Transition Metal Bisdithiolene Complexes Based on Extended Ligands with Fused Tetrathiafulvalene and Thiophene Moieties: New Single‐Component Molecular Metals

Abstract

The gold and nickel bisdithiolene complexes based on new highly extended ligands incorporating fused tetrathiafulvalene and thiophene moieties (alpha-tdt=thiophenetetrathiafulvalenedithiolate and dtdt=dihydro- thiophenetetrathiafulvalenedithiolate), were prepared and characterised by using cyclic voltammetry, single crystal X-ray diffraction, EPR, magnetic susceptibility and electrical transport measurements. These complexes, initially obtained under anaerobic conditions as diamagnetic gold monoanic [nBu(4)N][Au(alpha-tdt)(2)] (4), [nBu(4)N][Au(dtdt)(2)] (3) and nickel dianionic species [(nBu(4)N)(2)][Ni(alpha-tdt)(2)] (8), [(nBu(4)N)(2)][Ni(dtdt)(2)] (7), can be easily oxidised to the stable neutral state just by air or iodine exposure. The monoanionic complexes crystallise in at least two polymorphs, all of which have good cation and anion segregation in alternated layers, the anion layers making a dense 2D network of short SS contacts. All of the neutral complexes, obtained as microcrystalline or quasi amorphous fine powder, present relatively large magnetic susceptibilities that correspond to effective magnetic moments in the range 1-3 mu(B) indicative of high spin states and very high electrical conductivity that in case of the Ni compound can reach sigma(RT) approximately 250 S cm(-1) with a clear metallic behaviour. These compounds are new examples of the still rare single-component molecular metals.

Neutral Metal 1,2-Dithiolenes: Preparations, Properties and Possible Applications of Unsymmetrical in Comparison to the Symmetrical

“…They are compared to those obtained from the corresponding TTFs and similar single component materials. More information concerning the ligands of Table 1 can be found in [6][7][8][9][10][11][12][13][14][15][16]20,21,24,[26][27][28]30,31,34,36,[48][49][50]53,[61][62][63][64]72,77,79,88,89,92,94,[100][101][102][103][104]. More information concerning the ligands of Table 2 can be found in the corresponding references for L1 [34], L2 [34,98], L3 [33,95,102], L4 …”

Neutral d8 metal bis-dithiolene complexes: Synthesis, electronic properties and applications

“…The room temperature conductivity of 14 is 400 S cm −1 . Review articles report on these single-component molecular conductors [10,61,63].…”

“…[10] As a matter of fact, the best way for reaching metallic phases is to extend the -conjugated system on ligands. Several ligands of extended-TTF dithiolate have been reported [10,[57][58][59][60][61]. Complex 13 was the first reported extended-TTF dithiolate [57].…”

Single-Component Charge-Transfer Crystals Based on Spin-Carrying TCNQ (7,7,8,8-Tetracyanoquinodimethane) Derivatives

“…On the other hand, several single-component molecular conductors [4][5][6][7]. In turn, we found recently that some benzoquinone derivatives carrying TEMPO radical (e.g., 1a, 1b in Scheme 1) form single component CT complexes by assembling themselves, where benzoquinone works as an acceptor and the TEMPO group as a donor [8].…”