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1.
Psychol Rev ; 2024 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-39023936

RESUMO

The explanation of psychological phenomena is a central aim of psychological science. However, the nature of explanation and the processes by which we evaluate whether a theory explains a phenomenon are often unclear. Consequently, it is often unknown whether a given psychological theory indeed explains a phenomenon. We address this shortcoming by proposing a productive account of explanation: a theory explains a phenomenon to some degree if and only if a formal model of the theory produces the statistical pattern representing the phenomenon. Using this account, we outline a workable methodology of explanation: (a) explicating a verbal theory into a formal model, (b) representing phenomena as statistical patterns in data, and (c) assessing whether the formal model produces these statistical patterns. In addition, we provide three major criteria for evaluating the goodness of an explanation (precision, robustness, and empirical relevance), and examine some cases of explanatory breakdowns. Finally, we situate our framework within existing theories of explanation from philosophy of science and discuss how our approach contributes to constructing and developing better psychological theories. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

2.
J Am Chem Soc ; 146(31): 21710-21720, 2024 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-39054782

RESUMO

Exploring the relationship between thermal expansion and structural complexity is a challenging topic in the study of modern materials where volume stability is required. This work reports a new family of negative thermal expansion (NTE) materials, AM(CN)4 with A = Li and Na and M = B, Al, Ga, and In. Here, the compounds of LiB(CN)4 and NaB(CN)4 were only synthesized; others were purely computationally studied. A critical role of nonrigid vibrational modes and spiral acoustical modes has been identified in NaB(CN)4. This understanding has been exploited to design the colossal NTE materials of NaM(CN)4 (M = Al, Ga, In). A joint study involving synchrotron X-ray diffraction, Raman spectroscopy, and first-principles calculations has been conducted to investigate the thermal expansion mechanism. It has been found that the A atoms can either increase the symmetry of the crystal structure, inducing stronger NTE, or lower the crystal symmetry, thus resulting in positive thermal expansion. Conversely, the M-site atoms do not affect the crystal structure. However, as the radius of the M atoms increases, the ionic nature of the C-M bonds strengthens and the CN vibrations become more flexible, thereby enhancing the NTE behavior. This study provides new insights to aid in the discovery and design of novel NTE materials and the control of thermal expansion.

3.
Angew Chem Int Ed Engl ; 63(18): e202401279, 2024 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-38470074

RESUMO

A series of terminal mono- and disubstituted beryllium azides of the form [(CAAC)Be(N3)R] (R=CAACH, Dur; CAACH/CAAC=1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-yl/idene, Dur=2,3,5,6-tetramethylphenyl) and [L2Be(N3)2] (L=CAACNH=1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-imine, IiPrMe=1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene), respectively, were synthesized and characterized by NMR spectroscopy and X-ray crystallography. Thermolysis and photolysis products of these first examples of tricoordinate azidoberyllium complexes evidence extensive ligand scrambling and the formal insertion of nitrenes into the CAAC-Be bond, generating cyclic alkyl(amino)imine (CAAI) ligands. Furthermore, the reaction with a small N-heterocyclic carbene (NHC) leads to unexpected CAAC-NHC ligand exchange, while the reaction with pentaphenylborole yields the first γ-azide adduct of a borole, long postulated to be the first step in the synthesis of 1,2-azaborinines from boroles and azides.

4.
Angew Chem Int Ed Engl ; 63(13): e202401302, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38353130

RESUMO

Negative thermal expansion (NTE) is crucial for controlling the thermomechanical properties of functional materials, albeit being relatively rare. This study reports a giant NTE (αV ∼-9.2 ⋅ 10-5  K-1 , 100-200 K; αV ∼-3.7 ⋅ 10-5  K-1 , 200-650 K) observed in NaB(CN)4 , showcasing interesting ultralight properties. A comprehensive investigation involving synchrotron X-ray diffraction, Raman spectroscopy, and first-principles calculations has been conducted to explore the thermal expansion mechanism. The findings indicate that the low-frequency phonon modes play a primary role in NTE, and non-rigid vibration modes with most negative Grüneisen parameters are the key contributing factor to the giant NTE observed in NaB(CN)4 . This work presents a new material with giant NTE and ultralight mass density, providing insights for the understanding and design of novel NTE materials.

5.
Inorg Chem ; 63(4): 2204-2216, 2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38206799

RESUMO

Nickel(II) cyanoborates Ni[BH2(CN)2]2·H2O (1b·H2O), Ni[BH(CN)3]2·0.5H2O (1c·0.5H2O), and Ni[B(CN)4]2·0.5H2O (1d·0.5H2O) were synthesized, and their reactivity with respect to dppeO2 (=1,2-bis-(diphenylphosphinoethane dioxide)), pyNO (=pyridine-N-oxide), dppe (=1,2-bis-(diphenylphosphinoethane), and DMSO (=dimethyl sulfoxide) was examined. Using these ligands, either cyanoborate (CB) complex salts of [Ni(dppe)2]2+ (2b-d) and [Ni(pyNO)6]2+ (3c-d) were isolated or complexes [Ni(DMSO)4{NC-B(CN)3}2] (1dDMSO) and [Ni(dppeO2)2{NC-B(CN)3}2] (1ddppeO2) were formed. Salt metathesis of [Ni(dppe)Cl2] with alkali metal cyanoborates resulted in mono- and disubstituted coordination compounds [Ni(dppe){NC-BH(CN)2}Cl] (5c) and [Ni(dppe){NC-BH2CN)2}] (4b), which decomposed to salts 2b-d. The synthetical pathways explored offer convenient routes to nickel(II) cyanoborates, nickel(II) complexes ligated with cyanoborates, and nickel(II) complex salts of cyanoborates. Further, our studies demonstrate the diverse character of cyanoborates in coordination chemistry as noncoordinating counteranions and also as medium coordinating anions forming novel transition-metal complexes and salts.

6.
Chemistry ; 29(64): e202302701, 2023 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-37615512

RESUMO

A scalable straightforward synthesis of monofluoro- and difluoromethyl triflate CF3 SO2 OCH2 F (MH2F ) and CF3 SO2 OCHF2 (MHF2 ) through electrochemical fluorination (ECF, Simons process) of methyl triflate MH3 in anhydrous hydrogen fluoride at nickel anodes is presented. The ECF method is also feasible for the preparation of the deuterated analogues CF3 SO2 OCD2 F (MD2F ) and CF3 SO2 OCDF2 (MD2F ). Surprisingly, no H/D exchange occurs during ECF of CF3 SO2 OCD3 (MD3 ); this provides further evidence for a NiF3 /NiF4 -mediated ECF mechanism. The ECF of selected partially fluorinated ethyl triflates is described, and electrochemical fluorination of CF3 SO2 OCH2 CF3 (EH2F3 ) leads to the until now unknown chiral CF3 SO2 OCHFCF3 (EHFF3 ). The analogous fluoromethyl and fluoroethyl nonaflates are also accessible by ECF. This study contains detailed spectroscopic, structural, and thermal data on (fluoro)methyl and fluoro(ethyl) triflates.

7.
Chemistry ; 29(52): e202301497, 2023 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-37395305

RESUMO

A set of mixed-substituted potassium alkylcyano- and alkylcyanofluoroborates has been synthesized using easily accessible starting compounds and characterized by elemental analysis, NMR and vibrational spectroscopy, and mass spectrometry. In addition, single-crystal structures of salts of the cyanoborate anions have been derived from X-ray diffraction experiments. The 1-ethyl-3-methylimidazolium room temperature ionic liquids ([EMIm]+ -RTILs) with the new borate anions have been synthesized and their physicochemical properties, that is, high thermal and electrochemical stability, low viscosity, and high conductivity, have been compared to the properties of related [EMIm]+ -RTILs. The influence of the different alkyl substituents at boron has been assessed. The exemplary study on the properties with the [EMIm]+ -ILs with the mixed water stable alkylcyanoborate anions points towards the potential of these fluorine-free borate anions, in general.

8.
Phys Chem Chem Phys ; 25(6): 5037-5048, 2023 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-36722915

RESUMO

The synthesis and detailed characterization of low-viscosity room-temperature ionic liquids (RTILs) and [BnPh3P]+ salts with the cyano(fluoro)borate anions [BF(CN)3]- (MFB), [BF2(CN)2]- (DFB), and [BF3(CN)]- as well as the new mixed-substituted anion [BFH(CN)2]- (FHB) is described. The RTILs with [EMIm]+ or [BMPL]+ as countercations were obtained in yields of up to 98% from readily available alkali metal salts and in high purities that allow application in electrochemical devices. Trends in thermal stability, melting and freezing behavior, density, electrochemical stability, dynamic viscosity, specific conductivity and ion diffusivity have been assessed and compared to those of the related tetracyanoborate- and cyano(hydrido)borate-RTILs. The crystal structure analysis of the [BnPh3P]+ salts of [BFn(CN)4-n]- (n = 0-4), [BHn(CN)4-n]- (n = 1-3) and [BFH(CN)2]- provided experimental access to anion volumina that together with ion molecular mass, electrostatic potential, shape and chemical stability have been correlated to physicochemical properties. In addition, the cytotoxicity of the [EMIm]+-ILs and potassium or sodium salts was studied.

9.
Chem Sci ; 14(8): 2200-2214, 2023 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-36845914

RESUMO

Room temperature ionic liquids of cyclic sulfonimide anions ncPFSI (ring size: n = 4-6) with the cations [EMIm]+ (1-ethyl-3-methylimidazolium), [BMIm]+ (1-butyl-3-methylimidazolium) and [BMPL]+ (BMPL = 1-butyl-1-methylpyrrolidinium) have been synthesized. Their solid-state structures have been elucidated by single-crystal X-ray diffraction and their physicochemical properties (thermal behaviour and stability, dynamic viscosity and specific conductivity) have been assessed. In addition, the ion diffusion was studied by pulsed field gradient stimulated echo (PFGSTE) NMR spectroscopy. The decisive influence of the ring size of the cyclic sulfonimide anions on the physicochemical properties of the ILs has been revealed. All ILs show different properties compared to those of the non-cyclic TFSI anion. While these differences are especially distinct for ILs with the very rigid 6cPFSI anion, the 5-membered ring anion 5cPFSI was found to result in ILs with relatively similar properties. The difference between the properties of the TFSI anion and the cyclic sulfonimide anions has been rationalized by the rigidity (conformational lock) of the cyclic sulfonimide anions. The comparison of selected IL properties was augmented by MD simulations. These highlight the importance of π+-π+ interactions between pairs of [EMIm]+ cations in the liquid phase. The π+-π+ interactions are evident for the solid state from the molecular structures of the [EMIm]+-ILs with the three cyclic imide anions determined by single-crystal X-ray diffraction.

10.
Psychon Bull Rev ; 30(2): 516-533, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35969359

RESUMO

A tradition that goes back to Sir Karl R. Popper assesses the value of a statistical test primarily by its severity: was there an honest and stringent attempt to prove the tested hypothesis wrong? For "error statisticians" such as Mayo (1996, 2018), and frequentists more generally, severity is a key virtue in hypothesis tests. Conversely, failure to incorporate severity into statistical inference, as allegedly happens in Bayesian inference, counts as a major methodological shortcoming. Our paper pursues a double goal: First, we argue that the error-statistical explication of severity has substantive drawbacks; specifically, the neglect of research context and the specificity of the predictions of the hypothesis. Second, we argue that severity matters for Bayesian inference via the value of specific, risky predictions: severity boosts the expected evidential value of a Bayesian hypothesis test. We illustrate severity-based reasoning in Bayesian statistics by means of a practical example and discuss its advantages and potential drawbacks.


Assuntos
Teorema de Bayes , Humanos
11.
Chem Commun (Camb) ; 58(8): 1223-1226, 2022 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-34985079

RESUMO

Ethyl-, vinyl- and ethynyltricyano and dicyanofluoroborates were prepared on a gram scale from commercially available potassium trifluoroborates and trimethylsilylcyanide. Salt metathesis resulted in the corresponding EMIm-salts that are hydrophobic room-temperature ionic liquids (RTILs). The new RTILs exhibit unprecedented large electrochemical windows in combination with high thermal stabilities, low dynamic viscosities and high specific conductivities. These properties make them promising materials, especially for electrochemical applications.

12.
Chem Commun (Camb) ; 57(19): 2408-2411, 2021 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-33544098

RESUMO

Fully aromatic, luminescent, and highly robust BNB-doped phenalenyls have been prepared, which are isoelectronic to the phenalenyl cation. B-Fluoromesityl-substitution leads to fluorescence in an extremely narrow range and significant increase in the reduction potential. Detailed theoretical investigations revealed an intramolecular aromaticity switch upon one-electron reduction.

13.
ChemistryOpen ; 10(2): 164-170, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33492772

RESUMO

Based on the strand-like coordination polymer (CP) type 1 ∞ [Ln(BSB)3 (py)2 ], [BSB]- =bis-salicylatoborate anion, mixed Eu/Tb-containing compounds of the constitution 1 ∞ [Eux Tb1-x (BSB)3 (py)2 ] were synthesised ionothermally for a phase width of (x=0.25-0.75) and characterized regarding structure and optical properties. Previously, known only for other lanthanides, the mixed 1D-Eu/Tb-CPs show excellent options for statistic replacement of the Ln-cations during synthesis yielding solid solutions. The products are highly luminescent, with the chromaticity being a direct function of the amount of the respective Ln-ions. Corresponding to an overall addition of emission intensities, the green Tb3+ emission and the red Eu3+ emission allow for a chromaticity control that also includes yellow emission. Control of the luminescence colour renders them suitable examples of the versatility of statistic replacement of metal ions in coordination chemistry. In addition, crystallization of [EMIm]2 [YCl5 (py)] illuminates possible other products of the ionothermal reactions of [EMIm][BSB] with LnCl3 constituted by components not being part of the main CPs.

14.
Chemistry ; 26(50): 11625-11633, 2020 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-32453869

RESUMO

Different types of high-yield, easily scalable syntheses for cyano(fluoro)borates Kt[BFn (CN)4-n ] (n=0-2) (Kt=cation), which are versatile building blocks for materials applications and chemical synthesis, have been developed. Tetrafluoroborates react with trimethylsilyl cyanide in the presence of metal-free Brønsted or Lewis acid catalysts under unprecedentedly mild conditions to give tricyanofluoroborates or tetracyanoborates. Analogously, pentafluoroethyltrifluoroborates are converted into pentafluoroethyltricyanoborates. Boron trifluoride etherate, alkali metal salts, and trimethylsilyl cyanide selectively yield dicyanodifluoroborates or tricyanofluoroborates. Fluorination of cyanohydridoborates is the third reaction type that includes direct fluorination with, for example, elemental fluorine, stepwise halogenation/fluorination reactions, and electrochemical fluorination (ECF) according to the Simons process. In addition, fluorination of [BH(CN)2 {OC(O)Et}]- to result in [BF(CN)2 {OC(O)Et}]- is described.

15.
J Phys Chem A ; 124(5): 864-874, 2020 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-31914728

RESUMO

In this study, in situ infrared spectroscopy techniques and thermogravimetric analysis coupled with mass spectrometry (TGA-MS) are employed to characterize the reactivity of the ionic liquid, 1-butyl-3-methylimidazolium dicyanoborohydride (BMIM+DCBH-), in comparison to the well-characterized 1-butyl-3-methylimidazolium dicyanamide (BMIM+DCA-) ionic liquid. TGA measurements determined the enthalpy of vaporization (ΔHvap) to be 112.7 ± 12.3 kJ/mol at 298 K. A rapid scan Fourier transform infrared spectrometer was used to obtain vibrational information useful in tracking the appearance and disappearance of species in the hypergolic reactions of BMIM+DCBH- and BMIM+DCA- with white fuming nitric acid (WFNA) and in the thermal decomposition of these energetic ionic liquids. Attenuated total reflectance measurements recorded the infrared spectra of the reactant sample (BMIM+DCBH-) and the liquid reaction products after reacting with WFNA. Computational chemistry efforts, aided by the experimental results, were used to propose key reaction pathways leading to the hypergolic ignition of BMIM+DCBH- + WFNA. Experimental results indicate that the hypergolic reaction of BMIM+DCBH- with WFNA generates both common and unique intermediates as compared to previous BMIM+DCA- + WFNA investigations: nitrous oxide was generated during both hypergolic reactions indicating that it may play a crucial role in the hypergolic ignition process, NO2 was generated in significantly higher concentrations for BMIM+DCBH- than for BMIM+DCA-, CO2 was only generated for BMIM+DCA-, and HCN was only generated during thermal decomposition and hypergolic ignition of BMIM+DCBH-.

16.
Inorg Chem ; 58(24): 16689-16702, 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31765132

RESUMO

In recent years, salts of the hydridotricyanoborate anion [BH(CN)3]- (MHB) have become readily available. In spite of the unusually high stability of the MHB anion, it can be used as a valuable starting material for the preparation of selected tricyanoborates, for example, the boron-centered nucleophile B(CN)32-. A further unprecedented example is the hydroxytricyanoborate anion [B(OH)(CN)3]- that is accessible by oxidation of (H3O)MHB with elemental bromine in water. The Brønsted acid (H3O)[B(OH)(CN)3] was isolated as a crystalline solid. It serves as a versatile starting material for the synthesis of coordination compounds, metal salts, and ionic liquids. The [B(OH)(CN)3]- anion shows a rich coordination chemistry and a high tendency to form hydrogen-bonded motifs as demonstrated by a series of salts with different types of cations. Furthermore, the [B(OH)(CN)3]- anion itself serves as starting material for new tricyanoborates such as the unusual trianion [B{OB(CN)3}3]3- and the silylated anions [B(OSiR3)(CN)3]- (R = Me, Et, Ph). Some of these follow-up products have been characterized by single-crystal X-ray diffraction, e.g., [nBu4N]3[B{OB(CN)3}3] and [nBu4N][B(OSiPh3)(CN)3].

17.
Chemistry ; 25(14): 3560-3574, 2019 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-30600853

RESUMO

High-yield syntheses up to molar scales for salts of [BH(CN)3 ]- (2) and [BH2 (CN)2 ]- (3) starting from commercially available Na[BH4 ] (Na5), Na[BH3 (CN)] (Na4), BCl3 , (CH3 )3 SiCN, and KCN were developed. Direct conversion of Na5 into K2 was accomplished with (CH3 )3 SiCN and (CH3 )3 SiCl as a catalyst in an autoclave. Alternatively, Na5 is converted into Na[BH{OC(O)R}3 ] (R=alkyl) that is more reactive towards (CH3 )3 SiCN and thus provides an easy access to salts of 2. Some reaction intermediates were identified, for example, Na[BH(CN){OC(O)Et}2 ] (Na7 b) and Na[BH(CN)2 {OC(O)Et}] (Na8 b). A third entry to 2 and 3 uses ether adducts of BHCl2 or BH2 Cl such as the commercial 1,4-dioxane adducts that react with KCN and (CH3 )3 SiCN. Alkali metal salts of 2 and 3 are convenient starting materials for organic salts, especially for low viscosity ionic liquids (ILs). [EMIm]3 has the lowest viscosity and highest conductivity with 10.2 mPa s and 32.6 mS cm-1 at 20 °C known for non-protic ILs. The ILs are thermally, chemically, and electrochemically robust. These properties are crucial for applications in electrochemical devices, for example, dye-sensitized solar cells (Grätzel cells).

18.
J Phys Chem A ; 123(4): 780-795, 2019 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-30599094

RESUMO

To develop the next generation of hypergolic, ionic-liquid-based fuels, it is important to understand the fundamental reaction mechanisms for the oxidation of ionic liquids (ILs). We consequently studied the oxidation of a levitated 1-butyl-3-methylimidazolium dicyanoborate ([BMIM][DCBH]) droplet by nitrogen dioxide (NO2). The properties of [BMIM][DCBH], including short ignition-delay times, low viscosities, and a wide liquid temperature range, make the ionic liquid especially suitable as a component of a hypergolic fuel. The chemical modifications were monitored with Fourier-transform infrared (FTIR), Raman, and ultraviolet-visible spectroscopies. To identify changes induced by the oxidation, it was first necessary to assign vibrational modes to the FTIR and Raman spectra of unreacted [BMIM][DCBH]. The new features in the oxidized FTIR and Raman spectra could then be identified and assigned on the basis of the possible functional groups likely to form through addition with a nitrogen and an oxygen atom of nitrogen dioxide creating a new bond with the ionic liquid. The assignments suggest that organic nitro-compounds and boron-nitrogen and boron-oxygen containing compounds were produced. A large decrease in the intensity of some [DCBH]- fundamental modes suggests the nitrogen dioxide molecule prefers to react with the anion over the cation.

19.
PLoS One ; 13(4): e0194360, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29649220

RESUMO

Experimental philosophy (x-phi) is a young field of research in the intersection of philosophy and psychology. It aims to make progress on philosophical questions by using experimental methods traditionally associated with the psychological and behavioral sciences, such as null hypothesis significance testing (NHST). Motivated by recent discussions about a methodological crisis in the behavioral sciences, questions have been raised about the methodological standards of x-phi. Here, we focus on one aspect of this question, namely the rate of inconsistencies in statistical reporting. Previous research has examined the extent to which published articles in psychology and other behavioral sciences present statistical inconsistencies in reporting the results of NHST. In this study, we used the R package statcheck to detect statistical inconsistencies in x-phi, and compared rates of inconsistencies in psychology and philosophy. We found that rates of inconsistencies in x-phi are lower than in the psychological and behavioral sciences. From the point of view of statistical reporting consistency, x-phi seems to do no worse, and perhaps even better, than psychological science.


Assuntos
Filosofia , Psicologia/métodos , Estatística como Assunto , Ciências do Comportamento , Humanos , Modelos Estatísticos , Motivação , Padrões de Referência , Reprodutibilidade dos Testes , Projetos de Pesquisa , Ciências Sociais , Software
20.
Chemistry ; 24(14): 3474-3480, 2018 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-29266707

RESUMO

The role of borate anions in ionothermal syntheses of crystalline chalcogenidometalates was shown by the directed ionothermal synthesis of seven new selenidostannates in ionic liquids with either [BF4 ]- or [B(CN)4 ]- anions. Single crystal structures are presented of four compounds, (C4 C1 C1 Im)5 [Sn9 Se20 ][BF4 ] (1, Im=imidazolium), (DMMPH)4 [Sn2 Se6 ] (2, DMMP=2,6-dimethylmorpholine), (C2 C1 Im)2 (DMMPH)2 [Sn6 Se14 ] (3), and K2 [Sn3 Se7 ] (4), and how the chosen ionic liquid anion, and the reaction temperature, influences the product spectrum is discussed: Notably, 1 contains an entire formula unit of the ionic liquid, (C4 C1 C1 Im)[BF4 ], while 4 contains neither the cation nor the anion of the ionic liquid-both observations being very uncommon for ionothermal syntheses. Three further compounds were obtained that exhibit strong disorder in the crystal structures (I-III), for which only their anionic substructures are discussed herein. Compound 4 and I-III are based on the same layered selenidostannate substructure, 2D-{[Sn3 Se7 ]2- }, yet with different inter-layer distances, which is clearly reflected in the crystal colors and quantitative optical absorption properties.

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