A catalytic cycle for oxidation of tert-butyl methyl ether by a double C−H activation-group transfer process

A square-planar, iridium(I) carbene complex is shown to effect atom and group transfer from nitrous oxide and organic azides, releasing the corresponding formate or formimidate and an iridium(I)−dinitrogen adduct. The dinitrogen complex performs C−H activation upon photolysis or thermolysis, regenerating the carbene from tert-butyl methyl ether with loss of H_2. Taken together, these reactions represent a net catalytic cycle for C−H functionalization by double C−H activation to generate metal−carbon multiple bonds. Additionally, the unusual group transfer from diazo reagents underscores the unique nature of the reactivity observed for nucleophilic-at-metal carbene complexes

Synthesis and Reactivity of Iridium(III) Dihydrido Aminocarbenes

Iridium complexes supported by the PNP amidophosphine scaffold (PNP = [N(2-PiPr2-4-Me-C6H3)2]−) perform the selective double C−H activation of methyl amines to produce iridium(III) dihydrido aminocarbenes. The reactivity of these complexes is presented and contrasted with that observed for the previously reported iridium(I) alkoxycarbenes

Testing the q-Theory of Anomalies

The q-theory explanations of asset pricing anomalies are quantitatively important. We perform a new asset pricing test by using GMM to minimize the difference between average stock returns in the data and average investment returns constructed from observable firm characteristics. Under various specifications, the model-implied average returns display similar magnitudes of dispersion across portfolios sorted on investment-to-asset and on size and book-to-market. But the predicted dispersions in average returns among portfolios sorted on earnings surprises are somewhat smaller in magnitude than those observed in the dataq-theory, asset pricing anomalies, structural estimation

Complexes of iron and cobalt with new tripodal amido-polyphosphine hybrid ligands

Divalent complexes of iron and cobalt with new, monoanionic tripodal amido-polyphosphine ligands have been thoroughly characterized, and XRD analysis reveals geometries that are distinct for this class of ligand

Biomimetic Macromolecules for Macrophage Targeting and Modulation

Carbohydrate recognition has come to the forefront of biological aiming to uncover the mechanisms of physiological and pathological processes. Cell surface glycans are involved in processes including cellular adhesion, cell signaling, and immune response. A new approach for profiling cell surface glycans has great potential for a wide range of biomedical applications. Lectins have been conventionally used to determine the structure and function of glycoproteins, however, their numbers are still restricted compared to the number of glycan structures. Boronic acid has proven a remarkable small molecule capable of binding diols in aqueous solution. This interaction indicates boronic acid derived molecules may serve as lectin mimetics for profiling and targeting cell surface glycans. In the first part of this dissertation study the specific binding site of boronic acid to individual pyranosides was confirmed followed by the synthesis and evaluation of protein-boronic acid conjugates as lectin mimetics. 3-aminophenylboronic acid was conjugated to gluco-, manno- and galactopyranosides, followed by methylation, both under basic conditions. Based on a specific permethylation product for the carbohydrate, boronic acid specificity towards 1,2 and 1,3 diol configurations was confirmed by 1H, 13C NMR, and mass spectrometry. As a result, unique binding profiles were observed for each pyranoside. Next, bovine serum albumin (BSA)-PBA conjugates were synthesized in a density controlled affording multivalent lectin mimetics. The resultant BSA-PBA conjugates were characterized by SDS-PAGE and MALDI-TOF MS. Cell surface glycan binding capacity was confirmed by a competitive lectin assay examined by flow cytometry. Macrophages express lectins as receptors for specific immune responses. Synthetic glycans are candidates for targeting cell surface lectins and for immunomodulation applications. In the second part of this dissertation, novel N-glycan polymers were synthesized and their immunomodulation effects were examined. N-linked glycopolymers were synthesized via cyanoxyl-mediated free radical polymerization (CMFRP). Then, their cytotoxicity and cell activation abilities against RAW 264.7 cells were examined. As a result, N-glycan polymers showed no cytotoxicity at a concentration of 1,250 mg/mL except the N-alpha-2,6-sialolactosyl polymer, which proved cytotoxic at 1250 µg/mL. N-alpha-2,3-sialolactosyl polymer showed the strongest activity for inducing cell surface marker expression compared to controls, indicating high macrophage modulation activity

Biomimetic Macromolecules for Macrophage Targeting and Modulation

Carbohydrate recognition has come to the forefront of biological aiming to uncover the mechanisms of physiological and pathological processes. Cell surface glycans are involved in processes including cellular adhesion, cell signaling, and immune response. A new approach for profiling cell surface glycans has great potential for a wide range of biomedical applications. Lectins have been conventionally used to determine the structure and function of glycoproteins, however, their numbers are still restricted compared to the number of glycan structures. Boronic acid has proven a remarkable small molecule capable of binding diols in aqueous solution. This interaction indicates boronic acid derived molecules may serve as lectin mimetics for profiling and targeting cell surface glycans. In the first part of this dissertation study the specific binding site of boronic acid to individual pyranosides was confirmed followed by the synthesis and evaluation of protein-boronic acid conjugates as lectin mimetics. 3-aminophenylboronic acid was conjugated to gluco-, manno- and galactopyranosides, followed by methylation, both under basic conditions. Based on a specific permethylation product for the carbohydrate, boronic acid specificity towards 1,2 and 1,3 diol configurations was confirmed by 1H, 13C NMR, and mass spectrometry. As a result, unique binding profiles were observed for each pyranoside. Next, bovine serum albumin (BSA)-PBA conjugates were synthesized in a density controlled affording multivalent lectin mimetics. The resultant BSA-PBA conjugates were characterized by SDS-PAGE and MALDI-TOF MS. Cell surface glycan binding capacity was confirmed by a competitive lectin assay examined by flow cytometry. Macrophages express lectins as receptors for specific immune responses. Synthetic glycans are candidates for targeting cell surface lectins and for immunomodulation applications. In the second part of this dissertation, novel N-glycan polymers were synthesized and their immunomodulation effects were examined. N-linked glycopolymers were synthesized via cyanoxyl-mediated free radical polymerization (CMFRP). Then, their cytotoxicity and cell activation abilities against RAW 264.7 cells were examined. As a result, N-glycan polymers showed no cytotoxicity at a concentration of 1,250 mg/mL except the N-alpha-2,6-sialolactosyl polymer, which proved cytotoxic at 1250 µg/mL. N-alpha-2,3-sialolactosyl polymer showed the strongest activity for inducing cell surface marker expression compared to controls, indicating high macrophage modulation activity