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A series of platinum and palladium pincer complexes supported by achiral 1,3-bis(2′-imidazolinyl)benzene-based NCN ligands have been prepared via direct C2 metalation. Meanwhile, ligand precursor 3b and Pt(II) complex 4b were characterized by crystallographic studies, which reveals that the platinum atom in 4b adopts a distorted-square-planar geometry. The Pd(II) pincer complexes 5b was found to be an efficient catalyst for Suzuki cross-coupling reaction of aryl bromides and phenylboronic acid under air. In the presence of 0.5 mol% of Pd(II) 5b in DMF/K3PO4·3H2O for 8 h, the corresponding biaryl products could be obtained in 24–99% yields.

The design and easy fabrication of biocompatible and antifouling coatings on different materials are extremely important for biotechnological and biomedical devices. Here we report a substrate-independent biomimetic modification strategy for fabricating a biocompatible and antifouling ultra-thin coating. Cell membrane antifouling phosphorylcholine (PC) and/or mussel adhesive catechol (c) groups are grafted at the amino-ends of an 8-armed poly(ethylene glycol). The PC groups are introduced by grafting a random copolymer bearing both PC and active ester groups. The modified 8-arm PEGs (PEG-2c-23PC, PEG-6c-23PC and PEG-8c) anchor themselves onto various substrates from aqueous solution and form cell outer membrane mimetic surfaces. Static contact angle, atomic force microscope (AFM) and X-ray photoelectron spectra (XPS) measurements confirm the successful fabrication of coatings on polydopamine (PDA) precoated surfaces. Real-time interaction results between proteins/bacteria and the coatings measured by surface plasmon resonance (SPR) technique suggest excellent anti-protein adsorption and short-term anti-bacteria adhesion performance. The long-term bacteria adhesion, platelet and L929 cell attachment results strongly support the SPR conclusions. Furthermore, the cell membrane mimetic and mussel adhesive protein mimetic PEG-2c-23PC shows hardly any toxicity to L929 fibroblasts, and the coating surface demonstrates the best anti-biofouling performance. This PDA-assisted immobilization of PC and/or catechol modified multi-arm PEGs provides a convenient and universal way to produce a biocompatible and fouling-resistant surface with tailor-made functions, which hopefully can be expanded to a wider range of applications based on both structure and surface superiorities.

A series of palladium(II) and nickel(II) complexes based on unsymmetrical chiral (imidazolinyl)aryl NHC ligands are reported. The new ligand presursors 3a–g were prepared from commercially available 3-bromobenzoic acid, in which the carboxyl and bromo functionalities were converted to chiral imidazoline and NHC moieties, respectively, in three steps. Treatment of 3a–g with Pd(OAc)2 in dimethylacetamide in the presence of NaOAc, followed by addition of LiCl, gave the seven palladium(II) pincer complexes 4a–g via direct aryl C–H activation. Likewise, the six nickel(II) pincer complexes 5a–f were obtained by reacting 3a–f with anhydrous NiCl2. All of the ligand precursors and pincer complexes are bench-stable and were fully characterized. The absolute configurations of palladium complexes 4a,c and 5e were further determined by X-ray diffraction. Finally, Pd pincer complex catalyzed asymmetric Friedel–Crafts alkylation and aza-Morita–Baylis–Hillman reactions were briefly assessed.

Methanesulfonate (MSA−), found in substantial concentrations in the atmosphere, is expected to enhance aerosol nucleation and the growth of nanoparticles, but the details of methanesulfonate clusters are poorly understood. In this study, MSA− was chosen along with ammonia (NH3) or three common amines and water (H2O) to discuss the roles of ternary homogeneous nucleation and ion-induced nucleation in aerosol formation. We studied the structural characteristics and thermodynamics of the clusters using density functional theory at the PW91PW91/6-311++G(3df,3pd) level. The analysis of noncovalent interactions predicts that the amines can form more stable clusters with MSA− than NH3, in agreement with the results from structures and thermodynamics; however, the enhancement in stability for amines is not large enough to overcome the difference in the concentrations of NH3 and amines under typical atmospheric conditions. In addition, the favorable free energies of formation for the (MSA−)(NH3/amines)(H2O)n (n = 0–3) clusters at 298.15 K show that MSA− could contribute to the aerosol nucleation process with binding NH3/amines and H2O up to n = 3. There are strong temperature and humidity dependences for the formation of complexes; higher humidity and temperature promote the formation of larger hydrates. Finally, for the (MSA−)(NH3/amines)(H2O)n clusters, the evaporation rates were determined to further investigate the atmospheric implications.

A crosslinkable zwitterionic copolymer PMBT was coated onto the surfaces of polypropylene hollow fiber membrane (PP-HFM) oxygenator and its connecting tubes. The PMBT copolymer coating on the oxygenator circuit formed a cell outer membrane mimetic surface with excellent stability. The hemocompatibility of the PMBT copolymer coated PP-HFM oxygenator circuit was evaluated by animal extracorporeal circulation. The concentrations of clotting components fibrinogen and platelet in the blood were almost unchanged during the circulation through the PMBT copolymer coated oxygenator circuits. By contrast, the concentrations of fibrinogen and platelet were significantly reduced to 52% and 56% respectively in the uncoated oxygenator group due to adsorption and thrombogenesis of the blood during 2 h circulation. Moreover, concentration of activation marker beta-thromboglobulin for platelet in the blood was remarkably lower in the PMBT group than the uncoated control group ( p Statement of Significance Although a number of studies have reported the fabrication of zwitterionic phosphorylcholine coated oxygenators to resist the adsorption and activation of blood components and eliminate heparin-induced thrombocytopenia, none of them have fabricated stable and densely assembled film, especially with crosslinkable amphiphilic random copolymer described in our manuscript. The novel features of our work include: • The first study of fabricating crosslinked and densely assembled zwitterionic copolymer coating on surfaces of a commercial oxygenator system. • The first study on hemocompatibility of both the PMBT coated and the bare commercial PP-HFM oxygenator circuits by animal extracorporeal circulation. • Much better hemocompatibility was measured on the PMBT coated oxygenator circuit compared with the bare and other polymer coated oxygenator systems.

Hollow fiber membranes (HFMs) based artificial lungs require a large blood-contacting membrane surface area to provide adequate gas exchange. However, such a large surface presents significant challenges to hemocompatibility. For improving the hemocompatibility, amphiphilic and cell outer membrane mimetic 2-methacryloyloxyethyl phosphorylcholine (MPC) copolymers containing 3-(Trimethoxysilyl)propyl methacrylate (TSMA) and/or n-butyl methacrylate (BMA) units, poly(MPC-co-BMA-co-TSMA) (PMBT) and poly(MPC-co-BMA) (PMB) were coated on a commercial polypropylene (PP) HFM. Dynamic contact angle, ATR-FTIR and XPS results showed that both the PMB and PMBT phospholipid polymer coatings are stable in water, but only the crosslinked PMBT coating can resist the dissolution by ethanol or SDS aqueous solution. Protein adsorption, platelet adhesion and whole blood contact experiments showed significant improvement in hemocompatibility after being coated with the PMBT. Moreover, oxygenation experiments indicated that the blood compatible coating could resist blood permeance and did not hinder the gas exchange. Overall these findings revealed improved hemocompatibility which can be realized through crosslinkable phospholipid polymer coating, enabling more stable and more biocompatible HFMs respiratory assist devices.

Two kinds of biomembrane mimetic polymers P(MPC-co-SMA) and P(MPC-SMA-TSMA) were synthesized with acrylate monomers 2-methacryloyloxyethyl phosphorylcholine (MPC), stearyl methacrylate (SMA) and 3-(methacryloyloxy) propyltrimethoxysilane (TSMA) by free radical copolymerization in solution with AIBN as initiator. The phosphorylcholine containing copolymers were dip-coated on cover glasses. The hydrophilicity, stability and surface structure of the coatings were measured by dynamic contact angles (DCA) in water. It was found that the coating surfaces were amphiphilic. The P(MPC-SMA-TSMA) coating was more stable than the P(MPC-co-SMA) one in aqueous environment due to crosslinking and grafting. The biocompatibility of the coatings was evaluated by platelet adhesion and protein adsorption. The copolymer P(MPC-SMA-TSMA) can be simply coated on a surface to fabricate a stable biomimetic coating with excellent hemocompatibility.

In this paper, stable and homogeneous feather keratin was effectively extracted from feathers. Its molecular weight is 20kDa with low dispersivity. The extracted feather keratin (FK) and its derivatives (FK-ET) were used as natural polymer flocculants. It was a new kind of effective and innoxious flocculant for the COD removal of potato starch wastewater. The removal rate of COD was up to 75% under the following optimal condition: 100mL of initial wastewater (COD = 7380), T = 20°C, [FK-ET] = 0.4g/L, [Bent] = 4g/L, pH = 8.0. Compared with traditional flocculants, keratin flocculants are innoxious natural polymers. Their sludge is easy to be treated, and there is no further pollution. Also, the flocculating constituents, which containing keratin, starch, saccharide, protein and other solubility substances from wastewaters, should be reutilized. It has practical application value in water treatment as a kind of natural polymer flocculant.

Blood compatibility is a critical requirement for materials to be used in medical applications. We describe here a simple and robust method to enhance the biocompatibility of chitosan (CS) surfaces, using random copolymers (PMT) of 2-methacryloyloxyethyl phosphorylcholine (MPC) and trimethoxysilylpropyl methacrylate (TSMA, 6, 14, and 25 mol%) synthesized by free radical copolymerization. The copolymers dissolved in methanol were dip-coated on CS films. The PMT coatings were anchored on CS surfaces during the coating process by covalent bonding of the trimethoxysilane groups with surface amine and/or hydroxyl groups of CS. The composite films were stabilized by crosslinking of the copolymers via amine-catalyzed reactions of the trimethoxysilane groups and further heating (110 °C). Analysis of the PMT-modified CS surfaces by X-ray photoelectron spectroscopy and contact angle measurements indicated that the zwitterionic PC groups were located on or near the film outer surface, which mimics the structure of the cell outer membrane. Film stability studies indicated that PMT copolymers containing 14 mol% TSMA units were linked permanently to CS, whereas PMTs of lower TSMA content were released from the films upon prolonged soaking in water. The CS-PMT (14% TSMA) composite films possessed excellent hemocompatibility, as confirmed by a 60% decrease in protein (bovine serum albumin or fibrinogen) adsorption and a 96% suppression of platelet adhesion, compared to CS films. This simple and stable coating strategy should be useful in a variety of biomedical applications including drug delivery, tissue engineering, stent coatings, and implantable medical devices.