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

The kinetically favored triazole-based phosphine 1-(2-(diphenylphosphino)phenyl)-4-phenyl-1H-1,2,3-triazole (2,L1) and its thermodynamically preferred isomer, 5-(diphenylphosphino)-1,4-dipheny1-1H-1,2,3-triazole (3, L-2), were obtained by the temperature-controlled lithiation of 2-bromotriazole followed by the reaction with chlorodiphenylphosphine. The structures of phosphines 2 and 3 were determined by X-ray diffraction. Upon reaction with late transition-metal derivatives (Cu-I, Ag-I, and Au-I), phosphines 2 and 3 form complexes with monodentate (Cu-I, Ag-I, and Au-1; kappa(1)-P), chelate (Cu-I; kappa(2)-P,N), bridged bidentate (Cu-I; mu(2)-P,N), and tridentate (Cu-I; mu(2),kappa(2)-P,N,N) modes of coordination. Reactions with copper(I) halides produced mono-, di-, and tetranuclear complexes, whereas the reaction of 2 with [Cu(NCCH3)(4)]BF4 yielded the binuclear complex [Cu-2(CH3CN)(2){o-Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}-mu-(kappa-P,kappa-N)kappa-N}(2)](BF4)(2) (10) with the ligand acting as a six electron donor involving phosphorus and two triazole nitrogen atoms. The copper complexes of 2 and 3 containing rhomboid Cu2X2 units, [(Cu)(2)(mu-X)(2){o-Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}-kappa-P}(2)] (4, X = Cl; 5, X = Br), on treatment with 1,10-phenanthroline and 2,2'-bipyridine gave mixed-ligand complexes of the type [(CuX)(N boolean AND N-kappa(2)-N,N){o-Ph2P(C6H4){1,2,3-N3C(Ph)C(H)}-kappa-P}] (N boolean AND N = 1,10-phen and 2,2'-bipy; X = CI, Br, and I)