Group 11 complexes with the bidentate di(1H-indazol-1-yl)methane and di(2H-indazol-2-yl)methane) ligands

Abstract

Twenty-four new copper, silver and gold complexes based on a bis(pyrazolyl)methane ligand L (in detail L = L¹, di(1H-indazol-1-yl)methane; L = L², di(2H-indazol-2-yl)methane) are prepared. The [Cu(L)(PR₃)₂]X species have been obtained from the reaction of [CuX(PR₃)₂] with L upon the displacement of X from the copper coordination sphere. 1 : 1 [CuX₂(L)] complexes were obtained when L¹ reacts with CuX₂ whereas under the same conditions, L² gave the ionic species [CuX(L)₂]X. When L¹ reacts with CuCl₂, however, the dinuclear [CuCl₂(L¹)]₂ complex is formed which, upon treatment with dimethylformamide (DMF), gave the mononuclear derivative [CuCl₂(L¹)(DMF)]. L¹ and L² often show a different reactivity toward silver salts. For example, in the reaction with AgNO₃, the ionic compound [Ag(L¹)₂]NO₃ is obtained when L¹ is used as a starting reagent and the neutral 1 : 2 adduct [AgONO₂(κ-L²)(κ²-L²)] containing a mono and a bidentate ligand is formed when L² is employed as a ligand. L¹ gave 2 : 1 adducts with AgCX₃SO₃ (X = H or F) and AgClO₄, whereas 1 : 1 adducts are formed under the same conditions with L². L¹ and L² give analogous dinuclear ([Ag(O₂CCF₃)(L)]₂) and mononuclear ionic species ([Ag(L)₂]BF₄) when they react with Ag(O₂CCF₃) and AgBF₄ species. Two analogous gold(III) complexes [AuCl₂(L)][AuCl₄] have also been obtained in the reaction of L with AuCl₃ when the reaction was carried out in an excess of the ligands. All the air- and thermally stable complexes have been characterized by analytical and spectral (IR, conductivity, ESI-MS, ¹H and ¹³C NMR solution data) methods.