Silver-Rich Hybrid Framework Iodide Based on [Ag8I6]2+ Clusters Displays Low-Temperature Dual Emission and Luminescence Thermochromism.

Cluster-based framework metal iodides have diverse structures and excellent luminescence properties, and show promising applications in sensing and solid-state lighting. However, the design and synthesis of these materials remain great challenges because excess I- ions introduced into the synthesis systems decrease the condensation degree of M-I units. In this work, a new strategy is developed to control the condensation behavior of Ag-I units, and a new silver-rich cluster-based framework iodide [DabcoAg8I6(SPh)2]n (1) (Dabco = 1,4-diazabicyclo [2.2.2] octane) has been synthesized under solvothermal conditions in the presence of silver thiophenolate (AgSPh)n. Compound 1 features a three-dimensional (3-D) cluster-based framework with a pillared layer structure composed of cationic [Ag8I6]2+ clusters bridged by SPh- and Dabco, and displays low-temperature dual emission and luminescence thermochromism.

Cotemplating Assembly and Structural Variation of Three-Dimensional Open-Framework Sulfides.

Open-framework sulfides (H3O)KCu6Ge2S8 (1) and (H3O)RbCu6Ge2S8 (2) were prepared by a cotemplating strategy. This shows that alkali-metal and protonated water cations act as cotemplates to direct the three-dimensional open-framework sulfides. These templates direct two types of one-dimensional channels that arrange parallelly, and different types of templates reside in different types of channels. By introduction of the Cs cation into the synthetic systems of 1 and 2, (H3O)K0.6Cs0.4Cu6Ge2S8 (3) and (H3O)Rb0.75Cs0.25Cu6Ge2S8 (4) were obtained. Compound 3 has a different anionic framework from those of 1 and 2, while 4 is isostructural with 1 and 2.

Solvothermal Syntheses and Characterizations of Four Quaternary Copper Sulfides BaCu3MS4 (M = In, Ga) and BaCu2MS4 (M = Sn, Ge).

Hydro(solvo)thermal syntheses of quaternary copper sulfides containing alkaline earth metal ions remain a great challenge because of the low solubility of Cu-S compounds. Herein, a new facile solvothermal method was developed, and four quaternary copper sulfides, i.e., BaCu3InS4 (1), BaCu3GaS4 (2), BaCu2SnS4 (3), and BaCu2GeS4 (4), were prepared using excess sulfur as a mineralizer. Compound 1 possesses a novel three-dimensional (3D) anionic [Cu3InS4]2- framework constructed by an 8-membered ring of [Cu4S4] and [Cu2In2S4] alternatively. Compound 2 features a unique 3D anionic [Cu3GaS4]2- framework composed of [Cu3GaS10]n14n- anionic chains and 8-membered rings, in which [Cu4S4] and [Cu2Ga2S4] reside alternatively. Compounds 3 and 4 feature 3D anionic [Cu2MS4]2- (M = Sn, Ge) frameworks composed of CuS4 and MS4 tetrahedra with Ba2+ located in the channels. It is worth noting that different 3D Cu-S frameworks exist in the title crystal structures, in which main group ions are incorporated. This paper provides a new synthetic strategy for new quaternary sulfides.

Unusual Flexibility of Microporous Sulfides during Ion Exchange.

Open-framework chalcogenides with ion-exchange capacity are promising materials for removing hazardous heavy-metal ions and for capturing radioactive Cs+. However, research on the exchange mechanism is limited, especially for the framework chalcogenides that have multiple bridging anions. Generally, open-framework chalcogenides that have multiple bridging anions at the window or wall of the channels are rigid during the ion-exchange process. We show here that microporous sulfides with µ3-S2- (where µ3 = triple bridging mode) at the windows exhibit framework flexibility upon ion exchange. Three new microporous sulfides Na4Cu8Ge3S12·2H2O (1), Na3(Hen)Cu8Sn3S12 (where en = ethylenediamine) (2) and (dap)2(Hdap)4Cu8Ge3S18 (where dap = 1,2-diaminopropane) (3) were synthesized under solvothermal conditions. Compounds 1 and 2 contain a copper-rich framework composed of icosahedral [Cu8S12]16- units linked via monomeric GeS44- or SnS44- tetrahedral units, whereas compound 3 features an expanded framework composed of icosahedral [Cu8S12]16- units interconnected with dimeric Ge2S64- units. These compounds exhibit unusual ion-exchange properties. Specifically, the frameworks of 1 and 2 (with µ3-S at the small windows) show "breathing action" upon ion exchange of K+ or Rb+, which have relative large sizes, and compound 3 exhibits framework flexibility upon Cs+ ion exchange with both space group and channels changed.

Coordination-Induced Syntheses of Two Hybrid Framework Iodides: A Thermochromic Luminescent Thermometer.

Two new 3D hybrid framework iodides, Hmta[(Hmta)Ag4I4] (1; Hmta = hexamethylenetetramine) and [(Hmta)2Ag8I6]I2 (2), have been synthesized under solvothermal conditions. Compound 1 consists of a neutral 3D framework built up from alternation of the tetrahedral Ag4I4 unit and Hmta with dia-b topology. Compound 2 features a 3D cationic framework with flu topology, constructed by cationic [Ag8I6](2+) units linked with Hmta. Tetrahedral Hmta plays crucial structure-directing roles in the formation of these 3D frameworks with high symmetry. The temperature-dependent photoluminescent measurement reveals luminescent thermochromism of the compounds, the emission maximum of which shows a gradual blue shift with increasing temperature. The results indicate that 1 is a promising wavelength- and intensity-dependent luminescent thermometer applicable in two different temperature ranges.

Syntheses and Characterization of Chiral Zeolitic Silver Halides Based on 3-Rings.

The synthesis of chiral zeolites remains a significant challenge because the primary tetrahedral building units are achiral and weak interactions exist between the guest and host frameworks. Here, we present the syntheses and characterization of three new chiral zeolitic halides, [H3(Dabco)2]Ag3X6 (X = Br (1) or I (2), Dabco = 1,4-diazabicyclo[2.2.2]octane) and [H2(Dabco)][(Dabco)Ag4I6] (3). Compounds 1 and 2 are isostructural, containing a 4-connected zeolitic framework built up from 3-ring units, with high-charge [H3(Dabco)2]3+ located in chiral cages. Compound 3 contains a similar zeolitic [Ag3I6]3- framework to that of 2, but a [Ag(Dabco)]+ unit is incorporated in each 3-ring, with [H2(Dabco)]2+ located in channels. These frameworks are chiral, representing the first examples of chiral zeolitic halides. The chirality transference of the frameworks for 1 and 2 was attributed to the template effect of the chiral [H3(Dabco)2]3+ through strong electrostatic interactions and multiple hydrogen-bond interactions. For compound 3, direct coordination interactions play important roles in the chirality transference from the chiral Dabco ligand to the framework.

Mild solvothermal syntheses and characterization of layered copper thioantimonates(III) and thioarsenate(III).

The new copper thioantimonates(III) and thioarsenate(III) Rb2Cu2Sb2S5 (1), Cs2Cu2Sb2S5 (2), and Rb8Cu6As8S19 (3) have been synthesized solvothermally. Compound 1 contains a [Cu2SbS3] net to which [Sb2S4] chains adhere through Cu-S bonds and Sb-Cu interactions to give a layered structure. In compound 2, the layer is formed by edge-sharing tetrahedral CuS4 chains linked by dimeric [Sb2S5] units. The layered structure in compound 3 is constructed by helical chains built from [Cu3S7] moieties and dimeric [As2S5] units which are further connected by tetrameric [As4S9] groups. Their optical and thermal properties have been investigated.

Mild solvothermal syntheses of thioargentates A-Ag-S (A = K, Rb, Cs) and A-Ag-Ge-S (A = Na, Rb): crucial role of excess sulfur.

A series sulfides of A-Ag-S (1-3; A = K, Rb, Cs), Na5AgGe2S7 (4), and Rb2Ag2GeS4 (5) have been prepared solvothermally in the presence of excess sulfur. Among these compounds, 4 is a new compound that has a novel layered structure; the others were obtained under mild conditions. The results showed that excess sulfur could increase the solubility of silver sulfide and lower the synthetic temperature effectively. The mineralizer effect of excess sulfur is discussed in detail.

Syntheses and characterization of a series of silver-thioantimonates(III) and thioarsenates(III) containing two types of silver-sulfur chains.

Three framework silver-thioantimonates, K(3)Ag(9)Sb(4)S(12)(1), Rb(3)Ag(9)Sb(4)S(12)(2), and Cs(3)Ag(9)Sb(4)S(12)(3), and one layered silver-thioarsenate, CsAg(2)AsS(3)(4), have been synthesized solvothermally in the presence of thiophenol as a mineralizer. Compounds 1, 2, and 3 are isostructural and contain infinite silver-sulfur chains [Ag(9)S(12)](15-). These chains are connected to one another by the antimony atoms to generate wide channels along the [001] direction where the alkali metal cations reside. The structure of 4 consists of helical chains [Ag(2)S(3)](4-) linked by the arsenic atoms to form layers with potassium ions between the layers.

Copper-rich framework sulfides: A(4)Cu(8)Ge(3)S(12) (A = K, Rb) with cubic perovskite structure.

Two copper-rich open-framework sulfides, K(4)Cu(8)Ge(3)S(12) (1) and Rb(4)Cu(8)Ge(3)S(12) (2), have been synthesized under solvothermal conditions. Compounds 1 and 2 are isostructural and contain icosahedral [Cu(8)S(12)](16-) clusters as basic building blocks. These clusters are primitive cubic packed and connect to one another by discrete Ge(4+) ions to generate 3D copper-rich Cu-Ge-S framework and form 3D channels along 100 directions where the alkali metal cations reside. These two open-framework sulfides crystallize in cubic perovskite structure.

(H(2)en)(2)Cu(8)Sn(3)S(12): a trigonal CuS(3)-based open-framework sulfide with interesting ion-exchange properties.

(H(2)en)(2)Cu(8)Sn(3)S(12) contains a trigonal CuS(3)-based framework into which Sn(4+) ions are incorporated, and exhibits multiple channel systems and interesting ion-exchange properties.

New framework iodoargentates: M(en)3Ag2I4 (M=Zn, Ni) with tridymite topology.

Two novel framework compounds, Zn(en) 3Ag2I4 (1) and Ni(en) 3Ag2I4 (2), have been synthesized by a self-assembly reaction. Both of them contain an unexpected framework, Ag2I4(2-) with tridymite topology, and the discrete M(en)3(2+) cations are located in the channels. Their thermal properties and circular dichroism spectra were investigated.