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1.
改变聚(甲基丙烯酸甲酯-苯乙烯(P(MMA-co-St)中 甲基丙烯酸甲酯的含量(WMMA),通过一步法合成出聚环氧氯丙烷聚氨酯(PU(PECH)/P(MMA-co-St)IPN.DSC、TEM和动态粘弹谱研究结果表明:当P(MMA_co-St)中WMMA大于0.6时,IBN仅有一个Tg;当WMMA小于0.4时,IPN有2个Tg,TEM上出现相区,P(MMA-co-St)深度参数(δ)及δ的氢键作  相似文献   

2.
THEREACTIONOF(μ_3-CPh)Co_3(CO)_9WITH TRANSITIONMETALCARBONYLANIONM(CO)_3(RCOCp)ANDCHARACTERIZATIONOFCLUSTERS(μ_3-CPh)CO_2M(CO)_8(RCOCPp)(M=Mo,W;R=H,CH_3.C_2H_5O)Authortowhomcormspondenceshouldaddressed.ExperimentalsectionGeneralprocedureandmaterialAlloperationwascarriedoutunderhighlypurenitrogenatmosphereusingshadardSchlenlcandvacuumtechniques.He-cane,benzeneandtetrahydrofuranwerepredriedoversodiumwireanddistilledfromsodium-benzophenoneundernitrogen.NaM(CO)3(RCOCP)andPhCCo3(CO),werepreparedaccordingtoliteratUre  相似文献   

3.
用同步法合成了聚环氧氯丙烷聚氨酯/聚甲基丙烯酸甲酯互穿网络聚合物[PU(PECH)/PMMAIPN],调节IPN中两组分组成比制备出由完全弹性体、增强弹性体、增韧塑料到脆性塑料多种高聚物合金材料.用DSC、动态力学谱、TEM对IPN的研究结果表明,PU(PECH)/PMMAIPN的两组分是完全相容的;同时对各种组成比的IPN材料进行力学性能测试,用相容性IPN中互穿、缠结结构解释其力学行为,并用SEM对断面形貌进行了观察解释.  相似文献   

4.
STUDYONREACTIONOF(μ_3-CCO_2Et)CO_2M(CO)_8(CpMe)(M=Mo,W)WITHNa_2[Fe(CO)_4].SYNTHESISOFTWOKINDSOFTHENOVELCLUSTERSEtO_2CCFeCoM(CO)_8...  相似文献   

5.
SOLID STATE SYNTHESIS AND CRYSTAL STRUCTURE OF THE CLUSTER COMPOUND[MwS_4Cu_3(PPh_3)_3Cl](Mw=0,56W+0.44M0)SOLIDSTATESYNTHESISAN...  相似文献   

6.
ANOVELSYNTHETICMETHODFORTHECLUSTERSFeCo_2(CO)_9-(RCCR)(R=MeO_2C,EtO_2C).X-RAYCRYSTAL STRUCTURE ANALYSES OF THE CLUSTERS FeCo_2(?..  相似文献   

7.
PEPTIDES FORMATION FROM DIPP-HIS¥YaoWuSHAO;YuFenZHAO(DepartmentofChemistry,TsinghuaUniversity,Beijing.100084)Abstract:WhenDIP...  相似文献   

8.
SYNTHESIS AND ~(183)W NMR CHARACTERIZATION OF P_4W_(30)Al_4(H_2O)_2O_(112)~(20-) HETEROPOLYANIONSYNTHESISAND~(183)WNMRCHARACTERIZ?..  相似文献   

9.
MOLECULARANDCRYSTALSTRUCTUREOFCo_3(μ-PSCH_2CH_2O)_3(CO)_6CONTAININGNEWBRIDGINGHETEROCYCLICPHOSPHIDOLIGANDS¥QiWangLIU;XiangHU;Sh?..  相似文献   

10.
研究了(蓖麻油-聚乙二醇)聚氨酯/聚(苯乙烯-甲基丙烯酸甲酯-甲基丙烯酸)(PU/P(St-MMA-MAA))互穿聚合物网络(IPN).动态力学性能及透射电镜结果均表明该体系相分离较严重;IPN具有两个玻璃化转变温度,它们有不同程度的内移,形成一定程度分子水平的混合,而IPN(50/50)其分子混合水平较大,互穿缠结程度较高。形成IPN后,其力学性能得以改善。透射电镜结果表明,聚氨酯网的交联密度直接影响IPN的相区尺寸。形成IPN后热稳定性提高,易于降解断链的St-MMA-MAA单体起到了自由基消除剂的作用。  相似文献   

11.
An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.  相似文献   

12.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

13.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

14.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).  相似文献   

15.
An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6ag and imidazo[1,5-a]quinoxalines 7ah by the reaction of 2-imidazolyl anilines 4ac with aryl aldehydes 5ak under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4ab was found to be instrumental for the success of the reaction.  相似文献   

16.
The Diels-Alder reactivity of 1,2-heteroborines (H4C4B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.  相似文献   

17.
A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd2(dba)3-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.  相似文献   

18.
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.  相似文献   

19.
Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.  相似文献   

20.
In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.  相似文献   

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