Gold(III) Complexes of Asymmetrically Aryl‐Substituted 1,2‐Dithiolene Ligands Featuring Potential‐Controlled Spectroscopic Properties: An Insight into the Electronic Properties of bis(Pyren‐1‐yl‐ethylene‐1,2‐dithiolato)Gold(III)

Abstract

The electrochemical, UV/Vis-NIR absorption, and emission-spectroscopic features of (TBA(+))(1(-)) and the corresponding neutral complex 1 were investigated (TBA(+)=tetrabutylammonium; 1(-)=[Au(III)(Pyr,H-edt)(2)](-); Pyr,H-edt(2-)=pyren-1-yl-ethylene-1,2-dithiolato). The intense electrochromic NIR absorption (λ(max)=1432 nm; ε=13000 M(-1) cm(-1) in CH(2)Cl(2)) and the potential-controlled visible emission in the range 400-500 nm, the energy of which depends on the charge of the complex, were interpreted on the grounds of time-dependent DFT calculations carried out on the cis and trans isomers of 1, 1(-), and 1(2-). In addition, to evaluate the nonlinear optical properties of 1(x-) (x=0, 1), first static hyperpolarizability values β(tot) were calculated (β(tot)=78×10(-30) and 212×10(-30) esu for the cis isomer of 1(-) and 1, respectively) and compared to those of differently substituted [Au(Ar,H-edt)(2)](x-) gold dithiolenes [Ar=naphth-2-yl (2), phenyl (3); x=0, 1].

High Ambipolar Mobility in a Neutral Radical Gold Dithiolene Complex

“…At higher concentrations, weak (ε < 1000 dm 3 mol −1 cm −1 ) bands can be observed at 477 and 727 nm, likely corresponding to d‐d transitions. On oxidation a band in the NIR (1462 nm) is observed; this has been observed previously for neutral gold radical complexes and has been assigned to either a SOMO‐1 to SOMO transition, or an intervalence charge transfer (IVCT) band of the form [Au III (L • )(L)] → [Au III (L)(L • )] …”

“…The isomers can be distinguished by a 0.01 ppm difference between the dithiolene protons in the 1 H NMR, and the isomers do not appear to interconvert (Figure S1, Supporting Information). While rapid cis–trans isomerism in solution has been reported for asymmetric nickel dithiolene complexes, rapid interconversion for asymmetric gold dithiolene complexes has not been observed . In most cases, the isomers are separated after the oxidation to the neutral species by selective crystallization of one isomer over the other.…”

Electrochemical deposition of a semiconducting gold dithiolene complex with NIR absorption

“…As the dithiolone is asymmetric, the salt was initially obtained as a mixture of the cis and trans isomers, distinguishable by a small (0.01 ppm) difference between the dithiolene protons in the 1 H NMR. As reported for other gold dithiolene complexes, 8,24,[25][26][27][28][29][30][31][32][33][34][35][36][37] the two isomers do not appear to interconvert in solution, and thus a pure isomer Fig. S1 †) was isolated via selective precipitation/crystallization in reasonable yield (40%).…”

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 …”