OsO as the Contrast-Generating Chemical Species of Osmium-Stained Biological Tissues in Electron Microscopy.

Electron imaging of biological samples stained with heavy metals has enabled visualization of subcellular structures critical in chemical-, structural-, and neuro-biology. In particular, osmium tetroxide (OsO) has been widely adopted for selective lipid imaging. Despite the ubiquity of its use, the osmium speciation in lipid membranes and the process for contrast generation in electron microscopy (EM) have continued to be open questions, limiting efforts to improve staining protocols and therefore high-resolution nanoscale imaging of biological samples.

Molecular Orientation and Energy Transfer Dynamics of a Metal Oxide Bound Self-Assembled Trilayer.

Self-assembly of molecular multilayers via metal ion linkages has become an important strategy for interfacial engineering of metalloid and metal oxide (MO) substrates, with applications in numerous areas, including energy harvesting, catalysis, and chemical sensing. An important aspect for the rational design of these multilayers is knowledge of the molecular structure-function relationships. For example, in a multilayer composed of different chromophores in each layer, the molecular orientation of each layer, both relative to the adjacent layers and the substrate, influences the efficiency of vectorial energy and electron transfer.

Influence of AlO Overlayers on Intermolecular Interactions between Metal Oxide Bound Molecules.

Intermolecular interactions on inorganic substrates can have a critical impact on the electrochemical and photophysical properties of the materials and subsequent performance in hybrid electronics. Critical to the intentional formation or inhibition of these processes is controlling interactions between molecules on a surface. In this report, we investigated the impact of surface loading and atomic-layer-deposited AlO overlayers on the intermolecular interactions of a ZrO-bound anthracene derivative as probed by the photophysical properties of the interface.

Examining the influence of bilayer structure on energy transfer and molecular photon upconversion in metal ion linked multilayers.

Metal ion linked multilayers is a unique motif to spatially control and geometrically restrict molecules on a metal oxide surface and is of interest in a number of promising applications. Here we use a bilayer composed of a metal oxide surface, an anthracene annihilator molecule, Zn(II) linking ion, and porphyrin sensitizers to probe the influence of the position of the metal ion binding site on energy transfer, photon upconversion, and photocurrent generation. Despite being energetically similar, varying the position of the carboxy metal ion binding group (i.

Bis-Cyclometalated Iridium Complexes Containing 4,4'-Bis(phosphonomethyl)-2,2'-bipyridine Ligands: Photophysics, Electrochemistry, and High-Voltage Dye-Sensitized Solar Cells.

In this report, the synthesis and characterization of two bis-cyclometalated iridium(III) complexes are presented. Single-crystal X-ray diffraction shows that [Ir(ppy)(4,4'-bis(diethylphosphonomethyl)-2,2'-bipyridine)]PF adopts a pseudooctahedral geometry. The complexes have an absorption feature in the near-visible-UV region and emit green light with excited-state lifetimes in hundreds of nanoseconds.

Extracellular vs Intracellular Delivery of CO: Does It Matter for a Stable, Diffusible Gasotransmitter?

Carbon monoxide (CO) is a gasotransmitter produced in humans. An essential unanswered question in the design of carbon monoxide releasing molecules (CORMs) is whether the delivery molecule should be localized extra- or intracellularly to produce desired biological effects. Herein we show that extracellular CO release is less toxic and is sufficient to produce an anti-inflammatory effect similar to that of intracellular CO release at nanomolar concentrations.

Sterically demanding methoxy and methyl groups in ruthenium complexes lead to enhanced quantum yields for blue light triggered photodissociation.

Ruthenium complexes containing a sterically congested metal center can serve as light activated prodrugs through photo-activated chemotherapy (PACT). In this work, we modified PACT agents containing 6,6'-dihydroxybipyridine (6,6'-dhbp) (Papish et al., Inorg.