Inverted Cucurbit[n]urils: Density Functional Investigations on the Electronic Structure, Electrostatic Potential, and NMR Chemical Shifts

2009 ◽  
Vol 113 (7) ◽  
pp. 1368-1376 ◽  
Author(s):  
Rahul V. Pinjari ◽  
Shridhar P. Gejji
Keyword(s):  
Electronic Structure ◽  
Electrostatic Potential ◽  
Density Functional ◽  
Chemical Shifts ◽  
Nmr Chemical Shifts

scholarly journals 29Si NMR Chemical Shifts in Crystalline and Amorphous Silicon Nitrides

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1646 ◽  
Author(s):  
Ilia Ponomarev ◽  
Peter Kroll
Keyword(s):  
Silicon Nitride ◽  
Amorphous Silicon ◽  
Density Functional ◽  
Chemical Shifts ◽  
29Si Nmr ◽  
Hydrogenated Silicon ◽  
Nmr Chemical Shifts ◽  
Nmr Data ◽  
29Si Nmr Spectra ◽  
The Impact

We investigate 29Si nuclear magnetic resonance (NMR) chemical shifts, δiso, of silicon nitride. Our goal is to relate the local structure to the NMR signal and, thus, provide the means to extract more information from the experimental 29Si NMR spectra in this family of compounds. We apply structural modeling and the gauge-included projector augmented wave (GIPAW) method within density functional theory (DFT) calculations. Our models comprise known and hypothetical crystalline Si3N4, as well as amorphous Si3N4 structures. We find good agreement with available experimental 29Si NMR data for tetrahedral Si[4] and octahedral Si[6] in crystalline Si3N4, predict the chemical shift of a trigonal-bipyramidal Si[5] to be about −120 ppm, and quantify the impact of Si-N bond lengths on 29Si δiso. We show through computations that experimental 29Si NMR data indicates that silicon dicarbodiimide, Si(NCN)2 exhibits bent Si-N-C units with angles of about 143° in its structure. A detailed investigation of amorphous silicon nitride shows that an observed peak asymmetry relates to the proximity of a fifth N neighbor in non-bonding distance between 2.5 and 2.8 Å to Si. We reveal the impact of both Si-N(H)-Si bond angle and Si-N bond length on 29Si δiso in hydrogenated silicon nitride structure, silicon diimide Si(NH)2.

103Rh NMR Chemical Shifts in Organometallic Complexes: A Combined Experimental and Density Functional Study

2004 ◽  
Vol 10 (16) ◽  
pp. 4029-4040 ◽  
Author(s):  
Laura Orian ◽  
Annalisa Bisello ◽  
Saverio Santi ◽  
Alberto Ceccon ◽  
Giacomo Saielli
Keyword(s):  
Density Functional ◽  
Chemical Shifts ◽  
Organometallic Complexes ◽  
Functional Study ◽  
Density Functional Study ◽  
Nmr Chemical Shifts

Density functional computation of49Ti NMR chemical shifts

2004 ◽  
Vol 42 (9) ◽  
pp. 737-744 ◽  
Author(s):  
Michael Bühl ◽  
Frank T. Mauschick
Keyword(s):  
Density Functional ◽  
Chemical Shifts ◽  
Nmr Chemical Shifts
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