| Title | Facile post-growth doping of nanostructured hematite photoanodes for enhanced photoelectrochemical water oxidationChemoselective Allene Aziridination via Ag(I) CatalysisIn situ investigation of vapor-deposited glasses of toluene and ethylbenzene via alter |
| Publication Type | Journal Article |
| Year of Publication | 2013 |
| Authors | Franking, R, Li, LS, Lukowski, MA, Meng, F, Tan, YZ, Hamers, RJ, Jin, S, Rigoli, JW, Weatherly, CD, Vo, BT, Neale, S, Meis, AR, Schomaker, JM, Ahrenberg, M, Chua, YZ, Whitaker, KR, Huth, H, Ediger, MD, Schick, C, Hill, NJ, Hoover, JM, Stahl, SS, Ye, H, Hui, LM, Kellersberger, K, Li, LJ, Tang, Y, Yang, JH, Liu, J, Wang, CC, Lv, MC, Wu, YB, Yu, XL, Ko, CH, Hsung, RP |
| Journal | Energy & Environmental Science |
| Volume | 6 |
| Pagination | 500-512 |
| Date Published | FebJanDec |
| Type of Article | Article |
| ISBN Number | 1754-56921523-70600021-96060021-95841044-03050385-5414 |
| Accession Number | WOS:000313892400012 |
| Keywords | 1,3-diol acetonides, acid-promoted cyclizations, addition-reactions, aldehydes, aldol, alkene aziridination, alpha-fe2o3 thin-films, anion relay chemistry, atmospheric-pressure, aziridination, benzil, benzoin, bond-forming reactions, Brain, C-H amination, calorimeter, cancer-borealis, carbonyl-compounds, Complexes, convenient oxidation, copper, Crustacean, STNS, Neuropeptide, Imaging mass spectrometry, High resolution MS, crystal, def-bis-spiroacetal, efficient, electrical-properties, electrochemical deposition route, electrodes, electrospray-ionization, functionalization, glasses, heat, hydrogen-production, identification, indomethacin, Intermolecular amination, iron(iii) oxide, iron-oxide, kinetic stability, liquid, lobster homarus-americanus, low-temperature, maldi-fticr, metal-oxides, motor pattern generation, natural-products, nitrene, Olefin metathesis, oxygen, p-type, physiological actions, Second-Year Undergraduate, Laboratory Instruction, Organic Chemistry, Inorganic Chemistry, Hands-On Learning/Manipulatives, Inquiry-Based/Discovery Learning, Alcohols, Catalysis, Green Chemistry, Oxidation/Reduction, si, silver, Spirastrellolide A, Natural Product Synthesis, Cyclic Acetal Tethered RCM, Spiroketal Synthesis, Mukaiyama Aldol, spirastrellolide-a construction, stable, stereotriads, terphenyl, tissue, transition measurements |
| Abstract | We report a facile approach to perform post-growth doping of hematite (alpha-Fe2O3) nanostructures by depositing titanium (Ti) precursor solution and subsequent annealing in air. Using hematite nanowire photoanodes on fluorine doped tin oxide (FTO) glass substrates as a model system, the doping conditions were carefully optimized and highly photoactive hematite photoanodes were prepared at a more practically acceptable temperature of 650-700 degrees C than the >= 800 degrees C commonly used in previous works. A combination of microstructural characterization, elemental analysis, photoelectrochemical (PEC) measurements, and electrochemical impedance spectroscopy (EIS) analysis were employed to confirm the distribution of Ti atoms in hematite nanostructures and the role of Ti dopants in enhancing the photocurrent of hematite photoanodes. It was found that the Ti-treatment increases the donor concentration of hematite by about 10 fold and facilitates majority carrier transpo!Allene aziridination generates useful bicyclic methylene aziridine scaffolds that can be flexibly transformed into a range of stereochemically complex and densely functionalized amine-containing stereotriads. The scope of this chemistry has been limited by the poor chemoselectivity that often results when typical dinuclear Rh(II) catalysts are employed with homoallenic carbamates. Herein, Ag(I) catalysts that significantly improve the scope and yield of bicyclic methylene aziridines that can be prepared via allene aziridination are described.Vapor-deposited glasses of toluene and ethylbenzene have been characterized by in situ ac chip-nanocalorimetry. The high sensitivity of this method allows the detection of small changes in the heat capacity of nanogram size samples. We observe that vapor-deposited glasses have up to 4% lower heat capacities than the ordinary glass. The largest heat capacity decrease and the most kinetically stable glasses of toluene and ethylbenzene are observed in a range of deposition temperatures between 0.75 T-g and 0.96 T-g. Compared to larger molecules, deposition rate has a minor influence on the kinetic stability of these glasses. For both toluene and ethylbenzene, the kinetic stability is strongly correlated with the heat capacity decrease for deposition temperatures above 0.8 T-g. In addition, ac-nanocalorimetry was used to follow the isothermal transformation of the stable glasses into the supercooled liquid at temperatures slightly above T-g. Toluene and ethylbenzene stable gl!Modern undergraduate organic chemistry textbooks provide detailed discussion of stoichiometric Cr- and Mn-based reagents for the oxidation of alcohols, yet the use of such oxidants in instructional and research laboratories, as well as industrial chemistry, is increasingly avoided. This work describes a laboratory exercise that uses ambient air as the source of oxidant and a readily available Cu-I/TEMPO catalyst system to convert benzyl alcohols to the corresponding aldehydes in standard glassware at room temperature. The procedure is well suited for a high-enrollment undergraduate course, and the complete exercise fits easily within a 3-h lab period. The structures of the organic starting materials and products are determined by NMR spectroscopy and EI-MS. The protocol is adapted from the contemporary research literature and provides students with practical experience of a modern, "green" oxidation method. In addition to the practical aspects, the experiment encourages s!Considerable effort has been devoted to characterizing the crustacean stomatogastric nervous system (STNS) with great emphasis on comprehensive analysis and mapping distribution of its diverse neuropeptide complement. Previously, immunohistochemistry (IHC) has been applied to this endeavor, yet with identification accuracy and throughput compromised. Therefore, molecular imaging methods are pursued to unequivocally determine the identity and location of the neuropeptides at a high spatial resolution. In this work, we developed a novel, multi-faceted mass spectrometric strategy combining profiling and imaging techniques to characterize and map neuropeptides from the blue crab Callinectes sapidus STNS at the network level. In total, 55 neuropeptides from 10 families were identified from the major ganglia in the C. sapidus STNS for the first time, including the stomatogastric ganglion (STG), the paired commissural ganglia (CoG), the esophageal ganglion (OG), and the connecti!We describe herein details of our efforts in syntheses of A-ring and BC-ring of (+)-spirastrellolide A. While the former would constitute a facile 12-step synthetic endeavor starting from 1,5-pentanediol, the latter would showcase a cyclic acetal-tethered ring-closing metathesis [RCM] method that was developed in our lab for de novo synthesis of spiroketals. Constructing the entire Southern Half of the macrocycle would require 1,3-anti-Mukaiyama aldol addition for connecting A-ring and BC-ring specifically at C10 and C11, thereby culminating a 17-step approach for the Southern Macrocyclic Half linearly from (+)-2,3-(O)-iso-propylidene-L-threitol. Also discussed here is the possibility of pursuing a more convergent approach toward the assembly of the Southern Half through first connecting A-ring and C-ring via acetal formation that would first link together the free C13-OH with C17 at the spiro-BC-ring junction. An ensuing application of our cyclic acetal-tethered RCM stra! |