19853-09-9Relevant articles and documents
Carbon-13 chemical shift tensors in aromatic compounds. 3. Phenanthrene and triphenylene
Soderquist, Arien,Hughes, Craig D.,Horton, W. James,Facelli, Julio C.,Grant, David M.
, p. 2826 - 2832 (1992)
Measurements of the principal values of the 13C chemical shift tensor are presented for the three carbons in triphenylene and for three different α-carbons in phenanthrene. The measurements in triphenylene were made in natural abundance samples at room temperature, while the phenanthrene tensors were obtained from selectively labeled compounds (99% 13C) at low temperatures (～25 K). The principal values of the shift tensors were oriented in the molecular frame using ab initio LORG calculations. The steric compression at C4 in phenanthrene and in corresponding positions in triphenylene is manifested in a sizable upfield shift in the σ33 component relative to the corresponding σ33 values at C1 and C9 in phenanthrene. The upfield shift in σ33 is mainly responsible for the well-known upfield shift of the isotropic chemical shifts of such sterically perturbed carbons. In phenanthrene C9 exhibits a unique σ22 value reflecting the greater localization of π-electrons in the C9-C10 bond. This localization of the π-electrons at the C9-C10 bond in the central ring of phenanthrene also corresponds with the most likely ordering of electrons described by the various Kekule? structures in phenanthrene. The analysis of the 13C chemical shieldings of the bridgehead carbons in triphenylene provides significant experimental information on bonding between rings in polycyclic aromatic compounds. The results confirm that the electronic structure of triphenylene is best described by three fairly isolated benzene rings linked by C-C bonds of essentially single bond character. Similarly in phenanthrene, the bonding structure which correlates the shielding information may be characterized by the dominance of two benzene rings comprising the biphenyl moiety. A strong C9-C10 π-bond with only limited π-electron character in the C8a-C9 and C10-C10a bonds is indicated by both the experimental and theoretical results.
Binuclear metallocene compound, preparation method and applications thereof
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Paragraph 0077; 0120-0122; 0128-0131, (2020/05/30)
The invention relates to the field of olefin polymerization, and discloses a binuclear metallocene compound, a preparation method and applications thereof, wherein the binuclear metallocene compound has a structure represented by a formula (1). When the binuclear metallocene compound is applied to olefin polymerization as a catalyst component, good catalytic activity can be effectively provided, and a polyolefin product with improved isotacticity is prepared.
Method for preparing N,N-dimethyl-1-alkyl diphenylmethylamine
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Paragraph 0042-0046; 0061-0063; 0068-0070, (2019/01/21)
The invention discloses a method for preparing N,N-dimethyl-1-alkyl diphenylmethylamine and relates to the field of fine chemical engineering. The method disclosed by the invention comprises the following steps: taking waste alkyl biphenyl recovered in the conventional process as a raw material, carrying out a free radical reaction between the raw material and a halogenating reagent in the presence of a catalyst so as to obtain halogenated alkyl biphenyl; reacting the halogenated alkyl biphenyl and organic alkali to obtain a quaternary ammonium salt; and finally, performing low temperature inversion under liquid ammonia conditions, thereby obtaining N,N-dimethyl-1-(2-methyl-[1,1'-biphenyl]-3-yl) methylamine. Usage of a high-risk reagent lithium aluminum hydride and a strong carcinogen iodomethane can be avoided in the preparation process of the N,N-dimethyl-1-(2-methyl-[1,1'-biphenyl]-3-yl) methylamine, harm to the human body is eliminated, production of three wastes is reduced, the environmental pollution is avoided, and the method is safe and environmental-friendly.
