Stable Cu (I) Complexes for Intracellular Cu-Catalyzed Azide Alkyne Cycloaddition.

The copper-catalyzed azide-alkyne cycloaddition (CuAAC) has heralded a new era of chemical biology and biomedicine. However, caveats of the CuAAC include formation of reactive oxygen species (ROS) and other copper-related toxicity. This limits utility in sensitive biological samples and matrices.

Combination of Counterion Size and Doping Concentration Determines the Electronic and Thermoelectric Properties of Semiconducting Polymers.

In both chemical and electrochemical doping of organic semiconductors (OSCs), a counterion, either from the electrolyte or ionized dopant, balances the charge introduced to the OSC. Despite the large influence of this counterion on OSC optical and electronic response, there remains substantial debate on how a fundamental parameter, ion size, impacts these properties. This work resolves much of this debate by accounting for two doping regimes.

Hydrogen-Bonding Trends in a Bithiophene with 3- and/or 4-Pyridyl Substituents.

To improve the charge-carrier transport capabilities of thin-film organic materials, the intermolecular electronic couplings in the material should be maximized. Decreasing intermolecular distance while maintaining proper orbital overlap in highly conjugated aromatic molecules has so far been a successful way to increase electronic coupling. We attempted to decrease the intermolecular distance in this study by synthesizing cocrystals of simple benzoic acid coformers and dipyridyl-2,2'-bithiophene molecules to understand how the coformer identity and pyridine N atom placement affected solid-state properties.

Triarylphosphine-Coordinated Bipyridyl Ru(II) Complexes Induce Mitochondrial Dysfunction.

While cancer cells rely heavily upon glycolysis to meet their energetic needs, reducing the importance of mitochondrial oxidative respiration processes, more recent studies have shown that their mitochondria still play an active role in the bioenergetics of metastases. This feature, in combination with the regulatory role of mitochondria in cell death, has made this organelle an attractive anticancer target. Here, we report the synthesis and biological characterization of triarylphosphine-containing bipyridyl ruthenium (Ru(II)) compounds and found distinct differences as a function of the substituents on the bipyridine and phosphine ligands.

Structure and Piezoelectricity Due to B Site Cation Variation in ABCl Hybrid Histammonium Chlorometallate Materials.

To provide new insights for understanding the influence of B site cations on the structure in chlorometallate materials of the form ABCl, we report novel organic-inorganic hybrid metallates (OIHMs) incorporating histammonium (HistNH) dications and various transition-metal and main group B site cations. Single crystals of OIHMs with the basic formula (HistNHMCl, M = Fe, Co, Ni, Cu, Zn, Cd, Hg, Sb, Sn, Pb, Bi) were grown and their structures characterized by single-crystal X-ray crystallography. HistNHCoCl, HistNHZnCl, and HistNHSbCl were crystallized in a non-centrosymmetric space group and were subsequently studied with piezoresponse force microscopy (PFM).

Development of branched polyphenolic poly(beta amino esters) to facilitate post-synthesis processing.

Given their versatility and formability, polymers have proven to be a viable platform facilitating a controlled and tuned release for a variety of therapeutic agents. One growing area of polymer drug delivery is polymeric prodrugs, which covalently link active pharmaceutical ingredients to a polymeric form to enhance stability, delivery, and pharmacology. One such class of polymeric prodrugs, poly(beta amino esters) (PβAEs) can be synthesized into crosslinked, or "thermoset," networks which greatly limits their processability.

Preserving Porosity of Mesoporous Metal-Organic Frameworks through the Introduction of Polymer Guests.

High internal surface areas, an asset that is highly sought after in material design, has brought metal-organic frameworks (MOFs) to the forefront of materials research. In fact, a major focus in the field is on creating innovative ways to maximize MOF surface areas. Despite this, large-pore MOFs, particularly those with mesopores, continue to face problems with pore collapse upon activation.

Efficient Planar Perovskite Solar Cells Using Passivated Tin Oxide as an Electron Transport Layer.

Planar perovskite solar cells using low-temperature atomic layer deposition (ALD) of the SnO electron transporting layer (ETL), with excellent electron extraction and hole-blocking ability, offer significant advantages compared with high-temperature deposition methods. The optical, chemical, and electrical properties of the ALD SnO layer and its influence on the device performance are investigated. It is found that surface passivation of SnO is essential to reduce charge recombination at the perovskite and ETL interface and show that the fabricated planar perovskite solar cells exhibit high reproducibility, stability, and power conversion efficiency of 20%.

Bis(arylimidazole) Iridium Picolinate Emitters and Preferential Dipole Orientation in Films.

The straightforward synthesis and photophysical properties of a new series of heteroleptic iridium(III) bis(2-arylimidazole) picolinate complexes are reported. Each complex has been characterized by nuclear magnetic resonance, UV-vis, cyclic voltammetry, and photoluminescent angle dependency, and the emissive properties of each are described. The preferred orientation of transition dipoles in emitter/host thin films indicated more preferred orientation than homoleptic complex Ir(ppy).

Approaches for Selective Synthesis of Ullazine Donor-Acceptor Systems.

Methods for effective synthesis for the four possible isomeric 3,9-diphenylullazine carboxaldehydes and reactive halogen intermediates are described. Ullazine donor-acceptor (D-A) dyes were studied using UV/Vis, photoluminescence (PL) spectroscopy and cyclic voltammetry. X-ray single crystal diffraction analysis independently confirmed the structures of two key intermediates.

Indolizine-Squaraines: NIR Fluorescent Materials with Molecularly Engineered Stokes Shifts.

The development of deep red and near infrared emissive materials with high quantum yields is an important challenge. Several classes of squaraine dyes have demonstrated high quantum yields, but require significantly red-shifted absorptions to access the NIR window. Additionally, squaraine dyes have typically shown narrow Stokes shifts, which limits their use in living biological imaging applications due to dye emission interference with the light source.

Phosphorescent Neutral Iridium (III) Complexes for Organic Light-Emitting Diodes.

The development of transition metal complexes for application in light-emitting devices is currently attracting significant research interest. Among phosphorescent emitters, those involving iridium (III) complexes have proven to be exceedingly useful due to their relatively short triplet lifetime and high phosphorescence quantum yields. The emission wavelength of iridium (III) complexes significantly depends on the ligands, and changing the electronic nature and the position of the ligand substituents can control the properties of the ligands.

Molecular Design Principles for Near-Infrared Absorbing and Emitting Indolizine Dyes.

Desirable components for dye-sensitzed solar cell (DSC) sensitizers and fluorescent imaging dyes include strong donating building blocks coupled with well-balanced acceptor functionalities for absorption beyond the visible range. We have evaluated the effects of increasing acceptor strengths and incorporation of dye morphology controlling groups on molar absorptivity and absorption breadth with indolizine donor-based dyes. Indolizine-based D-A and D-π-A sensitizers incorporating bis-rhodanine, tricyanofuran (TCF), and cyanoacrylic acid functionalities were analyzed for performance in DSC devices.

Molecularly Engineered Ru(II) Sensitizers Compatible with Cobalt(II/III) Redox Mediators for Dye-Sensitized Solar Cells.

Thiocyanate-free isoquinazolylpyrazolate Ru(II) complexes were synthesized and applied as sensitizers in dye-sensitized solar cells (DSCs). Unlike most other successful Ru sensitizers, Co-based electrolytes were used, and resulting record efficiency of 9.53% was obtained under simulated sunlight with an intensity of 100 mW cm(-2).

A low recombination rate indolizine sensitizer for dye-sensitized solar cells.

A sensitizer incorporating a heavily alkylated surface blocking indolizine donor exhibits excellent light absorption and diminished recombination rates in dye-sensitized solar cells (DSCs). DSC device efficiencies (up to 8%) using either I(-)/I3(-) or Co(bpy)3(2+/3+) redox shuttles were obtained, which compare favourably to the known excellent surface coverage co-sensitization dye, .

Electrocatalytic Reduction of CO2 to CO With Re-Pyridyl-NHCs: Proton Source Influence on Rates and Product Selectivities.

A series of four electron-deficient-substituted Re(I) pyridyl N-heterocyclic carbene (pyNHC) complexes have been synthesized, and their electrocatalytic reduction of CO2 has been evaluated by cyclic voltammetry and controlled potential electrolysis experiments. All of the catalysts were evaluated by cyclic voltammetry under inert atmosphere and under CO2 and compared to the known benchmark catalyst Re(bpy)(CO)3Br. Among the four Re-NHC catalysts, Re(pyNHC-PhCF3)(CO)3Br (2) demonstrated the highest catalytic rate (icat/ip)(2) at the first and second reduction events with a value of 4 at the second reduction potential (TOF = 0.

Photocatalytic Reduction of CO2 with Re-Pyridyl-NHCs.

A series of Re(I) pyridyl N-heterocyclic carbene (NHC) complexes have been synthesized and examined in the photocatalytic reduction of CO2 using a simulated solar spectrum. The catalysts were characterized through NMR, UV-vis, cyclic voltammetry under nitrogen, and cyclic voltammetry under carbon dioxide. The complexes were compared directly with a known benchmark catalyst, Re(bpy) (CO)3Br.

Au₁₃₇(SR)₅₆ nanomolecules: composition, optical spectroscopy, electrochemistry and electrocatalytic reduction of CO₂.

Au137(SR)56, a nanomolecule with a precise number of metal atoms and ligands, was synthesized. The composition was confirmed by MALDI and ESI mass spectrometry using three unique ligands (-SCH2CH2Ph, -SC6H13, and -SC4H9) and nano-alloys with Ag and Pd. The electrocatalytic properties were tested for CO2 reduction.

An efficient synthesis of bis-1,3-(3'-aryl-N-heterocycl-1'-yl)arenes as CCC-NHC pincer ligand precursors.

A report that demonstrated an efficient methodology for the arylation of imidazoles has been extended to bis(N-heterocyclic) compounds. Using bis(aryl) iodonium salts provides high-yielding access to CCC-NHC ligand precursors in a single step. Examples of arylation using various iodonium salts are reported herein with an investigation into the factors governing their relative rate of reactivity.

Platinum CCC-NHC benzimidazolyl pincer complexes: synthesis, characterization, photostability, and theoretical investigation of a blue-green emitter.

The recently reported metallation/transmetallation route for the synthesis of CCC-bis(NHC) pincer ligand architectures was extended to 1,3-bis(3'-(trimethylsilylmethyl)-benzimidizol-1'-yl)benzene. The precursor was metallated with Zr(NMe2)4 and transmetallated to Pt using [Pt(COD)Cl2]. This Pt complex was found to resist photobleaching under UV irradiation in ambient conditions.