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A simple system to control the selectivities of C2 products in electrochemical CO2 reduction with copper phenanthroline on carbon paper.

We report the unprecedented electrocatalytic activity of a series of molecular nickel thiolate complexes (1-5) in reducing CO2 to C1 - 3 hydrocarbons on carbon paper in pH-neutral aqueous solutions. Ni(mpo)2 (3, mpo = 2-mercaptopyridyl-N-oxide), Ni(pyS)3- (4, pyS = 2-mercaptopyridine), and Ni(mp)2- (5, mp = 2-mercaptophenolate) were found to generate C3 products from CO2 for the first time in molecular complex. Compound 5 exhibits Faradaic efficiencies (FEs) of 10.6%, 7.2%, 8.2% for C1, C2, C3 hydrocarbons respectively at -1.0 V versus the reversible hydrogen electrode. Addition of CO to the system significantly promotes the FEC1 - C3 to 41.1%, suggesting that a key Ni-CO intermediate is associated with catalysis. A variety of spectroscopies have been performed to show that the structures of nickel complexes remain intact during CO2 reduction.

Organic dyes have been investigated extensively as promising photosensitizers in noble-metal-free photocatalytic systems for hydrogen production. However, other than functional group optimization, there are very few methods reported to be effective in improving their photocatalytic activity. Herein, we report the incorporation of Cu

Electrochemical CO

The transesterification reaction between cellulose and vinyl esters is regarded as a clean and facile strategy for the tunable synthesis of cellulose esters. In this study, a series of cellulose esters with degrees of substitution from 0.58 to 3.0 have been prepared successfully under mild conditions without adding any external catalysts when cellulose was dissolved in the 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)/DMSO/CO2 solvent system and then followed by adding equimolar amounts of long chain fatty, aromatic, branched and steric vinyl esters. The optimization study of different reaction parameters like reaction time, temperature and amounts of substrates demonstrates that the reaction can proceed smoothly even at room temperature. This is evidenced by a cellulose benzoate with a DS of 2.6 obtained when the reaction is performed at 25 °C in 4 h. The as-prepared cellulose esters structure has been confirmed by 1H NMR, 13C NMR and FTIR, and material thermal properties were evaluated by DSC and TGA for an in-depth understanding the relationship between the cellulose esters structure and properties. It is believed that the DBU not only acts as a reagent for the CO2-derivative dissolution of cellulose in DMSO, but also acts as an in situ organocatalyst for the subsequent transesterification reaction. Cellulose esters have been prepared successfully at low temperature using long chain fatty acids, aromatic, branched and steric vinyl esters as acyl donors in the DMSO/DBU/CO2 solvents system, and the DBU not only acts as reagents for the CO2-derivative dissolution of cellulose in DMSO, acts as an organocatalyst for the subsequent derivatisation.

Cellulose is the most abundant biorenewable resource on the earth, and is also characterized by its low price, easy derivatization and good biodegradable property. It is believed that derivatization is an important strategy to extend its applications. Cellulose carbonate is one of the most important classes of cellulose derivatives, as they have good potential in the field of green packaging film materials, thermoplastics, solid electrolyte, and so on. In this study, cellulose methyl carbonate has been synthesized successfully after the dissolution of cellulose in the novel 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)/DMSO/CO2 system followed by the addition of dimethyl carbonate via the in-situ organocatalysis by DBU. The structure and thermal properties of the as prepared cellulose methyl carbonate were systematically characterized by NMR, FTIR, TGA and DSC. The results show that cellulose methyl carbonate with a DS of 1.09 was achieved after 12 h at 60 °C with molar ratio of dimethyl carbonate/AGU at 8:1. The DSC/TGA results show that the cellulose methyl carbonate with DS=1.09 has a T g of 62.9 °C and starts thermal degradation at 305.5 °C .

The facile dissolution of cellulose via its reversible reaction with CO2 in the presence of 1, 8-diazabicyclo[5.4.0]undec-7-ene (DBU) in DMSO provides a new efficient platform for derivatization of cellulose, on which serials of grafted poly-(ϵ-caprolactone) copolymers were successfully prepared through ring-opening polymerization (ROP) under mild conditions without adding external catalysts. The strategy allows the preparation cellulose-graft-poly-(ϵ-caprolactone) copolymers with a molar substitution (MSPCL) of poly-(ϵ-caprolactone) ranging 2.29 to 8.01 under mild conditions. The results indicated that DBU acted as not only an important reagent to achieve cellulose dissolution, but it also acted as an organocatalyst for the subsequent ROP process. The grafting content of the prepared copolymers were characterized by 1H NMR. Their physiochemical structures were determined by NMR, FTIR, GPC and WXRD, and thermal properties were studied by TGA and DSC.

This report describes the synthesis and characterization of a family of unsymmetrical NCN pincer Ni(II) complexes 2–8 with NHC-triazole arms. All of these complexes have been fully characterized by X-ray single crystal analysis, NMR spectroscopy, and elemental analysis. Complexes 2 and 4–6 were square planar with a chloride trans to the carbene carbon atoms. Complex 3 was a paramagnetic octahedral complex with its central metal surrounded by two NCN pincer ligands. Complexes 7 and 8 contain [(NHC)2Ni2-OH] moieties bearing a OH bridge. Both the [(NHC)2Ni2-OH] complexes 7 and 8 and [(NCNHCN)Ni-Cl] complexes 2 and 4–6 were synthesized similarly via the reactions of the in situ formed Ag–NHCs from the corresponding imidazolium salts with [NiCl2(PPh3)2]. The catalytic activities of all complexes for Suzuki–Miyaura cross-coupling were examined. Under the optimized conditions, complex 4 was active in the Suzuki–Miyaura cross-coupling reactions of aryl iodides and aryl bromides at 110 °C. Aryl chlorides were successfully coupled in the presence of triphenylphosphine as an additive.

A series of copper complexes (3–6) stabilized by 1,2,3-triazole-tethered N-heterocyclic carbene ligands have been prepared via simple reaction of imidazolium salts with copper powder in good yields. The structures of bi- and trinuclear copper complexes were fully characterized by NMR, elemental analysis (EA), and X-ray crystallography. In particular, [Cu2(L2)2](PF6)2 (3) and [Cu2(L3)2](PF6)2 (4) were dinuclear copper complexes. Complexes [Cu3(L4)2](PF6)3 (5) and [Cu3(L5)2](PF6)3 (6) consist of a triangular Cu3 core. These structures vary depending on the imidazolium backbone and N substituents. The copper–NHC complexes tested are highly active for the Cu-catalyzed azide–alkyne cycloaddition (CuAAC) reaction in an air atmosphere at room temperature in a CH3CN solution. Complex 4 is the most efficient catalyst among these polynuclear complexes in an air atmosphere at room temperature.

Zwitterionic sulfobetaine groups were grafted onto polysulfone (PSU) membrane surface with 2-azidoethyl methacrylate and N,N-diethyl-N-propargyl-N-(3-sulfopropyl) ammonium (DEPAS) via surface-initiated Atom Transfer Radical Polymerization (ATRP) and “click” chemistry in a two-step process. The PSU membranes were fully characterized by attenuated total reflectance Fourier transform infrared spectra (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and static water contact angle (WCA) measurement. Results showed that zwitterionic monomers were efficiently grafted onto PSU surfaces. The water contact angle, bovine serum albumin (BSA) protein adsorption and platelet adhesion were obviously decreased after grafting zwitterionic sulfobetaine groups onto the membrane surface. These indicated that the zwitterionic sulfobetaine modified PSU membranes presented good biocompatibility. This study provides a new approach for surface modification of polysulfone with different functionalities.

A series of copper complexes (3–6) stabilized by 1,2,3-triazole-tethered N-heterocyclic carbene ligands have been prepared via simple reaction of imidazolium salts with copper powder in good yields. The structures of bi- and trinuclear copper complexes were fully characterized by NMR, elemental analysis (EA), and X-ray crystallography. In particular, [Cu2(L2)2](PF6)2 (3) and [Cu2(L3)2](PF6)2 (4) were dinuclear copper complexes. Complexes [Cu3(L4)2](PF6)3 (5) and [Cu3(L5)2](PF6)3 (6) consist of a triangular Cu3 core. These structures vary depending on the imidazolium backbone and N substituents. The copper–NHC complexes tested are highly active for the Cu-catalyzed azide–alkyne cycloaddition (CuAAC) reaction in an air atmosphere at room temperature in a CH3CN solution. Complex 4 is the most efficient catalyst among these polynuclear complexes in an air atmosphere at room temperature.

A new nonspecific protein antifouling polysulfone (PSU) material has been elaborated by grafting zwitterionic sulfobetaine (SB) complex by the means of PSU azidation (PSU-N3) followed by “Click-Chemistry” with acetylenic zwitterionic SB monomer (N,N'-diethyl-N-propargyl-N- (3-sulfopropyl) ammonium (DEPAS)). Azidation (PSU-N3) and functionalization (PSU-g-DEPAS) PSU materials were characterized by 1H NMR, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Contact angle and protein adsorption on PSU-g-DEPAS and unmodified PSU membrane were studied. The results show that the chemical modification of PSU improved both the hydrophilicity and antiprotein absorption ability. This new fouling-resistance to protein material has potential for biomaterials applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41327.