Synthesis of Luminescent Gold(I) and Gold(III) Complexes with a Triphosphine Ligand

We have synthesized and characterized a series of trinuclear gold(I) complexes [(AuX)<sub>3</sub>(μ-triphos)] (triphos = bis(2-diphenylphosphinoethyl)phenylphosphine; X = Cl <b>1</b>, Br <b>2</b>, I <b>3</b>, C<sub>6</sub>F<sub>5</sub> <b>4</b>) and di- and trinuclear gold(III) complexes [{Au(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>}<i><sub>n</sub></i>(μ-triphos)] (<i>n</i> = 2 (<b>5</b>), 3 (<b>6</b>)). The crystal structure of <b>6 </b>[{Au(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>}<sub>3</sub>(μ-triphos)] has been determined by X-ray diffraction studies, which show the triphosphine in a conformation resulting in very long gold−gold distances, probably associated with the steric requirements of the tris(pentafluorophenyl)gold(III) units. Complex <b>6</b> crystallizes in the triclinic space group <i>P</i>(−1) with <i>a</i> = 12.7746(16) Å, <i>b</i> = 18.560(2) Å, <i>c</i> = 21.750(3) Å, <i>α </i>= 98.215(3)°, <i>β </i>= 101.666(3)°, <i>γ</i> = 96.640(3)°, and <i>Z</i> = 2. Chloride substitutions in complex <b>1</b> afford trinuclear gold(I) complexes [(AuX)<sub>3</sub>(μ-triphos)] (X = Fmes (1,3,5-tris(trifluoromethyl)phenyl)<b> 7</b>, <i>p</i>-SC<sub>6</sub>H<sub>4</sub>Me <b>8</b>, SCN <b>9</b>) and [Au<sub>3</sub>Cl<sub>3</sub><sub>-</sub><i><sub>n</sub></i>(S<sub>2</sub>CNR<sub>2</sub>)<i><sub>n</sub></i>(μ-triphos)] (R = Me, <i>n</i> = 3 (<b>10</b>), 2 (<b>12</b>), 1 (<b>14</b>); R = CH<sub>2</sub>Ph, <i>n</i> = 3 (<b>11</b>), 2 (<b>13</b>), 1 (<b>15</b>)). The luminescence properties of these complexes in the solid state have been studied; at low temperature most of them are luminescent, including the gold(III) derivative <b>6</b>, with the intensity and the emission maxima being clearly influenced by the nature and the number of the ligands bonded to the gold centers.