三(2,6-二叔丁基-4-甲基-苯氧基)镧催化ε-己内酯低温聚合特征及与环碳酸酯嵌段共聚

摘要用三(2,6-二叔丁基-4-甲基-苯氧基)镧[La(OAr)₃]在-15 ℃引发ε-己内酯(CL)的开环聚合, 发现聚合体系具有活性聚合特征. 在第二步聚合过程中继续补加第二种单体三亚甲基环碳酸酯(TMC)或二甲基三亚甲基环碳酸酯(DTC), 可得到CL与环碳酸酯的嵌段共聚物.     

低结晶度聚ε-己内酯电纺膜的制备及其药物控释行为

以芳氧基稀土三(2,6-二叔丁基-4-甲基苯氧基)镧(La(OAr)3)为催化剂,通过加入少量(8.5 mol%)碳酸2,2-二甲基三亚甲基酯(DTC)与ε-己内酯(CL)进行无规共聚合,成功制备了低结晶度的脂肪族内酯-碳酸酯无规共聚酯(PCD)材料,并用1H-NMR、SEC、DSC和WAXS证明了产物的结构和性能.以...     

取代芳基钛酸酯类化合物催化苯乙烯间规聚合

以取代芳基钛酸酯化合物为催化剂催化苯乙烯聚合,考察了催化剂、聚合温度,摩尔比nAl/nTi以及聚合时间等因素对聚合行为及产物性质的影响。并用13C-NMR、FT-IR、DSC等手段表征了聚合产物。结果表明:在nAl/nTi=1 000,聚合温度为60℃条件下,2,2′-硫代双(4-甲基-6-叔丁基酚氧基)二氯化钛催化苯乙烯聚合显示出很高的催化活性,其活性为6.87×105g sPS/(mol Ti.h),所得聚合物为间规聚苯乙烯,间规度96.9%,分子量为1.98×105。     

巯基/(甲基)丙烯酸(甲基)烯丙酯光固化特性

通过对羧酸盐法改进后合成同时含有高活性的丙烯酸酯型C=C和低自由基活性的烯丙基型C=C的烯类单体(甲基)丙烯酸(甲基)烯丙酯,以实现(甲基)丙烯酸酯类紫外光固化与巯/烯光聚合结合在二元体系中;并以1173为光引发剂,利用实时红外(RT-IR)跟踪此类烯烃与三羟甲基丙烷三(3-巯基丙酸酯)(TMMP)光固化过程,探究烯烃结构、光强和引发剂用量对含有两类碳碳双键的烯类单体与巯基化合物二元体系的光固化行为的影响.研究发现,这类二元巯-烯光聚合反应中均有(甲基)丙烯酸酯双键的反应活性最大,(甲基)烯丙基次之,巯基的反应活性最小;甲基取代在烯烃的不同C=C上,对巯-烯光固化特性影响不同,甲基取代在烯丙基C=C上比甲基取代在丙烯酸基C=C上对巯-烯光固化行为影响更大;巯基最终转化率随甲基取代基数目增多而减少;丙烯酸甲基烯丙酯体系中两类双键(丙烯酸型/甲基烯丙基型)反应活性几乎相同且均具有高的转化率.     

天然氨基酸作用下2,2-二甲基三亚甲基碳酸酯的开环聚合

研究了几种中性天然氨基酸存在下2,2-二甲基-三亚甲基环碳酸酯(DTC)的开环聚合反应。1H-NMR和端基滴定分析表明,在聚合反应过程中,DTC上的酰氧键断裂,氨基酸通过氨基接在聚(2,2-二甲基-三亚甲基碳酸酯)链上。3-氨基丙酸、4-氨基丁酸、6-氨基己酸等存在时,DTC的聚合反应也可以发生,但单体的转化率和聚合物的分子量低于天然氨基酸引发的聚合反应。     

新型3-芳氧甲基喹喔啉-2-羧酸的简便有效合成及其抗菌活性研究

本文使用自制的3-溴甲基喹喔啉-2-甲酸乙酯(6)为反应物,经一锅连续的Williamson反应/酯基水解反应过程,简便有效地合成一系列结构新型的3-芳氧甲基喹喔啉-2-羧酸类化合物(4a-l)。然后选用五种菌株为研究对象,进行了初步的体外抗菌活性实验,结果表明含有叔丁基和卤素取代的化合物4j, 4k和4l对革兰氏阳性菌金黄色葡萄球菌和枯草芽孢杆菌表现出很好的抑制活性,其中化合物4j的活性比参考药物S环丙沙星还要高,其MIC值分别为15.625 和7.8125 μg/mL。     

α-{[4-(取代苯基亚甲基)亚氨基]苯氧基}丙酸乙酯的合成及植物生长调节活性

通过4．氨基苯氧丙酸乙酯与相应的取代芳香醛类化合物进行缩合反应得到了11个未见报道的α-{[4-(取代苯基亚甲基)亚氨基]苯氧基}丙酸乙酯类目标化合物,用UV、IR、~1H NMR和元素分析测试技术对其进行了表征。探讨了芳环上取代基对反应收率的影响,结果发现具有吸电子取代基的对硝基苯甲醛给出93％的最高反应产率:而有供电子取代基的对甲基苯甲醛给出54％的最低反应产率。初步生物活性测试证明,此类席夫碱化合物具有一定的植物生长调节活性:化合物6b和6f具有52％和55％的促黄瓜子叶生根活性,化合物6j具有75％的黄瓜子叶生根抑制活性;化合物6h具有53％的生长素活性;化合物6b具有51％的细胞分裂素活性。     

杯[6]芳烃钪配合物催化DTC开环聚合动力学及其机理

以对叔丁基杯[6]芳烃和异丙氧基钪为原料, 合成了对叔丁基杯[6]芳烃钪配合物, 该配合物可在温和条件下单组分引发2,2－二甲基三亚甲基环碳酸酯(DTC)开环聚合, 制备重均分子量为33700, 分子量分布为1.21的聚合产物. 动力学研究表明该聚合反应对单体和催化剂浓度均呈一次方关系, 表观活化能为22.7 kJ/mol; 通过1H NMR研究聚合物端基, 表明单体的开环机理为Sc-O活性中心引发的酰氧键断裂开环.     

三亚甲基环碳酸酯及2,2-二甲基三亚甲基环碳酸酯开环均聚合*

生物降解聚合物聚三亚甲基环碳酸酯（PTMC）及聚2,2-二甲基三亚甲基环碳酸酯（PDTC）在药物控释载体及其它生物医学技术领域有着良好的应用前景。与脂肪族聚酯不同,PTMC、PDTC降解时,不会产生有害的酸性化合物。PTMC、PDTC主要由三亚甲基环碳酸酯（TMC）及2,2-二甲基三亚甲基环碳酸酯（DTC）开环均聚合制备。本文总结了催化TMC、DTC开环均聚合的不同催化剂及其聚合机理,综述了近年来国内外在TMC、DTC均聚合催化剂开发上的研究进展,并对生物相容性催化剂如稀土催化剂、Ca、Mg、Zn、Fe催化剂以及酶催化剂催化TMC、DTC开环聚合的优缺点进行了比较。     

N-杂环甲基2-(4-杂芳氧基苯氧基)丙酰胺的合成及除草活性

以2-(4-羟基苯氧)丙酸为原料,设计合成了16个新的手性N-杂环甲基2-(4-杂芳氧基苯氧基)丙酰胺化合物,其化学结构经核磁共振、色谱-质谱、红外光谱及元素分析确证.初步生物活性测定结果表明,合成的化合物在2.25×103g/ha剂量时对单子叶杂草马唐(Digitaria sanguinalis)、稗草(Echinochloa crus-galli)及狗尾草(Setaria viridis)等均具有90%以上的活性;进一步活性及作物安全性测试表明,化合物(R)-(+)-N-[(6-氯吡啶-3-基)甲基]-2-[4-(3-氯-5-三氟甲基吡啶-2-基氧基)苯氧基]丙酰胺(2b)的除草活性高于噁唑酰草胺,且对水稻茎叶处理安全,同时对水稻田主要杂草千金子的活性远高于氰氟草酯;化合物的除草活性与立体构型有关,R构型为活性构型.     

Ring-opening polymerization of L-lactide with rare earth aryloxides substituted by various alkyl groups

<正>Rare earth aryloxides substituted by various alkyl groups[Ln(OAr)_3]such as methyl,isopropyl and tertbutyl,were used as single component catalysts to affect ring-opening polymerization of L-lactide(LLA).The catalytic activity, polymerization characteristics,polymerization kinetics and the mechanism were studied.It was found that the catalytic activity of rare earth aryloxides is influenced by both the structure and the number of alkyl groups on the phenyl ring.The stronger the electron-donation ability of the alkyl group,the higher the catalytic activity will be.An increase in the number of the substitute group will result in a higher catalytic activity.Lanthanum tris(2,4,6-tri-tert-butylphenolate)[La(OTTBP)_3] exhibits the highest activity among all lanthanum aryloxides.According to the ~1H-NMR data,it was proposed that the LLA polymerization proceeded via a coordination-insertion mechanism involving cleavage of acyl-oxygen bond of the lactide.     

Ring-Opening Copolymerization of 2,2-Dimethyltrimethylene Carbonate and ε-Caprolactone Using Rare Earth Aryloxides Substituted by Various Alkyl Groups

A variety of single component rare earth aryloxides substituted by various alkyl groups [Ln(OAr)₃] such as methyl, isopropyl, tert‐butyl have been surveyed in the ring‐opening copolymerization of 2,2‐dimethyltrimethylene carbonate (DTC) and ε‐caprolactone (ε‐CL). It was worthwhile to note that activity of the catalyst varied with both the ligands' structure and the number of alkyl groups on phenyl ring. The stronger ability of electron‐donation of alkyl groups on phenyl ring, and the more numbers of alkyl groups on phenyl ring, the higher catalytic activity. The experimental results show that lanthanum tris(2,4,6‐tri‐tert‐butylphenolate) [La(OTTBP)₃] exhibits highest activity in all lanthanum aryloxides. ¹H NMR spectral data of copolymer obtained showed that the polymerization mechanism is in agreement with the coordination insertion mechanism.     

Synthesis, Structure and Catalytic Activity Comparison of Tris- and Tetracoordinated Lanthanide Amides

Tetracoordinated lanthanide amides [(MeaSi)2N]3Ln (μ-C1)Li(THF)3 (Ln=La (1), Pr (2)) were synthesized by the reaction of anhydrous lanthanide(Ⅲ) chlorides LnCl3 (Ln=La, Pr) with 3 equiv, of lithium bis(trimethylsilyl)amide (Me3Si)2NLi in THF, followed by recrystallization from toluene. Sublimation of 1 and 2 afforded the triscoordinate lanthanide amides [(Me3Si)2N]3Ln (Ln=La, Pr). The crystal structure of 2 was determined by X-ray diffraction analysis. The catalytic activity studies show that the tetracoordinate amides can be used as single-component MMA (methyl methacrylate) polymerization catalysts, while the triscoordinate amides showed poor activity on MMA polymerization under the same conditions.     

漆酚缩甲醛镧配合物的制备、结构及性能

利用漆酚缩甲醛(PUF)和三氯化镧在非水热溶剂中反应制得漆酚缩甲醛镧配合物(PUFLa)，IR、XPS和TG表征结果表明：三氯化镧中La^3 与漆酚缩甲醛中酚羟基上的氧形成了配位键；在La^3 的作用下，PUF上的侧链进一步交联聚合。PUFLa在亚硫酸钠水溶液中能引发催化甲基丙烯酸甲酯聚合。通过正交实验设计考察了PUFLa用量、反应温度、反应时间、单体甲基丙烯酸甲酯用量和亚硫酸钠浓度对单体转化率的影响。结果表明。反应温度和反应时间是影响单体转化率的主要因素。PUFLa还具有良好的耐热性和抗溶剂性。     

Phenylene‐bridged β‐Ketoiminate Dilanthanide Aryloxides: Synthesis,Structure, and Catalytic Activity for Addition of Amines to Carbodiimides

The synthesis and reactivity of a series of bimetallic lanthanide aryloxides stabilized by a p‐phenylene‐bridged bis(β‐ketoiminate) ligand is presented. The reaction of 1,4‐diaminobenzene with acetylacetone in a 1:2.5 molar ratio in absolute ethanol gave the compound 1,4‐bis(4‐imino‐2‐pentanone)benzene ( 1 ) (LH₂) in high yield. Compound 1 reacted with (ArO)₃Ln(THF)₂ (ArO = 2,6‐tBu₂‐4‐MeC₆H₂O, THF = tetrahydrofuran) in a 1:2 molar ratio in THF, after workup, to give the corresponding dilanthanide aryloxides L[Ln(OAr)₂(THF)]₂ [Ln = Yb ( 2 ), Y ( 3 ), Sm ( 4 ), Nd ( 5 ), La ( 6 )] in high isolated yields. Compound 1 and complexes 2 – 6 were fully characterized, including X‐ray crystal structure analyses for complexes 2 , 3 , 5 , and 6 . Complexes 2 – 6 can be used as efficient pre‐catalysts for catalytic addition of amines to carbodiimides, and the ionic radii of the central metal atoms have a significant effect on the catalytic activity with the increasing sequence of La ( 6 ) < Nd ( 5 ) ≈ Sm ( 4 ) < Y ( 3 ) ≈ Yb ( 2 ). The catalytic addition reaction with 2 showed a good scope of substrates including primary and secondary amines.     

稀土催化四氢呋喃开环聚合

1937年Meerwein首次发现Et_3O~(+BF)可催化四氢呋喃(THF)开环聚合。到目前为止,发现能使THF开环聚合的催化剂有质子酸、Lewis酸、洋离子、正碳离子等。1990年吴健等将(Acac)_3Nd-(i-Bu)_3Al-H_2O-环氧氯丙烷催化体系应用于THF聚合,发现它和(i-Bu)_3Al-H_2O-环氧氯丙烷体系具有相同的活性,这说明稀土配合物没有参与活性中心的形成。本工作发现(CF_3CO-2)3Ln(Ln=Y,La,Ce,     

Schiff碱镧配合物的合成及其催化烷基异氰酸酯聚合

通过氯化镧与Schiff碱钠盐(NaSalen)的交换反应制备了4种镧的Schiff碱配合物La(HSalen1-4)3,对其中以3,5-二叔丁基水杨醛缩苯胺为配体的配合物La(HSalen2)3进行了X-射线单晶衍射分析,测定其单晶结构为五角双锥构型,七配位的镧金属中心与氮和氧原子相连.将所得的La(HSalen)3...     

二(芳氧基)稀土(Ⅱ)配合物催化ε-己内酯开环聚合

系统地研究了二（２，６ 二叔丁基 ４ 甲基酚基）钐［（ＡｒＯ）２Ｓｍ（ＴＨＦ）４］催化ε 己内酯的开环聚合，发现它具有很高的催化活性并显示“活性”聚合的特点，在甲苯中，当［Ｍ］／［Ｉ］＝２０００（摩尔比），６０℃，１ｈ，转化率可达９８％．并比较了不同的两价稀土化合物的催化活性．通过核磁分析末端基结构的方法，研究了（ＡｒＯ）２Ｓｍ催化己内酯开环聚合的引发机理，发现催化剂首先与己内酯反应，生成三价烯醇式稀土化合物，后者引发己内酯聚合．     

Ring-opening polymerization of 2,2-dimethyltrimethylene carbonate using rare earth aryl oxides substituted by alkyl groups

Single component rare earth aryl oxides substituted by various alkyl groups [Ln(OAr)3] such as methyl,isopropyl,and tertbutyl have been developed to initiate the ring-opening polymerization of 2,2-dimethyltrimethylene carbonate(DTC).The catalytic activity of rare earth aryl oxides,characteristics of the ring-opening polymerization as well as the polymerization kinetics and mechanism were intensively examined.The experimental results turn out that the catalytic activity of Ln(OAr)3 changes in good concordanc...     

Synthesis and catalytic activity of Ln(III) complexes with an unsymmetrical Schiff base including multi()C = N-groups

A synthetic method for a new unsymmetrical Schiff base and its Ln (III) complexes including multi C == N- groups is reported. The complexes are characterized by elemental analysis, IR spectra, 1H and 13C NMR, especially 2D-COSY1H, 1H NMR spectra. The general formula of the obtained complexes is [Ln3(TBLY)(NO3)3]@nH2O (Ln = La, n = 3; Ln = Nd, n = 5; Ln = Gd, Dy, Yb, Y, n = 7), whereTBLY = tetraglycol aldehyde-2,4-dihydroxy benzaldehyde bis-lysine Schiff base. In addition, the evidence for existence of C == CH-NH- group is supported bythe AM1 method. The complexes obtained may be used as a catalyst. Conversion rate of 80% with the viscosity-average molecular weight 220000 for the polymerization of methyl methacrylate (MMA) without addition of any cocatalyst has been obtained.