Air-stable, recyclable, and time-efficient diphenylphosphinite cellulose-supported palladium nanoparticles as a catalyst for Suzuki–Miyaura reactions

• Qingwei Du and
• Yiqun Li

Beilstein J. Org. Chem. 2011, 7, 378–385, doi:10.3762/bjoc.7.48

• in ethanol (Scheme 1). The as-prepared Cell–OPPh2–Pd0 catalyst was characterized by inductively coupled plasma-atomic emission spectrometry (ICP-AES), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analyses (TGA), scanning electron microscopy (SEM) and

• the Cell–OPPh2–Pd0, indicating coordination of the phosphine atom with the palladium and further confirming the formation of a palladium complex on the surface of the polymer. Figure 1 shows the XRD pattern of the cellulose-supported palladium catalyst and the Cell–OPPh2 matrix. The Cell–OPPh2

• ) lattice planes of the face-centered cubic crystalline structure of the Pd nanoparticles are correspondingly clearly seen from the XRD pattern of Cell–OPPh2–Pd0 catalyst. The thermal stability of Cell–OPPh2–Pd0 has a great effect on its catalytic activity and recyclability because the Suzuki–Miyaura

Amphiphilic dendritic peptides: Synthesis and behavior as an organogelator and liquid crystal

• Baoxiang Gao,
• Hongxia Li,
• Defang Xia,
• Sufang Sun and
• Xinwu Ba

Beilstein J. Org. Chem. 2011, 7, 198–203, doi:10.3762/bjoc.7.26

• organogels assembled from G3 formed thin fibres that underwent further aggregation to form fibre bundles. These fibre bundles constitute a highly developed entangled network. Figure 2 shows the XRD scan of organogelator G3 and liquid crystal G3. Being different from the liquid crystal, the XRD of

• crystalline behavior Thermotropic behavior of ADPs was investigated by a combination of differential scanning calorimetry (DSC), polarization optical microscopy (POM) and X-ray diffraction (XRD) experiments. Figure 4 shows DSC curves of amphiphilic dendritic peptides. In the DSC scan from −60 °C to 200 °C, G1

• characteristic of hexagonal columnar liquid crystals. The conic fan-shaped textures of G3 grow (Figure 6B), and no longer change at 50 °C (Figure 6C). Figure 7 shows the XRD scan for the birefringent phase of G3 at 50 °C. The birefringent phases of G3 were further confirmed as a hexagonal columnar liquid crystal

Thermal rearrangement of tert-butylsulfinamide

• Veera Reddy Arava,
• Laxminarasimhulu Gorentla and
• Pramod Kumar Dubey

Beilstein J. Org. Chem. 2011, 7, 9–12, doi:10.3762/bjoc.7.2

• 1. From the spectral data, structure 3 was assigned to the product shown in Figure 2. The structure of 3 was confirmed by chemical synthesis (Scheme 2) and finally by XRD [4] (Figure 3). Both tert-butylsulfanyl chloride 4 (Scheme 3) and tert-butylsulfonamide 5 (Scheme 4) were prepared by known

ROMP-Derived cyclooctene-based monolithic polymeric materials reinforced with inorganic nanoparticles for applications in tissue engineering

• Franziska Weichelt,
• Solvig Lenz,
• Stefanie Tiede,
• Ingrid Reinhardt,
• Bernhard Frerich and
• Michael R. Buchmeiser

Beilstein J. Org. Chem. 2010, 6, 1199–1205, doi:10.3762/bjoc.6.137

• (SEM) images of the powders showed agglomerates of nanoparticles (~50–100 nm) and a rhombohedral calcite crystal structure was detected both by X-ray diffraction (XRD) and Raman measurements. Nano-sized platelets with a thickness <20 nm were formed in the synthesis of HAp and exhibited a calcium

• phosphate hydroxide crystal structure again from XRD and Raman measurements (Figure 1). Preparation and characterization of monolithic materials Monolithic hybrid materials were then prepared via ROMP from cis-5-cyclooctene-trans-1,2-diol (COE), a 7-oxanorborn-2-ene-derived cross-linker (CL) and up to 12 wt

• monoliths. Powder X-ray diffraction (XRD) was performed on a Philips X’Pert wide-angle diffractometer with slit optics, Cu Kα radiation (λ = 154 nm) and Ni Kβ filter. The powder was applied to the specimen holder using double faced-adhesive tape and the upper site was covered with a thin layer of the powder

Pyridinium based amphiphilic hydrogelators as potential antibacterial agents

• Sayanti Brahmachari,
• Sisir Debnath,
• Sounak Dutta and
• Prasanta Kumar Das

Beilstein J. Org. Chem. 2010, 6, 859–868, doi:10.3762/bjoc.6.101

• microscopy (FESEM), atomic force microscopy (AFM), photoluminescence, FTIR studies, X-ray diffraction (XRD) and 2D NOESY experiments were carried out to elucidate the different non-covalent interactions responsible for the self-assembled gelation. The formation of three-dimensional supramolecular aggregates

• amphiphiles such as the aliphatic chain length and the polar head group was systematically carried out to understand their influence on the self-assembled hydrogelation. The various factors involved in the formation of supramolecular aggregates leading to hydrogelation were studied using FTIR, XRD and

• which is in accord with the absence of any kind of intermolecular interaction in the non-gelated state of the amphiphile. To investigate the molecular packing and orientation of the gelator molecules in the supramolecular self-assembled state, the xerogel of 2 was examined by X-ray diffraction (XRD). A

C-Arylation reactions catalyzed by CuO-nanoparticles under ligand free conditions

• Mazaahir Kidwai,
• Saurav Bhardwaj and
• Roona Poddar

Beilstein J. Org. Chem. 2010, 6, No. 35, doi:10.3762/bjoc.6.35

• differences which have been shown in the TEM image. The number of reactive sites on the surface is small in the case of larger crystallites and considerably greater in the case of smaller crystallites (Figure 1). To investigate further the surface morphology of CuO-nanoparticles, powder XRD and TEM images

• were taken. Figure 1 shows the XRD pattern of CuO-nanoparticles in which diffraction peaks can be indexed to a monoclinic structure. The intense diffraction peak at an angle 38.4 shows index plane (111) which contains more basic sites with higher density as compared to bulk CuO. During optimization of

• of the reaction mixture and washed thoroughly with ethyl acetate. The resulting nanoparticles could be reused for several cycles without any significant loss of activity. In our study, we used same nanoparticles three times and the results are summarized below (Table 5). The TEM and XRD analysis of

Solvent-free and time-efficient Suzuki–Miyaura reaction in a ball mill: the solid reagent system KF–Al₂O₃ under inspection

• Franziska Bernhardt,
• Ronald Trotzki,
• Tony Szuppa,
• Achim Stolle and
• Bernd Ondruschka

Beilstein J. Org. Chem. 2010, 6, No. 7, doi:10.3762/bjoc.6.7

• Table 2 resulted from XRD analyses (cf. Supporting Information File 1) and specific surface areas AS were determined using 6-point-BET measurements. γ-Al2O3 SRS1 and SRS3 differ in their surface characteristics. SRS1 possesses a neutral surface, whereas SRS3 shows a higher basicity that was verified by

• surface [72]. However, the authors were not able to prove the change in alumina modification as the XRD results only point out the formation of K3AlF6 phases, but not the proposed phase transformation. The main difference between our present study and the recently published study is the fact that

• , according to the previous study, the formation of K3AlF6 and KOH (Equation 1) [30][61][73][74] was reported to take place during calcination, whereas, in our study, this reaction occurs already in the solution. This was indicated by XRD measurements of the freshly prepared KF-loaded aluminas (cf. Supporting

Influence of spacer chain lengths and polar terminal groups on the mesomorphic properties of tethered 5-phenylpyrimidines

• Gundula F. Starkulla,
• Elisabeth Kapatsina,
• Angelika Baro,
• Frank Giesselmann,
• Stefan Tussetschläger,
• Martin Kaller and
• Sabine Laschat

Beilstein J. Org. Chem. 2009, 5, No. 63, doi:10.3762/bjoc.5.63

• confirmed by XRD experiments (see the Supporting Information). It should be noted that the allyloxy-substituted byproduct 9 showed a smectic mesophase between 50 °C and 67 °C as well. In contrast, the corresponding 4-allyloxy-4′-octylbiphenyl 11 showed only isotropic melting at 92 °C. The DSC results of

• crystallization peak at 42 °C were observed. POM investigation displayed fan-shaped and focal conic textures, as exemplified in Figure 4. XRD experiments proved the smectic phase. In contrast to the bromides 3 and chlorides 4, the hydroxy and azide derivatives 5a,b and 7b–e were non mesomorphic and showed only

• values obtained from the X-ray experiments fit with the molecular lengths derived from simple molecular modelling (Chem3D) [13]. For example, the XRD pattern of the azide derivative 6c results in a layer distance of 25.5 Å, whereas the calculated length of the molecule for the most elongated conformation

Saddle-shaped tetraphenylenes with peripheral gallic esters displaying columnar mesophases

• Eugen Wuckert,
• Constanze Hägele,
• Frank Giesselmann,
• Angelika Baro and
• Sabine Laschat

Beilstein J. Org. Chem. 2009, 5, No. 57, doi:10.3762/bjoc.5.57

• , clear evidence was possible only by XRD data, which are summarized in Table 2. While rectangular columnar mesophases were observed for tetraphenylenes 2e–i with shorter chains (n = 9–13) (shown for 2f in Figure S1 in the Supporting Information), hexagonal columnar mesophases were found for the long

• mesophases with increasing chain lengths has been also observed in other columnar systems [32][33] and has been attributed to the enhanced core–core interaction necessary for the formation of the Colr phases [34]. According to molecular modelling [35] and comparison with the XRD data each disk within the

A convenient method for preparing rigid-core ionic liquid crystals

• Julien Fouchet,
• Laurent Douce,
• Benoît Heinrich,
• Richard Welter and
• Alain Louati

Beilstein J. Org. Chem. 2009, 5, No. 51, doi:10.3762/bjoc.5.51

• general stability order to be I−< BF4− ≈ PF6−< CF3SO3−< (CF3SO2)2N− (Figure 4). For all the compounds, the mesomorphic behaviour and phase transition temperatures were investigated by polarized optical microscopy (POM), differential scanning calorimetry (DSC), and powder X-ray diffractometry (XRD). To

• confirmed by XRD. The X-ray pattern (Figure 6) of the Smectic A form recorded at 120 °C contains a diffuse band at 4.6 Å (wide angle), which shows clearly that the alkyl chains have a liquid-like structure and are segregated from the aromatic cores. The layer thickness in the Smectic A phase was determined