Solid-state Absorption Spectra Research Articles

Iodine-mediated substitution of terminal ligands in [{M6I8}I6]2– (M = Mo, W) by DMSO

The family of octahedral iodide cluster complexes of molybdenum and tungsten – [{M6I8}L6]n – exhibit a unique set of properties with significant practical potential. Due to the strong influence of terminal ligands L on these properties, the search for new simpler, more convenient and cheaper approaches for their substitution is an urgent task. This work demonstrates a new one-step method for terminal ligand substitution using well-known and readily available complexes [{M6I8}I6]2–. The synthetic technique involves the addition of molecular iodine to the reaction mixture in order to bind the released I– ions, thereby facilitating the reaction process. As a result, two new cluster complexes with dimethyl sulfoxide ligands [{M6I8}(DMSO)6](I3)4 (M = Mo (1), W (2)) have been obtained and structurally characterized. The optical properties of the obtained compounds have been studied both in solid state and in solution, and Eg values have been calculated from the solid-state absorption spectra. The presence of I3– anions has been shown to quench the emission of the cluster complexes, explaining the absence of luminescence in the obtained compounds.

Synthesis and Photophysical Properties of Bipolar Compound: Triphenylamine/Diazafluorene-Carbazole.

Carbazole and triphenylamine, are two well-known hole transporting units that are attached to electron transporting unit 4,5-diazafluorene in a fascinating way to bring out non-planar configuration of a molecule. The synthesized compound exhibits good thermal stability (Td > 515°C) and high glass transition temperature (Tg, 191°C). Optical bandgap (Egopt) obtained from solid state absorption spectra was calculated to be 2.93eV. Solid state photoluminescence spectra displays the emission maxima at 473nm. The emission characteristics of the compound observed in solvents of different polarity confirms the existence of intramolecular charge transfer in their excited state. Density functional theory studies reveal that HOMO and HOMO-1 localized on triphenylamine is spatially separated from LUMO of 4,5-diazafluorene, which manifest its bipolar character. The realization of long lived charge separated state upon photo-excitation from time resolved photoluminescence studies ascertains the charge transfer from triphenylamine to 4,5-diazafluorene. The experimental and theoretical analysis of the compound proved it to be a promising candidate for the fabrication of OLED devices.

Integration of WO3-Doped MoO3 with ZnO Photocatalyst for the Removal of 2-Nitrophenol in Natural Sunlight Illumination

Environmental contamination has become the most pressing issue in recent years. The value of clean water to mankind has sparked interest in heterogeneous photocatalysis. In this study, a novel photocatalyst has been synthesized by integrating WO3-doped MoO3 (WDM) and ZnO through composite formation. The composite nature of the synthesized photocatalyst was confirmed due to the presence of hexagonal ZnO and orthorhombic WDM phases in XRD pattern and scanning electron micrographs. Solid-state absorption spectra and a bandgap analysis showed that WDM-spectral ZnO’s response was better than that of pure ZnO. PL and EIS unveiled the effective role of WDM in suppressing the e−–h+ recombination process and charge-transfer resistance, respectively, in ZnO. The photocatalytic studies showed that WDM-ZnO was able to remove ~90% of 30 ppm 2-nitrophenol (2-NP) with a rate of 1.1 × 10−2 min−1, whereas ~65% 2-NP was removed by ZnO (6.1 × 10−3 min−1 rate) under the exposure of natural sunlight (800 × 102 ± 100 lx). Moreover, ~52% higher total organic carbon (TOC) removal was observed by WDM-ZnO as compared to ZnO. The photocatalytic removal of 2-NP by the produced photocatalysts followed the Langmuir–Hinshelwood kinetic model, as shown by the kinetic studies. The reactive oxygen species (ROS)-trapping established that the photocatalytic removal mechanism of 2-NP over WDM-ZnO in sunlight illumination was mainly triggered by the superoxide anion (O2•−) radical, however, the minor role of hydroxyl (•OH) radicals cannot be completely ignored.

Transition metal doped CeO2 for photocatalytic removal of 2-chlorophenol in the exposure of indoor white light and antifungal activity.

Besides natural sunlight and expensive artificial lights, economical indoor white light can play a significant role in activating a catalyst for photocatalytic removal of organic toxins from contaminated water. In the current effort, CeO2 has been modified with Ni, Cu, and Fe through doping methodology to study the removal of 2-chlorophenol (2-CP) in the illumination of 70W indoor LED white light. The absence of additional diffractions due to the dopants and few changes such as reduction in peaks' height, minor peak shift at 2θ (28.525°) and peaks' broadening in XRD patterns of modified CeO2 verifies the successful doping of CeO2. The solid-state absorption spectra revealed higher absorbance of Cu-doped CeO2 whereas a lower absorption response was observed for Ni-doped CeO2. An interesting observation regarding the lowering of indirect bandgap energy of Fe-doped CeO2 (∼2.7eV) and an increase in Ni-doped CeO2 (∼3.0eV) in comparison to pristine CeO2 (∼2.9eV) was noticed. The process of e -- h + recombination in the synthesized photocatalysts was also investigated through photoluminescence spectroscopy. The photocatalytic studies revealed the greater photocatalytic activity of Fe-doped CeO2 with a higher rate (∼3.9 × 10-3min-1) among all other materials. Moreover, kinetic studies also revealed the validation of the Langmuir-Hinshelwood kinetic model (R2 = 0.9839) while removing 2-CP in the exposure of indoor light with a Fe-doped CeO2 photocatalyst. The XPS analysis revealed the existence of Fe3+, Cu2+ and Ni2+ core levels in doped CeO2. Using the agar well-diffusion method, the antifungal activity was assessed against the fungus M. fructicola and F. oxysporum. Compared to CeO2, Ni-doped CeO2, and Cu-doped CeO2 nanoparticles, the Fe-doped CeO2 nanoparticles have outstanding antifungal properties.

A Smart Molecule Showing Spin Crossover Responsive Aggregation-Induced Emission

A Smart Molecule Showing Spin Crossover Responsive Aggregation-Induced Emission

Homochiral Mn3+ Spin-Crossover Complexes: A Structural and Spectroscopic Study.

Structural, magnetic, and spectroscopic data on a Mn3+ spin-crossover complex with Schiff base ligand 4-OMe-Sal2323, isolated in crystal lattices with five different counteranions, are reported. Complexes of [Mn(4-OMe-Sal2323)]X where X = ClO4– (1), BF4– (2), NO3– (3), Br– (4), and I– (5) crystallize isotypically in the chiral orthorhombic space group P21212 with a range of spin state preferences for the [Mn(4-OMe-Sal2323)]+ complex cation over the temperature range 5–300 K. Complexes 1 and 2 are high-spin, complex 4 undergoes a gradual and complete thermal spin crossover, while complexes 3 and 5 show stepped crossovers with different ratios of spin triplet and quintet forms in the intermediate temperature range. High-field electron paramagnetic resonance was used to measure the zero-field splitting parameters associated with the spin triplet and quintet states at temperatures below 10 K for complexes 4 and 2 with respective values: DS=1 = +23.38(1) cm–1, ES=1 = +2.79(1) cm–1, and DS=2 = +6.9(3) cm–1, with a distribution of E parameters for the S = 2 state. Solid-state circular dichroism (CD) spectra on high-spin complex 1 at room temperature reveal a 2:1 ratio of enantiomers in the chiral conglomerate, and solution CD measurements on the same sample in methanol show that it is stable toward racemization. Solid-state UV–vis absorption spectra on high-spin complex 1 and mixed S = 1/S = 2 sample 5 reveal different intensities at higher energies, in line with the different electronic composition. The statistical prevalence of homochiral crystallization of [Mn(4-OMe-Sal2323)]+ in five lattices with different achiral counterions suggests that the chirality may be directed by the 4-OMe-Sal2323 ligand.

Isomeric sp2-C-conjugated porous organic polymer-mediated photo- and sono-catalytic detoxification of sulfur mustard simulant under ambient conditions

Isomeric sp2-C-conjugated porous organic polymer-mediated photo- and sono-catalytic detoxification of sulfur mustard simulant under ambient conditions

Modulation of the optical properties of soluble N-alkylated 4-pyridyl diketopyrrolopyrrole derivatives

The absorption and fluorescence properties of N-alkylated 3,6-di (pyridin-4-yl)-2,5-dihydropyrrolo [3,4-c]pyrrole-1,4-dione (PyrDPP NH) derivatives in solution and the solid state are reported, along with the modulation of these properties under varying acidity or basicity. The compounds with hexyl (PyrDPP N-Hex) and methoxy ethoxy ethyl (PyrDPP N-MEE) chains were synthesised from PyrDPP NH giving highly soluble dyes. In addition, the mono-substituted derivatives were also isolated. A range of solvents was explored to provide understanding regarding their potential use in applications ranging from organic electronics to sensors. Optically the dyes are highly fluorescent and, as a result of N-alkylation breaking the hydrogen bond network, emissive in the solid state with large Stokes shifts. The nature of the chain dictates the π interactions and packing of the materials, resulting in modulation of the solid-state absorption spectra and theoretical mobility predicted from the crystal structures. The methoxy ethoxy ethyl chain twists out of the plane and bends to allow considerable molecular overlap and small interchromophore displacement with strikingly similar π interactions to the parent PyrDPP NH, resulting in a contribution of H-type aggregation to the absorption band and an order of magnitude improvement in theoretical mobility compared with the hexyl analogue. In contrast, PyrDPP N-Hex possesses a distorted CH-π interaction between pyridyl and lactam units, with greater molecular displacement manifesting in dominant J -aggregation contribution to absorption band and moderate mobility. The results emphasise the potential for sidechain modification and show structural evidence for the potential benefits of the flexible polar chains. The nitrogen lone pair of the pyridyl ring can be protonated in acidic environment to produce a photometric response suggesting potential as a proton sensor. The mono-substituted compounds are responsive to both base and acid, making them interesting for molecular logic applications.

The Coordination Between Pedal and Finger Forces During Piano Playing in Classical Passage With Respect to the Quality of Sound

A novel hybrid organic-inorganic molecular solid, 1-(4-methoxyphenyl)piperazinium (1–4MPPip) tetra(isothiocyanate)cobalt monohydrate (1–4MPPip)4[Co(NCS)4]2•H2O (I), was prepared using a slow evaporation growth technique at room temperature and characterized by elemental analysis, X-ray crystal structure, spectroscopic and computational studies. The crystal structural analysis reveals that the solid crystallizes in the triclinic space group P1¯. The [Co(NCS)4]2− anions are arranged in pairs along the c-axis direction to form anionic layers parallel to the (a,c) plane. Intermolecular interactions were investigated by Hirshfeld surfaces and contact enrichment tools. The organic entities are grouped into dimers through weak interactions OW-H…N and OW-H…O generated by the water molecules. The robustness of the crystal is also enhanced by CH…π and CH…S intermolecular interactions. Mulliken charge distribution, molecular electrostatic potential (MEP) maps and HOMO and LUMO energy gaps have been computed. The vibrational absorption bands were identified by infrared spectroscopy. The solid-state UV-Visible absorption spectrum of the title compound was obtained at room temperature in order to spotlight the optical properties.

Assigning Optical Absorption Transitions with Light-Induced Crystal Structures: Case Study of a Single-Crystal Nanooptomechanical Transducer

UV/vis absorption spectroscopy affords indirect structural information about the photochemistry and photophysics of molecules by inferring types of electronic transitions from spectral features. Direct structural information would become available, though, if light-induced crystal structures could be mapped against changes in optical absorption spectra as a photochemical process evolves. We present a series of light-induced crystal structures that track real-time changes in solid-state optical absorption spectra of a crystalline nanooptomechanical transducer, while the transduction process unfolds within its crystal lattice at 100 K. Results afford a combined structural and spectral mapping of its solid-state optical absorption, from which the operational mechanism of nanooptomechanical transduction is revealed. Metal-to-ligand and metal-centered charge-transfer bands are assigned to optical absorption peaks directly from their three-dimensional (3D) light-induced crystal structures. This approach could be used to characterize many solid-state optoelectronic materials.

Assembly of new quaternary TM-Cu-Ge-Se compounds (TM = Ni, Mn) by the combination of two types of metal coordination geometries

Two new quaternary TM-Cu-Ge-Se compounds(TM = Ni, Mn), namely, [Ni(tren)(en)]2∙[Cu2GeSe5]2 (tren = tris(2-aminoethyl)amine; en = ethylenediamine) (1) and [Mn(1,2-dap)2][Cu2GeSe5] (1,2-dap = 1,2-diaminopropane)(2) have been solvothermally prepared, and structurally characterized. Single-crystal X-ray diffraction analyses exhibit that Compounds 1 and 2 have different one-dimensional structures. Compound 1 is consists of one-dimensional anionic chain [Cu2GeSe5]2- with [Ni(tren)(en)]2+ cations as counterions. Compound 2 features a distinct one-dimensional neutral infinite ribbon-like structure. The compounds 1 and 2 by the combination of two types of metal coordination geometries. The solid-state optical absorption spectra indicate that the two compounds are semiconductor materials.

Double Free: A Promising Route toward Moisture-Stable Hypotoxic Hybrid Perovskites

Double Free: A Promising Route toward Moisture-Stable Hypotoxic Hybrid Perovskites

Two ternary antimony-chalcogenides of Cs4Sb4S8 and Cs3Sb5Se9

Two ternary antimony-chalcogenides of Cs4Sb4S8 (1) and Cs3Sb5Se9 (2), were synthesized in organic solvent under solvothermal conditions. Single-crystal X-ray diffraction analyses showed that compound 1 is characterized by an infinite [Sb2S8]n4n− chain formed by the alternating connection of two [Sb(1)S3] pyramidal and two [Sb(2)S4] tetrahedral. In compound 2, the [Sb2Se5]n4n− chain is interconnected by the two octahedral [Sb(3)Se6] units via corner-sharing, and the [Sb3Se5]− ribbon is interconnected by two [Sb2Se5]n4n− chains and pyramidal [Sb(5)Se3] unit via corner-sharing, finally, the[Sb5Se9]n3n− layer interconnected by [Sb3Se5]− ribbon and [Sb2Se5] dimer via corner-sharing. As estimated from the solid-state absorption spectra, the band gaps of 1 and 2 are 2.11 and 1.54 eV, respectively.

Synthesis, crystal structure, computational studies and spectroscopic characterization of a hybrid material self-assembly from tetra(isothiocyanate)cobalt(II) anion and 1-(4-methoxyphenyl)piperazinium

A novel hybrid organic-inorganic molecular solid, 1-(4-methoxyphenyl)piperazinium (1–4MPPip) tetra(isothiocyanate)cobalt monohydrate (1–4MPPip)4[Co(NCS)4]2•H2O (I), was prepared using a slow evaporation growth technique at room temperature and characterized by elemental analysis, X-ray crystal structure, spectroscopic and computational studies. The crystal structural analysis reveals that the solid crystallizes in the triclinic space group P1¯. The [Co(NCS)4]2− anions are arranged in pairs along the c-axis direction to form anionic layers parallel to the (a,c) plane. Intermolecular interactions were investigated by Hirshfeld surfaces and contact enrichment tools. The organic entities are grouped into dimers through weak interactions OW-H…N and OW-H…O generated by the water molecules. The robustness of the crystal is also enhanced by CH…π and CH…S intermolecular interactions. Mulliken charge distribution, molecular electrostatic potential (MEP) maps and HOMO and LUMO energy gaps have been computed. The vibrational absorption bands were identified by infrared spectroscopy. The solid-state UV-Visible absorption spectrum of the title compound was obtained at room temperature in order to spotlight the optical properties.

Spectroscopic characterization of neptunium(VI), plutonium(VI), americium(VI) and neptunium(V) encapsulated in uranyl nitrate hexahydrate.

The coordination of crystalline products resulting from the co-crystallization of Np(vi), Pu(vi), Am(vi), and Np(v) with uranyl nitrate hexahydrate (UNH) has been revealed through solid-state spectroscopic characterization via diffuse reflectance UV-Vis-NIR spectroscopy, SEM-EDS, and extended X-ray absorption fine structure (EXAFS) spectroscopy. Density functional and multireference wavefunction calculations were performed to analyze the An(vi/v)O2(NO3)2·2H2O electronic structures and to help assign the observed transitions in the absorption spectra. EXAFS show a similar coordination between the U(VI) in UNH and Np(vi) and Pu(vi); while Am resulted in a similar coordination to Am(iii), as reduction of Am(vi) occurred prior to EXAFS data being obtained. The co-crystallization of the oxidized transuranic species-penta- and hexavalent-with UNH, represents a significant advance from not only a practical standpoint in providing an elegant solution for used nuclear fuel recycle, but also as an avenue to expand the fundamental understanding of the 5f electronic behavior in the solid-state.

Mechanoluminescence and aggregation-enhanced emission (AEE) of an In-MOF based on a 9,9'-diphenyl-9H-fluorene tetraacid linker.

A water-stable In-MOF, constructed based on a conformationally-flexible tetraacid linker, i.e., 2,7-bis(3,5-dicarboxyphenyl)-9,9'-diphenyl-9H-fluorene, i.e., H4DPF, is shown to exhibit a significantly enhanced solid-state fluorescence quantum yield (φf) of 23% in comparison with that of the linker (φfca. 4%) as a consequence of rigidification of the latter by metalation. Application of external stimulus in the form of grinding of the In-MOF leads to a drastic enhancement by 29%, φf from 23 to 52%. Solid-state absorption and emission spectra show that the absorption in the region of 368-550 nm gets diminished with a concomitant change in the emission maximum with a blue shift upon grinding. Fluorescence enhancement with grinding is correlated with a gradual reduction in the size of the particles, as established by SEM analysis. MOF particle aggregation has been invoked to account for the observed fluorescence enhancement in addition to a subtle conformational change in the structure of the linker upon grinding. Intriguingly, the ground MOF particles exhibit aggregation behaviour in the DMF-water solvent system with the emission further increasing up to 75% for the increase in the water fraction (fw) from 0 to 60%; hydrophobic aggregation of particles evidently leads to a change in the conformation of the linker and particle aggregation-enhanced emission (AEE). De-aggregation of particles ensues for fw = 70-90%, as reflected by a gradual decrease in the emission intensity. It is shown that the suspension of ground In-MOF particles in water permits sensing of metal ions, in particular Al3+ ions, by fluorescence quenching with detection at a sub-ppb level. The observed results comprise first demonstration of both mechanoluminescence and AEE of MOF particles.

Design and Synthesis of Novel NIR Dyes with Phosphonic Acid Derivative Anchoring Groups Aiming Towards Stable Dye-Sensitized Solar Cells

Introduction: The solar energy is a promising solution to the sustainable energy supply and the relevant environmental concerns. Production of the traditional solar cells is expensive and this poses difficulty for the mass-level implementation of this kind of solar cells. So, there has been a lot of effort and interest to propose cost-effective and efficient solar cells, where dye-sensitized solar cells (DSSCs) are one of the potential candidates. DSSCs have emerged due to their good photo conversion efficiency (PCE) beyond 12 % in spite of photon harvesting window mainly in the visible region (400-700 nm). Dyes are the “Heart” of the solar cells and anchoring group present in it not only controls the overall PCE but also stability of photo anode, which ultimately controls the stability of DSSCs. Amongst various anchoring groups, phosphonic acid has been widely reported to give improved stability to the DSSCs as compared to their most commonly used carboxylic acid anchoring group counterparts. Owing to huge possibilities of molecular structures, quantum chemical (QC) calculations have emerged as one of the potential tools for the prediction of their energetics and spectral behavior. The goal of this research is to propose and develop of novel near infrared (NIR) dyes bearing phosphonic acid groups having the capability of improved stability as well as PCE focusing on Donor-Acceptor-Donor framework bearing squaraine dyes. Experimental: In this work, a series of unsymmetrical squaraine (SQ) dyes such as SQ-143, SQ-148, SQ-151, SQ-157, SQ-159 bearing different phosphonic acid anchoring groups with the molecular structure as shown in the Fig. 1 were logically designed and subjected to QC calculations using 6-311G/DFT/B3PW91 and PCM model using ethanol solvent to judge their suitability as sensitizer before the synthesis. Some of the suitable dyes having favorable energetics have been synthesized by multistep synthetic route. Structural characterization and confirmation have been done by 1H NMR and Fab Mass techniques followed by their Photophysical characterizations in 5 µM ethanolic solution for electronic absorption spectral behavior. Adsorption behavior of these dyes on the mesoporous TiO2 has been investigated by adsorbing the respective dyes from their 0.1 mM solution in ethanol. Photovoltaic characterization was also performed after fabricating DSSCs based on 10-12 µm thick mesoporous TiO2 with adsorbed dyes from their 0.2 mM solution as photo anode, catalytic amount of Pt coated conductive glass as counter electrode and I-/I3 - as redox electrolyte. Results and Discussion: After the successful synthesis and structural characterizations, SQ dyes under investigation were subjected to their photophysical characterizations. It can be clearly seen from the solution as well as solid-state absorption spectra shown in the Fig. 1 that due to extended p-conjugation in SQ-148 and SQ-157, exhibit bathochromically shifted absorption maxima as compared to their SQ-143 and SQ-151 dye counterparts. At the same time, in spite of having two free –OH groups in the dyes SQ-148 and SQ-143, former exhibited less extent of the dye aggregation. A swift dye adsorption in combination with reduced aggregated species are highly desired for commercial applications. Investigation pertaining to the dye adsorption behavior on the TiO2 reveals the trend of SQ-143>SQ-148>SQ-157>SQ-151 suggesting that less aggregation tends to the relatively higher rate of dye adsorption. This can be attributed to the swift diffusion of the dye molecules in the nanopores of the mesoporous TiO2 during the dye adsorption process. Stability of the adsorbed dyes on the mesoporous TiO2 is another important parameter responsible to impart the stability to the DSSCs. This was conducted by investigating the dye binding strength based on dye desorption studies. Apart from their synthesis and photophysical characterizations, dyes were also used as sensitizer to fabricate the DSSCs and implication of the nature anchoring groups on photon harvesting and overall PCE was also investigated. Results on the photovoltaic performance revealed that newly designed dye SQ-159 makes a good compromise imparting improved stability as well as PCE amongst the dyes under investigation. Acknowledgement: SSP would like to express sincere thanks to the Japan Society for Promotion of Science for the financial support by Grant-in-Aid for scientific research (C) [Grant No.-18K05300] to carry out the research Figure 1

Tuning the Optical Characteristics of Diketopyrrolopyrrole Molecules in the Solid State by Alkyl Side Chains.

The optical properties of two sets of donor–acceptor–donor molecules with terminal bithiophene donor units and a central diketopyrrolopyrrole (DPP) acceptor unit are studied. The two sets differ in the alkyl chains on the DPP, which are either branched at the α-carbon (3-pentyl) (1–4) or linear (n-hexyl) (5–8). Within each set, the molecules differ by the absence or presence of n-hexyl chains on the terminal thiophene rings in the 3′, 4′, or 5′ positions. While in solution, the optical spectra differ only subtly; they differ dramatically in the solid state. In contrast to 5–8, 1–4 are nonplanar as a consequence of the sterically demanding 3-pentyl groups, which inhibit π-stacking of the DPP units. Using the crystal structures of 2 (brick layer stacking) and 6 (slipped stacking), we quantitatively explain the solid state absorption spectra. By computing the molecular transition charge density and solving the dispersion relation, the optical absorption of the molecules in the crystal is predicted and in agreement with experiments. For 2, a single resonance frequency is obtained, while for 6 two transitions are seen, with the lower-energy transition being less intense. The results demonstrate how subtle changes in substitution exert large effects in optical properties.

Fenol-4-Sülfonik Asit ve 1,3-Bis(4-Piridil)Propan Tabanlı Yeni Organik Bileşiğin Hidrotermal Sentezi ve Karakterizasyonu

Bu çalışmada, yeni iki-boyutlu organik bileşik [PSA2][BPP2] (psa=fenol-4-sülfonik asit, bpp=1,3-Bis(4-piridil)propan) hidrotermal yöntem ile sentezlendi, tek kristal X-ışını kırınımı, toz kristal X-ışını kırınım yöntemi (PXRD), element analizi ve katı-hal UV-vis spektroskopisi ile karakterize edildi. Kristal yapı analizi, bileşiğin ortorombik kristal sisteminde Pca21 uzay grubunda kristalleştiğini ve asimetrik biriminde iki psa ve iki bpp ligandından oluştuğunu göstermektedir. Fenol ve piridil grupları neredeyse düzlemseldir. Ek olarak, bileşiğin kristal yapısı moleküller arası O–H…O, C–H…O hidrojen bağlarının yanı sıra molekül içi C–H…π ve bpp molekülleri arasında meydana gelen π - π etkileşimleriyle iki-boyutlu yapıyı oluşturmuş ve yapısal kararlılık sağlamıştır.

New quaternary selenogermanates of Rb2Ag2GeSe4 and Cs2Cu2GeSe4

Two new quaternary silver(I)/copper(I)-selenogermanates Rb2Ag2GeSe4 (1) and Cs2Cu2GeSe4 (2) have been solvothermally synthesized using mixed DMF/en (DMF = N, N-Dimethylformamide, en = ethylenediamine) solvents. Single-crystal X-ray diffraction analyses exhibit that 1 is characterized by an infinite anion chain [Ag2GeSe4]2− formed by two-coordinated silver ions interconnecting tetrahedral of [GeSe4]. 2 contains [CuGeSe4]3− chains interconnected by GeSe4 and Cu(2)Se4 units edgesharing, and two adjacent chains are further connected by tetra-coordinated Cu(1) ions to form ribbon. The title compounds are structurally characterized by powder X-ray diffraction, thermal analysis and solid-state optical absorption spectra.