Complexes of Metal Ions with Phosphorus or Arsenic containing Ligands. Part. XIII. Reactions of o-carboxyphenylmonotertiaryarsines and their oxides with beryllium(II) oxide acetate

Ligands, o-carboxyphenyldiphenylarsine, o-carboxyphenyldi(p-tolyl)arsine, o-carboxyphenyldiphenylarsine oxide and o-carboxyphenyldi(p-tolyl)arsine oxide react with beryllium(II) oxide acetate to form complexes of the general formula, [Be₄ · O · (CH₃COO)₃(L)₃] where LH is any of the aforementioned ligands. These have been found to be nonelectrolytes in nitrobenzene. Infrared spectral data suggest that arsenic(III or V) is not coordinated to the metal, while both the oxygens of acetate as well as carboxylate group are taking part in coordination, leaving the fundamental structure of beryllium oxide acetate intact.     

Complexation reaction of metal ions with peptide systems. Part II. Potentiometric studies of the complexes of glycyl-DL-valine with Gd, Dy, Er and Yb

The stable complexes of amino acids with rare earths have found importance in the separation of these metals¹. The complexation reactions of a number of dipeptides with copper and nickel have been reported in the literature^{2 – 9}; but little work appears to have been done with rare earth metals. This paper is a continuation of our earlier communication¹⁰, and deals with the study of complexes of Gd³⁺, Dy³⁺, Er ³⁺ and Yb³⁺ with Glycyl-DL-valine. The Calvin—Bjerrum^{11, 12} pH titration technique, as modified by Irving and Rossotti¹³, has been employed.     

Experimental realization of an on-chip all-optical analogue to electromagnetically induced transparency

We provide the first experimental observation of structure tuning of the electromagnetically induced transparency-like spectrum in integrated on-chip optical resonator systems. The system consists of coupled silicon ring resonators with 10 microm diameter on silicon, where the coherent interference between the two coupled resonators is tuned. We measured a transparency-resonance mode with a quality factor of 11,800.     

Detection of Staphylococcus aureus cell walls by enzyme-linked immunoassay using antibodies prepared from a semi-synthetic peptidoglycan precursor

The peptidoglycan layer of Staphylococcus aureus contains a (Gly)(5) cross-link which is not found in other bacteria, and which could be used to develop a specific immunoassay for detection of S. aureus in MRSA infections. A semi-synthetic route was used to prepare the S. aureus peptidoglycan precursor UDPMurNAc-L-Ala-γ-D-Glu-L-Lys(Gly)(5)-D-Ala-D-Ala, which was covalently attached to carrier protein bovine serum albumin via the UDP nucleotide. Serum raised using this antigen showed specificity for chemically immobilised peptidoglycan monomer containing (Gly)(5), using an ELISA immunoassay. ELISA assays using 0.1 or 1.0 μg samples of cell walls prepared from two MRSA strains and one penicillin-sensitive S. aureus strain, and from three other bacteria, showed the highest response against cell walls containing (Gly)(5), with a particularly high response against cell walls from one MRSA strain. Competition assays to investigate antibody selectivity demonstrated that the antibody response could be most effectively antagonised using ligands containing (Gly)(5). These data demonstrate that it is possible to generate antibodies with high affinity and selectivity for the (Gly)(5) containing monomer in S. aureus peptidoglycan, that could be used to develop an immunoassay for S. aureus.     

Ligating properties of tertiary phosphine/arsine sulphides or selenides,part V. Complexes of ditertiaryphosphine disulphides and diselenides with platinum(II) and platinum(IV) halides

Summary Platinum(IV)/platinum(II) chloride and bromide form 1 : 1, 1 : 2 or 3 : 2 (metal: ligand) addition compounds with 1,2-ethylene-, 1,3-propylene-and 1,4-butylene-bisdiphenyl-phosphine sulphide or selenide and 1,6-hexamethylene-bisdiphenylphosphine selenide. The adducts have been characterized by elemental analysis, i.r. and reflectance spectra, and molar conductance data. All adducts have been assigned bridged square planar or octahedral arrangements around platinum(II) or platinum(IV) ions respectively. Both oxidation states of platinum conform to class b behaviour with respect to the soft donor sulphur and selenium atoms of the ligands.Reprints of this article are not available.     

Complexes of metallons with phosphorus or arsenic containing ligands. II. complexes ortho-carboxyphenyltertiaryarsines with mercury (II) halides

Ortho-carboxyphenyl-dimethylarsine (CPDMA), ortho-carboxpyhenyldiphenylarsine (CPDPA) and ortho-carboxyphenyldi(p-tolyl)arsine (CPDTA) react with mercury(II) halides to yield complexes having the formula HgX₂L where X is Cl, Br or I and L is ligand. In view of infrared spectral data these complexes have been classified into two classes: (a) those in which the carboxyl group of the ligand remains free (ligand being monodentate), and (b) those in which the ligand acts as a bidentate group. The complex Hg(Cl₂) · CPDPA is the only example of type (a) and has been assigned a dimeric halogen bridged structure. The remaining eight complexes are assumed to be monomeric. A tetrahedral structure is proposed for all the nine complexes.     

Complexes of metal ions with phosphorus or arsenic containing ligands. III. Complexes of Mercury (II) halides with 1,2-ethylenebisdiphenylphosphine and 1,4-butylenebisdiphenylphosphine

Mercury(II) halides react with 1,2-ethylenebisdiphenylphosphine (DPE) and 1,4-butylenebisdiphenylphosphine (DPB) to give two types of complexes having the general formulae, [(diphos)HgX₂] and [(diphos)(HgX₂)₂]. The former seems to possess chain structure, while the latter has probably a bridged structure. In both the cases mercury(II) acquires sp³ tetrahedral configuration.     

Growth of carbon-doped base GaAs/AlGaAs HBT by gas-source MBE using TEG, TEA, TMG, AsH3, and Si2H6

High-performance carbon-doped-base GaAs/AlGaAs heterobipolar transistors (HBTs) were grown by gas-source MBE using only gaseous sources including dopant sources. The AlGaAs emitter layer was doped with Si from uncracked SI₂H₆ (n = 9 × 10¹⁷ cm^-3), and the base layer (92.5 nm) was doped with carbon from TMG (p = 4 × 10¹⁹ cm^-3). From SIMS analysis it was confirmed that a well-defined emitter-base junction with sharp carbon profile was obtained. The base-current ideality factor from the Gummel plot was 1.47, and the emitter-base junction ideality factor was 1.12. A high DC current gain of 53 was obtained at a current density of 4 × 10⁴ A/cm². The device characteristics of our carbon-doped HBTs were found to be stable under current stress.     

Supramolecular synthesis based on piperidone derivatives and pharmaceutically acceptable co‐formers

The target complexes, bis{(E,E)‐3,5‐bis[4‐(diethylamino)benzylidene]‐4‐oxopiperidinium} butanedioate, 2C₂₇H₃₆N₃O⁺·C₄H₄O₄²⁻, (II), and bis{(E,E)‐3,5‐bis[4‐(diethylamino)benzylidene]‐4‐oxopiperidinium} decanedioate, 2C₂₇H₃₆N₃O⁺·C₁₀H₁₆O₄²⁻, (III), were obtained by solvent‐mediated crystallization of the active pharmaceutical ingredient (API) (E,E)‐3,5‐bis[4‐(diethylamino)benzylidene]‐4‐piperidone and pharmaceutically acceptable dicarboxylic (succinic and sebacic) acids from ethanol solution. They have been characterized by melting point, IR spectroscopy and single‐crystal X‐ray diffraction. For the sake of comparison, the structure of the starting API, (E,E)‐3,5‐bis[4‐(diethylamino)benzylidene]‐4‐piperidone methanol monosolvate, C₂₇H₃₅N₃O·CH₄O, (I), has also been studied. Compounds (II) and (III) represent salts containing H‐shaped centrosymmetric hydrogen‐bonded synthons, which are built from two parallel piperidinium cations and a bridging dicarboxylate dianion. In both (II) and (III), the dicarboxylate dianion resides on an inversion centre. The two cations and dianion within the H‐shaped synthon are linked by two strong intermolecular N⁺—H...⁻OOC hydrogen bonds. The crystal structure of (II) includes two crystallographically independent formula units, A and B. The cation geometries of units A and B are different. The main N—C₆H₄—C=C—C(=O)—C=C—C₆H₄—N backbone of cation A has a C‐shaped conformation, while that of cation B adopts an S‐shaped conformation. The same main backbone of the cation in (III) is practically planar. In the crystal structures of both (II) and (III), intermolecular N⁺—H...O=C hydrogen bonds between different H‐shaped synthons further consolidate the crystal packing, forming columns in the [100] and [10] directions, respectively. Salts (II) and (III) possess increased aqueous solubility compared with the original API and thus enhance the bioavailability of the API.