A Correlation of Nuclear Magnetic Resonance Chemical Shifts in Pyramical Boron Compounds Using a Conical Ring Current Model

A Correlation of Nuclear Magnetic Resonance Chemical Shifts in Pyramical Boron Compounds Using a Conical Ring Current Model
Author: Dennis Marynick
Publisher:
Total Pages: 22
Release: 1968
Genre:
ISBN:

Download A Correlation of Nuclear Magnetic Resonance Chemical Shifts in Pyramical Boron Compounds Using a Conical Ring Current Model Book in PDF, Epub and Kindle

By adopting a classical free electron model for the pentagonal pyramidal systems CnB(6-n)H(10-n) (n = 0,1,2,3,4) and for the tetragonal pyramidal pentaborane and pentagonal bipyramidal 2,4-C2B5H7 it is possible to account for the relative chemical shifts of boron and terminal hydrogen atoms. Also a good correlation is obtained for alkyl protons in those methyl and ethyl derivatives for which spectra are available. In this approach the pyramidal framework is treated as a cone and one or more ring current loops are placed about the conical curved surface parallel to the base. The six 'delocalized' electrons bonding the apex to the base are treated in a manner similar to the ring current approach used for benzene. From the obtained correlations it is clear that this approach has considerable predictive value. (Author).

Journal

Journal
Author: Chemical Society (Great Britain)
Publisher:
Total Pages: 1100
Release: 1969
Genre: Chemistry, Physical and theoretical
ISBN:

Download Journal Book in PDF, Epub and Kindle

The Application of a Ring Current Model to Decaborane (14). a Correlation of Proton and Boron-11 Nuclear Magnetic Resonance Chemical Shifts

The Application of a Ring Current Model to Decaborane (14). a Correlation of Proton and Boron-11 Nuclear Magnetic Resonance Chemical Shifts
Author: Thomas Onak
Publisher:
Total Pages: 18
Release: 1970
Genre:
ISBN:

Download The Application of a Ring Current Model to Decaborane (14). a Correlation of Proton and Boron-11 Nuclear Magnetic Resonance Chemical Shifts Book in PDF, Epub and Kindle

A Ring-current approach was applied with modest success to decaborane(14) in an attempt to correlate the boron and terminal proton chemical shifts in the nuclear magnetic resonance spectra. The results can be improved when positional charge differences are taken into account along with the ring-current contributions. (Author).

Nuclear Magnetic Resonance Spectroscopy of Boron Compounds

Nuclear Magnetic Resonance Spectroscopy of Boron Compounds
Author: Heinrich Nöth
Publisher: Springer
Total Pages: 0
Release: 2011-12-13
Genre: Science
ISBN: 9783642667596

Download Nuclear Magnetic Resonance Spectroscopy of Boron Compounds Book in PDF, Epub and Kindle

The revolutionary impetus of the NMR methods in organic chemistry has parallels in the field of boron chemistry. lIB NMR spectroscopy provided a basis for the elucida tion of structures and reactions of the boron hydrides. However, although many studies have been carried out with the higher boranes, carboranes, metalloboranes, etc. , and although certain patterns have emerged, the correlation between the observed chemical shift and the assigned structural unit is still not fully understood. Therefore, predictions in this area are still rather limited, and semiquantitative interpretations are not yet pos sible. Several years ago Eaton and Lipscomb sUpImarized the status in this field in their book "NMR Studies of Boron Hydrides and Related Compounds" and a plethora of new data has accumulated since then. The book also contained material on simple bo rane derivatives, but they were not discussed in any detail. On the other hand many systematic studies, both synthetic and spectroscopic, have been conducted on these simple boron materials in the last decade. Thus a large amount of NMR information is available, not only on lIB but also on 1 H, 1 3 C, and 14 N. However, this information is widely scattered in the literature, and often the data are not discussed at all. It see med appropriate, therefore, to collect these data and to present them in one volume.