One-electron oxidation of [Fe₂(η-C₅H₅)₂(µ-CO)₂{µ-Ph₂PN(Et)PPh₂}] by 7,7,8,8-tetracyano-p-quinodimethane: formation of a charge-transfer salt with a novel solid-state stoichiometry and structure

Preparation and Characterization of {[M(dmb)2]TCNQ·xTCNQ°}n Polymers (M = Cu,Ag; dmb = 1,8-Diisocyano-p-menthane; x = 0, 0.5, 1.0, 1.5; TCNQ = 7,7,8,8-Tetracyano-p-quinodimethane) and Design of New Semi- and Photoconducting Organometallic Materials

“…In direct relevance to this work, the solid-state structure for {[Ag(dmb) 2 ]TCNQ·2THF} n also reveals the presence of dimeric TCNQ 2 2- species, consistent with our previous observations for other polymers . In this case the interplanar TCNQ - ···TCNQ - separation (3.24(4) Å) is somewhat shorter than that of the sum of the van der Waals radii for C (2 × 1.70 Å), the values found in the {[Ag(dmb) 2 ]TCNQ·solvate} n polymeric isomers (3.346, 3.436, and 3.312 Å), and the data reported for other dimer or trimer species (see for instance data for [Pd(CNCH 3 ) 4 ](TCNQ) 4 (3.29 and 3.36 Å), [Fe 2 (η 5 -C 5 H 5 ) 2 (μ-CO) 2 ((C 6 H 5 ) 2 PN(C 2 H 5 )P(C 6 H 5 ) 2 )](TCNQ) 3 (3.24 and 3.39 Å), ((H 7 C 3 ) 2 NH)(TCNQ) 2 (3.20 and 3.30 Å), and [C(C 6 Me 6 )Fe(η 5 -C 5 H 5 )](TCNQ) 2 (3.35 and 3.37 Å)). In the TCNQ° crystal, this distance is also shorter (3.45 Å) …”

“…There is no obvious chain of the type (TCNQ) 3 2- ···toluene··· etc., in this case. The interplanar distances within the (TCNQ) 3 2- species are 3.32(4) Å, and compare favorably to that of other literature examples as listed above. −

2 X-ray structure of {[Ag(dmb) 2 ]TCNQ·0.5TCNQ°· 0.5 toluene} n . Green = {[Ag(dmb) 2 + } n chains; red and blue = TCNQ; yellow = toluene.

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Charge-Transfer Salts of Octamethylferrocenyl Thioethers with Organic Acceptors (TCNQ and TCNQF4) and Trihalides (Br3- and I3-). Synthesis, Structure, and Physical Properties

“…The distances between the planes of the TCNQ moieties are between 3.25 Å for BC and 3.30 Å for AB . This is what is expected for van der Waals stacking of aromatic rings and what is observed also for other CT complexes with TCNQ. ,,, The molecular planes are almost parallel, with interplanar angles of 0.3° for BC and 3.30° for AB . There are two crystallographically independent ferrocenium cations, X and Y , the iron atom of the latter being placed on a symmetry center.…”

“…In general, depending on the redox potential and the steric demand of the donor molecules, TCNQ-containing complexes show different stoichiometries (donor-to-acceptor ratio), such as 1:1, 1:2, ,− 1:3, , 1:4, , and 2:5, although other proportions have been observed. Several organometallic derivatives containing TCNQ or TCNQF 4 have also been reported. ,− These materials turn out to be either insulators (e.g., the 1:1 salts containing ammonium cations) or semiconductors (e.g., the mixed valent 1:2 or 1:3 complexes with ferrocenium cations 2,7 ); alternatively they show metallic character (e.g., (TTF)(TCNQ) or (TSeF)(TCNQ)), as reported in excellent review articles concerning conducting organic compounds. , On the other hand, compounds with interesting magnetic properties (normal paramagnets, metamagnets, , but also low-temperature ferromagnets ,, ) have been found.

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