Molecular intercalates

The paper deals with the relations between host lattices and guest molecules. Several types of interaction of the guest molecules and the host material are explained and some conclusions are made about the arrangement of various guest molecules in the van der Waals' gap.     

Synthesis and characterization of n=5, 6 members of the La4Srn−4TinO3n+2 series with layered structure based upon perovskite

Layered compounds have been synthesized and structurally characterized for the n=5 and 6 members of the perovskite-related family La₄Sr_n−4Ti_nO_3n+2 by combining X-ray diffraction and transmission electron microscopy. Their structure can be regarded as comprising [(La,Sr)₅Ti₅O₁₇] and [(La,Sr)₆Ti₆O₂₀] perovskite blocks joined by crystallographic shears along the a-axis, with consecutive blocks shifted by 1/2 [100]_p. The n=5 member is similar to the previously reported n=5 member of other A_nB_nO_3n+2-related series. The n=6 member, which has only been briefly reported in other systems previously, is also a well-behaved member of this A_nB_nO_3n+2 series.     

Mössbauer Spectra of FePS3-Cobaltocene Intercalation Compound

Abstract

Mössbauer spectra of the FePS₃-cobaltocene intercalation compound were measured in the temperature range of 300K to 10K. The spectra, distinct from those of pure FePS₃, suggest the charge transfer from cobaltocene to Fe-S antibonding orbitals of the FePS₃ host lattice.     

Improved Electrochemical Cycling Durability in a Nickel Oxide Double‐Layered Film

For the first time, a crystalline–amorphous double‐layered NiO_x film has been prepared by reactive radio frequency magnetron sputtering. This film has exhibited improved electrochemical cycling durability, whereas other electrochromic parameters have been maintained at the required level, namely, a short coloration/bleaching time (0.8 s/1.1 s) and an enhanced transmittance modulation range (62.2 %) at λ =550 nm. Additionally, the double‐layered film has shown better reversibility than that of amorphous and crystalline single‐layered films.     

A FT-IR and V-UV Spectroscopic Study of Nickel-Containing Hydrotalcite-Like Compounds, [Ni1−xAlx(OH)2](CO3)x/2.nH2O

Hydrotalcite-like compounds containing Ni(II) and Al(III) cations and with different Ni/Al ratios in the brucite layers have been prepared and studied using FT-IR and V-UV/DR spectroscopies. It has been found that the local environment of the Ni(II) cations is the same in all cases, occupying octahedral holes, but the orientation of the interlayer carbonate anions changes with the Ni/Al ratio.     

Nanoindentation as a Probe for Mechanically‐Induced Molecular Migration in Layered Organic Donor–Acceptor Complexes

Nanoindentation and scratch experiments on 1:1 donor–acceptor complexes, 1 and 2 , of 1,2,4,5‐tetracyanobenzene with pyrene and phenanthrene, respectively, reveal long‐range molecular layer gliding and large interaction anisotropy. Due to the layered arrangements in these crystals, these experiments that apply stress in particular directions result in the breaking of interlayer interactions, thus allowing molecular sheets to glide over one another with ease. Complex 1 has a layered crystal packing wherein the layers are 68° skew under the (002) face and the interlayer space is stabilized by van der Waals interactions. Upon indenting this surface with a Berkovich tip, pile‐up of material was observed on just one side of the indenter due to the close angular alignment of the layers with the half angle of the indenter tip (65.35°). The interfacial differences in the elastic modulus (21 %) and hardness (16 %) demonstrate the anisotropic nature of crystal packing. In 2 , the molecular stacks are arranged in a staggered manner; there is no layer arrangement, and the interlayer stabilization involves C? H???N hydrogen bonds and π???π interactions. This results in a higher modulus (20 %) for (020) as compared to (001), although the anisotropy in hardness is minimal (4 %). The anisotropy within a face was analyzed using AFM image scans and the coefficient of friction of four orthogonal nanoscratches on the cleavage planes of 1 and 2 . A higher friction coefficient was obtained for 2 as compared to 1 even in the cleavage direction due to the presence of hydrogen bonds in the interlayer region making the tip movement more hindered.     

Biohybrid based on layered terbium hydroxide and applications as drug carrier and biological fluorescence probe

Aspirin (abbr. ASA) is intercalated into the layered terbium hydroxide (LTbH) by anion exchange method. Structure, chemical compositions, thermostability, morphology, luminescence property, cytotoxic effects and controlled‐release behaviors have been investigated. The ASA molecules may embed between layers with monolayered vertical arrangement, and the thermal stability of organics was enhanced after intercalation. The Tb³⁺ luminescence in ASA‐LTbH composites was enhanced compared with LTbH precusor and the luminescence intensity increased with the deprotonation degree. The cytotoxic effect of LTbH was observed with a sulforhodamine B (SRB) colorimetric assay, which revealed that the LTbH showed low cytotoxic effects. In addition, the ASA‐LTbH composites exhibited a sustained release of ASA in Na₂HPO₄‐NaH₂PO₄ buffer solution at pH 6.86 and 37°C. Construction of LRHs composites with drug molecules provided a beneficial pathway for preparing biohybrid based on LRHs, which may have potential applications in drug delivery carrier and biological fluorescence probe.     

Rapid Suzuki‐Miyaura cross‐coupling reaction catalyzed by zirconium carboxyphosphonate supported mixed valent Pd(0)/Pd(II) catalyst

Mixed valent Pd(0)/Pd(II) nano‐sized aggregates supported onto a chemically robust layered zirconium carboxyphosphonate framework is prepared and its catalytic activity in Suzuki‐Miyaura cross coupling reaction is explored. The exceptionally high catalytic efficacy of the heterogeneous catalyst in Suzuki‐Miyaura cross coupling reaction is signified by remarkably short reaction time 2 minutes and high turnover frequency of 1.3 x 10⁴ hr^?1. The catalyst can be recycled several times without significant loss of catalytic efficacy, while spectroscopic, structural and microscopic investigations suggest the integrity of the catalyst even after fifth catalytic cycle. The unique ability of the zirconium carboxyphosphonate framework to interact strongly with palladium in dual Pd(0)/Pd(II) oxidation states has been attributed to this remarkable augmentation of catalytic efficacy.