Cobalt complexes as artificial hydrogenases for the reductive side of water splitting

The generation of H-2 from protons and electrons by complexes of cobalt has an extensive history. During the past decade, interest in this subject has increased as a result of developments in hydrogen generation that are driven electrochemically or photochemically. This article reviews the subject of hydrogen generation using Co complexes as catalysts and discusses the mechanistic implications of the systems studied for making H-2. This article is part of a Special Issue entitled: Metals in Bioenergetics and Biomimetics Systems. (C) 2013 Elsevier B.V. All rights reserved

Synthesis of a magnetic π-extended carbon nanosolenoid with Riemann surfaces

Riemann surfaces are deformed versions of the complex plane in mathematics. Locally they look like patches of the complex plane, but globally, the topology may deviate from a plane. Nanostructured graphitic carbon materials resembling a Riemann surface with helicoid topology are predicted to have interesting electronic and photonic properties. However, fabrication of such processable and large π-extended nanographene systems has remained a major challenge. Here, we report a bottom-up synthesis of a metal-free carbon nanosolenoid (CNS) material with a low optical bandgap of 1.97 eV. The synthesis procedure is rapid and possible on the gram scale. The helical molecular structure of CNS can be observed by direct low-dose high-resolution imaging, using integrated differential phase contrast scanning transmission electron microscopy. Magnetic susceptibility measurements show paramagnetism with a high spin density for CNS. Such a π-conjugated CNS allows for the detailed study of its physical properties and may form the base of the development of electronic and spintronic devices containing CNS species

A Highly Selective Turn-On Colorimetric, Red Fluorescent Sensor for Detecting Mobile Zinc in Living Cells

We describe ZRL1, a turn-on colorimetric and red fluorescent zinc ion sensor. The Zn2+-promoted ring opening of the rhodamine spirolactam ring in ZRL1 evokes a 220-fold fluorescence turn-on response. In aqueous media, ZRL1 turn-on luminescence is highly selective for Zn2+ ions, with no significant response to other competitive cations, including Na+, K+, Ca2+, Mg2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Cd2+, or Hg2+. In addition to these characteristics, preliminary results indicate that ZRL1 can be delivered to living cells and can be used to monitor changes in intracellular Zn2+ levels.National Institute of General Medical Sciences (U.S.) (GM065519

Platinum(II) polypyridyl complexes for visible light-driven hydrogen production from water

Thesis (Ph. D.)--University of Rochester. Dept. of Chemistry, 2009.This thesis employs Pt(II) terpyridyl and cyclometalated complexes as the chromophores to construct photoactive systems for hydrogen production from water. Several catalysts, including Pt nanoparticles, Pt(II) bi- and terpyridyl chloro complexes, and cobalt dimethylglyoximate complexes, were investigated to catalyze the hydrogen production reactions. Chapter 1, as an introduction part, describes the recent progress in photoinduced hydrogen production from water, including heterogeneous multiple-component systems, homogeneous multiple-component systems and an integrated approach to artificial photosynthesis for photoinduced hydrogen production. Chapter 2 studies a multiple-component system containing a platinum(II) terpyridyl acetylide chromophore, a sacrificial donor (TEOA), an electron relay (MV2+ and diquats) and colloidal platinum catalyst for photocatalytic generation of hydrogen from water. Hydrogen efficiency varies by using different Pt(II) photosensitizers and electron relays, as well as the different concentrations of each species. Chapter 3 discusses the real role of [Pt(ttpy)Cl]+ and Pt(dcbpy)Cl2 as the hydrogen production catalysts. TEM, EDAX and mecury tests show the Pt(II) chloro complexes are only the precursors to form colloidal platinum, which is the real catalyst for hydrogen generation. Chapter 4 and chapter 5 study a novel homogeneous system for photochemical hydrogen production using a cobalt(III) dimethylglyoximate complex as the hydrogen production catalyst and a Pt(II) terpyridyl acetylide complex as the photosensitizer. Cobalt(III) dimethylglyoximate has been used for hydrogen generation by electrochemical method. But very few examples have been reported in photochemical way. The variation of the photosensitizers and cobaloximes are also discussed, as well as the reaction mechanism. Chapter 6 discusses a novel terpyridyl cationic complex [Pt(TPPPB)Cl]Cl, containing a bulky terpyridyl ligand (1-terpyridyl-2,3,4,5,6-pentaphenyl-benzene (TPPPB)). The complex exhibits reversible vapochromic behavior upon exposure to methylene chloride vapors, changing color from red to green. The shift to higher energy in the emission maximum from 654 nm to 514 nm is the largest vapochromic shift (140 nm) yet reported. The [Pt(TPPPB)Cl]Cl complex exhibits high selectivity for certain volatile organic compounds (VOCs) including only methylene chloride, ethanol, ethyl acetate and acetonitrile. The crystal structures of both the green and red forms have been determined by single crystal X-ray diffraction. Chapter 7 describes the perspectives and future directions in this project. More potential efficient and stable cobalt complexes are designed and discussed. The platinum-cobalt supramolecular assemblies towards photochemical molecular devices show interesting properties for hydrogen production

Screening and verification of potential gene targets in esophageal carcinoma by bioinformatics analysis and immunohistochemistry

BackgroundTo evaluate the potential of candidate proteins as diagnostic markers or drug targets in esophageal carcinoma (ESCA).MethodsGSE20347, GSE17351, and GSE45670 were downloaded from Gene Expression Omnibus (GEO). Differently expressed genes (DEGs) between ESCA and normal esophageal tissues from patients were obtained. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed. The genes commonly featured in ESCA were screened by least absolute shrinkage and selection operator (LASSO) logistic regression and Boruta feature selection algorithm. The transcriptome data and corresponding clinical data of ESCA were downloaded from The Cancer Genome Atlas (TCGA) public database. Kaplan-Meier survival analysis was used to explore the core genes related to the prognosis of patients. A protein-protein interaction (PPI) network was generated by GeneMANIA to visualize the functional network between genes. Expressions of CRIP2, FOS, and HOXA10 genes in ESCA cells were verified by immunohistochemistry (IHC).ResultsOut of 11,207 genes, 430 DEGs were identified, including 210 up-regulated genes and 220 down-regulated genes. After taking the intersection of LASSO regression and Boruta algorithm, 15 core genes were identified. Survival analyses demonstrated that low expression of CRIP2 (P=2.643e-02), as well as high expression of FOS (P=4.837e-02) and HOXA10 (P=4.97e-02), was significantly associated with the worse prognosis of ESCA patients. The 3 genes were strongly correlated with the content of immune cells and the stage of tumors. The expression of CRIP2 was correlated with the sensitivity of patients to dasatinib; FOS expression was correlated with the sensitivity of patients to erlotinib, and HOXA10 expression affected the sensitivity of patients to cisplatin, dasatinib, erlotinib, and gefitinib. The cBioportal database showed that 56 patients (31%) had the above core gene mutations: CRIP2 (8%), FOS (10%), and HOXA10 (17%). The IHC showed that there were differences in the expressions of these core genes between ESCA patients and the normal population (P<0.05), with ESCA patients showing higher expression.ConclusionsThe low CRIP2 expression and high expressions of FOS and HOXA10 are associated with more advanced tumor stage, which may have the potential to be novel biomarkers for treatment selection in ESCA

An Unexpected Dual-Emissive Luminogen: Tunable Aggregation-Induced Emission with Cyan-White-Red Colors, Stable Inherent Chirality, and Enhanced Chiroptical Property

Herein we report a novel chiral bismacrocycle with unexpected dual emission and tunable aggregation-induced emission colors. A facile four-step synthesis strategy is developed to construct this rigid bismacrocycle, (1,4)[8]cycloparaphenylenophane (SCPP[8]), which possesses a 1,2,4,5-tetraphenylbenzene core locked by two intersecting polyphenylene-based macrocycles. The luminescent behavior of SCPP[8] shows the unique characteristics of both aggregation-caused quenching effect and aggrega-tion-induced emission (AIE) effect, inducing remarkable redshift emission including near white-light emission. SCPP[8] is configurationally stable and possesses a novel shape-persistent bismacrocycle scaffold with a high strain energy (up to 127.83 kcal/mol). In addition, SCPP[8] displays enhanced circularly polarized luminescence properties due to AIE effect