Luminescence Tribochromism and Bright Emission in Gold(I) Thiouracilate Complexes

New dinuclear Au(I) complexes containing bridging thiouracilate and bis(diphenylphosphino)methane ligands have been synthesized and characterized structurally and spectroscopically. The compounds exhibit a unique behavior of solid-state luminescence tribochromism in which photoemission turns on upon gentle grinding of the sample and a sensitivity to pH in fluid solution. The emissive form in the solid state exhibits a bright blue or cyan emission upon irradiating at 375 nm. Structural studies show that the nonemissive form of the complexes has an extended helical ···Au···Au···Au··· structure in the solid with weak aurophilic interactions, whereas the blue emissive form has a strong intermolecular aurophilic interaction in the solid that leads to an arrangement of dimers of dinuclear (Au2) complexes. Interconversion between the two forms can be carried out by either recrystallization for solid-state samples or by exposure to vapors of volatile acid or base for fluid solutions of the complexes

Luminescence Tribochromism and Bright Emission in Gold(I) Thiouracilate Complexes

New dinuclear Au(I) complexes containing bridging thiouracilate and bis(diphenylphosphino)methane ligands have been synthesized and characterized structurally and spectroscopically. The compounds exhibit a unique behavior of solid-state luminescence tribochromism in which photoemission turns on upon gentle grinding of the sample and a sensitivity to pH in fluid solution. The emissive form in the solid state exhibits a bright blue or cyan emission upon irradiating at 375 nm. Structural studies show that the nonemissive form of the complexes has an extended helical ···Au···Au···Au··· structure in the solid with weak aurophilic interactions, whereas the blue emissive form has a strong intermolecular aurophilic interaction in the solid that leads to an arrangement of dimers of dinuclear (Au2) complexes. Interconversion between the two forms can be carried out by either recrystallization for solid-state samples or by exposure to vapors of volatile acid or base for fluid solutions of the complexes

Linkage Isomerism Dependent on Solvent and Temperature. Synthesis and Structural Properties of Diamineplatinum(II) Complexes of Allyl- and Diallylmalonate Ligands

The linkage isomerism between (O,O‘)- and (O,alkene)-chelates has been investigated for the complexes A2PtL2 (A2 = 2,2-dimethyl-1,3-propanediamine (DMPDA), trans-(±)-1,2-diaminocyclohexane (DACH); L2 = allylmalonate (AM), diallylmalonate (DAM)). The crystal structures of (DMPDA)Pt(AM)·2H2O (tetragonal P42/m, a = 13.614(3) Å, b = 13.614(3) Å, c = 8.451(4) Å, V = 1566.3(9) Å3, Z = 4, R = 0.0472) and (DMPDA)Pt(DAM)·2H2O (monoclinic P21/n, a = 11.021(3) Å, b = 8.996(2) Å, c = 18.765(7) Å, β = 106.92(3) °, V = 1780.0(9) Å3, Z = 4, R = 0.0531) have been solved. Each platinum atom adopts a typical square planar arrangement with two nitrogen atoms in cis positions. However, surprisingly, the AM anionic ligand is coordinated to the platinum atom via (O,O‘)-chelation mode through its two carboxylate groups with the alkene group uncoordinated in the solid state, breaking the hard/soft rule. The tetradentate DAM ligand is chelated to the platinum atom through one carboxylate and one alkene group resulting in (O,alkene)-chelation mode with another uncoordinated carboxylate and alkene group. Multinuclear (1H, 13C, and 195Pt) NMR studies clearly disclose that the linkage isomerism depends on the solvents employed. Both allyl- and diallylmalonate ligands are chelated exclusively to the platinum(II) atom via (O,O‘)-mode in dimethylformamide or Me2SO solution whereas only (O,alkene)-chelation mode is observed in an aqueous solution. At room temperature, the complexes both of the AM and DAM ligands exist in methanol as a mixture of (O,O‘)- and (O,alkene)-modes. Furthermore, interconversion between the two isomers occurs reversibly depending on temperature:  the (O,alkene)-chelate is predominant at low temperatures while the (O,O‘)-chelate is favorable at elevated temperatures

Self-Assembly between Silver(I) and Di- and Tri-2-pyridines with Flexible Spacer: Formation of Discrete Metallocycle versus Coordination Polymer

The self-assembly of metallosupramolecules from reactions of flexible 2-pyridyl ligands and silver salts is described. When 1,3-bis(2-pyridyl)propane (L1), tris[(2-pyridyl)methyl]methane (L2), and 1,3-bis(2-pyridyl)-2-tolylpropane (L3) are used in combination with silver ions, novel discrete metallocyclic complexes are formed in crystals. Moreover, the self-assembly of 1,3-bis(2-pyridyl)-2-phenylpropane (L4) with silver nitrate yields a coordination polymer. The examination of its solution shows that this coordination polymer is formed via the solution-based discrete metallocyclic species

Self-Assembly between Silver(I) and Di- and Tri-2-pyridines with Flexible Spacer: Formation of Discrete Metallocycle versus Coordination Polymer

The self-assembly of metallosupramolecules from reactions of flexible 2-pyridyl ligands and silver salts is described. When 1,3-bis(2-pyridyl)propane (L1), tris[(2-pyridyl)methyl]methane (L2), and 1,3-bis(2-pyridyl)-2-tolylpropane (L3) are used in combination with silver ions, novel discrete metallocyclic complexes are formed in crystals. Moreover, the self-assembly of 1,3-bis(2-pyridyl)-2-phenylpropane (L4) with silver nitrate yields a coordination polymer. The examination of its solution shows that this coordination polymer is formed via the solution-based discrete metallocyclic species

Social media usage and body image: Examining the mediating roles of internalization of appearance ideals and social comparisons in young women

There is increasing scholarly interest in the effects of social media use on women's body image. Here, we tested the utility of the Tripartite Influence Model – developed for traditional media influences on body image – in explaining the link between intensity of social media use and body image outcomes in young adult women from the United States (N = 579). The study tested a serial indirect mediation effect linking intensity of social media use and body esteem outcomes via internalization and social comparison, as well as a direct effect between intensity of social media use and body esteem measures. The results broadly supported for the applicability of the model. Internalization of appearance ideals and social comparison, respectively, were significant mediators of the relationship between intensity of social media use and body image outcomes. However, the direct link between intensity of social media use and body image was more equivocal. The overall findings suggest possible pathways through which intensity of social media use may influence body image outcomes in young adult women

Coordinating ability of anions: 3-D silver(I) coordination polymers of <i>C</i>₃-symmetric <i>N,N′,N″</i>-tris(2-pyridinylethyl)-1,3,5-benzenetricarboxamide

<div><p>Reaction of AgX (X⁻<i> </i> = <i> </i>NO₂⁻ and CF₃SO₃⁻) with <i>C</i>₃-symmetric <i>N,N′,N″</i>-tris(2-pyridinylethyl)-1,3,5-benzenetricarboxamide (L) produces, respectively, an unusual nitrite-bridged 3-D coordination polymer, [Ag₂(NO₂)₂L]·H₂O, with trinodal 3,3,4-connected <b>tfa</b> net topology and a unique 3-D coordination polymer, [Ag₃L₂](CF₃SO₃)₃·CH₂Cl₂·4H₂O, with sixfold interpenetrating uninodal 3-connected <b>ths</b> net topology. Nitrite anions are two kinds of chelating and bridging ligands, whereas trifluoromethanesulfonate anions are simple counteranions. Structure-related thermal behavior, anion exchangeability, and photoluminescence have been investigated.</p></div

“Cyclic Tetramer” vs “Dimer of Cyclic Dimer”: Subtle Anion Effects on the Cyclization of AgBF₄ vs AgClO₄ with Bis(3-pyridyl)dimethylsilane

Subtle anion effects have been observed for the cyclization of AgX (X- = BF4- vs ClO4-) with bis(3-pyridyl)dimethylsilane. For the two similar anions, BF4- affords a “cyclic tetramer” with two independent spaces, while ClO4- affords a “dimer of cyclic dimer” via an unusual intercyclic argentophilic interaction. For BF4-, the specific X-···H−C interactions seem to play an important role in the formation of the cyclic tetramer

A 20-Å-Thick Interwoven Sheet Consisting of Nanotubes

Slow diffusion of AgNO3 with Me2Si(4-Py)2 yields an interwoven 2-nm-thick sheet consisting of the building block [Ag3(Me2Si(4-Py)2)4](NO3)3·H2O. The interweaving induces unique nanotunnels with a 16 × 18 Å2 cross section with a 7 × 8 Å2 square pore. The anion NO3- of the skeletal sheet can be reversibly exchanged with appropriately sized anions without the collapse of its structural integrity. The compound has a melting point (140 °C) and exists as the first 2D ionic liquid up to 193 °C

“Cyclic Tetramer” vs “Dimer of Cyclic Dimer”: Subtle Anion Effects on the Cyclization of AgBF₄ vs AgClO₄ with Bis(3-pyridyl)dimethylsilane

Subtle anion effects have been observed for the cyclization of AgX (X- = BF4- vs ClO4-) with bis(3-pyridyl)dimethylsilane. For the two similar anions, BF4- affords a “cyclic tetramer” with two independent spaces, while ClO4- affords a “dimer of cyclic dimer” via an unusual intercyclic argentophilic interaction. For BF4-, the specific X-···H−C interactions seem to play an important role in the formation of the cyclic tetramer