Chemical shift parametrization for metal-ion nuclear magnetic resonance spectroscopy of d 6 transition metal complexes

1984 ◽  
pp. 1537 ◽  
Author(s):  
Nenad Jurani?
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Transition Metal ◽  
Magnetic Resonance Spectroscopy ◽  
Metal Complexes ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Transition Metal Complexes ◽  
Metal Ion ◽  
Resonance Spectroscopy

scholarly journals Exceptional uranium(VI)-nitride triple bond covalency from 15N nuclear magnetic resonance spectroscopy and quantum chemical analysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jingzhen Du ◽  
John A. Seed ◽  
Victoria E. J. Berryman ◽  
Nikolas Kaltsoyannis ◽  
Ralph W. Adams ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Transition Metal ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Chemical Bonding ◽  
Triple Bond ◽  
Resonance Spectroscopy ◽  
Nuclear Magnetic

AbstractDetermining the nature and extent of covalency of early actinide chemical bonding is a fundamentally important challenge. Recently, X-ray absorption, electron paramagnetic, and nuclear magnetic resonance spectroscopic studies have probed actinide-ligand covalency, largely confirming the paradigm of early actinide bonding varying from ionic to polarised-covalent, with this range sitting on the continuum between ionic lanthanide and more covalent d transition metal analogues. Here, we report measurement of the covalency of a terminal uranium(VI)-nitride by 15N nuclear magnetic resonance spectroscopy, and find an exceptional nitride chemical shift and chemical shift anisotropy. This redefines the 15N nuclear magnetic resonance spectroscopy parameter space, and experimentally confirms a prior computational prediction that the uranium(VI)-nitride triple bond is not only highly covalent, but, more so than d transition metal analogues. These results enable construction of general, predictive metal-ligand 15N chemical shift-bond order correlations, and reframe our understanding of actinide chemical bonding to guide future studies.

scholarly journals Carbon-13 nuclear-magnetic-resonance spectroscopy of Forssman hapten

1981 ◽  
Vol 195 (3) ◽  
pp. 529-533 ◽  
Author(s):  
T A W Koerner ◽  
L W Cary ◽  
S C Li ◽  
Y T Li
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Chemical Shift ◽  
Magnetic Resonance Spectroscopy ◽  
Nuclear Magnetic Resonance Spectroscopy ◽  
Intestinal Mucosa ◽  
Fatty Acyl ◽  
Resonance Spectroscopy ◽  
Chemical Shift Assignments ◽  
Amide Linkage

The 13C n.m.r. spectrum of Forssman hapten was obtained at 25.16 MHz in [3H] chloroform/[2H] methanol (1:1, v/v), using purified glycosphinogolipid from canine intestinal mucosa (glycolipid I). All amide, olefin, anomeric, intersaccharide glycosidic ether, amide linkage, methyl and many methylene resonances were resolved and assigned. Analysis of the anomeric region reveals the following pentaglycosylceramide structure as originally proposed [Siddiqui & Hakomori (1971) J. Biol. Chem. 246, 5766-5769]: GalNAc (alpha 1 leads to 3) GalNAc (beta 1 leads to 3) Gal (alpha 1 leads to 4) Gal (beta 1 leads to 1) ceramide. Analysis of the amide, olefin and methylene regions reveals no alpha-hydroxy fatty acyl group and less than or equal to 6 mol% unsaturated fatty acyl groups are present. Chemical-shift assignments are reported for the anomeric and glycosidic ether carbon atoms of intersaccharide-linked alpha-galactose and N-acetyl-alpha-galactosamine residues. Two rules are proposed for the assignment of the anomeric form of 1 leads to 3 and 1 leads to 4 linkages of galactose and N-acetylgalactosamine residues present in the glycone of glyco-conjugates. The present study emphasizes the importance of the anomeric “window” (80-120 p.p.m.) in studies of glycone structure.

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