【作者】 刘博；

【导师】 孙广平；

【作者基本信息】 吉林大学 ， 材料学， 2015， 博士

【摘要】 本论文合成了三类非茂稀土金属有机配合物:(1)β-双亚胺硫酯基稀土金属配合物;(2)胺基膦亚胺基稀土金属配合物;(3)不含配体三烷基和双烷基单卤素金属稀土配合物,实现了对传统共轭双烯烃和生物来源的共轭双烯烃的选择性聚合及共聚合。主要结果如下:(1)合成了不同空间位阻NSN型和NPN型稀土双烷基配合物,并对其进行了核磁共振和X-射线单晶结构的表征。在有机硼盐和三异丁基铝活化下,能高活性高选择性催化异戊二烯3,4-聚合。其中NSN型配体S原子上的取代基团吸电子能力越强,3,4-选择性和全同选择性也相应的越高。而对于NPN型配体,配位空间开阔则导致全同选择性,配位空间拥挤有利于间规选择性。DFT计算表明,单体以η4-cis-IP方式3,4插入形成η3-allyl中间体,下一个单体与烯丙基基团形成exo-endo构型,得到了全同选择性。(2)合成并表征了一系列具有不同中心金属的NPN型稀土双烷基配合物(NPNdipp=Ph2P(NC6H3iPr2-2,6)2)(Ln=Sc,Lu,Y,Er,Nd,La)。这些配合物在有机硼盐和烷基铝的作用下对异戊二烯聚合表现出截然不同催化活性和选择性。当助催化剂是Ali Bu3和[(Ph3C)(B(C6F5)4)]、中心金属为Lu,Sc,Y或Er时,催化体系表现为3,4-选择性。而当中心金属为La和Nd时,3,4-选择性有所降低;若使用较小位阻的AlEt3代替AliBu3为助催化剂,同样是中心金属为La和Nd的催化体系转变为高反-1,4选择性;首次通过简单变化催化剂组分,实现异戊二烯聚合3,4-和反-1,4选择性间的切换,为合成高性能橡胶提供了一种新思路。(3)合成了13种三烷基稀土均配物,并研究了它们对丁二烯聚合的影响,发现其选择性和金属中心离子半径有很大关系。中心金属为镝时,顺-1,4选择性达到最高值(91.6%)。还合成了钆的双苄基单卤素化合物,该配合物对2,3-二甲基-1,3丁二烯(DMB)和丁二烯(BD)表现出良好的聚合活性和顺-1,4选择性。改变加料方式的得到了非晶相和结晶相的PDMB和PBD的两嵌段共聚物。(4)可再生单体月桂烯的选择性聚合:利用NSN型稀土烷基配合物首次得到了完美全同3,4-聚月桂烯(3,4-选择性>99%,mmmm>99%)。该聚合物是一种新的弹性体,玻璃化温度为-42 oC。通过顺序投料和共同投料可以得到无规共聚物和嵌段共聚物;利用NPN型镥烷基配合物首次得到间规3,4-聚月桂烯(3,4-选择性>99%,rr=66%)。改变配体上取代基团,其立体选择性可实现由间规到全同的转变;我们利用NPN型镧烷基配合物在[Ph3C][B(C6F5)4]和AlEt3活化下,对月桂烯表现出高活性和高反-1,4选择性。这是首例非茂稀土催化剂催化月桂烯反-1,4聚合。(5)通过关环易位反应,合成了由可再生单体月桂烯衍生得到的环状共轭二烯3-亚甲基环戊烯(MCP),并首次利用配位聚合的方法得到了1,4-含量大于99%聚(3-亚甲基环戊烯)(PMCP),聚合活性高达11520 kg of PMCP/mol Lu·h。通过氢化反应,聚合物的热稳定性有了显著的提高。更多还原

【Abstract】 In this thesis, three kinds of rare-earth metal complexes based on non-cyclopentadienyl(non-Cp) were synthesized:(1) β-diimidosulfonate-ligated rare-earth metal complexes,(2) β-imidophosphonamido-ligated rare-earth metal complexes,(3) ligand-free trialkyl homoleptic rare-earth metal complexes and heteroleptic dialkyl rare-earth metal complexes and their catalytic behaviors towards the traditional and renewable conjugated dienes were thoroughly studied.(1) The rare-earth metal complexes bearing NSN-bidentate β-diimidosulfonate ligands(RNSNdipp)Ln(CH2SiMe3)2(THF)n and NPN-bidentate β-imidophosphonamido(NPN)Lu(CH2SiMe3)2(THF) were synthesized and confirmed by NMR spectrum and X-ray diffraction analysis. Upon activation with [PhMe2NH][B(C6F5)4] and AliBu3, all these complexes exhibited highly 3,4-regioselectivity for the polymerization of isoprene. The electronics of substituted groups on NSN-ligand frame works affects the catalytic performances that the electron withdrawing groups arouse increase of the activity and facilitates the formation of the isotactic sequences. For the precursors bearing the NPN-ligands, based on their 3,4-regio-selectivity, those having more opening coordination centers display excellent isospecific stereoselectivity while those bearing the crowded coordination sphere switch to the syndioselectivity. DFT calculation has revealed that isoprene coordinates to the active spieces in η4-cis-mode followed by 3,4-insertion to give η3-allyl intermediate; the next incoming isoprene molecule and the allyl group form exo-endo arrangement towards the active sites, which ensures the isoselective regularity.(2) A series of rare-earth metal bis(alkyl) complexes(Ln = Sc, Lu, Y, Er, Nd, La) bearing a sterically bulky iminophosphonamide ancillary ligand was synthesized and well defined, which were employed to initiate isoprene polymerization upon activation with aluminum alkyls and organoborate. The catalytic behavior was strongly depending on the size of rare-earth metals and the kinds of aluminum alkyls, of which complexes 1–4 based on the smaller Lu, Sc, Y, Er metals, under the assistance of AliBu3 and [(Ph3C)(B(C6F5)4)] exhibited high 3,4-selectivities, whilst those bearing larger La and Nd metals provided moderate 3,4-slectivities. Strikingly, these large La and Nd complexes activated by [Ph3C][B(C6F5)4] and less steric AlEt3 gives trans-1,4 selectivity up to 96.5% in high activity, realizing for the first time from 3,4- to trans-1,4 selectivity. These results shed a new light on controlling the stereoregularity of polydienes by choosing the metal size and the cocatalyst, which establishes an efficient route to access high performance diene based elastomers with variable microstructures.(3) 13 kinds of rare-earth metal trialkyl complexes were synthesized and used to polymerize 1,3-butadiene. The catalytic behavior was strongly depended on the metal ion radius. When the central metal was Dy, cis-1,4-selectivity was the highest(91.6%). A heteroleptic gadolinium dibenzyl complex was also synthesized and exhibited a good catalytic activity and cis-1,4-selectivity, based on which, the diblock copolymers of DMB and BD comprising the crystalline cis-1,4-PDMB and amorphous cis-1,4-PBD sequences were obtained by sequential addition or concurrent addition of both monomers.(4) Polymerization of renewable myrcene: by means of a cationic lutetium-based coordination complex bearing the β-diimidosulfonate ligand, perfect 3,4-regio- and isospecific stereo-selective(3,4-selectivity > 99%, mmmm > 99%) PMY was achieved for the first time. This unprecedented polymer is a new elastomer having a lower glass transition temperature(-42 oC). Moreover, the isoprene–myrcene diblock copolymers,(iso-3,4-PMY)-b-(iso-3,4-PIP), composed of the amorphous elastic iso-3,4-PMY unit and the iso-3,4-PIP unit, as well as the random copolymers, have been obtained through sequential addition or mixing the two monomers in one pot; by means of a cationic lutetium-based coordination complex bearing the β-imidophosphonamido ligand, moderate 3,4-PMY was obtained(3,4-selectivity > 99%, rr = 66%). Change the ligand substituting group, the stereoselectivity was switching from syndiotactic to isotactic; by the means of a cationic lanthanum-based coordination complex bearing the β-imidophosphonamido ligand, trans-1,4-PMY was achieved for the first time with non-Cp catalysis.(5) Renewable cyclic conjugated diene 3-methylenecyclopentene(MCP) was synthesized via closed-ring metathesis of myrcene. Perfect 1,4 selectivity-PMCP has been achieved for the first time using coordination polymerization, which catalytic activity was as high as 11520 kg of PMCP/mol Lu·h and the subsequent hydrogenation afforded that better thermal properties.更多还原