Dynamics of methyl groups in proteins as studied by proton-detected carbon-13 NMR spectroscopy. Application to the leucine residues of staphylococcal nuclease

Biochemistry ◽  
1992 ◽  
Vol 31 (23) ◽  
pp. 5253-5263 ◽  
Author(s):  
Linda K. Nicholson ◽  
Lewis E. Kay ◽  
Donna M. Baldisseri ◽  
Julian Arango ◽  
Paul E. Young ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Staphylococcal Nuclease ◽  
Methyl Groups

scholarly journals A quantum mechanical alternative to the Arrhenius equation in the interpretation of proton spin–lattice relaxation data for the methyl groups in solids

2015 ◽  
Vol 17 (43) ◽  
pp. 28866-28878 ◽  
Author(s):  
Piotr Bernatowicz ◽  
Aleksander Shkurenko ◽  
Agnieszka Osior ◽  
Bohdan Kamieński ◽  
Sławomir Szymański
Keyword(s):  
Nmr Spectroscopy ◽  
Arrhenius Equation ◽  
Lattice Relaxation ◽  
Proton Spin ◽  
Spin Lattice Relaxation ◽  
Quantum Mechanical ◽  
Methyl Groups ◽  
Relaxation Data ◽  
Spin Lattice ◽  
Nuclear Spin Lattice Relaxation

The issue of nuclear spin–lattice relaxation in methyl groups in solids has been a recurring problem in NMR spectroscopy.

Comprehensive and Cost-Effective NMR Spectroscopy of Methyl Groups in Large Proteins

2010 ◽  
Vol 132 (9) ◽  
pp. 2952-2960 ◽  
Author(s):  
Renee Otten ◽  
Byron Chu ◽  
Karla D. Krewulak ◽  
Hans J. Vogel ◽  
Frans A. A. Mulder
Keyword(s):  
Nmr Spectroscopy ◽  
Cost Effective ◽  
Methyl Groups ◽  
Large Proteins

Carbene Adducts of Dimethylcadmium

1999 ◽  
Vol 54 (11) ◽  
pp. 1350-1356 ◽  
Author(s):  
Anthony J. Arduengo ◽  
Jens R. Goerlicha ◽  
Fredric Davidson ◽  
William J. Marshall
Keyword(s):  
Nmr Spectroscopy ◽  
Bond Distance ◽  
Imidazole Ring ◽  
Methyl Groups ◽  
Carbene Ligands ◽  
Cadmium Complexes ◽  
Carbene Complexes ◽  
X Ray ◽  
Planar Geometries

The first examples of carbene-cadmium complexes are reported from the reactions of a variety of imidazol-2-ylidenes or imidazolin-2-ylidenes with dimethylcadmium. Four new carbene complexes are characterized by NMR spectroscopy (1H , 13C and 113Cd). The cadmium centers are strongly shifted downfield (100 -150 ppm) by interaction with the carbenes. X-ray structures are reported for three carbene-cadmium 1:1 adducts. The cadmium centers exhibit distorted trigonal-planar geometries in which the carbene ligands have an average 18.2 pm longer bond distance to cadmium compared to the methyl groups. The planes of cadmium coordination are twisted with respect to the plane of the imidazole ring. The more basic imidazolin-2-ylidene is shown to displace imidazol-2-ylidenes from the cadmium center.

13C and 119Sn NMR evidence of the presence and extent of σ-π conjugation in some benzyltin compounds and their complexes

1988 ◽  
Vol 53 (3) ◽  
pp. 571-580 ◽  
Author(s):  
Jaroslav Holeček ◽  
Antonín Lyčka ◽  
Karel Handlíř ◽  
Milan Nádvorník
Keyword(s):  
Nmr Spectroscopy ◽  
Coordination Number ◽  
Aromatic Ring ◽  
Electronic System ◽  
Methyl Groups ◽  
Chlorine Atoms ◽  
Nmr Data ◽  
Relative Extent ◽  
119Sn Nmr

The 13C and 119Sn NMR spectroscopy has been used to study the compounds types (C6H5CH2)4-nSn(CH3)n and (C6H5CH2)4-nSnCln (n = 0 - 3) in media of non-coordinating (deuteriochloroform) and coordinating (hexadeuteriomethyl sulphoxide) solvents. The analysis of the NMR data has confirmed the presence and established the relative extent of participation of the σ-π conjugative connection of the polarized σ(Sn-C) bond with the adjacent π electronic system of the aromatic ring in the Sn-CH2-C6H5 grouping. The extent of σ-π conjugation decreases with decreasing number of methyl groups in the compounds (C6H5CH2)4-nSn(CH3)n and with increasing number of chlorine atoms in the compounds (C6H5CH2)4-nSnCln and with increasing coordination number of the central tin atom in the complexes of the compounds (C6H5CH2)4-nSnCln.x(C2H3)2SO.

Novel Non-Symmetric Nickel-Diimine Complexes for the Homopolymerization of Ethene: Control of Branching by Catalyst Design

2002 ◽  
Vol 57 (10) ◽  
pp. 1141-1146 ◽  
Author(s):  
Markus Schmid ◽  
Robert Eberhardt ◽  
Jürgen Kukral ◽  
Bernhard Rieger
Keyword(s):  
Nmr Spectroscopy ◽  
Catalyst Design ◽  
Methyl Groups ◽  
Degree Of Branching ◽  
Diimine Ligands ◽  
Melting Transitions ◽  
Diimine Complexes ◽  
C Nmr ◽  
Ethene Polymerization

Non-symmetric diimine ligands (Ar-N=C(CH3)-(CH3)C=NAr*; Ar: 2,6-diisopropyl-phenyl; Ar*: 2,6-di(4-tert-butyl-phenyl)phenyl (4b), 2,6-di(4-OCH3)-phenyl)phenyl (4c)) were synthesized and converted in-situ into the corresponding nickel dibromo complexes (5b, c) by reaction with (DME)NiBr2. The complexes were activated for ethene polymerization by treatment with MAOat ambient temperature. The resulting highmolecular weight polymer products (MW > 4.0 x 106 g mol-1) have a branched microstructure (predominantly methyl groups), as indicated by 13C NMR spectroscopy. The degree of branching can be controlled by a proper choice of the 2,6-diphenyl modified aniline moieties resulting in melting transitions ranging from 92 - 130 °C.

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