State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
Dalton Trans. 2013 Jan 14;42(2):499-506. doi: 10.1039/c2dt31445b. Epub 2012 Oct 16.
A series of novel monochloro half-zirconocene complexes containing phosphine oxide-(thio)phenolate chelating ligands of the type, ClCp'ZrX-2-R(1)-4-R(2)-6-(Ph(2)P=O)C(6)H(2) (Cp' = C(5)H(5), 2a: X = O, R(1) = Ph, R(2) = H; 2b: X = O, R(1) = F, R(2) = H; 2c: X = O, R(1) = (t)Bu, R(2) = H; 2d: X = O, R(1) = R(2) = (t)Bu; 2e: X = O, R(1) = SiMe(3), R(2) = H; 2f: X = S, R(1) = SiMe(3), R(2) = H; Cp' = C(5)Me(5), 2g: X = O, R(1) = SiMe(3), R(2) = H), have been synthesized in high yields. These complexes were identified by (1)H {(13)C} NMR and elemental analyses. Structures for 2b, 2c and 2f were further confirmed by X-ray crystallography. Structural characterization of these complexes reveals crowded environments around the zirconium. Complexes 2b and 2c adopt six-coordinate, distorted octahedral geometry around the zirconium center, in which the equatorial positions are occupied by three oxygen atoms of two chelating phosphine oxide-bridged phenolate ligands and a chlorine atom. The cyclopentadienyl ring and one oxygen atom of the ligand are coordinated on the axial position. Complex 2f also folds a six-coordinate, distorted octahedral geometry around the Zr center, consisting of a Cp-Zr-O (in P=O) axis [177.16°] and a distorted plane of two sulfur atoms and one oxygen atom of two chelating phosphine oxide-bridged thiophenolate ligands as well as a chlorine atom. When activated by modified methylaluminoxane (MMAO), all the complexes exhibited high activities towards ethylene polymerization at high temperature (75 °C), giving high molecular weight polymers with unimodal molecular weight distribution. The formation of 14-electron, cationic metal alkyl species might come from the Zr-O (in phenol ring) bond cleavage based on the DFT calculations study.
一系列新型的单氯半锆茂配合物，含有膦氧化物-(硫代)酚酯螯合配体，类型为 ClCp'ZrX-2-R(1)-4-R(2)-6-(Ph(2)P=O)C(6)H(2)（Cp'=C(5)H(5)，2a：X=O，R(1)=Ph，R(2)=H；2b：X=O，R(1)=F，R(2)=H；2c：X=O，R(1)=（t）Bu，R(2)=H；2d：X=O，R(1)=R(2)=（t）Bu；2e：X=O，R(1)=SiMe(3)，R(2)=H；2f：X=S，R(1)=SiMe(3)，R(2)=H；Cp'=C(5)Me(5)，2g：X=O，R(1)=SiMe(3)，R(2)=H），以高产率合成。这些配合物通过（1）H{(13)C}NMR 和元素分析进行了鉴定。2b、2c 和 2f 的结构进一步通过 X 射线晶体学证实。这些配合物的结构特征表明锆周围环境拥挤。配合物 2b 和 2c 采用六配位，扭曲的八面体几何形状，锆中心的配位原子为两个螯合膦氧化物桥联酚酯配体的三个氧原子和一个氯原子。环戊二烯基环和配体的一个氧原子占据轴向位置。配合物 2f 也围绕 Zr 中心折叠成六配位，扭曲的八面体几何形状，由 Cp-Zr-O（在 P=O）轴[177.16°]和两个螯合膦氧化物桥联噻吩酯配体的两个硫原子和一个氧原子以及一个氯原子组成的扭曲平面组成。当用改性甲基铝氧烷（MMAO）活化时，所有配合物在高温（75°C）下对乙烯聚合表现出高活性，得到具有单峰分子量分布的高分子量聚合物。根据 DFT 计算研究，14 电子阳离子金属烷基物种的形成可能来自于 Zr-O（在苯酚环中）键的断裂。
