Syntheses and Structures of Mononuclear, Dinuclear and Polynuclear Silver(I) Complexes of 2‑Pyrazole-Substituted 1,10-Phenanthroline Ligands

A series of mononuclear, dinuclear and polynuclear silver­(I) complexes (1–6) bearing 2-pyrazole-substituted 1,10-phenanthroline derivatives (L1, FL1, L2) have been synthesized and characterized by 1H and 13C NMR, IR spectroscopy, elemental analysis, and single crystal X-ray diffraction. Reaction of L1 (L1 = 2-(3,5-dimethylpyrazol-1-yl)-1,10-phenanthroline) with AgClO4 or AgBF4 afforded two dinuclear silver­(I) complexes [Ag2(L1)2(CH3CN)2]­(ClO4)2 (1) and [Ag2(L1)2(CH3CN)2]­(BF4)2 (2), in which two [AgL1(CH3CN)]+ units are linked by Ag···Ag interaction (Ag···Ag separation: 3.208(2) and 3.248(1) Å, respectively). A one-dimensional polymer {[AgL1]­(BF4)}∞ (3) consisting of an infinite ···Ag···Ag···Ag··· chain (Ag···Ag separation: 3.059(1) Å), as well as a dinuclear complex [Ag2(ClO4)2(L1)2] (4) in which the perchlorate anions instead of solvents are involved in the metal coordination, have also been obtained. The mononuclear complex [Ag­(FL1)2]­(BF4) (5) was synthesized from FL1 (FL1 = 2-(3,5-bis­(trifluoromethyl)­pyrazol-1-yl)-1,10-phenanthroline) and AgBF4, while the dinuclear [Ag2(BF4)2(L2)2] (6) was isolated from L2 (L2 = 2-[N-(3-methyl-5-phenylpyrazole)]-1,10-phenanthroline). The photoluminescence properties of the ligands and complexes 1–6 have been studied both in the solid state and in solution.