Eu(O2C-C≡C-CO2): An EuII Containing Anhydrous Coordination Polymer with High Stability and Negative Thermal Expansion

Anhydrous Eu^II–acetylenedicarboxylate (EuADC; ADC²⁻ = ⁻O₂C-C≡C-CO₂⁻) was synthesized by reaction of EuBr₂ with K₂ADC or H₂ADC in degassed water under oxygen-free conditions. EuADC crystallizes in the SrADC type structure (I4₁/amd, Z=4) forming a 3D coordination polymer with a diamond-like arrangement of Eu²⁺ nodes (msw topology including the connecting ADC²⁻ linkers). Deep orange coloured EuADC is stable in air and starts decomposing upon heating in an argon atmosphere only at 440 °C. Measurements of the magnetic susceptibilities (μ_eff=7.76 μ_B) and ¹⁵¹Eu Mössbauer spectra (δ=−13.25 mm s⁻¹ at 78 K) confirm the existence of Eu²⁺ cations. Diffuse reflectance spectra indicate a direct optical band gap of E_g=2.64 eV (470 nm), which is in accordance with the orange colour of the material. Surprisingly, EuADC does not show any photoluminescence under irradiation with UV light of different wavelengths. Similar to SrADC, EuADC exhibits a negative thermal volume expansion below room temperature with a volume expansion coefficient α_V=−9.4(12)×10⁻⁶ K⁻¹.     

Improving the Switching Capacity of Glyco-Self-Assembled Monolayers on Au(111)

Self-assembled monolayers (SAMs) decorated with photoisomerizable azobenzene glycosides are useful tools for investigating the effect of ligand orientation on carbohydrate recognition. However, photoswitching of SAMs between two specific states is characterized by a limited capacity. The goal of this study is the improvement of photoswitchable azobenzene glyco-SAMs. Different concepts, in particular self-dilution and rigid biaryl backbones, have been investigated. The required SH-functionalized azobenzene glycoconjugates were synthesized through a modular approach, and the respective glyco-SAMs were fabricated on Au(111). Their photoswitching properties have been extensively investigated by applying a powerful set of methods (IRRAS, XPS, and NEXAFS). Indeed, the combination of tailor-made biaryl-azobenzene glycosides and suitable diluent molecules led to photoswitchable glyco-SAMs with a significantly enhanced and unprecedented switching capacity.     

Sensor Array Based Determination of Edman Degradated Amino Acids Using Poly(p-phenyleneethynylene)s

A cross-reactive optical sensor array based on poly(p-phenyleneethynylene)s (PPEs) determines Edman degraded amino acids. We report a sensor array composed of three anionic PPEs P1–P3 , and their electrostatic complexes with metal ions (Fe²⁺, Cu²⁺, Co²⁺). We recorded distinct fluorescence intensity response patterns as “fingerprints” of this chemical tongue toward standard phenylthiohydantoin (PTH) amino acids—degradation products of the Edman process. These “fingerprints” were converted into canonical scores by linear discrimination analysis (LDA), which differentiates all of the PTH-amino acids. This array discriminates PTH-amino acid residues degraded from an oligopeptide through Edman sequencing. This approach is complementary to chromatography approaches which rely on mass spectrometry; our array offers the advantage of simplicity.     

trans‐Selective Insertional Dihydroboration of a cis‐Diborene: Synthesis of Linear sp3‐sp2‐sp3‐Triboranes and Subsequent Cationization

The reaction of aryl‐ and amino(dihydro)boranes with dibora[2]ferrocenophane 1 leads to the formation 1,3‐trans‐dihydrotriboranes by formal hydrogenation and insertion of a borylene unit into the B=B bond. The aryltriborane derivatives undergo reversible photoisomerization to the cis‐1,2‐μ‐H‐3‐hydrotriboranes, while hydride abstraction affords cationic triboranes, which represent the first doubly base‐stabilized B₃H₄⁺ analogues.     

From Plato to Frege: Paradigms of Predication in the History of Ideas

One of the perennial questions of philosophy concerns the simple statements which say that an object is so and so or that such and such objects are so and so related: simple predicative statements. Do such statements have an ontological basis, and if so, what is that basis? The answer to this question determines—or in any case, is expressive of—a specific fundamental outlook on the world. In the course of the history of Western philosophy, various philosophers have given various answers to the question of predication. This essay presents the main, crucial answers: the paradigms and theories of predication of the Sophists (and of all later radical relativists), of Plato, of Aristotle, of the Aristotelian-minded non-nominalists, of Leibniz, and of Frege. In addition, the essay follows (to some extent) the most influential—the Aristotelian or mereological—paradigm of predication in its continuity and modification through the many centuries of its reign. However, the essay is not content to adopt the merely historical point of view; it also poses the question of adequacy. Prior to Frege, there was no philosophically adequate theory of predication, and the essay points out the shortcomings (besides aspects that can be viewed as advantages) of each pre-Fregean predication theory considered in it. Frege, in the nineteenth century, brought the philosophy of predication on the right track, but his own theory of predication has its own deficits. The essay ends with the presentation of a theory of predication that the author himself considers adequate.     

A computational approach to calculating frequency-dependent structural operators using the spectral finite element method and a wavenumber-based gridding technique

Spectral finite element methods are used to compute exact vibration solutions of structural models at specific frequencies. The applicability of these methods to certain areas of structural dynamics is limited by two major factors: the lack of separate structural operators (mass, damping, and stiffness matrices), and the subsequent difficulty in computing mode shapes via eigenvalue decomposition. In the work presented in this article, a method is investigated to accurately calculate spectral finite elements while overcoming these limitations. The approach incorporates a two-dimensional, discrete solution utilizing a wavenumber-based gridding technique to compute frequency-dependent local mass, damping, and stiffness matrices which can be assembled into the global structural operators. Computed models are able to be used for precise vibration analysis as well as modal analysis via eigenvalue decomposition of the structural operators.