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

Homometallic Silver(I) Complexes of a Heterotopic NHC-Bridged Bis-Bipyridine Ligand

By varying the metal to ligand ratio, stepwise formation of a series of homonuclear silver­(I) complexes of a carbene-bridged bis-bipyridine ligand (L) was achieved. In the mononuclear 1:2 complex [AgL₂]Br (<b>1</b>) only the carbene carbon is involved in the metal coordination, while both of the 2,2′-bipyridine (bpy) arms are free. When the amount of silver­(I) ion was increased, isomorphous 2:2 dinuclear complexes with different counteranions, [Ag₂L₂]­X₂ (X = Br^– (<b>2a</b>), PF₆^– (<b>2b</b>), BPh₄^– (<b>2c</b>)), were synthesized from the ligand LX, in which the carbene carbon and one of the bpy units participate in the coordination with silver­(I) ions. Further addition of Ag^I salt afforded the one-dimensional coordination polymer {[Ag₃L₂]­(PF₆)₃·4CH₃CN}_<i>n</i> (<b>3</b>), wherein the hanging bipyridine units also coordinate with Ag^I and thus all the coordination sites of the ligand are employed. The results reveal the preference of Ag^I ion for the carbene carbon donor rather than the bpy units. The synthesis, structures, and interconversion of the complexes and the counteranion effects on the structures are reported, and the luminescent properties of the ligand LX and the silver complexes have also been studied

Asymmetric Synthesis of CF₃- and Indole-Containing Thiochromanes via a Squaramide-Catalyzed Michael–Aldol Reaction

A Michael–aldol reaction of 2-mercaptobenzaldehyde with β-indole-β-CF₃ enones catalyzed by a squaramide has been realized. The method affords a series of 2-CF₃-2-indole-substituted thiochromanes featuring a CF₃-containing quaternary stereocenter in excellent yields, diastereoselectivities, and enantioselectivities