Assembly of Soft Metal Complexes of an O₄S₂‑Macrocycle Displaying Endocyclic Monomer, Dumbbell-Like Dimer, and Endo-/Exocyclic Polymer Structures

A comparative investigation of the coordination behavior of an O₄S₂-donor macrocycle <b>L</b> with the thiaphilic soft metal ions Ag⁺, Cu⁺, Hg²⁺, and Pd²⁺ is reported. The X-ray structures of seven complexes (<b>1</b>–<b>7</b>) have been determined, and a range of structural types and coordination modes, including discrete to continuous forms, mono- to multinuclear, and endo- to exocyclic structures involving M–S bonds, are presented. First, reactions of <b>L</b> with AgClO₄, Hg­(NO₃)₂, and K₂PdCl₄ afforded the typical endocyclic 1:1 complexes [Ag<b>L</b>]­ClO₄ (<b>1</b>) without anion binding, as well as [Hg<b>L</b>(NO₃)₂] (<b>2</b>), and [Pd<b>L</b>Cl₂] (<b>3</b>), with anion binding. Further reaction of the anion-free complex <b>1</b> with different spacer ligands (<b>L′</b>: dabco = 1,4-diazabicyclo[2.2.2]­octane and bpp = 1,4-bis­(4-pyridyl)­piperazine) resulted in the formation of the interesting “dumbbell”-like complexes [Ag₂<b>L</b>₂(dabco)]­(ClO₄)₂ (<b>4</b>) and [Ag₂<b>L</b>₂(bpp)]­(ClO₄)₂ (<b>5</b>), exhibiting a [(<b>L</b>Ag)-<b>L′</b>-(Ag<b>L</b>)] arrangement, respectively. Furthermore, the straightforward one-pot reactions of <b>L</b> with AgClO₄ in the presence of <b>L′</b> also resulted in the isolation of the corresponding “dumbbell” complexes. Comparative NMR studies suggest the existence of corresponding structures of this type in solution. Contrasting with the discrete structures of <b>1</b>–<b>5</b>, reactions of <b>L</b> with CuBr and AgSCN afforded a double-stranded 1D network {[(Cu₂Br₂)<b>L</b>₂]·2CH₂Cl₂}_<i>n</i> (<b>6</b>) linked with a rhomboidal Cu₂Br₂ cluster and an endo-/exocyclic 1D network [Ag₄<b>L</b>₂(SCN)₄]_<i>n</i> (<b>7</b>), respectively. The latter complex features an unusual fishbone-like structure in which endocyclic silver­(I) complexes are attached to a “looped” exocyclic backbone of type {Ag-(1,3-μ₂-SCN)₂-Ag-(1,1,3-μ₃-SCN)-Ag}_<i>n</i> via Ag-SCN bonds

Assembly of Soft Metal Complexes of an O₄S₂‑Macrocycle Displaying Endocyclic Monomer, Dumbbell-Like Dimer, and Endo-/Exocyclic Polymer Structures

A comparative investigation of the coordination behavior of an O₄S₂-donor macrocycle <b>L</b> with the thiaphilic soft metal ions Ag⁺, Cu⁺, Hg²⁺, and Pd²⁺ is reported. The X-ray structures of seven complexes (<b>1</b>–<b>7</b>) have been determined, and a range of structural types and coordination modes, including discrete to continuous forms, mono- to multinuclear, and endo- to exocyclic structures involving M–S bonds, are presented. First, reactions of <b>L</b> with AgClO₄, Hg­(NO₃)₂, and K₂PdCl₄ afforded the typical endocyclic 1:1 complexes [Ag<b>L</b>]­ClO₄ (<b>1</b>) without anion binding, as well as [Hg<b>L</b>(NO₃)₂] (<b>2</b>), and [Pd<b>L</b>Cl₂] (<b>3</b>), with anion binding. Further reaction of the anion-free complex <b>1</b> with different spacer ligands (<b>L′</b>: dabco = 1,4-diazabicyclo[2.2.2]­octane and bpp = 1,4-bis­(4-pyridyl)­piperazine) resulted in the formation of the interesting “dumbbell”-like complexes [Ag₂<b>L</b>₂(dabco)]­(ClO₄)₂ (<b>4</b>) and [Ag₂<b>L</b>₂(bpp)]­(ClO₄)₂ (<b>5</b>), exhibiting a [(<b>L</b>Ag)-<b>L′</b>-(Ag<b>L</b>)] arrangement, respectively. Furthermore, the straightforward one-pot reactions of <b>L</b> with AgClO₄ in the presence of <b>L′</b> also resulted in the isolation of the corresponding “dumbbell” complexes. Comparative NMR studies suggest the existence of corresponding structures of this type in solution. Contrasting with the discrete structures of <b>1</b>–<b>5</b>, reactions of <b>L</b> with CuBr and AgSCN afforded a double-stranded 1D network {[(Cu₂Br₂)<b>L</b>₂]·2CH₂Cl₂}_<i>n</i> (<b>6</b>) linked with a rhomboidal Cu₂Br₂ cluster and an endo-/exocyclic 1D network [Ag₄<b>L</b>₂(SCN)₄]_<i>n</i> (<b>7</b>), respectively. The latter complex features an unusual fishbone-like structure in which endocyclic silver­(I) complexes are attached to a “looped” exocyclic backbone of type {Ag-(1,3-μ₂-SCN)₂-Ag-(1,1,3-μ₃-SCN)-Ag}_<i>n</i> via Ag-SCN bonds

Cooperative Effect of Anion and Mole Ratio on the Coordination Modes of an NO₂S₃‑Donor Macrocycle

Synthesis of an NO₂S₃-macrocycle (<b>L</b>) incorporating a pyridine subunit and its anion and/or mole ratio-dependent coordination modes in the formations of mercury­(II) complexes is reported. When the mercury­(II) salts with different anions (ClO₄^– or Br^–) were reacted with <b>L</b>, the Hg­(ClO₄)₂ afforded a typical endocyclic complex [Hg<b>L</b>]­(ClO₄)₂ (<b>1</b>). Meanwhile, the HgBr₂ gave an exocyclic complex [Hg<b>L</b>Br₂] (<b>2</b>) in which the metal ion exists outside the macrocyclic cavity. The observed anion effect on the coordination modes can be explained by the anion coordination ability toward the metal cation. In the mole ratio variation experiments, notably, the use of 1.5 equiv or above of HgBr₂ in the same reaction condition gave a unique endo/exocyclic dumbbell-type complex <b>3</b>, [Hg₄<b>L</b>₂Br₆]­[Hg₂Br₆]. However, the formation of the endocyclic Hg­(ClO₄)₂ complex <b>1</b> shows no mole ratio dependency. To monitor the observed mole ratio-dependent exocoordination products as well as their reactivities and reversibility, systematic powder X-ray diffraction (PXRD) analysis was also applied. From single crystal X-ray and PXRD analyses, it was found that endocyclic complex <b>1</b> is not reactive, but complexes <b>2</b> and <b>3</b> are reactive and show the reversibility between them in the presence of the corresponding reactants

Assembly of Silver(I) Complexes of Isomeric NS₂-Macrocycles Displaying Cyclic Oligomer, Helix, and Zigzag Structures

An isomeric series of NS₂-macrocycles, incorporating <i>ortho</i>- (<i><b>o</b></i><b>-L</b>), <i>meta</i>- (<i><b>m</b></i><b>-L</b>), and <i>para</i>-xylyl (<i><b>p</b></i><b>-L</b>) groups in their backbones between the sulfur donors, have been synthesized. A comparative investigation of the coordination behavior of these macrocyclic ligands with silver­(I) salts is reported. The X-ray structures of six complexes (<b>1</b>–<b>6</b>) were determined, and a variety of structural types that range from cyclic oligomers to zigzag or helical chains is shown to occur. Reactions of <i><b>o</b></i><b>-L</b> with silver nitrate and perchlorate afforded three complexes with different topologies: the cyclic hexamer [Ag₆(<i><b>o</b></i><b>-L</b>)₆]­(NO₃)₆·0.5DMF·7H₂O (<b>1</b>), the cyclic hexamer with two terminal complex units [Ag₈(<i><b>o</b></i><b>-L</b>)₈]­(ClO₄)₈ (<b>2</b>), and a one-dimensional (1D) zigzag coordination polymer of type {[Ag₂(<i><b>o</b></i>-<b>L</b>)₂]­(ClO₄)₂·2CH₃CN·CHCl₃}_<i>n</i> (<b>3</b>). Reaction of <i><b>m</b></i>-<b>L</b> with silver­(I) perchlorate gave the 1D zigzag coordination polymer, {[Ag­(<i><b>m</b></i><b>-L</b>)]­ClO₄·CH₂Cl₂}_<i>n</i> (<b>4</b>). Reaction of <i><b>p</b></i><b>-L</b> with silver perchlorate yielded a crystalline product whose X-ray analysis confirmed it to be a mixture of two different species: the discrete helical complex {[Ag₃(<i><b>p</b></i><b>-L</b>)₃]­(ClO₄)₃}_<i>n</i> (<b>5</b>) and the cyclic tetramer [Ag₄(<i><b>p</b></i><b>-L</b>)₄(ClO₄)₄]·3DMF (<b>6</b>). The influence of macrocyclic ring flexibility and sulfur donor atom spacing on the topologies adopted by the respective complexes is discussed

Cooperative Effect of Anion and Mole Ratio on the Coordination Modes of an NO₂S₃‑Donor Macrocycle

Synthesis of an NO₂S₃-macrocycle (<b>L</b>) incorporating a pyridine subunit and its anion and/or mole ratio-dependent coordination modes in the formations of mercury­(II) complexes is reported. When the mercury­(II) salts with different anions (ClO₄^– or Br^–) were reacted with <b>L</b>, the Hg­(ClO₄)₂ afforded a typical endocyclic complex [Hg<b>L</b>]­(ClO₄)₂ (<b>1</b>). Meanwhile, the HgBr₂ gave an exocyclic complex [Hg<b>L</b>Br₂] (<b>2</b>) in which the metal ion exists outside the macrocyclic cavity. The observed anion effect on the coordination modes can be explained by the anion coordination ability toward the metal cation. In the mole ratio variation experiments, notably, the use of 1.5 equiv or above of HgBr₂ in the same reaction condition gave a unique endo/exocyclic dumbbell-type complex <b>3</b>, [Hg₄<b>L</b>₂Br₆]­[Hg₂Br₆]. However, the formation of the endocyclic Hg­(ClO₄)₂ complex <b>1</b> shows no mole ratio dependency. To monitor the observed mole ratio-dependent exocoordination products as well as their reactivities and reversibility, systematic powder X-ray diffraction (PXRD) analysis was also applied. From single crystal X-ray and PXRD analyses, it was found that endocyclic complex <b>1</b> is not reactive, but complexes <b>2</b> and <b>3</b> are reactive and show the reversibility between them in the presence of the corresponding reactants

Cooperative Effect of Anion and Mole Ratio on the Coordination Modes of an NO₂S₃‑Donor Macrocycle

Synthesis of an NO₂S₃-macrocycle (<b>L</b>) incorporating a pyridine subunit and its anion and/or mole ratio-dependent coordination modes in the formations of mercury­(II) complexes is reported. When the mercury­(II) salts with different anions (ClO₄^– or Br^–) were reacted with <b>L</b>, the Hg­(ClO₄)₂ afforded a typical endocyclic complex [Hg<b>L</b>]­(ClO₄)₂ (<b>1</b>). Meanwhile, the HgBr₂ gave an exocyclic complex [Hg<b>L</b>Br₂] (<b>2</b>) in which the metal ion exists outside the macrocyclic cavity. The observed anion effect on the coordination modes can be explained by the anion coordination ability toward the metal cation. In the mole ratio variation experiments, notably, the use of 1.5 equiv or above of HgBr₂ in the same reaction condition gave a unique endo/exocyclic dumbbell-type complex <b>3</b>, [Hg₄<b>L</b>₂Br₆]­[Hg₂Br₆]. However, the formation of the endocyclic Hg­(ClO₄)₂ complex <b>1</b> shows no mole ratio dependency. To monitor the observed mole ratio-dependent exocoordination products as well as their reactivities and reversibility, systematic powder X-ray diffraction (PXRD) analysis was also applied. From single crystal X-ray and PXRD analyses, it was found that endocyclic complex <b>1</b> is not reactive, but complexes <b>2</b> and <b>3</b> are reactive and show the reversibility between them in the presence of the corresponding reactants

Assembly of Silver(I) Complexes of Isomeric NS₂-Macrocycles Displaying Cyclic Oligomer, Helix, and Zigzag Structures

An isomeric series of NS₂-macrocycles, incorporating <i>ortho</i>- (<i><b>o</b></i><b>-L</b>), <i>meta</i>- (<i><b>m</b></i><b>-L</b>), and <i>para</i>-xylyl (<i><b>p</b></i><b>-L</b>) groups in their backbones between the sulfur donors, have been synthesized. A comparative investigation of the coordination behavior of these macrocyclic ligands with silver­(I) salts is reported. The X-ray structures of six complexes (<b>1</b>–<b>6</b>) were determined, and a variety of structural types that range from cyclic oligomers to zigzag or helical chains is shown to occur. Reactions of <i><b>o</b></i><b>-L</b> with silver nitrate and perchlorate afforded three complexes with different topologies: the cyclic hexamer [Ag₆(<i><b>o</b></i><b>-L</b>)₆]­(NO₃)₆·0.5DMF·7H₂O (<b>1</b>), the cyclic hexamer with two terminal complex units [Ag₈(<i><b>o</b></i><b>-L</b>)₈]­(ClO₄)₈ (<b>2</b>), and a one-dimensional (1D) zigzag coordination polymer of type {[Ag₂(<i><b>o</b></i>-<b>L</b>)₂]­(ClO₄)₂·2CH₃CN·CHCl₃}_<i>n</i> (<b>3</b>). Reaction of <i><b>m</b></i>-<b>L</b> with silver­(I) perchlorate gave the 1D zigzag coordination polymer, {[Ag­(<i><b>m</b></i><b>-L</b>)]­ClO₄·CH₂Cl₂}_<i>n</i> (<b>4</b>). Reaction of <i><b>p</b></i><b>-L</b> with silver perchlorate yielded a crystalline product whose X-ray analysis confirmed it to be a mixture of two different species: the discrete helical complex {[Ag₃(<i><b>p</b></i><b>-L</b>)₃]­(ClO₄)₃}_<i>n</i> (<b>5</b>) and the cyclic tetramer [Ag₄(<i><b>p</b></i><b>-L</b>)₄(ClO₄)₄]·3DMF (<b>6</b>). The influence of macrocyclic ring flexibility and sulfur donor atom spacing on the topologies adopted by the respective complexes is discussed

Fragments

Stepwise synthesis and structural characterization of one-dimensional coordination polymers whose topologies depend on the anions are reported. A simple ladder-type precursor, {[Ag₂(<b>L</b>)₂]­(ClO₄)₂}_<i>n</i> (<b>1</b>), was prepared by the reaction of bis­(4-pyridylmethyl)­sulfide (<b>L</b>) with AgClO₄. Treatment of <b>1</b> with potassium thiocyanate and potassium cyanide afforded a twisted ribbon-type chain of type [Ag­(<b>L</b>)­SCN]_<i>n</i> (<b>2</b>) and a triple-rail ladder of type [Ag₃(<b>L</b>)₂(CN)₃]_<i>n</i> (<b>3</b>), respectively. The result demonstrates that replacement of the noncoordinated perchlorate anions by pseudohalide ions in the coordination sphere of <b>1</b> plays a crucial role in determining the structures of the resulting species

Tubular Arrangement of 1,3-Alternate Calix[4]arene with Bipyridines: A Platform for [2 + 2] Photocyclization

By using a 1,3-alternate conformation of calix[4]­arene tetrabenzoic acid (H₄CTB), a pair of 4,4′-bipyridine has been aligned forming a cocrystallized one-dimensional tubular product <b>1</b>. Inspired by this result, the 1,3-alternate H₄CTB has been utilized as “clips” to anchor the CC bond pairs of 4,4′-bipyridylethene to give an isotypical H-bonded tubular product <b>2</b> which undergoes the solid-state photodimerization

Tubular Arrangement of 1,3-Alternate Calix[4]arene with Bipyridines: A Platform for [2 + 2] Photocyclization

By using a 1,3-alternate conformation of calix[4]­arene tetrabenzoic acid (H₄CTB), a pair of 4,4′-bipyridine has been aligned forming a cocrystallized one-dimensional tubular product <b>1</b>. Inspired by this result, the 1,3-alternate H₄CTB has been utilized as “clips” to anchor the CC bond pairs of 4,4′-bipyridylethene to give an isotypical H-bonded tubular product <b>2</b> which undergoes the solid-state photodimerization