Two Triazole-Based Phosphine Ligands Prepared via Temperature-Mediated Li/H Exchange: Cu<sup>I</sup> and Au<sup>I</sup> Complexes and Structural Studies

The kinetically favored triazole-based phosphine 1-(2-(diphenylphosphino)­phenyl)-4-phenyl-1<i>H</i>-1,2,3-triazole (<b>2</b>, L<sub>1</sub>) and its thermodynamically preferred isomer, 5-(diphenylphosphino)-1,4-diphenyl-1<i>H</i>-1,2,3-triazole (<b>3</b>, L<sub>2</sub>), were obtained by the temperature-controlled lithiation of 2-bromotriazole followed by the reaction with chlorodiphenylphosphine. The structures of phosphines <b>2</b> and <b>3</b> were determined by X-ray diffraction. Upon reaction with late transition-metal derivatives (Cu<sup>I</sup>, Ag<sup>I</sup>, and Au<sup>I</sup>), phosphines <b>2</b> and <b>3</b> form complexes with monodentate (Cu<sup>I</sup>, Ag<sup>I</sup>, and Au<sup>I</sup>; κ<sup>1</sup>-<i>P</i>), chelate (Cu<sup>I</sup>; κ<sup>2</sup>-<i>P</i>,<i>N</i>), bridged bidentate (Cu<sup>I</sup>; μ<sup>2</sup>-<i>P</i>,<i>N</i>), and tridentate (Cu<sup>I</sup>; μ<sup>2</sup>,κ<sup>2</sup>-<i>P</i>,<i>N</i>,<i>N</i>) modes of coordination. Reactions with copper­(I) halides produced mono-, di-, and tetranuclear complexes, whereas the reaction of <b>2</b> with [Cu­(NCCH<sub>3</sub>)<sub>4</sub>]­BF<sub>4</sub> yielded the binuclear complex [Cu<sub>2</sub>(CH<sub>3</sub>CN)<sub>2</sub>{<i>o</i>-Ph<sub>2</sub>P­(C<sub>6</sub>H<sub>4</sub>)­{1,2,3-N<sub>3</sub>C­(Ph)­C­(H)}-μ-(κ-<i>P</i>,κ-<i>N</i>),κ-<i>N</i>}<sub>2</sub>]­(BF<sub>4</sub>)<sub>2</sub> (<b>10</b>) with the ligand acting as a six-electron donor involving phosphorus and two triazole nitrogen atoms. The copper complexes of <b>2</b> and <b>3</b> containing rhomboid Cu<sub>2</sub>X<sub>2</sub> units, [(Cu)<sub>2</sub>(μ-X)<sub>2</sub>{<i>o</i>-Ph<sub>2</sub>P­(C<sub>6</sub>H<sub>4</sub>)­{1,2,3-N<sub>3</sub>C­(Ph)­C­(H)}-κ-<i>P</i>}<sub>2</sub>] (<b>4</b>, X = Cl; <b>5</b>, X = Br), on treatment with 1,10-phenanthroline and 2,2′-bipyridine gave mixed-ligand complexes of the type [(CuX)­(N<b>∩</b>N-κ<sup>2</sup>-<i>N,N</i>)­{<i>o</i>-Ph<sub>2</sub>P­(C<sub>6</sub>H<sub>4</sub>)­{1,2,3-N<sub>3</sub>C­(Ph)­C­(H)}-κ-<i>P</i>}] (N∩N = 1,10-phen and 2,2′-bipy; X = Cl, Br, and I).