methods and refinedto a final R of 0.048 for 2 338 observed reflections. The radical anions stack, plane-to-plane, in columns parallel to 6, the mean inter-TCNQ spacings being 3.28, 3.36, and 3.00 A between TCNQ(A)-TCNQ(A'), TCNQ(A)-TCNQ( B), and TCNQ( B)-TCNQ( B'), respectively. Adjacent columns form sheets, parallel to (OOI), successive sheets being interleaved along c by the CPP dications. The electrical conductivity along b, the direction of stacking, varies as o = ooexp( -E,/kT) where ~3 0 0 0.1 S cm-' and E, 0.1 0 eV.Our interest in CPP-TCNQ, and the TCNQ salts, in general, of diquaternised 4,4'-bipyridyl stems partly from the recently observed ' high conductivity of the simple salt (4,4'-bipyrid-

The 1:2 simple salt, [1,2‐bis(4‐pyridinium)ethane]2+ (7,7,8,8‐tetracya‐no‐p‐quinodimethanide) 22−, (DHPA)(TCNQ)2, is monoclinic, space group C2/c, with a = 29.517(15), b = 7.426(5), c = 13.528(6) Å, β= 93.98(5)°, U = 2958 Å3, Dm, = 1.34 Mg m−3, Z = 4, De, = 1.34 Mg m−3. The structure is solved by direct methods and refined to a final R of 0.042 for 1884 observed reflections. The TCNQ's are arranged in sheets, parallel to the bc‐plane, the sheets being interleaved along a by the DHPA dications. Within the stoichiometric unit the TCNQ's overlap in an exocyclic bond to qoinonoid ring manner, with a mean intermolecular spacing of 3.04 Å, whereas between diads there is no direct overlap. (DHPA)(TCNQ)2, is a diamagnetic insulator with χm, = −3.2 × 10−4e.m.u. mol−1 and σ300K = 1 × 10−7S cm−1. The 1:3 complex salt, (DHPA) (TCNQ)2, is similarly monoclinic, space group P21/c, with a = 12.91(3), b = 3.93(3), c = 27.62(3) Å, β = = 109.9(3) °, U = 1318 Å3, Dm = 1.35 Mg m−3, Z = 4/3, Dc = 1.34 Mg m−3. (DHPA) (TCNQ) 3 is a small band gap semiconductor with d300K= 10 S cm−1. The magnetic susceptibility shows Curia‐Weiss behaviour.

a) [l,t-bis( l-ethyI-4-pyridini~m)ethane]~+ (7,7,8,8-tetracyano-p-quinodimethanide);-salt, (DEPA) (TCNQ),, crystallises in the monoclinic system, space group P2,/c, with a = 15.21(1), b = 25.97(2), c = 7.77(1) A, / 3 = 116.3(1)'. The TCNQs stack, plane-to-plane, in isolated groups of four, with b as the general direction of stacking. The conductivity along b varies as IJ = oo exp (-E,/kT) where (~3 0 0~ = 1 x 10-3 S cm-1 and E, = 0.26 eV. The stoichiometric variation with cation length and the electrical properties of some related TCNQ salts are discussed. [1,2-bis(1-Ethyl-4-Pyridinium)hithan]*+(7,7,8,8-Tetrazyano-p-Q~ino~methanid)~-Sa1z, (DEPA) (TCNQ),, kristallisiert im monoklinen System, Raumgruppe P2Jc mit a = 15,21(1), b = 25,97(2), c = 7,77(1) A, , ! ? = 116,3(1)". Die TCNQ stapelt sich, Ebene auf Ebene, in isolierten Gruppen zu vier mit b als allgemeine Stapelrichtung. Die Leitfiihigkeit in Richtung b variiert wie u = = a, exp (-E,/kT) wobeia3oo~ = 1 x 10+ S cm-l und E, = 0,26 eV ist. Die h d e r u n g der Stochiometrie mit der Kationenliinge und die elektrischen Eigenschaften einiger verwandter TCNQ-Salze werden diskutiert.

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