Luminescent cyanometallates based on phenylpyridine-Ir(III) units: solvatochromism, metallochromism, and energy-transfer in Ir/Ln and Ir/Re complexes

[Ir(ppy)(2)(CN)(2)](-) (ppy = anion of 2-phenylpyridine) and some substituted derivatives have been investigated for their ability to interact with additional metal cations, both in solution and the solid state, via the externally-directed cyanide lone pairs, and to act as energy-donors in the resulting assemblies. [Ir(ppy)(2)(CN)(2)](-) is slightly solvatochromic, showing a blue-shift of the lowest energy absorption manifold in water compared to organic solvents, and the solubilised (t)Bu-substituted analogue [Ir((t)Buppy)(2)(CN)(2)](-) [(t)Buppy = anion of 2-(4-(t)Bu-phenyl)pyridine] is also metallochromic with coordination of the cyanide lone pairs to two M(II) cations in MeCN (M = Ba, Zn) resulting in blue-shifts of the lowest-energy absorption and emission maxima. These effects are however modest because of (i) the presence of only two cyanide groups, and (ii) the fact that the lowest-energy excited state has a substantial (3)LC component and is therefore not purely charge-transfer in nature. Crystallisation of [Ir(ppy)(2)(CN)(2)](-) as its (PPN)(+) salt in the presence of excess of lanthanide(III) salts leads to formation of assemblies based on Ir-CN-Ln bonds, which generate in the solid state either Ir(2)Ln(2)(μ-CN)(4) square assemblies or linear trinuclear species with Ir-CN-Ln-NC-Ir cores. In the Ir(2)Eu(2)(μ-CN)(4) and Ir(2)Nd(2)(μ-CN)(4) complexes the Ir-based emission is substantially quenched due to energy-transfer to lower-lying f-f states of these lanthanide ions. In addition reaction of [Ir(F(2)ppy)(2)(CN)(2)](-) [F(2)ppy = cyclometallating anion of 2-(2,4-difluorophenyl)pyridine] with [Re(phen)(CO)(3)(MeCN)][PF(6)] in solution affords dinuclear IrRe and trinuclear IrRe(2) species in which {Re(phen)(CO)(3)} units are attached to the N-donor termini of one or both of the cyanide groups; these complexes have been structurally characterised and display quantitative Ir→Re energy-transfer, showing luminescence only from the Re(I) terminus on excitation of the Ir(III) unit.     

Effects of lipopolysaccharide-induced inflammation on expression of growth-associated genes by corticospinal neurons

Background  

Inflammation around cell bodies of primary sensory neurons and retinal ganglion cells enhances expression of neuronal growth-associated genes and stimulates axonal regeneration. We have asked if inflammation would have similar effects on corticospinal neurons, which normally show little response to spinal cord injury. Lipopolysaccharide (LPS) was applied onto the pial surface of the motor cortex of adult rats with or without concomitant injury of the corticospinal tract at C4. Inflammation around corticospinal tract cell bodies in the motor cortex was assessed by immunohistochemistry for OX42 (a microglia and macrophage marker). Expression of growth-associated genes c-jun, ATF3, SCG10 and GAP-43 was investigated by immunohistochemistry or in situ hybridisation.     

Shears bands in the Pb region

The properties of the M1 bands in the Pb region are reviewed. They can be explained by ‘magnetic rotation’ which is a new concept in nuclear excitations. Spin and excitation energy along the bands are increased by the shears effect, a step-by-step alignment of large proton-particle and large neutron-hole spins into the direction of the total angular momentum. First evidence is presented for band termination connected with the closing of the shears.     

Future contributions toJournal of Crystallographic and Spectroscopic Research

Future contributions toJournal of Crystallographic and Spectroscopic Research     

Oxygen rearrangement processes in mass spectrometry

The recent publication¹ concerning oxygen rearrngement process in the mass spectra of aromatic and unsturated esters parallels an investigation by the auther on similar compounds. Some further definitive aspects of this study are reported here.     

Quantitative analysis by pyrolysis gas chromatography of thermosetting acrylic resins used in automotive enamels

Chromatographia - The thermosetting acrylic resins used on car bodies usually contains a mixture of styrene, methyl and butyl methacrylates and an alkyl acrylate which are readily identified by...     

The toxic extractives from wedelia asperrima—I : The structure and synthesis of the unusual glycosidic portion of wedeloside

The major toxic constituent of the plant, Wedelia asperrima, is the diterpene aminoglycoside, wedeloside. MS and NMR analysis of the unusually substituted aminoglycosidic portion of wedeloside and comparison with synthetic analogues have permitted the assignment of its structure as a 2 - deoxy - 2 - (3 - methyl - 1 - oxobutyl)amino - 3 - 0 - (1 - oxo - 3 - phenylpropyl) - D - glucopyranoside, β-linked to the diterpene aglycone.     

Quieting Weinberg 5C: a case study in hospital noise control

Weinberg 5C of Johns Hopkins Hospital is a very noisy hematological cancer unit in a relatively new building of a large medical campus. Because of the requirements for dealing with immuno-suppressed patients, options for introducing sound absorbing materials are limited. In this article, a case study of noise control in a hospital, the sound environment in the unit before treatment is described, the chosen noise control approach of adding custom-made sound absorbing panels is presented, and the impact of the noise control installation is discussed. The treatment of Weinberg 5C involved creating sound absorbing panels of 2-in.-thick fiberglass wrapped in an anti-bacterial fabric. Wallpaper paste was used to hold the fabric to the backing of the fiberglass. Installation of these panels on the ceiling and high on corridor walls had a dramatic effect. The noise on the unit (as measured by the equivalent sound pressure level) was immediately reduced by 5 dB(A) and the reverberation time dropped by a factor of over 2. Further, this drop in background noise and reverberation time understates the dramatic impact of the change. Surveys of staff and patients before and after the treatment indicated a change from viewing the unit as very noisy to a view of the unit as relatively quiet.     

Stereoisomer analysis of wastewater-derived beta-blockers, selective serotonin re-uptake inhibitors, and salbutamol by high-performance liquid chromatography-tandem mass spectrometry

A reversed-phase enantioselective liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) method was developed to measure enantiomer fractions (EF) and concentrations of pharmaceuticals in wastewater. Enantiomer resolution of six beta-blockers (atenolol, metoprolol, nadolol, pindolol, propranolol, and sotalol) along with two selective serotonin re-uptake inhibitors (citalopram, fluoxetine) and one beta(2)-agonist (salbutamol) was achieved with the Chirobiotic V stationary phase. Analyte recovery averaged 86% in influent and 78% in effluent with limits of detection ranging from 0.2 to 7.5 ng/L. These results represent an improvement in wastewater EF measurement for atenolol, metoprolol and propranolol as well as the first EF measurements of citalopram, fluoxetine, nadolol, pindolol, salbutamol and sotalol in wastewaters. Changes in EF through treatment indicate biologically mediated stereoselective processes were likely occurring during wastewater treatment.     

Solvent-free direct aza-Friedel-Crafts reactions between 3,4-dihydroisoquinoline and 1- or 2-naphthols

A self-catalytic aza-Friedel-Crafts method was employed to generate 1-naphtholyl tetrahydroisoquinoline products under neat conditions. In addition, a derivative was prepared in its enantiomerically pure form and has shown moderate activity for asymmetric catalysis in the asymmetric diethylzinc addition to aldehydes.