具有两个向列相的不对称液晶二聚体的质子去耦氘核磁共振研究。
Proton-decoupled deuterium NMR study of an asymmetric liquid crystal dimer having two nematic phases.
作者信息
Chamignon C, Lelli M, Emsley J W, Luckhurst G R, Zimmermann H
机构信息
Centre de RMN à Très Hauts Champs de Lyon (FRE 2034-CNRS, UCB Lyon 1, ENS Lyon), 5 rue de la Doua, 69100 Villeurbanne, France.
Department of Chemistry "Ugo Schiff", Center for Magnetic Resonance (CERM), University of Florence, Sesto Fiorentino (FI) 50019, Italy.
出版信息
Phys Rev E. 2023 Aug;108(2-1):024702. doi: 10.1103/PhysRevE.108.024702.
Proton-decoupled deuterium NMR spectra were obtained for an asymmetric liquid crystal dimer 1-(4-cyanobiphenyl-4'-yloxy)-6-(4-cyanobiphenyl-4'-yl)hexane (CB6OCB) containing a single -CD_{2}- group. The sample has two nematic liquid crystal phases: a twist-bend nematic, N_{TB}, at the lowest temperature followed by a uniaxial nematic, N_{U}, on increasing the temperature. Proton decoupling reduces the linewidths of the peaks in the deuterium spectrum from kHz to ∼100Hz, enabling quadrupolar splittings, Δν, to be obtained with enhanced precision as well as the dipolar coupling between deuterium nuclei within the CD_{2} group, hence enhancing the information content.
对含有单个 -CD₂- 基团的不对称液晶二聚体 1-(4-氰基联苯-4'-氧基)-6-(4-氰基联苯-4'-基)己烷 (CB6OCB) 进行了质子去耦氘核磁共振光谱测定。该样品有两个向列相液晶相：在最低温度下为扭曲弯曲向列相，Nₜb，随着温度升高接着是单轴向列相，Nᵤ。质子去耦将氘谱中峰的线宽从千赫兹减小到约100赫兹，使得能够更精确地获得四极分裂 Δν 以及 CD₂ 基团内氘核之间的偶极耦合，从而提高了信息含量。
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