Monocyclometalated Gold(III) Complexes Bearing π-Accepting Cyanide Ligands: Syntheses, Structural, Photophysical, and Electrochemical Investigations.

The synthesis, structural, photophysical, and electrochemical investigations of a series of gold(III) monocyclometalated complexes bearing ancillary ligands with π-accepting properties is reported. Complexes of the type [(C(∧)N)Au(C≡N)2] [C(∧)N = 2-phenylpyridine (ppy) (1), 2-(p-tolyl)pyridine (tpy) (2), 2-(2-thienyl)-pyridine (thpy) (3), 2-(5-methyl-2-thienyl)pyridine (5m-thpy) (4), 1-phenylisoquinoline (piq) (5)], and [(N(∧)N)Au(C≡N)2] [N(∧)N = 3,5-bis(phenyl)-2-(2'-pyridyl)pyrrole (pyrpy) (6)] were prepared, and the influence of both the cyanide as an ancillary ligand as well as the different electronic properties of the cyclometalating ligands (1-5) and the chelating bidentate (6) on the triplet emission properties were studied. The physicochemical properties were evaluated by a variety of physical methods, and the structure of selected complexes was further confirmed by X-ray diffraction studies.

Monocyclometalated gold(III) monoaryl complexes--a new class of triplet phosphors with highly tunable and efficient emission properties.

Highly tunable and rich phosphorescent emission properties based on the stable monocyclometalated gold(III) monoaryl structural motif are reported. Monochloro complexes of the type cis-[(N^C)Au(C6 H2 (CF3)3)(Cl)] N^C=2-phenylpyridine (ppy)] (1), [N^C=benzo[h]quinoline (bzq)] (2), [N^C=2-(5-Methyl-2-thienyl)pyridine (5m-thpy)] (3) were successfully prepared in modest to good yields by reacting an excess of 2, 4, 6-tris(trifluoromethyl)phenyl lithium (LiFmes) with the corresponding dichloride complexes cis-[(N^C)AuCl2]. Subsequent replacement of the chloride ligand in 1 with strong ligand field strength such as cyanide and terminal alkynes resulted in complexes of the type cis-[(ppy)Au(Fmes)(R)] R=CN (4), I (5), C≡C-C6 H5 (6) and C≡C-C6 H4 N(C6 H5)-p (7).