scholarly journals Unequivocal structure confirmation of a breitfussin analog by anisotropic NMR measurements

2020 ◽  
Vol 11 (44) ◽  
pp. 12081-12088
Author(s):  
Ikenna E. Ndukwe ◽  
Yu-hong Lam ◽  
Sunil K. Pandey ◽  
Bengt E. Haug ◽  
Annette Bayer ◽  
...  
Keyword(s):  
Natural Products ◽  
Nmr Spectroscopy ◽  
Structural Features ◽  
Structure Confirmation

Structural features of proton-deficient heteroaromatic natural products, such as the breitfussins, can severely complicate their characterization by NMR spectroscopy.

scholarly journals Layer-by-Layer Structural Identification of 2D Ruddlesden-Popper Hybrid Lead Iodide Perovskites by Solid-State NMR Spectroscopy

2020 ◽  
Author(s):  
Jeongjae Lee ◽  
Woocheol Lee ◽  
Keehoon Kang ◽  
Takhee Lee ◽  
Sung Keun Lee
Keyword(s):  
Solid State ◽  
Nmr Spectroscopy ◽  
Solid State Nmr ◽  
Structural Features ◽  
Layer By Layer ◽  
Lead Iodide ◽  
Materials Properties ◽  
Non Invasive ◽  
Local Bonding ◽  
Halide Perovskites

Application of two-dimensional (2D) organic-inorganic hybrid halide perovskites for optoelectronic devices requires detailed understanding of the local structural features including the Pb-I bonding in the 2D layers and the capping ligand-perovskite interaction. In this study, we show that <sup>1</sup>H and <sup>207</sup>Pb solid-state Nuclear Magnetic Resonance (NMR) spectroscopy can serve as a non-invasive and complementary technique to quantify the composition and to probe the local structural features of 2D Ruddlesden-Popper phase BA<sub>2</sub>MA<i><sub>n</sub></i><sub>-1</sub>Pb<i><sub>n</sub></i>I<sub>3<i>n</i>+1</sub> (<i>n</i>=1-4) with butylammonium (BA) spacers. <sup>207</sup>Pb echo and <sup>1</sup>H-detected <sup>207</sup>Pb→<sup>1</sup>H heteronuclear correlation (HETCOR) experiments enables layer-by-layer structural detection of 2D halide perovskites. We show that the observed correlation between <sup>207</sup>Pb NMR shifts and mean Pb-I bond lengths around each Pb site allows us to probe the local bonding environment of Pb via its <sup>207</sup>Pb NMR shift. We envisage that this technique will be vital for better understanding the materials properties as determined by the local atomistic environments in multi-dimensional halide perovskites.

Elucidation of Polymer Microstructure by High Resolution NMR Spectroscopy

1967 ◽  
Vol 40 (2) ◽  
pp. 385-399 ◽  
Author(s):  
Raymond C. Ferguson
Keyword(s):  
Nmr Spectroscopy ◽  
High Resolution ◽  
Spectral Data ◽  
High Field ◽  
Structural Features ◽  
Polymer Microstructure ◽  
Structural Isomerism ◽  
High Resolution Nmr ◽  
Polymer Tacticity

Abstract High resolution NMR spectroscopy is proving to be a useful experimental technique for determining the microstructures of high polymers. Its major utility, aside from identifying structural features often not detectable by other methods, lies in quantitative applications. Some examples are the determination of monomer ratios in copolymers, polymer tacticity, sequence isomerism of monomer units, and other types of structural isomerism. The applicability of the method is being enhanced by continuing development of high-field spectrometers, special accessories, and new experimental techniques, and by application of computers to the analysis of spectral data.

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