Highly isotactic poly(2-vinylpyridine)s were produced with rare-earth metal complexes supported by a symmetric β-diketiminate ligand in the presence of borate.
Treatment of β‐diketiminate ligands bearing different N‐aryl monoatomic substituents [HLH = (C6H5)N = C(Me)CH=C(Me)NH(C6H5), HLF = (2,6‐F2C6H3)N=C(Me)CH=C(Me)NH(2,6‐F2C6H3), and HLCl = (2,6‐Cl2C6H3)N=C(Me)CH=C(Me)NH(2,6‐Cl2C6H3)] with Ln(CH2SiMe3)3(THF)2 (Ln = Y and Lu) afforded a variety of β‐diketiminato rare‐earth metal complexes depending on substituents, namely, phenyl ring C–H bond activated complexes (L')(LH)Lu(THF) (1b, L' = (C6H4)N = C(Me)CH=C(Me)N(C6H5)), six‐coordinate homoleptic complexes (LH)3Ln [Ln = Y (1aa), Lu (1bb)], five‐coordinate monoalkyl complexes (LF)2Ln(CH2SiMe3) [Ln = Y (2a), Lu (2b)], and four‐coordinate dialkyl complexes (LCl)Ln(CH2SiMe3)2 [Ln = Y (3a), Lu (3b)]. All these complexes were characterized with NMR spectroscopy, and lutetium complexes 1b, 1bb and 3b were structurally validated by single‐crystal X‐ray diffraction analysis. Moreover, dialkyl complexes 3 promoted the polymerization of 2‐vinylpyridine (2‐VP) to produce atactic poly(2‐vinylpyridine) (P2VP) with quantitative yield. On activation with an equimolar amount of [Ph3C][B(C6F5)4], complexes 3 afforded highly isotactic P2VP with an mm value up to 94 %. Both 1H NMR spectrum and MALDI‐TOF mass analysis of an oligomer indicate that the polymerization was initiated by coordination insertion of 2‐VP into the Y‐CH2SiMe3 bond.
Widespread NW-SE-trending faults and Cenozoic basins in the coastal area of Fujian Province demonstrate unique tectonic deformations from the influence of the modern arc-trench system on the adjacent continent. Field-based structural analyses in the Zhangzhou region identify two-stage deformation in the Cenozoic. The early stage was dominated by normal faulting and mafic intrusions. The structural configuration was differentiated as a graben in the estuary area and linear ridges in the western mountains, representing outer arc extension caused by orthogonal flexure of the coast. Late-stage deformation turned early stage normal faults into sinistral strike-slip faults and induced a transtensional setting that greatly facilitated the evolution of the basin as well as a small rotation of the segmented structures. The tectonic dynamics are attributed to far-field effects of the west Pacific subduction zones. Additionally, a strike-slip fault-controlled scissor-like structure is proposed to demonstrate the mechanism of the redefined, fan-shaped basin.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.