Synthesis and Characterization of Novel Gold(III) Complexes of Asymmetrically Aryl‐Substituted 1,2‐Dithiolene Ligands Featuring Potential‐Controlled Spectroscopic Properties

Abstract

The tetrabutylammonium (TBA(+)) salts of square-planar monoanionic gold complexes of the unsymmetrically substituted Ar,H-edt(2-) 1,2-dithiolene ligands (Ar,H-edt(2-)=arylethylene-1,2-dithiolato; Ar=phenyl (1(-)), 2-naphthyl (2(-)), and 1-pyrenyl (3(-))) were synthesized and characterized by spectroscopic and electrochemical methods and the corresponding neutral species (1, 2, and 3, respectively) were obtained in CH(2)Cl(2) solution at room temperature by diiodine oxidation. The single-crystal X-ray diffraction structural data collected for (TBA(+))(2(-)), supported by DFT theoretical calculations, are consistent with the ene-1,2-dithiolate form of the ligand and the Au(III) oxidation state. All complexes feature intense near-IR absorptions (at about 1.5 microm) in their neutral states and Vis-emitting properties in the 400-550 nm range, the energy of which is controlled by the charge of the complex in the case of the 3(-)/3 couple. The spectroscopic and electrochemical features of 1(x-) and 2(x-) (x=0, 1), both in their cis and trans conformations, were investigated by means of DFT and time-dependent (TD) DFT calculations.

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)

“…Notwithstanding numerous attempts, no crystals suitable for X‐ray diffraction analysis were obtained for this compound. The spectroscopic and electrochemical features of (TBA + )( 1 − ) have been discussed previously and compared to those of (TBA + )( 2 − ) and (TBA + )( 3 − ) 21. The electrochemical behavior of the title complex reflects what is expected for this class of compounds.…”

“…The complex (TBA + )( 1 − ) was synthesized following the well‐established route of treating the corresponding vinylene dithiocarbonate (4‐pyren‐1‐yl‐[1,3]dithiol‐2‐one) with potassium tetrachloroaurate in the presence of tetrabutylammonium iodide 21. Notwithstanding numerous attempts, no crystals suitable for X‐ray diffraction analysis were obtained for this compound.…”

“…the corresponding monoanionic radical form of the Pyr,H‐edt 2− ligand 14. 21 No waves to indicate a further oxidation to the cationic species [Au III (L . ) 2 ] + were found in the explored potential range.…”

“…Very recently, prompted by the NIR absorption characteristic of neutral gold 1,2‐dithiolenes14–16 and by the second‐order NLO potential applications of noncentrosymmetric complexes containing asymmetrically substituted 1,2‐dithiolene ligands,17–20 we reported on bis(1,2‐dithiolene) complexes belonging to the general class [Au(Ar,H‐edt) 2 ] x − (Ar,H‐edt 2− =arylethylene‐1,2‐dithiolato; x =0, 1, 2), which feature 1‐pyrenyl, 2‐naphthyl, and phenyl substituents [Ar=Pyr ( 1 x − ), Naph ( 2 x − ), and Ph ( 3 x − ); x =0, 1, 2], and combine in a single molecular compound the properties of the luminescent substituents along with the linear and nonlinear optical properties of the dithiolene core 21…”

New PtIIdiimine–dithiolate complexes containing a 1,2-dithiolate-1,2-closo-dicarbadodecarborane: an experimental and theoretical investigation

“…The possibility of tuning both the electrochemical and photophysical properties of these chromophores by systematically varying both the central metal ion 28 and the S^S and N^N ligand 29 was distinctly proved. In this context, some of the authors recently reported on a series of new Pt II diimine-dithiolate complexes featuring differently functionalized 1,2-dithiolato ligands belonging to the classes of R-edt 2− (monosubstituted ethylene-1,2-dithiolates; R = phenyl, 2-naphtyl, 1-pyrenyl) 30,31 and R-dmet 2− (N-substituted…”