Transformation of carbon dioxide into valuable chemicals over bifunctional metallosalen catalysts bearing quaternary phosphonium salts

The chemical transformation of CO2under mild conditions remains a great challenge because of itsexceptional kinetic and thermodynamic stability.Two important reactions in the transformation ofCO2are the N‐formylation reaction of amines using hydrosilanes and CO2,and the cycloaddition ofCO2to epoxides.Here,we report the high efficiency of bifunctional metallosalen complexes bearingquaternary phosphonium salts in catalyzing both of these reactions under solvent‐free,mild conditionswithout the need for co‐catalysts.The catalysts’bifunctionality is attributed to an intramolecularcooperative process between the metal center and the halogen anion.Depending on the reaction,this activates CO2by permitting either the synergistic activation of Si–H bond via metal–hydrogen coordinative bond(M–H)or the dual activation of epoxide via metal–oxygen coordinativebond(M–O).The one‐component catalysts are also shown to be easily recovered and reusedfive times without significant loss of activity or selectivity.The current results are combined withprevious work in the area to propose the relevant reaction mechanisms.

Synthesis of Quaternary Phosphonium Salts with Ester Functional Group and Its Application to Improve the Thermal Stability of Modified Montmorillonite

Both of quaternary ammonium and quaternary phosphonium salts of bis-hydroxyethyl terephthalate （BHET） were successfully synthesized and characterized by fourier transform infrared spectroscopy （FT-IR）. These two kinds of salts were used to intercalate Na-MMT to yield two kinds of respective organo-modified MMTs. Basal spacing and thermal stability were investigated by using X-ray diffraction （XRD） and thermogravimetric analysis （TGA）, respectively. The experimental results show that, as compared with Na-MMT, basal spacings of both of MMTs modified by the quaternary phosphonium salt of BHET （BHETPP） and the quaternary ammonium salt of BHET （BHEA）, increase from 12.4 A to 19.7/k and 31.3 A, respec-tively. Thermal stability of BHETPP-modified MMT is much better than that of BHEA-modified MMT, i e, T otof BHETPP-modified MMT is around 400℃ while Tcmset of BHEA-modified MMT is near 250℃. Therefore, with en-larged basal spacing and excellent thermal stability, BHETPP-modified MMT is a promising organo-modified MMT which may be used to prepare polyethylene terephthalate/MMT nanocomposite with high thermal and mechanical performance.

Synthesis and Antibacterial Performance of Quaternary Phosphonium Salts with Reactive Hydroxyl Group

Quaternary phosphonium salts （QPS） with reactive groups used as antibacterial agents are promising which could be covalently linked to inert polymer surfaces by in situ polymerization. In this work, two kinds of quaternary phosphonium salts with hydroxyl groups were synthesized successfully. Characterization of these two quaternary phosphonium salts was performed by the Fourier transform infrared spectroscopy （FT-IR） and nuclear magnetic resonance （NMR） spectrometry. The thermal stability and antibacterial activity of antibacterial agents were also investigated by using thermo-gravimetric analysis, differential scanning calorimetry （TG-DSC） and agar diffusion method. The test results showed that these two QPS exhibited good thermal stability and excellent antibacterial activity against both bacteria： Staphylococcus aureus and Escherichia coll.

Antibacterial performance of cationic quaternary phosphonium-modified chitosan polymer in water

Microbial contamination in water has emerged as a critical concern and thus developing biocide materials for controlling microbial contamination is crucial.Removing all pathogenic bacteria in water is difficult when using traditional water treatment technologies.Moreover,these bacteria can easily reproduce during pipeline distribution.In this work,a facile and effective chitosan derivative biocide denoted as PCC was developed by grafting with quaternary phosphonium salt(QPS).PCC became positively charged with a wide range of p H and demonstrated antibacterial activity up to 95%and 100%against Escherichia coli and Staphylococcus aureus as model pathogens,respectively.The grafting of QPS may disrupt the cell membrane and lead to bacterial inactivation,as demonstrated by the scanning electron microscopy image and the concentration of intracellular substance leakage.MTT assay results indicate that PCC achieved good biocompatibility with negligible in vitro cytotoxicity.These findings introduce a promising approach for bacterial decontamination due to its low cytotoxicity and high biocidal activity.

Asymmetric Nucleophilic Additions Promoted by Quaternary Phosphonium Ion-Pair Catalysts

Chiral quaternary phosphonium ion-pair catalysis showcases a distinctive catalytic and stereoinductive mode arising from the synergy between ionic and noncovalent interactions.Over recent decades,this methodology has been widely adopted to facilitate enantioselective nucleophilic addition reactions,including conjugate addition,Henry reaction,Mannich reaction,Strecker reaction,and hydrophosphonylation.This strategy has been successfully applied to the synthesis of numerous structurally diverse and multifunctionalized molecules,featuring challenging stereogenic centers.This minireview specifically highlights the accomplishments in asymmetric nucleophilic addition facilitated by chiral quaternary phosphonium catalysts.Its purpose is to cultivate interest among researchers,encouraging more engagement in this field and establishing quaternary phosphonium ion-pair catalysis as a potent and dependable tool for synthetic and pharmaceutical chemists.

Poly(aryl ether nitrile)s containing flexible side-chain-type quaternary phosphonium cations as anion exchange membranes

In order to effectively improve the properties of anion exchange membrane(AEM)materials,a series of novel poly(aryl ether nitrile)s with flexible side-chain-type quaternary phosphonium cations(PAEN-TPP-x)were designed and prepared on the basis of considering the influences of polymer backbone,cationic group species and the connection way between the cations and polymer chains.The synthetic method,structure and ion-exchange capacity,water absorption,swelling,hydroxide conductivity and alkaline stability of the obtained AEMs were studied.A comparative study with other reported AEMs was also performed for further exploration of the relationship between the structure and properties.These AEMs with flexible side-chain-type quaternary phosphonium cations displayed good comprehensive properties.Their water uptakes and swelling ratios were in the range of 11.6%–22.7%and 4.4%–7.8%at 60℃,respectively.They had hydroxide conductivity in the range of 28.6–45.8 mS cm^-1 at 60℃.Moreover,these AEMs also exhibited improved alkaline stability,and the hydroxide conductivity for PAEN-TPP-0.35 could remain 82.1%and 80.6%of its initial value at 60 and 90℃in 2 mol L^-1 NaOH solution for480 h,respectively.

Functionalized COFs with Quaternary Phosphonium Salt for Versatilely Catalyzing Chemical Transformations of CO_(2)

Currently,it encounters great challenges to accomplish catalyzing various kinds of carbon dioxide(CO_(2))conversion reactions efficiently with single catalyst,let alone control the interplay among catalytic efficiency and selectivity evenly.Here,we prepared a functional covalent organic framework,[PTPP]X%-TD-COF[PTPP=3-bromopropyltriphenylphosphonium;TD=1,3,5-tri(4-aminophenyl)benzene-1,4-diformylbenzene],by immobilizing the quaternary phosphonium salt onto the skeleton of COFs through a post-synthesis strategy for versatilely catalyzing reduction of CO_(2) and CO_(2) fixation on epoxide and aziridine facilely.With the typical features of COFs(such as porosity and ordered structure)and catalytic activity of the quaternary phosphonium salt,[PTPP]X%-TD-COF possesses an intensely synergistic effect for catalyzing the chemical transformations of CO_(2).Noteworthily,the quaternary phosphonium salt functionalized COFs catalyze the CO_(2) reduction reaction with amine and phenylsilane to produce formylated and methylated products under gentle reaction conditions with high selectivity and efficiency.Furthermore,[PTPP]_(X%)-TD-COF shows high catalytic ability in CO_(2) chemical fixation reactions.

A facile preparation of a novel nonleaching antimicrobial waterborne polyurethane leather coating functionalized by quaternary phosphonium salt

The aim of this research is to develop a novel non-leaching antimicrobial waterborne polyurethane(WPU)leather coating material with covalently attached quaternary phosphonium salt(QPS).The structure of the QPS-bearing WPU has been identified,and their thermal stability,mechanical property,and antimicrobial performance have been investigated.The results reveal that the incorporation of QPS slightly reduces the thermal stability of WPU material but would not affects its usability as leather coating.Despite the presence of hydrophobic benzene in QPS structure,the strong hydration of its cationic groups leads to the increased surface contact angle(SCA)and water absorption rate(WAR)of the films,suggesting that the water resistance of the films needs to be improved for the purpose of leather coatings.Antibacterial tests demonstrate that when the QPS content is 20 wt%,QPS-bearing WPU shows effective antimicrobial activity against bacteria.The WPU containing QPS prepared in this study is a non-leaching antimicrobial material and has great potential application as leather coating.

POLYMER-SUPPORTED SINGLE AND MIXED AMMONIUM AND PHOSPHONIUM SALTS AS CATALYSTS FOR PHASE-TRANSFER REACTIONS

In this study was to investigate, by phase-transfer catalysis, the activity of single and mixed ammonium and phosphonium salts grafted on a 揼el-type?styrene-7% divinylbenzene copolymer in the oxidation of benzyl alcohol with hydrogen peroxide. A wide variety of catalysts with different quaternary groups and different quaternary chain length substituents were examined. The activity of single 搊nium?salts increases as a consequence of the association of ammonium and phosphonium salts grafted on the same polymeric support. The activity of polymer-supported ammonium and phosphonium salts increases with the number of carbon atoms contained in the alkyl radicals of the onium and of the functionalization degree with phosphonium groups.

ANTIBACTERIAL ACTIVITY OF SINGLE AND MIXED AMMONIUM AND PHOSPHONIUM SALTS GRAFTED ON "GEL-TYPE" STYRENE-DIVINYLBENZENE COPOLYMERS

A systematic study on the synthesis and antibacterial activity of the quaternary "onium" salts grafted on an insoluble "gel-type" styrene-7% divinylbenzene copolymer by polymer-analogous reactions is showed. Antibacterial activity of quaternary ammonium and/or phosphonium salts grafted on polymer-supports has been studied against Staphylococcus aureus and Escherichia coli. A wide variety of "onium" salts bound to macromolecular supports with different quaternary groups and different quaternary chain length substituents were examined. The antibacterial activity of mixed "onium" salts increases as a consequence of the association of ammonium and phosphonium salts grafted on the same polymeric support.

Synthesis and Structural Characterization of Mono-and Di-nuclear Zinc(Ⅱ) Coordination Compounds of Triphenylphosphoniopropionate

Two novel coordination compounds of Zn(Ⅱ) with Ph_3P+(CH_2)_2CO-_2(L), namely, [ZnL_4(H_2O)_2]·(ClO_4)_2·2H_2O(compound 1) and [Zn_2Cl_4(μ-L-O,O′)_2](compound 2), have been prepared. The single crystal X-ray structure analysis of these compounds indicates that in compound 1 the Zn(Ⅱ) atom is coordinated by four monodentate carboxylato groups on the equatorial plane and two aqua ligands occupy the axial coordination positions. The pendant oxygen atoms form strong hydrogen bonds with the aqua molecules which results in the stability of this structure. In compound 2, two Zn(Ⅱ) atoms are bridged by a pair of carboxylato groups, showing a skew-bridge mode, and thus enabling a long Zn(Ⅱ)…Zn(Ⅱ) separation. As we know, it is a dinuclear coordination compound with the longest Zn…Zn separation.