A new weakly coordinating aluminate anion incorporating a chelating perfluoro-bis-anilido ligand

Smith, Joshua; Ma, Kuangbiao; Piers, Warren E.; Parvez, Masood; McDonald, Robert

doi:10.1039/c0dt00846j

Cited by 9 publications

(6 citation statements)

References 42 publications

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“…The presence of multiple 31 P NMR peaks for 2-Me 3 + [B(C 6 F 5 ) 4 ] − (two main peaks of comparable integrals compatible with an asymmetric dimer and a third one being slightly smaller and compatible with a symmetric dimer) can be traced to the rac and meso diastereomers and up to four rotamers thereof, since rotation around the bridging group is sterically hindered by bulky Cp* and NP t Bu 3 groups (Figure S3). The relative stability of the various isomers was explored by 2D-NMR and DFT modeling. NOESY NMR experiments clearly indicate the presence of two major species, one bearing a set of magnetically equivalent terminal Ti-Me moieties and one showing distinct terminal Ti-Me groups (Figure S4).…”

Section: Resultsmentioning

confidence: 99%

BHT-Modified MAO: Cage Size Estimation, Chemical Counting of Strongly Acidic Al Sites, and Activation of a Ti-Phosphinimide Precatalyst

et al. 2019

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The MAO/BHT (MAO = methylaluminoxane; BHT = 2,6-di-tert-butyl-4-methylphenol) cocatalyst for olefin polymerization has been investigated by NMR spectroscopy. It has been found that it consists of oligomeric [AlOMe 0.9 (bht) 0.1 ] n cages and monomeric MeAl(bht) 2 (bht = deprotonated BHT). Diffusion NMR indicates an average n for Al clusters of 62−96, i.e., 2−3 times higher than that estimated for unmodified MAO under analogous conditions (n ≈ 26− 41). The reactivity of MAO/BHT has been explored by monitoring the activation of the Cp*−phosphinimide titanium dichloride precatalyst Cp*(tBu 3 PN)TiCl 2 . Comparison with independently synthesized model species and DFT modeling allowed characterization of the reaction mixtures obtained at varying aluminum to titanium ratios. Homodinuclear adducts [Cp*(tBu 3 PN)TiX] 2 (μ-Y) + (X, Y = Me or Cl) forming outer sphere ion pairs (OSIPs) with MAO/ BHT-derived anions are dominant at low Al/Ti ratios, whereas mononuclear inner sphere ion pairs [Cp*(tBu 3 P N)TiX] + [MAO/BHT] − are formed at high Al/Ti ratios; both types of species are found to be viable precursors for the cationic active species. Activation of dibenzyl analogue Cp*(tBu 3 PN)TiBn 2 results in the clean formation of [Cp*(tBu 3 PN)Ti-Bn] + [MAO/BHT] − OSIP, giving sharp 1 H and 31 P NMR signals; this reaction was exploited to quantify the amount of strongly acidic sites on Al clusters, shedding further light on the structure and properties of MAO/BHT.

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Section: Resultsmentioning

confidence: 99%

BHT-Modified MAO: Cage Size Estimation, Chemical Counting of Strongly Acidic Al Sites, and Activation of a Ti-Phosphinimide Precatalyst

et al. 2019

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“…The “clean reaction” strategy is based on thermally eliminating a lactam bridge from precursors to give pure polycyclic compounds through a retro Diels–Alder reaction at high temperature . The attractive factor to employ a “clean” reaction to approach larger acenes is that this method could avoid the tedious purification problem due to the instability and poor solubility of the larger acenes. , Although N-heteroacenes − have been demonstrated to be promising materials for ion sensing , or as active elements in organic semiconducting devices such as field effect transistors, , light-emitting devices, phototransistors, memory devices, , and solar cells, the same dilemma has been encountered in challenging larger N-heteroacenes (more than six linearly fused benzene rings) due to their poor stability, especially the existence of water during the reaction. Thus, a “clean reaction” might be a feasible method to address larger N-heteroacenes.…”

Section: Introductionmentioning

confidence: 99%

Azaisoquinolinones: N Positions Tell You Different Stories in Their Optical Properties

Gao

et al. 2013

J. Org. Chem.

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Since isoquinolinones and their derivatives have been demonstrated to be powerful building blocks in constructing larger acenes and twistacenes, azaisoquinolinones and their analogues could also be important intermediates to approach larger N-heteroacenes. In this paper, we are interested in developing a concise method to synthesize novel azaisoquinolinones building blocks and studying their physical properties. Our results showed that the different N positions have a large effect on the optical and electrochemical properties of azaisoquinolinones. For example, protonation of 6- and 7-azaisoquinolinones shows different shifts of UV-vis and FL spectra. More interestingly, 6- and 7-azaisoquinolinones exhibited different interactions with metal ions in CH3CN solution. Upon the addition of 2 equiv of Fe(3+), 6-azaisoquinolinone displayed an absorption wavelength red-shifted from 470 to 540 nm (Δλ = 70 nm) with a color change from yellow to red, while the interaction between Fe(3+) and 7-azaisoquinolinone was very weak and there was no obvious color change (Δλ = 18 nm). Moreover, theoretical calculations confirmed the different optical properties with 6- and 7-azaisoquinolinones.

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“…Complexes of germanium and tin based on that and the related ligands and their X-ray structures have been described by Huang et al (2011Huang et al ( , 2012. For related structures having short AlÁ Á ÁF-C contacts, see: Smith et al (2010); Jansen & Mokros (1992). For a description of the Cambridge Structural Database, see: Allen (2002).…”

Section: Related Literaturementioning

confidence: 99%

6-Benzyl-2-methyl-1,3-bis(pentafluorophenyl)-1,3,6,2-triazaalumocane

Kireenko¹,

Zaitsev²,

Churakov³

et al. 2012

Acta Cryst E

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A new weakly coordinating aluminate anion incorporating a chelating perfluoro-bis-anilido ligand

Cited by 9 publications

References 42 publications

BHT-Modified MAO: Cage Size Estimation, Chemical Counting of Strongly Acidic Al Sites, and Activation of a Ti-Phosphinimide Precatalyst

BHT-Modified MAO: Cage Size Estimation, Chemical Counting of Strongly Acidic Al Sites, and Activation of a Ti-Phosphinimide Precatalyst

Azaisoquinolinones: N Positions Tell You Different Stories in Their Optical Properties

6-Benzyl-2-methyl-1,3-bis(pentafluorophenyl)-1,3,6,2-triazaalumocane

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