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

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

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 (1) 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– (2a), PF6– (2b), BPh4– (2c)), 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 AgI salt afforded the one-dimensional coordination polymer {[Ag3L2]­(PF6)3·4CH3CN}n (3), wherein the hanging bipyridine units also coordinate with AgI and thus all the coordination sites of the ligand are employed. The results reveal the preference of AgI 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

Magnesium−Magnesium Bond Stabilized by a Doubly Reduced α-Diimine: Synthesis and Structure of [K(THF)₃]₂[LMg−MgL] (L = [(2,6-^<i>i</i>Pr₂C₆H₃)NC(Me)]₂²⁻)

Magnesium−Magnesium Bond Stabilized by a Doubly Reduced α-Diimine: Synthesis and Structure of [K(THF)3]2[LMg−MgL] (L = [(2,6-iPr2C6H3)NC(Me)]22−

Magnesium−Magnesium Bond Stabilized by a Doubly Reduced α-Diimine: Synthesis and Structure of [K(THF)₃]₂[LMg−MgL] (L = [(2,6-^<i>i</i>Pr₂C₆H₃)NC(Me)]₂²⁻)

Magnesium−Magnesium Bond Stabilized by a Doubly Reduced α-Diimine: Synthesis and Structure of [K(THF)3]2[LMg−MgL] (L = [(2,6-iPr2C6H3)NC(Me)]22−

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

Syntheses and Structures of Magnesium Complexes with Reduced α-Diimine Ligands

The reduction of neutral α-diimine ligands bearing different substituents on the N-aryl rings by different amounts of potassium metal and subsequent reaction with anhydrous MgCl2 in THF afforded a series of magnesium compounds, [(LiPr)2–Mg­(THF)2]·THF (2), [(LMes)2–Mg­(THF)3] (3), [(LiPr)−2Mg]·THF (4), [(LMes)−2Mg] (5), and [(LMes)2–2Mg­(η6:η6-K­(THF)2)]­[K­(THF)6]·(THF)2 (6) (LiPr = [(2,6-iPr2C6H3)­NC­(Me)]2), LMes = [(2,4,6-Me3C6H2)­NC­(Me)]2). Complexes 2–6 have been characterized by single-crystal X-ray diffraction, elemental analysis, NMR spectroscopy, and EPR studies (for 4 and 5). The noninnocent α-diimine ligands exist as the dianionic form in compounds 2, 3, and 6 and as a monoanion in 4 and 5. Effects of the ligand substituents and the amount of the reducing agent on the structure of the product have been discussed

Tetraureas versus Triureas in Sulfate Binding

By mimicking the scaffolds of oligopyridine-based ligands, triurea and tetraurea receptors have been developed for sulfate binding. The triureas (L1, L2) show stronger binding of sulfate than tetraureas (L3, L4) in DMSO because of their better conformational complementarity with sulfate, while the tetraureas display better “water tolerance” benefiting from the chelate effect and hydrophobic effect

Syntheses and Structures of Magnesium Complexes with Reduced α-Diimine Ligands

The reduction of neutral α-diimine ligands bearing different substituents on the N-aryl rings by different amounts of potassium metal and subsequent reaction with anhydrous MgCl2 in THF afforded a series of magnesium compounds, [(LiPr)2–Mg­(THF)2]·THF (2), [(LMes)2–Mg­(THF)3] (3), [(LiPr)−2Mg]·THF (4), [(LMes)−2Mg] (5), and [(LMes)2–2Mg­(η6:η6-K­(THF)2)]­[K­(THF)6]·(THF)2 (6) (LiPr = [(2,6-iPr2C6H3)­NC­(Me)]2), LMes = [(2,4,6-Me3C6H2)­NC­(Me)]2). Complexes 2–6 have been characterized by single-crystal X-ray diffraction, elemental analysis, NMR spectroscopy, and EPR studies (for 4 and 5). The noninnocent α-diimine ligands exist as the dianionic form in compounds 2, 3, and 6 and as a monoanion in 4 and 5. Effects of the ligand substituents and the amount of the reducing agent on the structure of the product have been discussed

Tetraureas versus Triureas in Sulfate Binding

By mimicking the scaffolds of oligopyridine-based ligands, triurea and tetraurea receptors have been developed for sulfate binding. The triureas (L1, L2) show stronger binding of sulfate than tetraureas (L3, L4) in DMSO because of their better conformational complementarity with sulfate, while the tetraureas display better “water tolerance” benefiting from the chelate effect and hydrophobic effect