Chain-like [Sx] (x=2–6) Units Realizing Giant Birefringence with Transparency in the Near-Infrared for Optoelectronic Materials

Birefringent crystals are requisite optical devices in laser and modern opto-electronic fields. Development of excellent birefringent materials is still challenging. Herein, the linear or chain-like [S_x] (x=2–6) species were theoretically proved to be the origin of the large birefringence, and could be regarded as birefringent genes. Besides, the metal polysulfide family was first proposed to be rich birefringent materials source, among which Cs₂S₆ realizes giant birefringence 0.58@1064 nm together with a wide band gap of 1.70 eV (based on the generalized gradient approximation). Moreover, the first dual-anion group polysulfide Na₄Ba₃(S₂)₄S₃ was obtained, showing wide infrared transmission range (0.5–6.2 μm), wide band gap (2.3 eV), and large birefringence (0.37 at 1064 nm). This work provides a new guiding thought for exploring large birefringence crystals in the future.     

[Ge2S5(S2)]4−, A NLO-Active Unit Leading to an Asymmetric Structure Discovered in Li2Cs4Ge2S5(S2)Cl2: An Experimental and Theoretical study

Metal-centered MS₄ tetrahedra are fundamentally important building blocks for the structural construction of infrared (IR) nonlinear optical (NLO) mateirals, because they have a large effect on properties like second-harmonic generation, birefringence, band gap, etc. Therefore, rational design and selection of these tetrahedra could effectively help synthesize new materials and give satisfactory properties. In this work, we reported a new NLO-active [Ge₂S₅(S₂)]⁴⁻ unit composed of two corner-shared GeS₄ tetrahedra with a nonpolar covalent S−S bond, discovered in a new compound of Li₂Cs₄Ge₂S₅(S₂)Cl₂. To the best of our knowledge, this [Ge₂S₅(S₂)]⁴⁻ unit has never been discovered. [Ge₂S₅(S₂)]⁴⁻ units have intrinsic asymmetric features and lead to the whole structure being noncentrosymmetric (NCS). Further, real-space atom-cutting methods reveal that they make almost all the contribution to the second-harmonic generation response (SHG) for Li₂Cs₄Ge₂S₅(S₂)Cl₂. All of the above indicate that the [Ge₂S₅(S₂)]⁴⁻ unit is a new functional unit and a good choice for designing new IR NLO materials.     

Structural Expansion of Chalcogenido Tetrelates in Ionic Liquids by Incorporation of Sulfido Antimonate Units

Multinary chalcogenido (semi)metalate salts exhibit finely tunable optical properties based on the combination of metal and chalcogenide ions in their polyanionic substructure. Here, we present the structural expansion of chalcogenido germanate(IV) or stannate(IV) architectures with Sb^III, which clearly affects the vibrational and optical absorption properties of the solid compounds. For the synthesis of the title compounds, [K₄(H₂O)₄][Ge₄S₁₀] or [K₄(H₂O)₄][SnS₄] were reacted with SbCl₃ under ionothermal conditions in imidazolium-based ionic liquids. Salt metathesis at relatively low temperatures (120 °C or 150 °C) enabled the incorporation of (formally) Sb³⁺ ions into the anionic substructure of the precursors, and their modification to form (Cat)₁₆[Ge₂Sb₂S₇]₆[GeS₄] ( 1 ) and (Cat)₆[Sn₁₀O₄S₂₀][Sb₃S₄]₂ ( 2 a and 2 b ), wherein Cat=(C₄C₁C₁Im)⁺ ( 1 and 2 a ) or (C₄C₁C₂Im)⁺ ( 2 b ). In 1 , germanium and antimony atoms are combined to form a rare noradamantane-type ternary molecular anion, six of which surround an {GeS₄} unit in a highly symmetric secondary structure, and finally crystallize in a diamond-like superstructure. In 2 , supertetrahedral oxo-sulfido stannate clusters are generated, as known from the ionothermal treatment of the stannate precursor alone, yet, linked here into unprecedented one-dimensional strands with {Sb₃S₄} units as linkers. We discuss the single-crystal structures of these uncommon salts of ternary and quaternary chalcogenido (semi)metalate anions, as well as their Raman and UV-visible spectra.     

[VO(dien)]2GeS4: Solvothermal Synthesis and Crystal Structure with an Ortho‐Thiogermanate as Tetradentate Ligand

The compound [VO(dien)]₂GeS₄ ( 1 , dien = diethylenetriamine) features an ortho‐thiogermanate anion [GeS₄]^4–, which acts as tetradentate ligand joining [VO(dien)]^2– complexes. The compound was obtained under solvothermal conditions crystallizing in thenon‐centrosymmetric orthorhombic space group Pna2₁ with a =19.8310(11), b = 8.0814(5), c = 12.0889(9) Å, V = 1937.4(2) ų and Z = 4. The V⁴⁺ cations are in a distorted octahedral environment of a tridentate dien molecule, one oxygen atom and two sulfur atoms from the [GeS₄]^4– anion. A three‐dimensional network is generated by hydrogen bonding interactions.     

K4VP2S9

The new quaternary group V thio­phosphate K₄VP₂S₉ (tetrapotassium vanadium di­phosphorus nona­sulfide) was prepared by reacting a mixture of K₂S₃, VP, P₄S₃ and S. The crystal structure consists of discrete [VS(PS₄)₂]⁴⁻ anions and K⁺ cations. The V⁴⁺ cation is in a fivefold coordination of S atoms which form a square‐pyramidal environment. Each VS₅ group shares a common edge with two bidentate [PS₄] tetrahedra, yielding the complete anion. The anions are stacked in the direction of the crystallographic b axis and are separated by the K⁺ ions.     

Evidence of network demixing in GeS2-Ga2S3 chalcogenide glasses: A phase transformation study

The information of phase transformation is attained by in situ XRD experiments leading to the knowledge of topological threshold in GeS₂-Ga₂S₃ glasses. The turning point of phase transformation behavior is demonstrated to be glasses containing 14-15 mol% Ga₂S₃. To interpret it a network demixing model is further improved and proposed for the structure of these ternary or quasi-binary chalcogenide glasses. For the nearest-neighbor coordination environment of glass with a transitional composition of 85.7 mol% (6/7) GeS₂·14.3 mol% (1/7) Ga₂S₃, six-coordinated [S₃Ga-X-GaS₃] units (X=S or None) are well isolated by the [GeS₄] structures, which contributes to the decreasing of precipitation of Ga₂S₃ crystals in (100−x)GeS₂-xGa₂S₃ (x≤14.3) glasses corresponding to the experimental evidence of the phase transformation behavior. This scenario of intermediate-range structural order, firstly, includes the arrangement of structural units which is consistent with and provides an atomistic explanation of the compositional evolution of phase transformation behavior in these glasses.     

New trans-[Re6S8(CN)4L2] n− Rhenium Cluster Complexes: Syntheses, Crystal Structures and Properties

Reaction of polymeric compound Cs₄[Re₆S₈(CN)₄S_2/2] with aqueous solution of KOH led to formation of trans-[Re₆S₈(CN)₄(OH)₂]⁴⁻ anion which was crystallized in ordered Cs_1.68K_2.32[Re₆S₈(CN)₄(OH)₂] · 2H₂O (1a) and disordered Cs_1.83K_2.17[Re₆S₈(CN)₄(OH)₂] · 2H₂O (1b) modifications. The presence of two types of apical ligands, inert cyanides and labile hydroxides, opened a way to other trans-[Re₆S₈(CN)₄L₂] ⁿ⁻ rhenium cluster complexes: trans-[Re₆S₈(CN)₄Cl₂]⁴⁻, trans-[Re₆S₈(CN)₄(H₂O)Br]³⁻, and trans-[Re₆S₈(CN)₄Br₂]⁴⁻, crystallized as Cs_1.84K_1.16(H)[Re₆S₈(CN)₄Cl₂] (2), Cs_1.68K_1.32[Re₆S₈(CN)₄(H₂O)Br] (3), (Me₄N)₃(H₅O₂)[Re₆S₈(CN)₄Br₂] (4), and CsK{Cu(H₂O)₂[Re₆S₈(CN)₄Cl₂]} · 4H₂O (5) salts.     

Drei Alkalimetall‐Erbium‐Thiophosphate: Von der Schichtstruktur bei KEr[P2S7] zur dreidimensionalen Vernetzung in NaEr[P2S6] und Cs3Er5[PS4]6

Three Alkali‐Metal Erbium Thiophosphates: From the Layered Structure of KEr[P₂S₇] to the Three‐Dimensional Cross‐Linkage in NaEr[P₂S₆] and Cs₃Er₅[PS₄]₆ The three alkali‐metal erbium thiophosphates NaEr[P₂S₆], KEr[P₂S₇], and Cs₃Er₅[PS₄] show a small selection of the broad variety of thiophosphate units: from ortho‐thiophosphate [PS₄]^3? and pyro‐thiophosphate [S₃P–S–PS₃]^4? with phosphorus in the oxidation state +V to the [S₃P–PS₃]^3? anion with a phosphorus‐phosphorus bond (d(P–P) = 221 pm) and tetravalent phosphorus. In spite of all differences, a whole string of structural communities can be shown, in particular for coordination and three‐dimensional linkage as well as for the phosphorus‐sulfur distances (d(P–S) = 200 – 213 pm). So all three compounds exhibit eightfold coordinated Er³⁺ cations and comparably high‐coordinated alkali‐metal cations (CN(Na⁺) = 8, CN(K⁺) = 9+1, and CN(Cs⁺) ≈ 10). NaEr[P₂S₆] crystallizes triclinically ( ; a = 685.72(5), b = 707.86(5), c = 910.98(7) pm, α = 87.423(4), β = 87.635(4), γ = 88.157(4)°; Z = 2) in the shape of rods, as well as monoclinic KEr[P₂S₇] (P2₁/c; a = 950.48(7), b = 1223.06(9), c = 894.21(6) pm, β = 90.132(4)°; Z = 4). The crystal structure of Cs₃Er₅[PS₄] can also be described monoclinically (C2/c; a = 1597.74(11), b = 1295.03(9), c = 2065.26(15) pm, β = 103.278(4)°; Z = 4), but it emerges as irregular bricks. All crystals show the common pale pink colour typical for transparent erbium(III) compounds.     

Syntheses, crystal structures and spectroscopic properties of Ag2Nb[P2S6][S2] and KAg2[PS4]

Ag₂Nb[P₂S₆][S₂] (1) was obtained from the direct solid state reaction of Ag, Nb, P₂S₅ and S at 500 °C. KAg₂[PS₄] (2) was prepared from the reaction of K₂S₃, Ag, Nd, P₂S₅ and extra S powder at 700 °C. Compound 1 crystallizes in the orthorhombic space group Pnma with a=12.2188(11), b=26.3725(16), c=6.7517(4) Å, V=2175.7(3) Å³, Z=8. Compound 2 crystallizes in the non-centrosymmetric tetragonal space group with lattice parameters a=6.6471(7), c=8.1693(11) Å, V=360.95(7) Å³, Z=2. The structure of Ag₂Nb[P₂S₆][S₂] (1) consists of [Nb₂S₁₂], [P₂S₆] and new found puckered [Ag₂S₄] chains which are along [001] direction. The Nb atoms are located at the center of distorted bicapped trigonal prisms. Two prisms share square face of two [S₂²⁻] to form one [Nb₂S₁₂] unit, in which Nb-Nb bond is formed. The [Nb₂S₁₂] units share all S²⁻ corners with ethane-like [P₂S₆] units to form 14-membered rings. The novel puckered [Ag₂S₄] chains are composed of distorted [AgS₄] tetrahedra and [AgS₃] triangles that share corners with each other. These chains are connected with [P₂S₆] units and [Nb₂S₁₂] units to form three-dimensional frame work. The structural skeleton of 2 is built up from [AgS₄] and [PS₄] tetrahedra linked by corner-sharing. The three-dimensional anionic framework contains orthogonal, intersecting tunnels directed along [100] and [010]. This compound possesses a compressed chalcopyrite-like structure. The structure is compressed along [001] and results from eight coordination sphere for K⁺. Both compounds are characterized with UV/vis diffuse reflectance spectroscopy and compound 1 with IR and Raman spectra.     

Synthesis,crystal structure,magnetism and vibrational spectrum of Dipotassium Iron(II) Hexathiodiphosphate(IV), K2Fe[P2S6]

K₂Fe[P₂S₆] was synthesized from the elements at 1173 K in sealed quartz tubes. The compound forms transparent orange crystals, stable against air and moisture. K₂Fe[P₂S₆] crystallizes in the monoclinic system, space group P2₁/n (No. 14), with cell dimensions (T = 298.5 K) a = 6.0622(4), b = 12.172(1) and c = 7.3787(8) Å, β = 101.113(7)°, Z = 2. The novel structure type (mP22) is characterized by columns of alternating face-sharing S₆ octahedra and trigonal antiprisms (both distorted) parallel to the a axis, which are interconnected by inserted K⁺ (CN 10; {2,6,2}-polyhedra; d(K? S) = 3.231 ? 3.845 Å). The S₆ polyhedra of the columns are centered alternately by Fe (d?(Fe? S) = 2.577 Å) and P₂ pairs which are inclined to the a axis by 73.4°. The bond lengths in the hexathiodiphosphate(IV) anions, [P₂S₆]^4?, with approximate 3 2/m – D_3d symmetry, are d?(P? P) = 2.20 and d?(P? S) = 2.02 Å. The compound is paramagnetic above T_N = 28 K with μ = 4.69 B.M. and orders antiferromagnetically below T_N. The internal modes of the observed Raman and FIR spectra of K₂Fe[P₂S₆] are in accord with the factor group analysis, and the spectra are assigned on the basis of [P₂S₆]^4? units, taking into account the deviation from D_3d symmetry.     

Crystal Structure and Vibrational Spectrum of Dipotassium Manganese(II) Hexathiodiphosphate(IV), K2Mn[P2S6]

K₂Mn[P₂S₆] was synthesized from the elements in sealed quartz ampoules at 1 173 K. The compound forms transparent light brown crystals, stable against air and moisture. The crystal structure (monoclinic; space group P2₁/n, No. 14; a = 6.1966(9), b = 12.133(2), c = 7.424(1) Å, β = 101.52(1)°, Z = 2; Pearson code mP22) consists of columns of face-sharing S₆ polyhedra (distorted octahedra and trigonal antiprisms) parallel to the a axis, interconnected by inserted K⁺ (CN 10; d(K? S) = 3.23–3.92 Å). The S₆ polyhedra of the columns are centered alternately by Mn (in octahedra with d?(Mn? S) = 2.647 Å) and P₂ pairs (in trigonal antiprisms) which are inclined to the a axis by 73.1°. The bond lengths in the resulting hexathiodiphosphate(IV) anions, [P₂S₆]^4?, with approximate 3 2/m–D_3d symmetry, are d(P? P) = 2.211 Å and d(P? S) = 2.018 Å. K₂Mn[P₂S₆] is isotypic to K₂Fe[P₂S₆], being the second member of this structure type. The internal modes of the observed Raman and FIR/IR spectra of K₂Mn[P₂S₆] are in accord with the factor group analysis, and the fundamentals are assigned on the basis of [P₂S₆]^4? units, taking into account the deviation of the D_3d symmetry.     

Studies of unusual oxidation states of transition metals III-kinetics and mechanism of oxidation of triethanolamine by diperiodatoargenate(III) ion in aqueous alkaline medium

The kinetics of oxidation of triethanolamine (TEA) by diperiodatoargenate(III) anion, [Ag(HIO₆)₂]^5?, has been studied in aqueous alkaline medium by conventional spectrophotometry. The reaction is pseudo-first-order in [Ag(III)] disappearance with k_obs = (k₁ + k₂[OH^?]) K₁K₂[TEA]/{[H₂IO₆^3?]_e + K₁ + K₁K₂[TEA]}, where k₁ = 8.05 × 10^?3 S^?1, k₂ = 0.46 M^?1 S^?1, K₁ = 6.15 × 10^?4 M, and K₂ = 537 M^?1 at 25°C, and μ = 0.30 M. Based on the inference that an inner-sphere complex is formed by indirect replacement of a ligand of [Ag(HIO₆)₂]^5? by a TEA molecule, a reaction mechanism has been proposed. The complex undergoes redox by two modes, both internal and one hydroxide ion assisted.     

Synthesis,characterization, and biocide activity of new dithiocarbamate-based complexes of In(III), Ga(III), and Bi(III) – Part III

In this work, we describe the syntheses, characterization, and antifungal activity of [In{S₂CNR(R¹)}₃] (1), [Ga{S₂CNR(R¹)}₃] (2), [Bi{S₂CNR(R¹)}₃] (3), [In{S₂CNR(R²)}₃] (4), [Ga{S₂CNR(R²)}₃] (5), and [Bi{S₂CNR(R²)}₃] (6) {R?=?Me; R¹?=?CH₂CH(OMe)₂; and R²?=?2-methyl-1,3-dioxolane}. All complexes have been characterized using infrared and ¹H and ¹³C spectroscopy, and the structures of 1, 3, 4, and 6 have been authenticated by X-ray diffraction. The In(III)–dithiocarbamate bonding scheme depicts a distorted octahedral with asymmetric In(III)–S bonds and S–In–S angles. A pentagonal bipyramid is observed for the corresponding Bi(III) complexes with intermolecular Bi–S associations through the lone pair of electrons. The antifungal activities of 1–6 have been screened against Aspergillus niger, Aspergillus parasiticus, and Penicillium citrinum, and the results have been compared with those of nystatin and miconazole nitrate, as control drugs.     

Tetrakis[(4S)-4-phenyloxazolidin-2-one]dirhodium(II) and Its Catalytic Applications for Metal Carbene Transformations

The synthesis and X-ray structure of the binuclear complex tetrakis[(4S)-4-phenyloxazolidin-2-one]-dirhodium(II) ([Rh₂{(4S)-phox}₄]) are reported. Structure-selectivity comparisons are made for typical metal carbene transformations, such as inter- and intramolecular cyclopropane formation, intermolecular cyclopropene formation and intramolecular C–H insertions of diazoacetates and diazoacetamides. The enantioselectivity achieved in the [Rh₂{(4S)-phox}₄]-catalyzed reactions is intermediate between that of [Rh₂{(5S)-mepy}₄] and [Rh₂{(4R)-bnox}₄], which were described previously (mepy = methyl 5-oxopyrrolidine-2-carboxylate; bnox = 4-benzyloxazolidin-2-one). In contrast to other catalyzed intermolecular cyclopropane formations, those using [Rh₂{(4S)-phox}₄] result preferentially in formation of the cis-cyclopropane.     

The Borosulfates K4[BS4O15(OH)], Ba[B2S3O13], and Gd2[B2S6O24]

K₄[BS₄O₁₅(OH)], Ba[B₂S₃O₁₃], and Gd₂[B₂S₆O₂₄] were obtained by a new synthetic approach. The strategy involves initially synthesizing the complex acid H[B(HSO₄)₄] which is subsequently reacted in an open system with anhydrous chlorides of K, Ba, and Gd to the respective borosulfates and a volatile molecule (HCl). Furthermore, protonated borosulfates should be accessible by appropriate stoichiometry of the starting materials, particularly in closed systems, which inhibit deprotonation of H[B(HSO₄)₄] via condensation and dehydration. This approach led to the successful synthesis of the first divalent and trivalent metal borosulfates (Ba[B₂S₃O₁₃] with band‐silicate topology and Gd₂[B₂S₆O₂₄] with cyclosilicate topology) and the first hydrogen borosulfate K₄[BS₄O₁₅(OH)].     

[Cp2TiNi(S2N2)2] – The First Organometallic Derivative of [Ni(S2N2H)2]

The synthesis and structural characterization of the first organometallic derivative of [Ni(S₂N₂H)₂] ( 1 ) are reported. Treatment of K₂[Ni(S₂N₂)₂] ( 2 ) with stoichiometric amounts of [Cp₂TiCl₂] in boiling toluene afforded black, crystalline [Cp₂TiNi(S₂N₂)₂] ( 3 ) in 50 % yield. According to a single‐crystal X‐ray diffraction study, the novel heterobimetallic complex 3 comprises a nearly planar TiNi(S₂N₂)₂ arrangement. The Ti···Ni separation in 3 is 2.8348(5) Å, a value that is typical for bridged early‐late heterobimetallic complexes.     

Poly[di‐μ‐aqua‐[μ6‐N‐(4‐bromophenylsulfonyl)dithiocarbimato]dipotassium] and poly[di‐μ‐aqua‐[μ4‐N‐(4‐iodophenylsulfonyl)dithiocarbimato]dipotassium]

The rigid organic linkers N‐(4‐bromophenylsulfonyl)dithiocarbimate(2−) and N‐(4‐iodophenylsulfonyl)dithiocarbimate(2−) crystallize with two potassium cations and two water molecules in their asymmetric units, forming the title coordination polymers, [K₂(C₇H₄BrNO₂S₃)(H₂O)₂]_n and [K₂(C₇H₄INO₂S₃)(H₂O)₂]_n. The anions and the water molecules link the potassium cations into broad two‐dimensional networks, which are further linked by K...halide interactions.     

Chiral [2H]-Labelled Methylene Groups in Trienoic- and Dienoic Fatty Acids: A Facile Approach via Asymmetric Epoxidation of [2H] Allyl Alcohols

Chiral [²H] -labelled methylene groups flanked by two double bonds within (poly)unsaturated fatty acids are readily available from trans-2,3-epoxy[2,3-²H₂] alk-4-yn-l-ols, obtained in their turn by asymmetric epoxidation of the corresponding (E)-[2,3-²H₂] alk-2-en-4-yn-l-ols (see Scheme 3). The procedure is exemplified for (8S,3Z,6Z,9Z)-[7,8-²H₂] trideca-3,6,9-trienoic acid ((8S)- 11 ) and (8R)- 11 (Scheme 4) as well as for (5S,3Z,6Z)-[4,5^?2H₂]deca-3,6-dienoic acid ((5S)- 13 ) and (5R)- 13 (Scheme 5).     

The in vitro antifungal activity of some dithiocarbamate organotin(IV) compounds on Candida albicans— a model for biological interaction of organotin complexes

The in vitro antifungal activity of the dithiocarbamate organotin complexes [Sn{S₂CN(CH₂)₄}₂Cl₂] ( 1 ), [Sn{S₂CN(CH₂)₄}₂Ph₂] ( 2 ), [Sn{S₂CN(CH₂)₄}Ph₃] ( 3 ), [Sn{S₂CN(CH₂)₄}₂n‐Bu₂] ( 4 ), [Sn{S₂CN(CH₂)₄}Cy₃] {Cy = cyclohexyl} ( 5 ), [Sn{S₂CN(C₂H₅)₂}₂Cl₂] ( 6 ), [Sn{S₂CN(C₂H₅)₂}₂Ph₂] ( 7 ), [Sn{S₂CN(C₂H₅)₂}Ph₃] ( 8 ), [Sn{S₂CN(C₂H₅)₂}₃Ph] ( 9 ) and [Sn{S₂CN(C₂H₅)₂}Cy₃] ( 10 ) has been screened against Candida albicans (ATCC 18804), Candida tropicalis (ATCC 750) and resistant Candida albicans collected from HIV‐positive Brazilian patients with oral candidiasis. All compounds exhibited antifungal activities and complexes 3 and 8 displayed the best results. We have investigated the effect of compounds 1–10 on the cellular activity of the yeast cultures. Changes in mitochondrial function have not been detected. However, all drugs reduced ergosterol biosynthesis. Preliminary studies on DNA integrity indicated that the compounds do not cause gross damage to yeast DNA. The data suggest that these compounds share some mechanisms of action on cell membranes similar to that of polyene but not with azole drugs, normally used in Candida infections. Copyright © 2008 John Wiley & Sons, Ltd.     

Dimeric [Mo2S12]2− Cluster: A Molecular Analogue of MoS2 Edges for Superior Hydrogen‐Evolution Electrocatalysis

Proton reduction is one of the most fundamental and important reactions in nature. MoS₂ edges have been identified as the active sites for hydrogen evolution reaction (HER) electrocatalysis. Designing molecular mimics of MoS₂ edge sites is an attractive strategy to understand the underlying catalytic mechanism of different edge sites and improve their activities. Herein we report a dimeric molecular analogue [Mo₂S₁₂]^2?, as the smallest unit possessing both the terminal and bridging disulfide ligands. Our electrochemical tests show that [Mo₂S₁₂]^2? is a superior heterogeneous HER catalyst under acidic conditions. Computations suggest that the bridging disulfide ligand of [Mo₂S₁₂]^2? exhibits a hydrogen adsorption free energy near zero (?0.05 eV). This work helps shed light on the rational design of HER catalysts and biomimetics of hydrogen‐evolving enzymes.