Tetrathiafulvalenoparacyclophanes

Abstract

Owing to its "metallic conductivity""] the crystalline 1 : 1 molecular complex of tetrathiafulvalene (TTF) and tetracyanoquinodimethane (TCNQ) is one of the most interesting organic electron donor-acceptor compounds. Other than in the usual crystal lattices of strong donor-acceptor complexes, in which the donor and acceptor molecules alternate within a stack, in the TTF-TCNQ crystal the components form separate stacks131. Whether the special conducting properties are connected with this difference in molecular structure cannot be established experimentally owing to the lack of other crystal modifications of the same complex. Since it appeared a priori very unlikely that the crystal structure of the TTF-TCNQ complex is optimal with respect to the electrical conductivity we tried to effect other TTF-TCNQ arrays in the crystal lattice by changing the molecular architecture. For example crystallization in alternating donor-acceptor stacking should be enforced if TTF and TCNQ are bonded to each other cyclophane-like as in (1) (n=3 or 4). Donor-acceptor cyclophanes with TCNQ as acceptor component have already been synthesized[41. For the incorporation of TTF in cyclophane structures, however, a novel reaction sequence had to be developed. As example we describe here the synthesis of the parent compounds of (l), namely [3]tetrathiafulvaleno[3]paracyclophane (2) and [4]tetrathiafulvaleno[4]paracyclophane (3).For the synthesis of (2), 4,4-@-phenylene)dibutyryl chloride (4)I'l (prepared by reaction of the corresponding dicarboxylic with thionyl chloride, 2 h, 90°C; 83% yield) was converted via the bis(diazoketone) (obtained on reaction with diazomethane in ether) into the bis(ch1oroketone) (5)"l (m.p. 70-71 "C; 51% yield) (sodium chloride, hydrochloric acid, methanol) [']. Reaction of (5) with potassium O-isopropyldithiocarbonate (acetone, 30 minutes' reflux) afforded the corresponding bis(0-isopropyldithiocarbonate) (6)l5] (m. p. 63-64 "C; 89% yield). Subsequent cyclization (70% perchloric acid, chloroform/ether, 1 : I)['] furnished the bis(l,3-dithiol-2-one) (71, which on reaction with phosphorus(v) sulfide (xylene, 2.5 h, 140 "C) gave the bis(l,3-dithiol-2-thione) (8)Is1 [m.p. 99-100°C; 10% yield based on (6)].141 151. X = t l f71> x = o 161, X = 5 -CS-OiPr 181, X = S f91, X:SMeIQ 8 [' I Prof.

An oligooxamacrocycle containing a π-donor tetrathiafulvalene and a π-acceptor quinone. Molecular and supramolecular structure

“…1 An important structural feature in these materials is the spatial arrangement of the TTF with respect to the p-acceptor unit, either a noncovalent self-assembled array, or a covalently bonded system in which the position of the interacting (charge transfer groups) is fixed by synthetic design. Structures of increasingly evolved synthetic design have been reported, notably, the synthesis of tetrathiafulvalenoparacyclophanes and tetrathiafulvalenophanes by Staab et al, 2 the joining of TTF-thiols by Hg 2+ or Ni 2+ , 3 the incorporation of TTF into crown ethers, 4 cages 5 and [3]-pseudocatenanes, 6 the coupling of TTF to a ferrocenyl unit, 7 and the incorporation of TTF into a dimacrocycle with a catenated cyclobis(paraquat-p-phenylene). 8 Incorporation of TCNQ into a [2.2]paracyclophane has been accomplished; however, the p-donor was not TTF but the essentially irrelevant phenyl 9 and 1,4-dimethoxyphenyl groups.…”