Synthesis and Characterization of Dual Acidic Ionic Liquids

Novel ionic liquids with dual acidity, of which the cation contains Brφnsted acidity and anions contain Lewis acidity were synthesized. These ionic liquids obtained were identified by NMR, FF-IR, SDT and FAB-MS. Their acidities were determined by pyridine probe on IR spectrography.     

A strategy for synthesis of polymer-protective bimetallic colloids

A strategy for the synthesis of polymer-protective bimetallic sols is proposed which has the advantage of the strong protective effect of the polymer agent on one of the composites to stabilize the bimetallic colloidal particles. This strategy is certified to be useful to the predication of the formation of stable bimetallic colloids protected by polymer and to the control of the particle size to a certain extent. A series of new PVP-protective bimetallic colloidal dispersions containing noble metal element (Pt, Rh, Pd), light transition metal element (Co, Fe), and boron are obtained from the corresponding salts by the methods of reduction by stage and coreduction, using the NaBH4 as reductant. The TEM, XRD and EPMA measurements indicate the formation of bimetallic colloids. An interesting kind of coil aggregation is observed in the systems of PVP-Pt-Co and PVP-Rh-Co prepared by the method of reduction by stage.     

High-performance liquid chromatography of micelle-solubilized complexes-IV Reversed-phase ion-pair chromatography of metal-3,5-diBr-PADAP-Triton X-100 complexes

The micellar solubilization complex systems of V(V), Cu(II), Zr(IV), Pd(II), Fe(III), Ni(II) and Co(II) with 3,5-diBr-PADAP and Triton X-100 have been investigated by HPLC on an ODS (5 x 250 mm) column with a ternary eluent of methanol-acetone-acetone-water containing TBA(+) and acetate buffer (pH 3.0) at 600 or 572 nm wavelength for the detection of the complexes. An HPLC-spectrophotometric method for determination of seven metal ions has been developed. The peak height calibration curves are linear up to 50-100 mu/1, metal ion concentration. The relative standard deviations for the determination of 30.0 mu/1 metal ion were 0.9-1.6% and the detection limits (S/N = 3) were 1.1-3.6 mug/1.     

Fibrous crystalline hydrogels formed from polymers possessing a linear poly(ethyleneimine) backbone

Novel thermoreversible physical hydrogels formed from polymers with linear and star architectures possessing a linear poly(ethyleneimine) (PEI) backbone have been investigated. The hydrogelation occurred simply upon natural cooling of hot aqueous solutions of PEIs to room temperature. The X-ray diffraction and differential scanning calorimetry measurements for the resultant hydrogels unambiguously indicated that the hydrogelation originated from the formation of dihydrate crystalline structures of PEI. These crystalline hydrogels are structurally unique and hierarchical. Microscopic images revealed that the morphologies of the crystalline hydrogels depend on their molecular architectures. The linear PEI resulted in branched fibrous bundles organized by unit crystalline nanofibers with a width of ca. 5-7 nm. The six-armed star with benzene ring core produced fanlike fibrous bundles while the four-armed star with porphyrin core assembled into asterlike aggregates. The critical concentration of gelation (C(G)) was low (about 0.2 approximately 0.3%) and the thermoreversible gel-sol transition temperatures (T(G)) were controllable from approximately 43 to approximately 79 degrees C. The hydrogels formed in the presence of the various aqueous additives including organic solvents, hydrophilic polymers, physical cross-linker, chemical cross-linker, and base enabling modification and functionalization during synthesis. The mechanical properties of the hydrogels could be improved by chemical cross-linking of preformed hydrogels by glutaraldehyde. Physically and physical/chemical cross-linked hydrogels served as excellent template roles in biomimetic silicification, which produced silica-PEI hybrid powder or monolith constructed by nanofibers.     

Soft vesicles formed by diblock codendrimers of poly(benzyl ether) and poly(methallyl dichloride)

The synthesis of a block codendrimer (g3-PBE-b-g3-PMDC), composed of a third-generation poly(benzyl ether) (PBE) monodendron and an aliphatic polyether (PMDC) monodendron is reported. In THF/diiospropyl ether (1:1) the PMDC block functions as a "hydrophilic" block, while the PBE acts as a "hydrophobic" block. The codendrimer can form interdigitated layers leading to vesicle formation. Tapping mode atomic force microscopy (AFM), dynamic light scattering (DLS), and transmission electron microscopy (TEM) were used to characterize the vesicles. The effect of molecular architecture on the formation of the interdigitated layers and vesicles was studied.     

Ultraviolet photodissociation dynamics of the SH radical

Ultraviolet (UV) photodissociation dynamics of jet-cooled SH radical (in X 2pi(3/2), nu"=0-2) is studied in the photolysis wavelength region of 216-232 nm using high-n Rydberg atom time-of-flight technique. In this wavelength region, anisotropy beta parameter of the H-atom product is approximately -1, and spin-orbit branching fractions of the S(3P(J)) product are close to S(3P2):S(3P1):S(3P0)=0.51:0.36:0.13. The UV photolysis of SH is via a direct dissociation and is initiated on the repulsive 2sigma- potential-energy curve in the Franck-Condon region after the perpendicular transition 2sigma(-)-X 2pi. The S(3P(J)) product fine-structure state distribution approaches that in the sudden limit dissociation on the single repulsive 2sigma- state, but it is also affected by the nonadiabatic couplings among the repulsive 4sigma-, 2sigma-, and 4pi states, which redistribute the photodissociation flux from the initially excited 2sigma- state to the 4sigma- and 4pi states. The bond dissociation energy D0(S-H)=29,245+/-25 cm(-1) is obtained.     

High extraction ability of 1,3-dialkynyl calixarene towards mercury（Ⅱ） ion

The reaction of 1,3-dipropyn-2-yloxycalix[4]arene with mercury(II)acetate could give mercury-containing alkynyl calixarenepolymer.The extraction behavior of 1,3-dipropyn-2-yl-oxycalix[4]arene towards mercury(II)ion was examined.When the moleratio of Hg~(2 )/calixarene was 1:1,the extractive percent can reach to 99.1%,and the extraction capacity was up to 431 mg/g.It couldalso decrease the Hg~(2 )concentration from 5 to 0.85 mg/L,which was only 17%of the national standard of effluent and satisfied thenational standard of drinking water.The extraction process included chemical reaction.     

Simultaneous Reduction of Nitro Group and S-S Bond in Nitrodisulfides by Samarium Diiodide: A New Approach to Benzothiazolines

Asapowerfulandversatileone-electrontransferreductant,Sml,hasbeenappliedwidelyinorganicsynthesis'.OurpreviousworksonthereductionofnitrocompoundsandreductivecleavageofS-S,Se-Se,Te-TebondswithSml,'ledustoinvestigatethesimultaneousreductionofnitrogroupandS-SbondbySml,.Benzothiazolinesderivativesareimportantreagentsandusefulintermediatesinorganicsynthesisandpharmaceuticalchemistry.Forinstance,theycanbeusedasadditionagentsforphotographicemulsions",effectiveacaricides",antituberculousagents",lubr…     

Intramolecular C-N bond formation reactions catalyzed by ruthenium porphyrins: amidation of sulfamate esters and aziridination of unsaturated sulfonamides

Ruthenium porphyrins [Ru(F(20)-TPP)(CO)] (F(20)-TPP = 5,10,15,20-tetrakis(pentafluorophenyl)porphyrinato dianion) and [Ru(Por*)(CO)] (Por = 5,10,15,20-tetrakis[(1S,4R,5R,8S)-1,2,3,4,5,6,7,8-octahydro-1,4:5,8-dimethanoanthracen-9-yl]porphyrinato dianion) catalyzed intramolecular amidation of sulfamate esters p-X-C(6)H(4)(CH(2))(2)OSO(2)NH(2) (X = Cl, Me, MeO), XC(6)H(4)(CH(2))(3)OSO(2)NH(2) (X = p-F, p-MeO, m-MeO), and Ar(CH(2))(2)OSO(2)NH(2) (Ar = naphthalen-1-yl, naphthalen-2-yl) with PhI(OAc)(2) to afford the corresponding cyclic sulfamidates in up to 89% yield with up to 100% substrate conversion; up to 88% ee was attained in the asymmetric intramolecular amidation catalyzed by [Ru(Por)(CO)]. Reaction of [Ru(F(20)-TPP)(CO)] with PhI[double bond]NSO(2)OCH(2)CCl(3) (prepared by treating the sulfamate ester Cl(3)CCH(2)OSO(2)NH(2) with PhI(OAc)(2)) afforded a bis(imido)ruthenium(VI) porphyrin, [Ru(VI)(F(20)-TPP)(NSO(2)OCH(2)CCl(3))(2)], in 60% yield. A mechanism involving reactive imido ruthenium porphyrin intermediate was proposed for the ruthenium porphyrin-catalyzed intramolecular amidation of sulfamate esters. Complex [Ru(F(20)-TPP)(CO)] is an active catalyst for intramolecular aziridination of unsaturated sulfonamides with PhI(OAc)(2), producing corresponding bicyclic aziridines in up to 87% yield with up to 100% substrate conversion and high turnover (up to 2014).     

Rhodium(II,II) dimer as an efficient catalyst for aziridination of sulfonamides and amidation of steroids

[reaction: see text] Unsaturated sulfonamides underwent direct intramolecular aziridination catalyzed by Rh(2)(OAc)(4) with PhI(OAc)(2) and Al(2)O(3) to give the corresponding aziridine products in excellent yields (up to 98%) and with good to excellent conversions. High turnovers (up to 1375) were achieved. The intermolecular rhodium-catalyzed amidation of cholesteryl acetate with PhI=NTs or PhI(OAc)(2)/NH(2)R as the nitrogen source exhibited both excellent regio- and alpha-selectivity (alpha/beta ratio up to 9:1).