摘要:

AbstractAlumina supported 12‐tungstophosphoric acid catalyzes efficiently the reaction ofo‐phenylenediamine with ketones under solvent‐free condition to afford the corresponding 1,5‐benzodiazepines in good to excellent yields. The catalyst can be recovered and

ISSN:0009-4536    

DOI:10.1002/jccs.200800001

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractIn an environmentally benign solvent free system aldoximes are rapidly transformed into nitriles using trimethylsilylchloride under mild conditions.

ISSN:0009-4536    

DOI:10.1002/jccs.200800002

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractA simple and high‐yield method for the synthesis of several 1,5‐diaryl‐1,5‐dicarbonyl compounds has been established starting from TBAF‐mediated isomerization and dimerization reaction of β,γ‐unsaturated arylketones (allyl arylketones) with mono‐, di‐, and tri‐methoxy groups, which is derived from allylation of commercially available different benzaldehydes and followed by oxidation of the resulting

ISSN:0009-4536    

DOI:10.1002/jccs.200800003

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractThe direct mixing of CoCl2, sodium 2,6‐pyridinedicarboxylate (Na2(2,6‐pda)), KSCN, and 1,2‐bis(4‐pyridyl)ethane (bpye) in water at the ambient temperature afforded purple crystals readily. The crystal structure, as determined by X‐ray diffraction crystallography, consists of discrete inorganic [Co2(η3‐2,6‐pda)2(μ‐SCN)2(H2O)2] and organic bpye molecules. Adjacent dicobalt molecules are connected via intermolecular hydrogen bonds, to form one‐dimensional hydrophobic channels in the solid state, which serve as a host framework to incarcerate bpye guests inside. Every organic molecule attaches to four adjacent inorganic species via arene‐arene interactions. The facile approach in assembling the dicobalt and bpye molecules together into an inorganic clat

ISSN:0009-4536    

DOI:10.1002/jccs.200800004

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractFree energies of transfer (ΔGt) of RibonucleaseA (RNaseA) from water to aqueous solutions of urea (4 M, 6 M and 8 M), a protein denaturing solvent as well as ΔGtof RibonucleaseA, β‐Lactoglobulin, α‐Chymotripsin and ChymotrypsinogenA from water to aqueous glycerol (10%, 20%, 30% and 40%), a protein stabilizing solvent has been dissected into cavity term [ΔGt(cav)] and interaction term [ΔGt(int)]. The interaction free energy includes all types of interactions like hard‐soft, hydrogen bonding, electrostatic, etc. The cavity forming free energies have been calculated using the standard version of scaled particle theory (SPT) with well‐reported SPT parameters. It has been found that transfer free energies of cavity terms ΔGt(cav) for native protein from water to urea‐water and water to aqueous glycerol follow almost opposite trends. This primarily indicates there may be some correlation between cavity creation energies and protein denaturing and stabilizing ability of a solvent. The results are in agreement with those obtained from preferential binding coefficient studie

ISSN:0009-4536    

DOI:10.1002/jccs.200800005

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractTime‐resolved transient absorption technique is used to investigate the thickness dependence of acoustic phonon modes of silver nanoprisms with two thicknesses, 7.8 ± 1.2 and 8.5 ± 0.69 nm, and a similar bisector length of 31.4 ∼ 31.6 nm. Coherent acoustic phonon signals are observed. A new acoustic phonon frequency within 7.81 cm−1∼ 11.7 cm−1is found and this phonon mode is associated with the thickness of the nanoprism. Another phonon frequency between 1.95 cm−1and 1.71 cm−1is also observed, and its origin can be associated with the bisector length o

ISSN:0009-4536    

DOI:10.1002/jccs.200800006

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractVarious structures of CrAPO‐5 clusters are studied via density functional B3LYP exchange‐correlation method. The optimized structures are compared with data from X‐ray absorption. Their total energies and atomic net charges are also analyzed. Results indicate that the substitution of the aluminum site of an AFI framework by chromium is in general not feasible. The chromium ion is more likely docked in between two neighboring 12‐membered rings of the framework of AFI. To further verify our claim, the excitation energies of the representative chromium structures of CrAPO‐5 clusters are calculated via the TDDFT method. The results for excitation energies further support that Cr3+is not incorporated into the

ISSN:0009-4536    

DOI:10.1002/jccs.200800007

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractThe hydrothermal reaction of 2,3‐pyridinedicarboxylic acid (2,3‐H2pda) with a mixture of Cd(NO3)2and Ni(NO3)2afforded a coordination polymer, [CdNi(2,3‐pda)2(H2O)3]∞(1); in contrast, that with a mixture of Cd(NO3)2and Zn(NO3)2surprisingly produced a discrete molecule, trans‐[Cd(3‐pa)2(H2O)4] (2) (3‐pa−= 3‐pyridinecarboxylate). Since a direct reaction between a single metal salt, Cd(NO3)2or Zn(NO3)2, and 3‐pyridinecarboxylic acid (3‐Hpa) under similar hydrothermal conditions yielded different coordination polymers containing 3‐pa−, it appears that the apparently thermal decarboxylation from ligated 2,3‐pda2−to 3‐pa−occurs after complexation of both metal cations, Cd(II) and Zn(II). A new coordination mode, formed for 2,3‐pda2−in structure1, appears to help formation of microporous channels by piling up the observed 2D hydrogen‐bonded heteropolynuclear layers. Each channel apparently consists of two in

ISSN:0009-4536    

DOI:10.1002/jccs.200800008

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractTwo new 1‐D silver(I) complexes, [Ag(I)1.5(IM‐oBA)(NO3)0.5] (1) and [Ag(I)(NIT‐pBA)] (2), (IM‐oBAH = 2‐(2‐carboxyphenyl)‐4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazol‐1‐yloxyl, NIT‐pBAH = 2‐(4‐carboxyphenyl)‐4,4,5,5‐tetramethyl‐4,5‐dihydro‐3‐oxido‐H‐imidazol‐3‐ium‐1‐yloxyl) have been prepared and structurally characterized. Complexes1and2crystallized in the monoclinic space groups ofC2/c andP21/c, respectively. In complex1, the structure consists of trinuclear Ag(I) atoms with different linkages of IM‐oBA and nitrates. The trinuclear Ag(I) atoms are further coordinated to the neighbor IM‐oBA radicals via self‐assembly of the nitrogen atom of imine moiety and extended into formation of a polymeric chain. Complex2is constructed from a bis(carboxylato‐O,O')‐bridged centrosymmetric dimeric subunit and extended into a polymeric chain through self‐assembly coordination between metal ions and nitroxide groups of NIT‐pBA radicals. Temperature dependence of magnetic susceptibility measurements showed a weak ferromagnetic coupling between ni

ISSN:0009-4536    

DOI:10.1002/jccs.200800009

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY

摘要:

AbstractThis paper deals with determining points of zero charge of natural and Na+‐saturated mineral kaolinites using two methods: (1) acid‐base potentiometric titration was employed to obtain the adsorption of H+and OH−on amphoteric surfaces in solutions of varying ionic strengths in order to determinate graphically the point of zero net proton charge (PZNPC) defined equally as point of zero salt effect (PZSE); (2) mass titration curve at different electrolyte concentrations in order to estimate PZNPCs by interpolation and to compare with those determined by potentiometric titrations. The two methods involved points of zero charge approximately similar for the two kaolinites between 6.5‐7.8, comparable to those reported previously and were in the range expected for these clay minerals. The comparison of potentiometric surface titration curves obtained at 25 °C and those published in the literature reveals significant discrepancies both in the shape and in the pH of PZNPC

ISSN:0009-4536    

DOI:10.1002/jccs.200800010

出版商:WILEY‐VCH Verlag    

年代:2008

数据来源: WILEY