Amalgamation of Ortholattices

We show that the variety of ortholattices has the strong amalgamation property and that the variety of orthomodular lattices has the strong Boolean amalgamation property, i.e. that two orthomodular lattices can be strongly amalgamated over a common Boolean subalgebra. We give examples to show that the variety orthomodular lattices does not have the amalgamation property and that the variety of modular ortholattices does not even have the Boolean amalgamation property. We further show that no non-Boolean variety of orthomodular lattices which is generated by orthomodular lattices of bounded height can have the Boolean amalgamation property.     

Phosphinsubstituierte chelatliganden: XI. NMR-spektroskopische untersuchungen (1H, 13C, 31P, 55Mn) an halogentricarbonylmangan-chelatkomplexen mit phosphino-thioformamid- und -thioformimidoester-liganden

A series of halotricarbonylmanganese chelate complexes, fac-(CO)₃Mn(X)L (X = Cl (a), Br (b), I (c)), with thioformamide (L = Ph₂PC(S)NRMe; R = H (1), Me (2), Ph (3)) and the isomeric thioformimidoester (L = Ph₂PC(NR)SMe; R = Me (4), Ph (5)) ligands were prepared by thermal CO substitution of the pentacarbonylmanganese halides. The IR and NMR data indicate P,S-coordination of the ambidentate ligands and uniform Z configuration in 3–5. Due to the large linewidth of the NMR signals, the ⁴J(PH) and ³J(PC) coupling constants could not be determined for the thioamide complexes 1–3. Coordination of the thioimide 4 causes an increase in ⁴J(PH) whereas ³J(PC) remains unchanged. δ(³¹P) shows a downfield coordination shift as usual for manganese complexes. The broad ⁵⁵Mn NMR signals cover a range of +90 to ?730 ppm (rel. KMnO₄) with the imidoester complexes 4 and 5 at the low-field side. The normal halogen dependence Cl < Br < I is observed for ⁵⁵Mn shielding.     

Dynamic behavior of chiral sulfonimidoyl-substituted allyl and alkyl (dimethylamino)titanium(IV) complexes: metallotropic shift, reversible beta-hydride elimination/reinsertion, and ab initio calculations of allyl and alkyl aminosulfoxonium ylides

Variable-temperature (1)H and (13)C NMR spectroscopy of the sulfonimidoyl-substituted allyltitanium(IV) complexes E-1a-c and Z-1a-c, which carry diethylamino groups at the Ti atom, revealed a fast 1,3-C,N-shift of the Ti atom, leading to an equilibrium between the epimeric Calpha-titanium allyl complexes A and C and the N-titanium allyl aminosulfoxonium ylide B. Based on these findings a model for the reactions of E-1a-c and Z-1a-c with aldehydes is proposed, which features regio- and diastereoselective reactions of the N-titanium ylide B at the alpha-position and the Calpha-titanium complex A at the gamma-position. Model ab initio calculations of the methylene and allyl (dimethylamino)sulfoxonium ylides 10 and 14, respectively, revealed short Calpha-S bonds, a stabilization by both electrostatic interaction and negative hyperconjugation, and a low Calpha-S rotational barrier. The ylides preferentially adopt Calpha-S and Calpha-N conformations in which the lone pair orbital at the Calpha atom is periplanar to the S=O bond and that at the N atom periplanar to the Calpha-Ph bond. Variable-temperature NMR spectroscopy of the sulfonimidoyl-substituted alkyltitanium(IV) complex 16, which carries diethylamino groups at the Ti atom, revealed a dynamic behavior leading to a complete topomerization of all four methylene hydrogens of the Calpha-ethyl groups. Two fast processes are held responsible for the topomerization of the hydrogens of 16. The first one is a reversible intramolecular beta-hydride elimination/alkene-Ti-H insertion with the intermediate formation of a complex between (Et(2)N)TiH and a 1-alkenyl sulfoximine, and the second one consists of a reversible 1,3-C,N-shift of the Ti atom in combination with a Calpha-S bond rotation. Interestingly, the room-temperature NMR spectra of the corresponding sulfonimidoyl-substituted alkyltitanium(IV) complex 17, which carries isopropoxy groups at the Ti atom, give no indication of a similar dynamic behavior of this complex.     

Synthesis and Biological Activities of Azalamellarins

The synthesis of azalamellarins, a new series of lactam analogues of biologically active lamellarins, was achieved using Cu^I‐mediated and microwave‐assisted C? N_amide bond formation. Seventeen azalamellarins, including N‐allylazalamellarins and N‐propylazalamellarins χ‐D, L ‐N, and J‐dehydro J, were synthesized and evaluated for their cytotoxicity against the cancer cell lines HuCCA‐1, A‐549, HepG2, and MOLT‐3. The results showed that certain azalamellarins exhibited good activities in the micromolar IC₅₀ value range (IC₅₀=the drug concentration that causes 50 % of cell‐growth inhibition after 72 h of continuous exposure to the test molecule), comparable to their parent lamellarin analogue.     

A Highly Triflated Rare‐Earth Ion in [Eu(O3SCF3)8]5−

The reaction of Eu₂O₃ with fuming nitric acid, trifluormethanesulfonic acid, and its anhydride in torch‐sealed glass ampoules at 120 °C gave the europium compound (NO)₅[Eu(O₃SCF₃)₈] (orthorhombic, Fddd, Z=16, a=1932.69(4), b=2878.44(7), c=2955.12(7) pm, V=16439.7(7) ų). The compound exhibits the [Eu(O₃SCF₃)₈]^5? anion showing for the first time a lanthanide ion that is exclusively coordinated by eight triflate anions. The anion has been further investigated by DFT calculations, which also allowed clear assignment of the vibrational spectra. Moreover, magnetochemical and luminescence measurements gave additional insight into the properties of this complex. The luminescence spectra revealed that the Eu³⁺ ions are in a pseudo D_4d symmetric environment.     

Principal component analysis and hierarchical cluster analysis for homogeneity evaluation during the preparation of a wheat flour laboratory reference material for inorganic analysis

The development of a homogeneity study during the preparation of a wheat flour laboratory reference material (LRM) for use in the quantification of metals and metalloids is reported. Inductively coupled plasma optical emission spectrometry (ICP OES) was used with validation performed using a certified reference material of wheat flour furnished by the National Institute of Standards and Technology (NIST). Copper, iron, manganese, phosphor, strontium and zinc were studied in a within-bottle homogeneity test whereas barium, copper, iron, zinc, manganese, strontium, phosphor and calcium were included in a between batch homogeneity study. Standard univariate analysis of variance (ANOVA) was performed for all analytes. Furthermore an alternative multivariate analysis for homogeneity is proposed by performing ANOVA of principal component scores and by inspection of principal component score graphs and hierarchical cluster analysis dendrograms. The ANOVA F-tests performed on both, the univariate and multivariate parameters, were not significant at the 95% confidence level and indicated homogeneous wheat flour samples. A 10 kg amount of material was processed, which was distributed in 100 bottles, each containing 100 g. For the between-bottle homogeneity test, three replicates were taken from each of 10 bottles selected of the 100 bottles obtained. The results were evaluated using an F-test, which demonstrated no significant difference for the between-bottle results. It is indicative that this material is homogeneous. Afterwards, the influence of the sample mass on the homogeneity of the material was also evaluated by quantification of the elements for 100, 300, 500, 700 and 1000 mg sample masses with all the experiments being performed in triplicate. The F-test was also used for evaluation of these results and demonstrated that the material is homogeneous for masses taken in the 100 to 1000 mg range. All these results were further evaluated employing the principal component analysis (PCA) and hierarchical cluster analysis (HCA) multivariate techniques. Both techniques also demonstrated that the material is perfectly homogeneous for use as laboratory reference material.