Concrete quantum logics with covering properties

LetL be a concrete (=set-representable) quantum logic. Letn be a natural number (or, more generally, a cardinal). We say thatL admits intrinsic coverings of the ordern, and writeL C _n , if for any pairA, BL we can find a collection {C _i iI}, where cardI<n andC _i L for anyiI, such thatA B= _il C _i . Thus, in a certain sense, ifLC _n , then the rate of noncompatibility of an arbitrary pairA,BL is less than a given numbern. In this paper we first consider general and combinatorial properties of logics ofC _n and exhibit typical examples. In particular, for a givenn we construct examples ofL C _n+1\C _n . Further, we discuss the relation of the classesC _n to other classes of logics important within the quantum theories (e.g., we discover the interesting relation to the class of logics which have an abundance of Jauch-Piron states). We then consider conditions on which a class of concrete logics reduce to Boolean algebras. We conclude with some open questions.     

Configurationally and conformationally homogeneous cyclic n-aryl sulfimides—IV : Synthesis,configuration and stereochemistry of the rearrangement of 1,3-di-thiane-1-N-p-chlorophenylimides

1,3-Dithiane-1-N-p-chlorophenylimides (1,4-9) were prepared and their configuration and conformation was determined by ¹H and ¹³C NMR. The compounds were rearranged to the corresponding 2-(2'-amino-5'-chlorophenyl)-1, 3-dithianes (1U,4U,9U). The rearrangement reactions took place with ?95% stereospecifity. The mechanism of the reaction was investigated with the aid of analogs specifically deuterated at C-2.     

Dipolar and nonpolar altitudinal molecular rotors mounted on an Au(111) surface

We describe the preparation of a compound whose molecules consist of two metal sandwich stands carrying tentacles with affinity to metal surfaces and holding an axle that carries a dipolar or a nonpolar rotator. The dipolar rotor exists as three pairs of enantiomers, rapidly interconverting at room temperature. When mounted on a gold surface, each molecule represents a chiral altitudinal rotor, with the rotator axle parallel to the surface. The surface-mounted rotor molecules are characterized by several spectroscopic and imaging techniques. At any one time, in about one-third of the dipolar rotors the rotator is free to turn and the direction of its dipole can be flipped by the electric field applied by an STM tip, as revealed by differential barrier height imaging. Molecular dynamics calculations suggest that electric field normal to the surface causes members of one pair of enantiomers to rotate unidirectionally.     

Performance of the general-model-space state-universal coupled-cluster method

The capabilities of the recently developed multireference, general-model-space (GMS), state-universal (SU) coupled-cluster (CC) method have been extended in order to enable the handling of any excited state that represents a single (S) or a double (D) excitation relative to the ground state. A series of calculations concerning the ground and excited states of the CH(+), HF, F(2), H(2)O, NH(2), and CH(2) molecules were carried out so as to assess the performance of the GMS SU CCSD method. For diatomics we have computed the entire potential energy curves, while for triatomics we have focused on vertical excitation energies. We demonstrate how a systematic enlargement of the model space enables a consideration of a larger and larger number of excited states. A comparison of the CC and full configuration interaction or large-scale CI results enables an assessment of the accuracy and reliability of the GMS SU CCSD method within a given basis set. In all cases very good results have been obtained, including highly excited states and those having a doubly-excited character.     

Uridine binding by Zn(II) macrocyclic complexes: diversion of RNA cleavage catalysts

Zn(II) complexes of 1-oxa-4,7,10-triazacyclododecane (12[ane]N3O), 1,5,9-triazacyclododecane (12[ane]N3), and 1-hydroxyethyl-1,4,7-triazacyclononane (9[ane]N3OH) promote cleavage of the RNA analogue, 2-hydroxypropyl-4-nitrophenyl phosphate (HpPNP) at pH 8.0, I=0.10 M (NaCl), 25 degrees C with second-order rate constants of 8.9x10(-3), 9.0x10(-3), and 3.3x10(-3) M-1 s-1, respectively. Cleavage of HpPNP by these catalysts is inhibited by uridine with inhibition constants (Ki) of 1.2, 0.46, and 45 mM, respectively, under these conditions. Binding constants derived from these inhibition constants are 2-200-fold larger than those for binding of related Zn(II) complexes to phosphate diesters under similar conditions, suggesting that uridine sequences in RNA will inhibit Zn(II)-catalyzed cleavage by competing with phosphate diester binding sites. Further studies are carried out that utilize pH-potentiometric titrations to monitor uridine binding to five Zn(II) macrocyclic complexes in aqueous solution at 25 degrees C, I=0.10 M (NaCl). The data are consistent with binding of the Zn(II) complexes to the N3-deprotonated form of uridine to give log KU.-values of 5.29, 4.57, 4.56, 3.47, and 2.65 for the Zn(II) complexes of 12[ane]N3, 12[ane]N4, 12[ane]N3O, 15[ane]N3O2, and 9[ane]N3OH, respectively (12[ane]N4=1,4,7,10-tetraazacyclododecane, 15[ane]N3O2=1,4-dioxa-7,10,13-triazacyclopentadecane). For the five Zn(II) complexes studied, there is a linear relationship between uridine anion binding constants and hydroxide binding constants.     

X-ray and Thermal Analysis of Selected Drugs Containing Acetaminophen

Studies carried out by X-ray and thermal analysis confirmed that acetaminophen (paracetamol), declared by the manufacturers as an Active Pharmaceutical Ingredient (API), was present in all studied medicinal drugs. Positions of diffraction lines (2θ angles) of the studied drugs were consistent with standards for acetaminophen, available in the ICDD PDF database Release 2008. |Δ2θ| values were lower than 0.2°, confirming the authenticity of the studied drugs. Also, the values of interplanar distances d_hkl for the examined samples were consistent with those present in the ICDD. Presence of acetaminophen crystalising in the monoclinic system (form I) was confirmed. Various line intensities for API were observed in the obtained diffraction patterns, indicating presence of the preferred orientation of the crystallites in the examined samples. Thermal analysis of the studied substances confirmed the results obtained by X-ray analysis. Drugs containing only acetaminophen as an API have melting point close to that of pure acetaminophen. It was found that presence of other active and auxiliary substances affected the shapes and positions of endothermal peaks significantly. A broadening of endothermal peaks and their shift towards lower temperatures were observed accompanying an increase in the contents of additional substances being “impurities” in relation to the API. The results obtained by a combination of the two methods, X-ray powder diffraction (XRPD) and differential scanning calorimetry/thermogravimetry (DSC/TGA), may be useful in determination of abnormalities which can occur in pharmaceutical preparations, e.g., for distinguishing original drugs and forged products, detection of the presence of a proper polymorphic form or too low content of the active substance in the investigated drug.     

Uranium (III) scorpionates: synthesis and structure of [(TpMe2)2U[N(C6H5)2]] and [(TpMe2)2U[N(SiMe3)2]

Reaction of [(Tp(Me)2)(2)UI] with KNR(2) (R = C(6)H(5), SiMe(3)) in tetrahydrofuran (THF) afforded the monomeric trivalent actinide amide complexes [(Tp(Me)2)(2)U[N(C(6)H(5))(2)]], 1, and [(Tp(Me)2)(2)U[N(SiMe(3))(2)]], 2. The complexes have been fully characterized by spectroscopic methods and their structures were confirmed by X-ray crystallographic studies. In the solid state 1 and 2 exhibit distorted pentagonal bipyramidal geometries. The U-NR(2) bond lengths in both complexes are the same but in complex 2 the greater steric demands of the N(SiMe(3))(2) ligand led to elongated U-N(pz) bonds, especially those opposite the amido ligand.     

(PPh4)2[MoN(N3)3Cl]2; Synthese,IR-Spektrum und Kristallstruktur

(PPh₄)₂[MoN(N₃)₃Cl]₂; Synthesis, IR Spectrum, and Crystal Structure The title compound is formed in the reaction of molybdenum (II) benzoate with trimethylsilyl azide and PPh₄Cl in dichloro methane forming dark red single crystals. A PPh₃Me⊕ salt of the ion [MoN(N₃)₃Cl]₂^2? is obtained from (PPh₃Me)₂MoNCl₄] treated with silver azide in CH₂Cl₂ suspension. The solvent CH₂Cl₂ participates in both reactions as oxidizing agent. (PPh₄)₂[MoN(N₃)₃Cl₂ is characterized by a structural analysis based upon X-ray data: space group P1 , Z = 1, a = 1050.7 pm; b = 1185.4 pm; c = 1190.8 pm; α = 98.90°; β = 106.87°; γ = 103.97° (4505 independent, observed reflexions, R = 0.039). The compound consists of PPh₄⊕ cations and centrosymmetric anions [MoN(N₃)₃Cl₂^2? in which the molybdenum atoms are bridged by the N_α atoms of two azide groups; the resulting Mo? N bond lengths are 208 pm and 260 pm. In trans position to the long Mo? N bond the terminal nitrido ligand is situated, the Mo?N distance of 164 pm corresponds to a triple bond. Two terminal azido ligands and the chloro ligand are filling up the coordination sphere of the molybdenum atoms to a coordination number of six. The i.r. spectrum is reported and assigned.     

Formation of two isomeric closo-[(eta5-C5H5)FePC2B8H10] phosphadicarbaborane analogues of ferrocene via isolable eta1-bonded complexes of the [7-[(eta5-C5H5)Fe(CO)2]-(eta1-nido-PC2B8H10)] type

The reaction of nido-[7,8,9-PC(2)B(8)H(11)] (1) with [[CpFe(CO)(2)](2)] (Cp=eta(5)-C(5)H(5) (-)) in benzene (reflux, 3 days) gave an eta(1)-bonded complex [7-Fp-(eta(1)-nido-7,8,9,-PC(2)B(8)H(10))] (2; Fp=CpFe(CO)(2); yield 38 %). A similar reaction at elevated temperatures (xylene, reflux 24 h) gave the isomeric complex [7-Fp-(eta(1)-nido-7,9,10-PC(2)B(8)H(10))] (3; yield 28 %) together with the fully sandwiched complexes [1-Cp-closo-1,2,4,5-FePC(2)B(8)H(10)] 4 a (yield 30%) and [1-Cp-closo-1,2,4,8-FePC(2)B(8)H(10)] 4 b (yield 5%). Compounds 2 and 3 are isolable intermediates along the full eta(5)-complexation pathway of the phosphadicarbaborane cage; their heating (xylene, reflux, 24 h) leads finally to the isolation of compounds 4 a (yields 46 and 52%, respectively) and 4 b (yields 4 and 5%, respectively). Moreover, compound 3 is isolated as a side product from the heating of 2 (yield 10%). The structure of compound 4 a was determined by an X-ray structural analysis and the constitution of all compounds is consistent with the results of mass spectrometry and IR spectroscopy. Multinuclear ((1)H, (11)B, (31)P, and (13)C), two-dimensional [(11)B-(11)B]-COSY, and (1)H[(11)B(selective)] magnetic resonance measurements led to complete assignments of all resonances and are in excellent agreement with the structures proposed.