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Late Holocene diatoms were identified from four sediment cores from the Gonggeomji Wetland in Korea. In total, 52 diatom species belonging to three classes, 21 families, and 29 genera were investigated. Of these, 14 species were new records for Korea: Caloneis wardii, Cocconeis klamathensis, Encyonema vulgare, Eunotia myrmica, Fallacia californica, Gomphonema asiaticum, Gomphonema insigniturris, Gomphonema neoapiculatum, Gomphonema tumens, Pinnularia fusana, Pinnularia parvulissima, Punctastriata lancettula, Sellaphora capitata, and Staurosira dimorpha. Eleven taxa could not be identified to the species level. All identified diatoms are illustrated by high-quality scanning electron microphotographs, reference taxonomic data, dimensions of the observed cells, and information on ecology and distribution are included. [ABSTRACT FROM AUTHOR]

Abstract: The conceptual design of a coal gasification system for the production of hydrogen is undertaken here using the PRO-II Simulation program. The operating conditions for the gasifier were tuned to between 1200 °C–1500 °C, 15 atm–30 atm and to a feed molar ratio of C:H2O:O2 = 1:0.5–1:0.25–0.5. The refinery temperature and pressure were kept at 550 °Cand 24.5 atm. The syngas produced goes to water gas shift (WGS) reactors operated at 400 °C, 24 atm (HTS) and 250 °C, 23.5 atm (LTS). The production of hydrogen was found to be independent of the concentration of steam in the feed. However, when other operating conditions are constant, the hydrogen output changes dramatically with changes to the concentration of O2 in the feed. The optimal operating conditions for the production of hydrogen by the gasification of Drayton coal were found to be: 1500 °C, 25 atm and a feed ratio C:H2O:O2 = 1:0.58:0.43. [ABSTRACT FROM AUTHOR]

The in vivo fate of drugs conjugated to macromolecules inevitably depends on that of macromolecules. However, the in vivo fate of macromolecules also may be altered by conjugation to drugs. For the efficient design of carboxymethyldextran (CMD) conjugates of a new analgesic drug, DA5018, we investigated whether the chemical modifications alter the pharmacokinetics and tissue distribution of CMD itself. [[sup 14] C]CMD, oxidized [[sup 14] C]CMD ([[sup 14] C]OCMD), [[sup 14] C]OCMD conjugates of DA5018 ([[sup 14] C]OCMD-DA5018) and [[sup 14] C]OCMD conjugates of ethanolamine ([[sup 14] C]OCMD-EA) were prepared and their molecular sizes were compared by size exclusion HPLC. The pharmacokinetics, biliary excretion, and tissue distribution of total radioactivity were compared after intravenous administration of each CMD derivative, 2.0 MBq/kg, to rats. The effective molecular sizes of CMD derivatives decreased in the order of [[sup 14] C]CMD, [[sup 14] C]OCMD-DA5018, [[sup 14] C]OCMD, and [[sup 14] C]OCMD-EA. After administration of each derivative, the mean AUC values of total radioactivity decreased with the decrease in the effective molecular size. The values of CL, Vss, and the amount of total radioactivity excreted in 24-hr urine increased considerably with the decrease in the effective molecular size. The tissue-to-plasma ratios of total radioactivity remaining in heart, liver, lung, kidney, and spleen at 24 hr also increased in the opposite order of the effective molecular size. Taken together, all these results demonstrate that the chemical modifications and physicochemical properties of attached chemicals can alter the pharmacokinetics and tissue distribution of CMD. One possible reason might be the difference in the effective molecular size of various CMD derivatives. Our study demonstrates that it may be necessary to consider the effect of chemical modification on the in vivo fate of macromolecules in designing macromolecular drug conjugates. [ABSTRACT FROM AUTHOR]

A drug delivery system (DDS) is a useful technology that efficiently delivers a target drug to a patient's specific diseased tissue with minimal side effects. DDS is a convergence of several areas of study, comprising pharmacy, medicine, biotechnology, and chemistry fields. In the traditional pharmacological concept, developing drugs for disease treatment has been the primary research field of pharmacology. The significance of DDS in delivering drugs with optimal formulation to target areas to increase bioavailability and minimize side effects has been recently highlighted. In addition, since the burst release found in various DDS platforms can reduce drug delivery efficiency due to unpredictable drug loss, many recent DDS studies have focused on developing carriers with a sustained release. Among various drug carriers, mesoporous silica DDS (MS-DDS) is applied to various drug administration routes, based on its sustained releases, nanosized porous structures, and excellent solubility for poorly soluble drugs. However, the synthesized MS-DDS has caused complications such as toxicity in the body, long-term accumulation, and poor excretion ability owing to acid treatment-centered manufacturing methods. Therefore, biosilica obtained from diatoms, as a natural MS-DDS, has recently emerged as an alternative to synthesized MS-DDS. This natural silica carrier is an optimal DDS platform because culturing diatoms is easy, and the silica can be separated from diatoms using a simple treatment. In this review, we discuss the manufacturing methods and applications to various disease models based on the advantages of biosilica. [ABSTRACT FROM AUTHOR]

To utilize carbohydrates in lignocellulosic biomass, a fractionation of lignocellulose is crucial. In this study, poplar wood sawdust was treated with a mixture of ionic liquids, 1-butyl-3-methylimidazolium acetate ([Bmim][ OAc]) and 1,3-dimethylimidazolium methyl phosphite ([Dmim][ MeO(H) PO2]), to separate carbohydrate and lignin components from wood. Three types of product were isolated: water-soluble wood ( WSW), water-insoluble wood ( WIW), and wood in ionic liquids ( WIL). At a dissolution temperature of 130°C for 18 h, WSW was found to have high carbohydrate and low lignin contents of 81.0 and 3.5%, respectively, corresponding to a delignification efficiency of 88.9%. WIW isolated under the same condition was found to have 55% of the lignin of native poplar. However, with an increase in the dissolution temperature and the time, the yield of WIL increased due to the increased phosphorylation in both carbohydrate and lignin, forming a mixture of carbohydrate and lignin having phosphorylated ionic functional groups. [ABSTRACT FROM AUTHOR]

Thalassiosira species are an important component of phytoplankton populations, and most species are considered cosmopolitan. Many authors have investigated the diversity of Thalassiosira species in order to understand their ecological roles in local areas. Our regional taxonomic study revealed the presence of 44 Thalassiosira species at 124 sites in Korean coastal waters. Of these, 14 species are newly reported in Korean waters and are described in detail with external and internal valve illustrations. Some morphologically confused taxa, such as the Thalassiosira s.s. group, T. curviseriata/ T. tealata, T. simonsenii/ Planktoniella blanda and T. proschkinae/ T. spinulata, are clearly distinguished using additional morphological criteria. In addition, the full biogeographical distribution of Thalassiosira is described and compared with the Korean species. Korean waters seem to be the 'Maginot Line' for the cold- and warm-water Thalassiosira species. Knowledge of Thalassiosira species diversity will increase with more intensive work in relatively little-studied regions, such as the Indo-Pacific and tropical Atlantic Oceans. [ABSTRACT FROM AUTHOR]

Abstract: The transesterification of dimethyl carbonate (DMC) with glycerol to produce glycerol carbonate was investigated in the presence of CaO under various reaction conditions. CaO was completely dissolved in the reaction mixture of glycerol and DMC in 5min at 75°C and at the molar ratio of glycerol/DMC/CaO of 1/2/0.01. The isolation and the characterization of the dissolved Ca species by means of TOF-SIMS, elemental analysis, and FT-IR revealed that an active species, Ca(C3H7O3)(OCO2CH3) is generated from the interaction of CaO with glycerol and DMC. The mechanistic pathways to the formations of Ca(C3H7O3)(OCO2CH3) and glycerol carbonate are discussed on the basis of experimental and spectroscopic results. [Copyright &y& Elsevier]

Abstract: The tri-reforming reaction was carried out over NiO–YSZ–CeO2 catalyst to produce a synthesis gas from greenhouse gases like CH4 and CO2 contributing to the greenhouse effect. The NiO–YSZ–CeO2 catalysts were characterized by N2 physisorption, X-ray diffraction (XRD), transmission electron microscope (TEM) and scanning electron microscope (SEM) techniques. It was found that the tri-reforming reaction was more favorable than the dry reforming reaction for the production of synthesis gas. It was also observed that NiO–YSZ–CeO2 catalyst showed higher catalytic activity and stability than commercial Holder Topsoe (HT) and Imperial Chemical Industries (ICI) catalysts in the tri-reforming of CH4. The results suggest that the tri-reforming process can be applied to the production of high-valued chemicals and the fuel processor of solid oxide fuel cell (SOFC) and molten carbonate fuel cell (MCFC) systems. [Copyright &y& Elsevier]

The partial oxidation (POX) reforming process of gasoline is an attractive option for the applications to fuel cell-powered vehicles. As a part of the development of a gasoline fuel processor, various supported transition metal formulations for the POX-reforming of iso-octane were investigated. Many of the tested catalysts displayed reasonably good activity towards the POX-reforming of iso-octane. Some catalyst formulations showed better activity than a commercial ICI catalyst under the tested conditions. It was found that catalytic formulations of Ni/M/MgO/Al2O3 were more active than the other catalyst formulations in the POX-reforming of iso-octane. Especially, Ni/Fe/MgO/Al2O3 catalyst with high stability in POX-reforming of iso-octane (Cs<5 ppm) showed better sulfur tolerance over the commercial ICI catalyst in the POX-reforming of iso-octane containing sulfur (Cs=100 ppm), even though none of the systems was found to be completely sulfur resistant. It was suggested that Ni/Fe/MgO/Al2O3 catalyst may be used as an alternative option in place of the commercial ICI reforming catalyst for fuel cell-powered vehicles. [Copyright &y& Elsevier]

The purpose of this research was to assess the acylation reactions of peptides, salmon calcitonin (sCT), human parathyroid hormone 1–34 (hPTH1–34) and leuprolide, in poly(lactic-co-glycolic acid) (PLGA) microspheres. Capillary electrophoresis (CE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) were used for determining and monitoring peptide acylation and quantitating acylation products in the degrading PLGA microspheres. In the degrading PLGA microspheres of sCT and hPTH1–34, the acylation products were observed and determined to be adducts with glycolic acid units from degradable PLGA polymer by MALDI-TOF MS. In the microsphere of leuprolide, however, the acylation product was not observed even after 28 days of incubation at the release medium, which represents the different stabilities among peptides according to the primary structure. As the leuprolide contains tyrosine and serine having hydroxyl group of nucleophilic amino acids, the acylation reaction of peptide is shown to be mainly due to the primary amino groups of N-terminus or lysine residue. The complementary use of CE and MALDI-TOF MS will be useful for searching the counter measures as well as determining the peptide acylation in the manufactured formulations on the market. [Copyright &y& Elsevier]

East Asian summer monsoon (EASM)-driven rapid hydroclimatic variation is a crucial factor with major socioeconomic impacts. Nevertheless, decadal- to centennial-scale EASM variability over the last two millennia is still poorly understood. Pollen-based quantitative annual precipitation (PqPann) and annual precipitation reconstructed by artificial neural networks (ANNs) for the period 650–1940 CE were reconstructed from a paleo-reservoir in South Korea. ANNs reconstruction was performed to compensate for a hiatus section. On a decadal timescale, 10 high-precipitation periods were identified, and PqPann and ANNs reconstructions were comparable to local instrumental rainfall and historic drought records. Biotic lags to rapid climatic changes ranging from 25 to 100 years were recognized by asynchronous pollen and speleothem responses to precipitation. We suggest that PqPann-based decadal- to centennial-scale climatic change reconstruction should take biotic lags into account, although the lags can be ignored on the millennial scale. The position of the EASM rainband influenced rainfall magnitude. [ABSTRACT FROM AUTHOR]

• Propose a new water lean amine solvent for CO 2 capture. • The low regeneration energy of K 2 Sol is demonstrated through pilot plant operation. • K 2 Sol presents superior performances about cyclic capacity and thermal stability. • GPBO is used as a new way to optimize operating conditions in pilot-scale testing. • K 2 Sol requires only 65% of regeneration energy of MEA. The development of new amine solvents without the major drawbacks of conventional amines is crucial to industrial applications of CO 2 capture. This paper presents a water-lean CO 2 capture solvent having a low regeneration energy and low degradation. The water-lean solvent, K 2 Sol, is a sterically hindered diamine; because of the hindered amine site, K 2 Sol easily forms bicarbonate, resulting in a high absorption capacity. The minimum solvent regeneration energy is obtained using Gaussian process Bayesian optimization (GPBO) and bench-scale pilot plant experiments. GPBO finds the optimal solution using the input and output relationship of experiments; thus, expensive first-principle model construction can be avoided. According to the pilot plant experiment, the optimal regeneration energies of monoethanolamine (MEA) and K 2 Sol are 4.3 and 2.8 GJ/t CO 2 , respectively, indicating that K 2 Sol requires only 65% of the regeneration energy of MEA. Fewer than 30 experiments are required to find the optimal pilot plant operation for both the MEA and K 2 Sol experiments. We also describe the superior properties of K 2 Sol in terms of the CO 2 loading, cyclic capacity, regeneration temperature, and degradation. [ABSTRACT FROM AUTHOR]

The paleoenvironmental history of the artificial Reservoir Gonggeomji in Sangju City, Korea, was reconstructed using fossil diatom analysis of four sediment cores: GG01, 02, 03, and 04. Accelerator mass spectrometer (AMS) radiocarbon dating results suggest that Reservoir Gonggeomji was maintained from ca. 1350 to 150 cal year BP, and the diatom record in core sediment samples revealed well-defined hydrological changes and paleoenvironmental conditions during this period. The fossil diatom assemblages were predominantly benthic freshwater diatoms. The highest diatom concentrations in all cores were in diatom zone II, in which species richness and diversity were also very high. Cymbella, Eunotia, Gomphonema, Gyrosigma, Navicula, and Pinnularia were the dominant genera in all core sediments. The long-term trend in diatom species abundance and species diversity showed a stronger relationship to temperature anomalies in the northern hemisphere during the past 2000 years with changes in precipitation. These diatom changes could have been controlled by natural climate change, despite anthropogenic activities linked to construction of the dyke in the artificial reservoir. [ABSTRACT FROM AUTHOR]

As part of an effort to prepare a refrigerant with zero ozone depletion potential (ODP) and with a low global warming potential (GWP), the catalytic dehydrofluorination of 1,1,1,2,3-tetrafluoropropane (HFC-245eb) is performed to produce 2,3,3,3-tetrafluoropropene (HFO-1234yf). Cr 2 O 3 prepared by the sol-gel method (Cr 2 O 3 (SG)) exhibits good catalytic activity attributable to the formation of surface chromium oxyfluoride, which exhibits better catalytic activity with high-valent chromium and a larger fluorine content. The formation of chromium oxyfluoride from chromium oxide is achieved by in-situ fluorination in the early stage of dehydrofluorination, avoiding the conventional fluorination method using toxic HF. [ABSTRACT FROM AUTHOR]

Zn(OAc) 2 -catalyzed carbonylation and decarboxylation of glycerol and urea for the synthesis of glycidol were conducted at 150 °C, 2.7 kPa for 2 h and 170 °C, 2.0 kPa for 1.5 h, respectively. When the reaction conducted in a one-pot consecutive way, the yield of glycidol was 20%. However, when the formed zinc glycerolate (Zn(C 3 H 6 O 3 )) was filtered out after the carbonylation, the yield increased to 50% with respect to the amount of glycerol, whereas the yields of glycidol were very low when other zinc salts such as ZnCl 2 , ZnSO 4 and Zn(NO 3 ) 2 , were used as catalysts. The high catalytic activity of Zn(OAc) 2 for this carbonylation and decarboxylation of glycerol and urea could be ascribed to the formation of Zn(NH 3 ) x (OAc) 2 , which was determined from IR and TOF-SIMS studies. [ABSTRACT FROM AUTHOR]

• We studied flocculation of microalgae- and clay-containing suspensions. • Investigations were done in different microalgal growth phases. • A two-class flocculation kinetic model and Bayesian calibration were applied. • Effect of organic matter secreted by algae on flocculation kinetics was evaluated. • Distinct flocculation mechanisms were identified in different microalgal growth phases. Interplays between microalgae and clay minerals enhance biologically mediated flocculation, thereby affecting the sedimentation and transportation of suspended particulate matter (SPM) in water and benthic environments. This interaction forms larger flocs with a higher settling velocity and enhances SPM sinking. The aim of this study was to investigate the flocculation kinetics of microalgae and clay in suspension and to elucidate the mechanisms associated with such interactions. Standard jar test experiments were conducted using various mixtures of kaolinite and microalgal samples from batch cultures (Chlorella vulgaris) to estimate biologically mediated flocculation kinetics. The organic matter (OM) composition secreted by the microalgae was characterized using a liquid chromatography - organic carbon detection system, and quantitative analysis of transparent exopolymer particles was conducted separately. A two-class flocculation kinetic model, based on the interaction between flocculi and flocs, was also adopted to quantitatively analyze the experimental data from flocculation. Results from the flocculation kinetic tests and OM analyses, in association with other data analyses (i.e., floc size distribution and flocculation kinetic model), showed that flocculation increased with OM concentration during the growth phase (10–20 d). However, on day 23 during the early stationary phase, flocculation kinetics started decreasing and substantially declined on day 30, even though the amount of OM (mainly biopolymers) continued to increase. Our results indicate that an adequate quantity of biopolymers produced by the microalgal cells in the growth phase enhanced floc-to-floc attachment and hence flocculation kinetics. In contrast, an excessive quantity of biopolymers and humic substances in the stationary phase enhanced the formation of polymeric backbone structures and flocculation via scavenging particles but simultaneously increased steric stabilization with the production of a large number of fragmented particles. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract: Decarboxylation of glycerol carbonate (GLC) to produce 2,3-epoxy-1-propanol (glycidol) was conducted using various kinds of ionic liquids (ILs) as catalysts. ILs bearing an anion with medium hydrogen-bond basicity such as and I− exhibited the higher glycidol yields than those having an anion with low or strong hydrogen-bond. FT-IR spectroscopic analysis shows that both GLC and glycidol interact with anions of ILs through their hydroxyl groups. It was possible to improve the yield of glycidol when a zinc salt with a medium Lewis acidity was co-present along with an IL. The yield of glycidol was greatly increased up to 98% when the decarboxylation was conducted in the presence of a high-boiling aprotic solvent. Computational calculations on the mechanism using 1-butyl-3-methylimidazolium nitrate as a catalyst revealed that the first step is the -assisted ring-opening of GLC followed by the ring closure, resulting in the formation of a 3-membered ring intermediate species. [Copyright &y& Elsevier]

Abstract: Homogeneous zinc-catalyzed synthesis of glycerol carbonate from the reaction of glycerol with urea was investigated. Among the zinc-based catalysts tested, ZnCl2 showed the highest catalytic activity. Spectroscopic and elemental analyses of the zinc species, isolated from the reaction conducted in the presence of ZnCl2, revealed that Zn(NH3)Cl2 was generated first as an intermediate species, which in turn reacted with glycerol to produce zinc glycerolate, Zn(C3H6O3) and NH4Cl. The activity of Zn(C3H6O3) was considerably lower than that of ZnCl2, but the activity was greatly enhanced by the combined use of NH4Cl, implying that both Zn(C3H6O3) and NH4Cl were functioning as essential ingredients for the carbonylation of glycerol by urea. The formation of Zn(C3H6O3) was also observed when ZnBr2, ZnI2, ZnF2, Zn(NO3)2, Zn(CH3CO2)2, or ZnO was used as the catalyst. [Copyright &y& Elsevier]

Abstract: The solubility of carbon dioxide in room temperature ionic liquids (RTILs), dialkylimidazolium dialkylphosphates, was measured at 313–333K and at pressures close to atmospheric pressure, from which Henry''s law coefficients, standard Gibbs free energy, enthalpy, and entropy changes of solvation were derived. The CO2 solubility in the dialkylimidazolium dialkylphosphate was found to increase with increasing chain length of the alkyl groups on the cation and/or the anion as was similarly found in other RTILs. Among various dialkylimidazolium dialkylphosphates tested, 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM][Et2PO4]) and 1-butyl-3-methylimidazolium dibutylphosphate ([BMIM][Bu2PO4]) exhibited the comparable or better capability of dissolving CO2 in comparison with that of [BMIM][BF4], but their absorption capacities were still lower than that of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([BMIM][Tf2N]). [Copyright &y& Elsevier]

CF3CHFCF2OCH2CF3 (1,1,2,3,3,3-hexafluoropropyl--trifluoroethylether), one of the third generation CFC alternatives, was obtained in high yield and selectivity from the hydroalkoxylation reaction of hexafluoropropene with 2,2,2-trifluoroethanol conducted in the presence of a catalytic system consisting of a potassium salt and an ionic liquid, 1-butyl-3-methylimidazolium chloride ([BMIm]Cl). The formation of commonly observed olefinic side products in the hydroalkoxylation catalyzed by potassium salts was greatly reduced by the co-presence of [BMIm]Cl. Theoretical calculations and mechanistic studies suggested that potassium ion is largely responsible for the formation of olefinic side products. [Copyright &y& Elsevier]

Abstract: An iso-octane fuel processor system with three different reaction stages, autothermal reforming (ATR) reaction of iso-octane, high temperature shift (HTS) and low temperature shift (LTS) reactions, was developed for applications in a fuel cell system. Catalytic properties of the prepared Ni/Fe/MgO/Al2O3 and Pt–Ni/CeO2 or molybdenum carbide catalysts were compared to those of commercial NiO/CaO/Al2O3 and Cu/Zn/Al2O3 catalysts for ATR and LTS reaction, respectively. It was found that the prepared catalysts formulations in the fuel processor system were more active than those of the commercial catalysts. As the exit gas of iso-octane ATR over the Ni/Fe/MgO/Al2O3 catalyst was passed through Fe3O4–Cr2O3 catalyst for HTS and Mo2C or Pt–Ni/CeO2 catalyst for LTS reaction, the concentration of CO in hydrogen-rich stream was reduced to less than 2400ppm. The results suggest that the iso-octane fuel processor system with prepared catalysts can be applied to PEMFC system when a preferential partial oxidation reaction is added to KIST iso-octane reformer system. [Copyright &y& Elsevier]

Abstract: The performance and operation results of the reformer that supplies synthesis gases to a 100kW class molten carbonate fuel cell are reported. A CH4 conversion ratio of 95.6%, a CO conversion ratio of 31.2%, a reforming reaction temperature of 745°C and a produced hydrogen rate of 70.7Nm3 h−1 are obtained from a comparison of post gas analysis and theoretical estimation of thermodynamics at 87.6h. To calculate the efficiency, the Cycle-Tempo 5.0 program is used. The thermal efficiency of the designed system is 61.1% and the real thermal efficiency of the system is 44.5% at 108h. The low thermal efficiency is mainly attributed to supplying excess fuel to meet the outlet temperature of the reforming reactors. In the present system, the outlet temperature of the reforming reactors appears to be below the temperature required at the stack of molten carbonate fuel cell (MCFC), that is, over 580°C. In order to maintain the outlet temperature of the reforming reactor over 580°C, it is necessary to heat the reformed gases at the convection zone of combustion gases. For higher thermal efficiency, the combustion space and the excess fuel should be reduced until reaching minimum temperature of the surface of reforming tube, at which point has no influence on the CH4 conversion ratio. [Copyright &y& Elsevier]

Abstract: A series of ionic liquid-based zinc tetrahalide complexes were synthesized and their effects in the coupling reactions of ethylene oxide (EO) and carbon dioxide to produce ethylene carbonate (EC) were evaluated. The zinc tetrahalide complexes displayed high catalytic activities for the coupling reaction, but were found to cause a severe decomposition of EC during the vacuum-distillation of the product mixture. Among the various factors affecting the EC decomposition, the concentration of zinc tetrahalide species was most responsible for the decomposition: the lower the concentration, the lesser the decomposition. The addition of an imidazolium or ammonium halide was effective for enhancing the activity of the zinc tetrahalide complex while having only a minor effect on the decomposition rate. The optimum catalyst composition was discussed for producing EC feasibly with minimized product decomposition. [Copyright &y& Elsevier]

Abstract: Phosphine adducts of zinc(II) halides, ZnX2L2 (X=Cl, Br, I; L=PMe2Ph, PEt3, PBu3, PPh3, PCy3), prepared by the reaction of ZnX2 with two equivalents of corresponding phosphines, showed high activities for the coupling reaction of CO2 and ethylene oxide to produce ethylene carbonate. The catalytic activity of ZnX2L2 was hardly affected by the nucleophilicity of the phosphine ligands, with the exception of ZnX2(PCy3)2, but depended strongly on the nature of halide ligands. An active species containing ethoxyphosphonium ligands, Zn3Br6[μ-OCH2CH2-P(C6H5)3]3, was isolated and characterized by X-ray crystallography, elemental analysis, and NMR spectroscopy. The mechanistic pathway for the formation of active species and cyclic carbonates is discussed. [Copyright &y& Elsevier]

The original version of this article unfortunately contained a mistake. The authors wish to revise the "Acknowledgements" section of their article. [ABSTRACT FROM AUTHOR]