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Solvothermal reactions of copper(I) cyanide with tetramethylammonium salts in anhydrous tetrahydrofuran (THF) lead to two novel halogeno(cyano)cuprates namely [Me4N][Cu3(CN)2Br2] with a 1 - D ribbon motif and [Me4N]2[Cu4(CN)5CI] and with a 3-D nanoporous framework. The optical and luminescent studies indicate that both the complexes are potential materials for semiconductors and long-lived highly luminescent material.c

Three new 'lower molar ratio' double salts of silver acetylide with silver nitrate were synthesized and their crystal structures determined. These are Ag2C2*5.5AgNO3*0.5H2O, Ag2C2*5AgNO3 and Ag2C2*AgNO3, wherein the acetylide dianion is located inside a silver cage shaped like a monocapped pctahedron, a monocapped trigonal prism and an octahedron, respectively. This series of related complexes adopted different structural alternatives, which indicate that a higher molar composition of silver acetylide in a double salt prefers the formation of a network of edge- and vertex-sharing silver polyhedra that closely resemble the structure of neat silver acetylide.

A novel method for the synthesis of a new [Me4N]3[MoS4Cu3(S5)2] mixed-metal polysulfide complex was developed based on the reaction of (NH4)2MoS4 with CuCl, K2S4, Me4NBr and EtOH. Analysis of the chemical structure of the novel discrete tetranuclear heterometal polysulfide cluster in the complex indicated the presence of a tetranuclear trianion with a C2 symmetry. The complex also exhibited boat-chair eight-membered metallacyclic S5Cu2S rings that interact through weak S-S bonds to form infinite chemical chains.

Transition metal complex [[Mn[(2,2'-bipy).sub.2]].sup.2+] is incorporated into thioarsenate, resulting in the formation of two novel compounds, [[Mn.sub.3][(2,2'-bipy).sub.3][([As.sup.V][S.sub.4]).sub.n].n[H.sub.2]O] and [[Mn.sub.2][(2,2'-bipy)[As.sub.2.sup.III][S.sub.5]. The main-group chalcogenide framework is incorporated in these compounds with a [[tm[(2,2'-bipy).sub.m].sup.n+] complex.

The structural characterization and synthesis of two series of novel rare earth complexes with dicyanamide [Ln(dca)2(phen)2(H2O)3][dca].(phen), (Ln = Gd, Sm, and La) is presented. X-ray crystallography is used for this purpose.

Noncentrosymmetric phosphides have garnered significant attention as promising systems of infrared (IR) nonlinear optical (NLO) materials. Herein, a new quaternary diamond-like phosphide family I-III-IV 2 -V 4 and its inaugural member, namely, CuInSi 2 P 4 (CISP), were successfully fabricated by isovalent and aliovalent substitution based on ZnGeP 2 . First-principles calculations revealed that CISP has a large NLO coefficient ( d 14 = 110.8 pm/V), which can be attributed to the well-aligned tetrahedral [CuP 4 ], [InP 4 ], and [SiP 4 ] units. Remarkably, the extremely small thermal expansion anisotropy (0.09) of CISP enables it to exhibit a considerable laser-induced damage threshold (LIDT, 5.0 × AgGaS 2 @1.06 μm) despite the relatively narrow band gap (0.81 eV). This work improves the chemical diversity of inorganic phosphide and promotes the development of phosphide systems, which may provide valuable perspectives for future exploration of IR NLO materials.

Luminescent metal halides have been exploited as a new class of X-ray scintillators for security checks, nondestructive inspection, and medical imaging. However, the charge traps and hydrolysis vulnerability are always detrimental to the three-dimensional ionic structural scintillators. Here, the two zero-dimensional organic-manganese(II) halide coordination complexes 1-Cl and 2-Br were synthesized for improvements in X-ray scintillation. The introduction of a polarized phosphine oxide can help to increase the stabilities, especially the self-absorption-free merits of these Mn-based hybrids. The X-ray dosage rate detection limits reached up to 3.90 and 0.81 μGy air /s for 1-Cl and 2-Br , respectively, superior to the medical diagnostic standard of 5.50 μGy air /s. The fabricated scintillation films were applied to radioactive imaging with high spatial resolutions of 8.0 and 10.0 lp/mm, respectively, holding promise for use in diagnostic X-ray medical imaging.

Two examples of efficient cathode-ray scintillation coordination polymers with good stability at high voltage were prepared by conjugating luminescent groups with d 10 metal ions. The synergistic effect of inorganic metal and organic ligand suppresses the self-quenching of the conjugated luminescent groups and enhances the scintillation performance. This work provides new ideas for the design of new field-emission displays and cathode-ray scintillation materials.

Exploring new infrared nonlinear optical (IR NLO) materials with superior overall properties is scientifically and technically important. However, large second-order harmonic generation (SHG) efficiencies and high laser-induced damage thresholds (LIDT) are incompatible, which makes realizing this goal a challenge. The IR NLO performance of an A-N IIB -M IIIA -Q (Q: chalcogen) system was optimized by simultaneously modulating A/(M + N) and M/N ratios (A: alkali metal; N, M: tetra-coordinated metals), and SHG-LIDT balance was achieved. Three new sulfides, KCd 3 Ga 5 S 11 ( 1 ), RbCd 4 Ga 3 S 9 ( 2 ), and Cs 2 Cd 2 Ga 8 S 15 ( 3 ), containing the same CdS 4 and GaS 4 but with different A/(Ga + Cd) and Ga/Cd ratios were obtained. Among these compounds, compound 3 exhibits both the largest SHG efficiency (0.5 × AgGaS 2 ) and LIDT (35 × AgGaS 2 ), which can be ascribed to the Ga/Cd modulation for enhancing the NLO functional motif distortions and SHG efficiency as well as the A/(Ga + Cd) modulation for enlarging the band gap and LIDT. Remarkably, compound 3 is the first phase-matchable IR NLO material in the A-N IIB -M IIIA -Q family. This article proposes a novel avenue to explore infrared nonlinear materials with superior comprehensive properties by modulating the A/(M + N) and M/N ratios.

A high contrast of ∼67 times, exceeding those of all known photoswitching bulk quadratic nonlinear-optical materials, has been realized in a photochromic semiconductor, by the strategy of increasing electron-transfer efficiency and self-absorption.

Exploration of a new nonlinear optical (NLO)-active functional motif is important in the rational design of promising infrared (IR) NLO materials. Compared with typical tetrahedral MQ 4 (M = IIB, III, IV metals; Q = S, Se) motifs, MQ 3 (M = As, Sb) pyramids favor high second-harmonic generation (SHG) efficiency while frequently hindering phase matching (PM) because of excessively large optical anisotropy. The surfactant-thermal method was first adopted to achieve PM in MQ 3 -containing systems and synthesize mixed covalent-ionic IR NLO materials. Two new thioarsenates of AMnAs 3 S 6 (A = Cs, Rb) exhibiting strong PM SHG efficiencies comparable to commercial AGS and laser-induced damage thresholds of one order higher than AGS were obtained. The [As 3 S 6 ] 3- unit in their structures is an unprecedented NLO-active functional motif, which can be useful in designing new IR NLO compounds with large SHG efficiency. In addition, the surfactant-thermal method provides a new general strategy for synthesizing new IR NLO materials.

Noncentrosymmetry (NCS) is a prerequisite for second-order nonlinear optical (NLO) materials. In this work, a new polycation-substitution-induced centrosymmetry (CS)-to-NCS transformation strategy was applied in CS RbGaS 2 , affording two novel NCS salt-inclusion chalcogenides: [ABa 2 Cl][Ga 4 S 8 ] (A = Rb, 1 ; Cs, 2 ). Remarkably, they exhibit the key merits of both Vis and IR NLO candidates, including strong phase-matchable second harmonic generation intensities (10.4-15.3 × KH 2 PO 4 at 1064 nm; 0.9-1.0 × AgGaS 2 at 1910 nm), high laser-induced damage thresholds (11-12 × AgGaS 2 ), and a wide transparent window. Their prominent NLO performances originate from the orderly packing of T2-supertetrahedral Ga 4 S 10 motifs resulting from the template effect of acentric polycation [ClA 2 Ba 3 ] 7+ . The CS-to-NCS transformation first realized by polycation-substitution-induced NLO-functional motif ordering provides an effective approach for designing new NLO materials.

A solvothermal reaction of Co(CH 3 COO) 2 ·4H 2 O and 5-mercapto-1-methyl-tetrazole (Hmmtz) in methanol (MeOH) yielded a one-dimensional solvent-free energetic coordination polymer, namely, [Co(mmtz) 2 ] n 1 , which was structurally characterized. The enthalpy of formation (Δ f H °) of 1 (907 kJ mol -1 ) is much larger than that of commercial 2,4,6-trinitrotoluene (-59 kJ mol -1 ). The impact sensitivity and the friction sensitivity are greater than 40 J and 360 N, respectively, indicating that compound 1 exhibits a potential application as a safe explosive. Temperature-dependent molar magnetic susceptibilities show that weak antiferromagnetic behavior exists in 1 ., Competing Interests: The authors declare no competing financial interest.

Lanthanide(III) ion (Ln(III)) sensing has become a major research area owing to its intriguing prospect in clinic, biology, and environmental studies. However, the existing methods have limitations like requirement of expensive instrumentation, long analytical times, and sample pretreatments, revealing the necessity of other methods. In this work, by using N -methyl-4-pyridinium tetrazolate (mptz) zwitterion as an electron acceptor, we obtained several new Ln(III) compounds with electron-transfer (ET) photochromic properties: [Ln(NO 3 ) 3 (H 2 O) 4 ]·mptz [Ln = Sm ( 1 ), Eu ( 2 ), Gd ( 3 ), La ( 4 ), Ce ( 5 ), Pr ( 6 ), Nd ( 7 ), Tb ( 8 ), Dy ( 9 ), Ho ( 10 ), Er ( 11 ), Tm ( 12 ), Yb ( 13 ), Lu ( 14 )]. Notably, different Ln(III) ions in these compounds can be visually identified by their different photoinduced color changes related to the ET process. This work may not only contribute to the more understanding of the structure-photosensitivity relationships of pyridinium-based compounds, but also provide a new approach for Ln(III) ion sensing., Competing Interests: The authors declare no competing financial interest.

Two new infrared (IR) nonlinear optical (NLO) sulfides, Na 2 Ga 2 GeS 6 and Na 2 Ga 2 SnS 6 , were obtained by mixing different typical NLO-active motifs GaS 4 and GeS 4 /SnS 4 in the alkali metal-containing system. The IR NLO sulfides present laser-induced damage thresholds that are 18.1 and 17.9 times that of the reference AgGaS 2 (AGS) and second-harmonic generation efficiencies that are 0.8 and 1.1 times that of AGS. These properties originate from the GaS 4 , GeS 4 , and SnS 4 tetrahedral blocks in the structures of the sulfides. Both compounds also exhibit a broad transparency range and type-I phase-matching behavior, which support their high potential in high-power laser applications. This work sheds new light on the development of promising mid-IR NLO materials by combining different NLO-active motifs.

Vapor-responsive magnetic materials are highly promising for applications as chemical switches or sensors. Compared with porous materials, nonporous species benefit in overcoming the intrinsic conflict between magnetic exchange and porosity but usually suffer from the powdering of single crystals, which hinders the understanding of the structural nature of vapor response and magnetic switch. Single-crystal-to-single-crystal (SCSC) transformation of nonporous compounds through the desorption/absorption of gaseous HCl is unprecedented. Reported here is a discrete nonporous copper(II) complex, (H 3 O)[K(15-crown-5) 2 ][CuCl 4 ], that exhibits reversible SCSC transformation and magnetic change by the chemisorption/desorption of HCl and H 2 O. Significant changes in the coordination number (4 ↔ 3), space group (P1̅ ↔ P2 1 /c), color (green ↔ red), and magnetic behavior (antiferromagnetic ↔ paramagnetic) were found during the SCSC transformation.

For designing energetic materials (EMs), the most challenging issue is to achieve a balance between energetic performance and reliable stability. In this work, we employed an efficient and convenient method to synthesize a new class of EMs: nitrogen-rich tetranuclear metal complexes [M(Hdtim)(H 2 O) 2 ] 4 (M = Zn 1 , Mn 2 ; H 3 dtim = 1 H -imidazol-4,5-tetrazole) with the N content of >46%. The structural analyses illustrate that isomorphous compounds 1 and 2 feature isolated hollow ellipsoid tetranuclear units, which are linked by both π-π interactions and hydrogen-bonding interactions to give a 3D supramolecular architecture. Compounds 1 and 2 exhibit prominent energetic characteristics: excellent detonation performances and reliable thermal, impact, and friction stabilities. Being nitrogen-rich tetrazolate compounds, the enthalpies of combustion of 1 (-11.570 kJ g -1 ) and 2 (-12.186 kJ g -1 ) are higher than those of classical EMs, RDX and HMX, and they possess high positive heats of formation. Sensitivity tests demonstrate that 1 and 2 are insensitive to external mechanical action. Excellent energetic performances and low sensitivities promote 1 and 2 to serve as a new class of promising EMs with a desirable level of safety., Competing Interests: The authors declare no competing financial interest.

Quaternary metal thiophosphates containing second-order Jahn-Teller distorted d 10 Ag + and lone-pair cations, Ag 3 Bi(PS 4 ) 2 (1), Ag 7 Sn(PS 4 ) 3 (2), and Ag 7 Pb(PS 4 ) 3 (3), were obtained by solid-state synthesis. The structural frameworks of 2 and 3 feature an infinite 1-D interchiral double helix ∞ 1 (Ag 3 P 2 S 11 ), which is rare in inorganic compounds. Compound 3 undergoes a significant first-order structural phase transition from monoclinic to hexagonal at ∼204 °C. This can be ascribed to the significant mismatch in the expansion coefficients between Pb-S (Ag-S) and P-S bonds evaluated by bond valence theory. The three compounds are Ag + ionic conductors, and Ag + ion migration pathways are proposed by calculating maps of low bond valence mismatch. Moreover, the optical properties of the three compounds were studied, and electronic structure calculations were performed. The combination of second-order Jahn-Teller distorted d 10 cation and lone-pair cation provides a new strategy to explore new metal thiophosphates with interesting structures and promising properties.

Two new phases in the Ag-Cd-P-S system containing two second-order Jahn-Teller (SOJT) distorted d 10 cations (Cd 2+ and Ag + ), namely, Ag 2 Cd(P 2 S 6 ) (1) and AgCd 3 (PS 4 )S 2 (2), are obtained via medium-temperature solid-state synthesis. Compound 1 exhibits a two-dimensional layered structure and undergoes a first-order structural phase transition at approximately 280 °C. This outcome can be ascribed to the significant mismatch in the expansion coefficients between Cd-S (Ag-S) and P-P (P-S) bonds evaluated through bond valence theory. The three-dimensional non-centrosymmetric (NCS) framework of 2 is constructed by two types of tetrahedral layers consisting of corner-shared CdS 4 , AgS 4 , and PS 4 tetrahedra. Compound 2 exhibits second harmonic generation (SHG) intensity of 0.45 times that of commercial AgGaS 2 (AGS) at a laser irradiation of 1.85 μm and an optical band gap of 2.56 eV, and no intrinsic vibrational absorption of chemical bonds is observed in the range of 2.5-18.2 μm. Both phase transition in 1 and SHG properties in 2 are closely related to the SOJT distorted d 10 cations and diverse phosphorus-sulfur polyanions (P a S b ) n- , which together can easily result in NCS distorted structures and interesting properties.

A flexible metal-organic framework (FMOF) with functionalized pores was hydrothermally synthesized to improve CO2 affinity and selectivity. The obtained FMOF exhibits a reversible shrinking and swelling framework transformation, which is triggered by the adsorption of CO2 rather than by the adsorption of N2 and CH4. At ambient temperature and an atmospheric pressure, this FMOF shows not only a high CO2 uptake (98 cm(3) g(-1), 19.3 wt %) but also a good calculated adsorption selectivity for CO2 over both CH4 and N2 (CO2/CH4 50:50 v/v: 28.6:1, CO2/N2 15:85 v/v: 210.4:1 calculated by ideal adsorbed solution theory), indicating potential applications in the purification of natural gas and industrial flue gas.

The first two new Na-containing sulfides Na₂In₂MS₆ (M = Si (1), Ge (2)) in the Na₂Q-B₂Q₃-CQ₂ (B = Ga, In; C = Si, Ge, Sn; Q = S, Se) system were prepared for the first time through conventional high-temperature solid-state reaction. They are isostructural with space group Cc (No. 9) in monoclinic phases and feature three-dimensional frameworks built by the (∞)¹[In₂MS₆]²⁻ (M = Si, Ge) chains through corner-sharing InS₄ tetrahedra and MS₄ (M = Si, Ge) tetrahedra, with Na⁺ cation located in the cavities. They display moderate second harmonic generation (SHG) conversion efficiencies compared with commercial AgGaS₂, with phase-matching behavior at 1800 nm and laser-induced damage thresholds 6.9 and 4.0 times higher than that of AgGaS₂, respectively. Therefore, the output SHG intensities of 1 and 2 will be ∼4.3 and 4.0 times larger than that of AgGaS₂, when the intensity of incident laser increased to close the damage energy of 1 and 2, indicating their potential for high-power nonlinear optical application.

Polycyanometallate compounds with both photochromism and photomagnetism have appealing applications in optical switches and memories, but such optical behaviors were essentially restricted to the cryogenic temperature. We realized, for the first time, the photochromism and photomagnetism of 3d-4f hexacyanoferrates at room temperature (RT) in [Eu(III)(18C6)(H2O)3]Fe(III)(CN)6·2H2O (18C6 = 18-crown-6). Photoinduced electron transfer (PET) from crown to Fe(III) yields long-lived charge-separated species at RT in air in the solid state and also weakens the magnetic susceptibility significantly. The PET mechanism and changing trend of photomagnetism differ significantly from those reported for known 3d-4f hexacyanoferrates. This work not only develops a new type of inorganic-organic hybrid photochromic material but opens a new avenue for RT photomagnetic polycyanometallate compounds.

Two new metal sulfides, Ba(2)Ga(8)MS(16) (M = Si, Ge), have been synthesized by high-temperature solid-state reactions. They are isostructural and crystallize in the noncentrosymmetric space group P6(3)mc (No. 186) with a = 10.866(5) Å, c = 11.919(8) Å, and z = 2 for Ba(2)Ga(8)SiS(16) (1) and a = 10.886(8) Å, c = 11.915(3) Å, and z = 2 for Ba(2)Ga(8)GeS(16) (2). Their three-dimensional frameworks are constructed by corner-sharing mixed (Ga/M)S(4) (M = Si, Ge) and pure GaS(4) tetrahedra, with Ba(2+) cations filling in the tunnels. Compounds 1 and 2 are transparent over 0.42-20 μm and have wide band gaps of around 3.4 and 3.0 eV, respectively. Polycrystalline 2 displays strong nonlinear second-harmonic-generation (SHG) intensities that are comparable to that of the benchmark AgGaS(2) (AGS) with phase-matching behavior at a laser irradiation of 1950 nm. Of particular interest, compound 2 also possesses a high powder laser-induced damage threshold of ∼22 times that of AGS. The alternate stacking of the mixed (Ga/M)S(4) (M = Si, Ge) tetrahedral layer with the pure GaS(4) tetrahedral layer along the c axis and the alignment of these two types of tetrahedra in the same direction may be responsible for the large SHG signals observed.

Two new member of (V)((2n+2)/2)[Bi(2n)Cl(8n+2)] series hybrids, (BzV)2[Bi2Cl10] (1) and (BzV)5[Bi3Cl14]2·(C6H5CH2)2O (2) (where BzV(2+) = N,N'-dibenzyl-4,4'-bipyridinium and (C6H5CH2)2O = dibenzyl ether) have been obtained, and compound 2 contains an unprecedented discrete trimer [Bi3Cl14](5-) counterion. The novel in situ-synthesized symmetric viologen cation with aromatic groups on both sides of 4,4'-bipy would provide more opportunities to create π···π interactions to optimize the photochromic property of the hybrid, and different bismuthated-halide oligomers enable us to discuss the size effect in this series of compounds. Both 1 and 2 are photochromic, and their photoresponsive rate is faster than that of reported viologen-metal halide hybrids. Experimental and theoretical data illustrated that the size of the inorganic oligomer can significantly influence the photoresponsive rate of the viologen dication, and the π···π interaction behaves as not only a powerful factor to stabilize the viologen monocation radical but also the second electron-transfer pathway, from a π-conjugated substituent to a viologen cation, for the photochromic process.

A 3D metal-organic framework (MOF), [Zn(BPHY)(SA)]n (1; BPHY = 1,2-bis(4-pyridyl)hydrazine, H2SA = succinic acid), which crystallizes in a noncentrosysmmetric space group (Cc), has been solvothermally obtained and testified to be a good nonlinear-optical material with the largest second-harmonic-generation response among the known MOFs based on sysmmetric ligands and high stability. Ultraviolet-to-visible tunable emission for 1 is observed.

The model compound [Zn(HCOO)2(4,4'-bipy)] (1; 4,4'-bipy = 4,4'-bipyridine) is selected in this work to demonstrate the effectiveness of our previously proposed design strategy for electron-transfer photochromic metal-organic complexes. The electron-transfer photochromic behavior of 1 has been discovered for the first time. Experimental and theoretical data illustrate that the photochromism of 1 can be attributed to the electron transfer from formato to 4,4'-bipy and the formation of a radical photoproduct. The electron transfer prefers to occur between formato and 4,4'-bipy, which are combined directly by the Zn(II) atoms. A high-contrast (up to 8.3 times) photoluminescence switch occurs during the photochromic process. The similarity of photochromic behaviors among 1 and its analogues as well as viologen compounds has also been found. Photochromic studies of this model compound indicate that new electron-transfer photochromic metal-organic complexes can be largely designed and synthesized by the rational assembly of nonphotochromic electron-donating and electron-accepting ligands.