新[(N -,N,N -)ZRR 2 ]二烷基配合物(N -,N,N - =吡咯基吡啶基-酰氨基或吲哚基-吡啶基-酰胺基; R = Me或CH 2 PH)已被合成并测试作为乙烯和丙烯聚合的预催化剂,可与不同的活化剂结合使用,例如B(C 6 F 5)3,[Ph 3 C] [B(C 6 F 5)4 ],[HNMe 2 Ph] [B( C 6 F 5)4 ]或固体AlMe 3耗尽的甲基铝氧烷(DMAO)。聚乙烯(M如果用1000当量的DMAO(基于Al)活化预催化剂,则会产生w > 2 MDa和M w / M n = 1.3–1.6)[活性> 1000 kg PE (mol [Zr] h mol atm)- 1 ]或使用较高的预催化剂浓度和[HNPhMe 2 ] [B(C 6 F 5)4 ](1当量)和Al i Bu 2 H(60当量)的混合物。在丙烯聚合的情况下,仅在用过量的Al i Bu
Anilidopyridyl-Pyrrolide and Anilidopyridyl-Indolide Group 3 Metal Complexes: Highly Active Initiators for the Ring-Opening Polymerization of <i>rac</i>-Lactide
Three new group3 metal complexes, bearing anilidopyridyl-pyrrolide (L1) and anilidopyridyl-indolide (L2) as dianionic tridentate ligands, with the general formula LMN(SiHMe2)2 were synthesized (complex 1, M = Y, L = L1; complex 2, M = Sc, L = L1; complex3, M = Y, L = L2). All complexes were fully characterized and tested as initiators for the ROPs of rac-lactide. The yttrium complexes 1 and 3 resulted
合成了三个新的第3组金属配合物,分别带有苯胺基吡啶基-吡咯化物(L 1)和苯胺基吡啶基-吲哚化物(L 2)作为二阴离子三齿配位体,通式为LMN(SiHMe 2)2(配合物1,M = Y,L = L 1;复数2,M = Sc,L = L 1;复数3,M = Y,L = L 2)。所有复合物均经过充分表征,并作为外消旋丙交酯ROP的引发剂进行了测试。钇配合物1和3产生了高活性催化剂(TOF高达10 4 mol丙交酯mol Y –1 h –1),而the络合物则表现出中等活性。这类催化剂可以很好地控制聚合物的大分子结构,即端基的性质,分子量及其分布。此外,根据引发剂和溶剂的性质,所获得的PLA的P r值在0.57–0.84范围内。良好控制的和快速的ROP消旋在130℃下在无溶剂的聚合反应得到的丙交酯为好,这表明复合物1 - 3在高温下稳定。最后,在2-丙醇的存在下,配合物1促进了rac-丙交酯的永生ROP
New Titanium and Hafnium Complexes Bearing [<sup>−</sup>NNN<sup>–</sup>] Pyrrolylpyridylamido Ligands as Olefin Polymerization Catalysts
Four new complexes bearing either unsubstituted or substituted pyrrolylpyridylanilido ligands, with the general formula [-NNN-]M(NMe2)(2) (M = Ti(IV), Hf(IV)), were synthesized and fully characterized by NMR spectroscopy and elemental analyses. The solid-state structures of one Ti and one Hf complex (both bearing the 2-isopropylphenyl substituent on the carbon bridging the pyridine and the aniline moieties) were obtained by single-crystal X-ray diffraction analyses, showing in both cases slightly distorted square pyramidal geometries, with the [-NNN-] ligand and one Me2N forming the base plane and the second Me2N as the apex. The new complexes and, for comparison, their zirconium analogues were tested as precatalysts for olefin polymerization, after activation with (AlBu2H)-Bu-i/methylalumoxane. Polymerization of ethylene under mild conditions (25 degrees C and 1 atm) was promoted by all catalysts with high activities, resulting in highly linear polyethylenes with ultrahigh molecular weights (M-w to 2.7 MDa). Polymerization of propylene (at 25 degrees C and 6 atm) was promoted by all complexes, with activities decreasing in the order Ti > Zr > Hf for the C-s-symmetric complexes and in the order Zr >> Ti > Hf for the C-1-symmetric complexes. Concerning stereoselectivity, catalysts based on Zr and Hf complexes behave similarly, with the C-1-symmetric species of both metals affording much more isotactic polymers than the C-5-symmetric species ([mmmm] 95% vs 73-79%) and performing better also in terms of activities and production of high-molecular-weight polypropylenes (M-w to 1.8 MDa for He. The Ti-based catalysts are less stereospecific and produce polypropylenes having very high molecular weights and rather broad molecular weight distributions. Solvent extraction of the raw samples showed the presence, in both cases, of an isotactic and an atactic fraction, also having different regioerrors, suggesting the formation of at least two active species.
Random Copolymerization of ε-Caprolactone and Lactides Promoted by Pyrrolylpyridylamido Aluminum Complexes
The monomethylaluminum complexes 1 and 2, bearing pyrrolylpyridylamido as dianionic [-NNN-] tridentate ligands with general formula [NNN]AIMe, were synthesized and tested as initiators in the ring-opening polymerization (ROP) of epsilon-caprolactone, L-lactide, and D,L-lactide. In the presence of 1 equiv of alcohol, compounds 1 and 2 were highly active initiators in the ROP of epsilon-CL (TOF up to 4000 mol(CL) mol(Al-1) h(-1)), and they showed moderate activity in the ROP of lactides (TOF up to 1.7 mol(LA) mol(AL)(-1) h(-1)) The polymerization processes proceeded with a living mechanism; moreover, the obtained PLAs resulted isotactic-enriched with P-m values up to 76%. More interestingly, this class of catalysts promoted the random copolymerization of epsilon-caprolactone and lactides. In particular, compound 1 allowed excellently controlled random copolymerization of epsilon-caprolactone and D,L-lactide as indicated by both the values of the reactivity ratios of the two monomers (r(LA) = 1.17; r(CL) = 1.36) and the average lengths of the caproyl and lactidyl sequences (L-CL = 2.0; L-LA = 2.5).
Two new anilinepyridinepyrrole ligand precursors bearing bulky substituents on the carbon bridging the pyridine and the aniline moieties were synthesized and used to prepare the corresponding zirconium complexes with general formula [−NNN−]Zr(NMe2)2. NMR spectra analysis of the obtained complexes indicated a C1-symmetry in solution. Both complexes were tested as precatalysts for ethylene and α-olefins
两个新的anilinepyridinepyrrole配体前体轴承,对碳大体积取代基桥接吡啶和苯胺部分合成,并用于与通式制备相应的锆配合物[ - NNN - ]锆(NME 2)2。所得配合物的NMR光谱分析表明溶液中具有C 1对称性。两种配合物均经过Al i Bu 2活化后作为乙烯和α-烯烃聚合的预催化剂进行测试H为烷基化剂,MAO为电离活化剂。获得了具有良好生产率的线性聚乙烯和高度全同立构的聚丙烯以及聚(1-己烯)。特别地,所获得的聚丙烯样品的特征,在全同规整度的术语([ MMMM ]高达95%),分子量(中号瓦特最多至950千克/摩尔)和熔点(Ť中号高达150℃),很棒。发现这类催化剂的活性和同种特异性强烈地依赖于桥接吡啶和苯胺部分的碳上的取代基的空间体积。
NMR Spectroscopy and X-Ray Characterisation of Cationic<i>N</i>-Heteroaryl-Pyridylamido Zr<sup>IV</sup>Complexes: A Further Level of Complexity for the Elusive Active Species of Pyridylamido Olefin Polymerisation Catalysts
unit, which relegates the counterions in the second coordination sphere. The solid‐state structure of the dimeric indolyl‐pyridyl‐amidomethylzirconium derivative, determined by X‐ray diffraction studies, points toward a weak Zr⋅⋅⋅η3‐indolyl interaction. It can be hypothesised that the formation of dimeric cationic species hampers monomer coordination (especially of less reactive α‐olefins) and that addition
新[(N -,N,N -)ZRR 2 ]二烷基配合物(N -,N,N - =吡咯基吡啶基-酰氨基或吲哚基-吡啶基-酰胺基; R = Me或CH 2 PH)已被合成并测试作为乙烯和丙烯聚合的预催化剂,可与不同的活化剂结合使用,例如B(C 6 F 5)3,[Ph 3 C] [B(C 6 F 5)4 ],[HNMe 2 Ph] [B( C 6 F 5)4 ]或固体AlMe 3耗尽的甲基铝氧烷(DMAO)。聚乙烯(M如果用1000当量的DMAO(基于Al)活化预催化剂,则会产生w > 2 MDa和M w / M n = 1.3–1.6)[活性> 1000 kg PE (mol [Zr] h mol atm)- 1 ]或使用较高的预催化剂浓度和[HNPhMe 2 ] [B(C 6 F 5)4 ](1当量)和Al i Bu 2 H(60当量)的混合物。在丙烯聚合的情况下,仅在用过量的Al i Bu