ChemInform Abstract: First Electroconductive Cationic Bisdithiolene Ni and Au Complexes.

Molecular Conductors Based on M(dddt)2 Bisdithiolene Cation Complexes

“…However, the attempts to obtain coordination polymers based on the Ni(dddt) 2 cation complexes by varying counterions turned to be unsuccessful yet. In contrast to [Ni(dddt) 2 ] 3 (ClO 4 ) 2 , no shortened Ni?S contacts were found in the structures of the Ni(dddt) 2 salts of the same stoichiometry (3:2) with the other tetrahedral anions (BF 4 (2), HSO 4 (3), HSeO 4 (4)) (9,(14)(15)(16). The stacks in 2-4 are subdivided into the [Ni(dddt) 2 ] 3 triads depending on the overlapping mode between the cations.…”

“…The cations in the dimers are arranged face-to-face and the M-M distances are equal to 3.0-3.3 ( A depending on the anion. Though the Pt(dddt) 2 and Pd(dddt) salts with the linear IBr 2, ICl 2 , AuBr 2 anions have the same stoichiometry (2:1) as metallic and superconducting b-ET salts with these anions and their layered crystal structures are similar, the former is a semiconductor unlike the latter as a result of the Pt(Pd)(dddt) 2 strong dimerization in the stacks (10,11,21,23).…”

“…In this aspect of great interest is the synthesis of cation salts based on Au(dddt) 2 , which has the k-type packing and is isostructural to the ET molecule in contrast to the neutral isostructural Ni(Pt)(Pd)(dddt) 2 complexes (3,6,7,29). Though it has already been reported on the synthesis of several conducting cation salts of Au(dddt) 2 (9,11), the data about their structures are completely lacking. In the context of chemical modification of M(dddt) 2 system, the nickel complexes of 5,6-dihydro-1,4-dithiin-2,3-diselenolate ligand (ddds) were synthesized (30).…”

“…Interest in the M(dddt) 2 complexes newly arose in the early 1990, when it was, for the first time, found that the neutral M(dddt) 2 complexes behave like ET, i.e. form electroconducting cation salts in a partially oxidized state under electrochemical oxidation (8)(9)(10)(11). It should be noted that the discovery of stable M(dddt) 2 cation salts was unexpected since the neutral complexes have high irreversible (or quasi-reversible) oxidation potentials (E0.9 V vs Ag/AgCl) (12).…”

Formation of thiolene versus dithiolene species from TTBEO. Crystal structures of [Au(ddtCO2Et)(PPh3)] and [Sn(ddtCO2Et)2Me2] {TTBEO = 2,5,7,9-tetrathiabicyclo[4.3.0]non-1(6)-en-8-one; ddtCO2Et = 3-(ethoxycarbonylsulfanyl)-5,6-dihydro-1,4-dithiine-2-thiolate}

“…The latter is a donor organic molecule which forms superconductor salts 14, 15 and some of the charge transfer salts with [M(dddt) 2 ] have been reported to present metallic behaviour at low temperatures. [16][17][18][19][20][21][22][23][24][25][26][27][28] Continuing with our latest research in dithiolene gold chemistry and the role of dithiolene tin() and zinc() complexes as transmetallating reagents, [29][30][31] in this work we select TTBEO {2,5,7,9-tetrathiabicyclo[4.3.0]non-1(6)-en-8-one} as starting material for the synthesis of dddt complexes of gold(), zinc() and tin(). Formation of monothiolene ddtCO 2 R, 3-(alkoxycarbonylsulfanyl)-5,6-dihydro-1,4-dithiine-2-thiolate (R = Me or Et), derivatives occurs in competition with the more frequent dithiolene formation as evidenced by the crystal structures of [Au(ddtCO 2 Et)(PPh 3 )] and [Sn(ddtCO 2 Et) 2 Me 2 ].…”