Photoinduced Mo−CN Bond Breakage in Octacyanomolybdate Leading to Spin Triplet Trapping

The photoinduced properties of the octacoordinated complex K₄Mo^IV(CN)₈?2 H₂O were studied by theoretical calculations, crystallography, and optical and magnetic measurements. The crystal structure recorded at 10 K after blue light irradiation reveals an heptacoordinated Mo(CN)₇ species originating from the light‐induced cleavage of one Mo?CN bond, concomitant with the photoinduced formation of a paramagnetic signal. When this complex is heated to 70 K, it returns to its original diamagnetic ground state, demonstrating full reversibility. The photomagnetic properties show a partial conversion into a triplet state possessing significant magnetic anisotropy, which is in agreement with theoretical studies. Inspired by these results, we isolated the new compound [K(crypt‐222)]₃[Mo^IV(CN)₇]?3 CH₃CN using a photochemical pathway, confirming that photodissociation leads to a stable heptacyanomolybdate(IV) species in solution.     

A Low-Temperature Approach for the Phase-Pure Synthesis of MIL-140 Structured Metal–Organic Frameworks

In a systematic investigation, the synthesis of metal–organic frameworks (MOFs) with MIL-140 structure was studied. The precursors of this family of MOFs are the same as for the formation of the well-known UiO-type MOFs although the synthesis temperature for MIL-140 is significantly higher. This study is focused on the formation of Zr-based MIL-140 MOFs with terephthalic acid (H₂bdc), biphenyl-4,4′-dicarboxylic acid (H₂bpdc), and 4,4′-stilbenedicarboxylic acid (H₂sdc) and the introduction of synthesis field diagrams to discover parameters for phase-pure products. In this context, a MIL-140 network with H₂sdc as linker molecule is first reported. Additionally, an important aspect is the reduction of the synthesis temperature to make MIL-140 MOFs more accessible even though linkers with a more delicate nature are used. The solvothermal syntheses were conducted in highly concentrated reaction mixtures whereby a targeted synthesis to yield the MIL-140 phase is possible. Furthermore, the effect of the often-used modulator approach is examined for these systems. Finally, the characteristics of the synthesized MOFs are compared with physisorption measurements, thermogravimetric analyses, and scanning electron microscopy.     

Fast and efficient VUV/UV emissions from (Ba,La)F2:Er crystals

We report observation of fast and efficient VUV/UV luminescence from the mixed (Ba,La)F₂:Er crystals. The broad bands, peaking at 162.5, 181.9, 194.2, 202.8, 216.1, 233.5 and 281.5 nm and decaying, at 10 and 293 K, with time constants of 46 and 35 ns respectively, are due to spin-allowed transitions from the low-spin (LS) state of the 4f¹⁰5d configuration.We also observed a weak and slow broad band emission peaking at 170 nm due to the spin-forbidden transition from the high-spin (HS) state of the 4f¹⁰5d configuration.While at room temperature the excitation into any of the three identified LS bands (J=8, 7 and 6) dominating the excitation spectrum yields fast VUV and UV emissions, at 10 K the excitation into higher lying J=7 and 6 bands generates slow and sharp line emissions. The positions of these lines fit energies of transitions originating from the ²G_7/2 multiplet at 66140 cm⁻¹. The emission from the ²G_7/2 multiplet has been never, to the best of our knowledge, observed before.The efficient and fast VUV and UV emissions from the higher (LS, J=8) with almost no contribution from the lower (HS, J=8) level of the 4f¹⁰5d configuration are possible because the modified crystal field in (Ba,La)F₂ shifts the level of the (LS, J=8) state below the ²F_5/2 multiplet which, therefore, does not contribute to nonradiative relaxation between the LS and HS levels.We conclude that the ²G_7/2 and ²F_5/2 levels have major impact on VUV and UV emissions from the Er³⁺ ion in (Ba,La)F₂ contributing to complex emission pattern described in this report Their key role, elucidated by the VUV and UV luminescence spectroscopy, is consistent with predictions from a simple configuration coordinate model based on experimental results and calculations of the 4f¹¹ energy levels.     

Dynamic strategic interaction between an innovating and a non-innovating incumbent

This paper analyzes the effects of product innovation on the firms’ investment behavior in a dynamic duopoly framework. A differential game setting is considered where initially two firms are active on a homogeneous product market. One of the firms has an option to introduce a new product that is horizontally and vertically differentiated from the established product. The resulting differential game has three states corresponding to three capital stocks: one for each firm to produce the established product, and one for the innovating firm to produce the new product. We numerically derive Markov perfect equilibria. One of the most remarkable results is that in most cases the non-innovating firm benefits when the other firm carries out the innovation option. The intuition is that, to increase demand for the innovative product, the innovative firm reduces capacity on the established market, which increases the price of the established product and thus the payoff of the non-innovating firm.     

Linear and nonlinear response of pipeline suspension bridge due to moving fluid

Basing on the nonlinear dynamic model of flexible pipeline suspended by spatial system of cables, described in Ref. [1], the linear and nonlinear vibrations are investigated in order to estimate the nonlinear effects. The model is based on substructure technique and formulated including features specific to analyzed structure, for example large displacements and time dependent parameters appearing in equations of motion due to fluid flowing inside the pipeline. Due to the fact that modelling problem for the analyzed structure is one's own complicated, a simple case when the conveying fluid is idealized simply as a ballast moving inside the pipe is considered. This paper presents a short numerical analysis of linear and nonlinear, static and dynamic response of exemplary structure for three different cases: during filling the pipe with fluid, when the pipeline is completely filled and during emptying the pipe. Moreover, for the linear problem, the influence of a speed of the fluid on the stability of the pipeline suspension bridge is investigated. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Dynamical and structural properties of 4-cyano-4-n-pentylbiphenyl (5CB) molecules adsorbed on carbon nanotubes of different chiralities: Computer simulation

An ensemble of mesogenic molecules adsorbed on the surface of single walled carbon nanotubes (SWCNTs) of different chiralities has been simulated using the MD technique. We have investigated the influence of the geometry of a carbon nanotube on the mesogene layer arrangement. Several structural and dynamical characteristics of mesogenes in such specific environment have been calculated: the radial distribution function, the orientational distribution functions, the angular and linear velocity autocorrelation functions. We have found a substantial chirality dependence of the structure and dynamics of a mesogene layer developed over the carbon nanotube surface.     

Practical application of the Average Information Content Maximization (AIC-MAX) algorithm: selection of the most important structural features for serotonin receptor ligands

The Average Information Content Maximization algorithm (AIC-MAX) based on mutual information maximization was recently introduced to select the most discriminatory features. Here, this methodology was applied to select the most significant bits from the Klekota-Roth fingerprint for serotonin receptors ligands as well as to select the most important features for distinguishing ligands with activity for one receptor versus another. The interpretation of selected bits and machine-learning experiments performed using the reduced interpretations outperformed the raw fingerprints and indicated the most important structural features of the analyzed ligands in terms of activity and selectivity. Moreover, the AIC-MAX methodology applied here for serotonin receptor ligands can also be applied to other target classes.