Chemical shifts for tritons in chlorobenzene, bromobenzene, fluorobenzene and toluene as determined by tritium NMR spectroscopy

Background: Nanobodies, or VHHs, are derived from heavy chain-only antibodies (hcAbs) found in camelids. They overcome some of the inherent limitations of monoclonal antibodies (mAbs) and derivatives thereof, due to their smaller molecular size and higher stability, and thus present an alternative to mAbs for therapeutic use. Two nanobodies, Nb23 and Nb24, have been shown to similarly inhibit the self-aggregation of very amyloidogenic variants of β2-microglobulin. Here, the structure of Nb23 was modeled with the Chemical-Shift (CS)-Rosetta server using chemical shift assignments from nuclear magnetic resonance (NMR) spectroscopy experiments, and used as prior knowledge in PONDEROSA restrained modeling based on experimentally assessed internuclear distances. Further validation was comparatively obtained with the results of molecular dynamics trajectories calculated from the resulting best energy-minimized Nb23 conformers. Methods: 2D and 3D NMR spectroscopy experiments were carried out to determine the assignment of the backbone and side chain hydrogen, nitrogen and carbon resonances to extract chemical shifts and interproton separations for restrained modeling. Results: The solution structure of isolated Nb23 nanobody was determined. Conclusions: The structural analysis indicated that isolated Nb23 has a dynamic CDR3 loop distributed over different orientations with respect to Nb24, which could determine differences in target antigen affinity or complex lability.

Download Full-text

Resolving Entangled JH-H-Coupling Patterns for Steroidal Structure Determinations by NMR Spectroscopy

Molecules ◽

10.3390/molecules26092643 ◽

2021 ◽

Vol 26 (9) ◽

pp. 2643

Author(s):

Danni Wu ◽

Kathleen Joyce Carillo ◽

Jiun-Jie Shie ◽

Steve S.-F. Yu ◽

Der-Lii M. Tzou

Keyword(s):

Nmr Spectroscopy ◽

1H Nmr Spectroscopy ◽

Chemical Shifts ◽

Atomic Level ◽

Molecular Structures ◽

Naturally Occurring ◽

Structure Determinations ◽

Ligand Interactions ◽

Synthetic Steroids ◽

The Individual

For decades, high-resolution 1H NMR spectroscopy has been routinely utilized to analyze both naturally occurring steroid hormones and synthetic steroids, which play important roles in regulating physiological functions in humans. Because the 1H signals are inevitably superimposed and entangled with various JH–H splitting patterns, such that the individual 1H chemical shift and associated JH–H coupling identities are hardly resolved. Given this, applications of thess information for elucidating steroidal molecular structures and steroid/ligand interactions at the atomic level were largely restricted. To overcome, we devoted to unraveling the entangled JH–H splitting patterns of two similar steroidal compounds having fully unsaturated protons, i.e., androstanolone and epiandrosterone (denoted as 1 and 2, respectively), in which only hydroxyl and ketone substituents attached to C3 and C17 were interchanged. Here we demonstrated that the JH–H values deduced from 1 and 2 are universal and applicable to other steroids, such as testosterone, 3β, 21-dihydroxygregna-5-en-20-one, prednisolone, and estradiol. On the other hand, the 1H chemical shifts may deviate substantially from sample to sample. In this communication, we propose a simple but novel scheme for resolving the complicate JH–H splitting patterns and 1H chemical shifts, aiming for steroidal structure determinations.

Download Full-text

27Al-MAS-NMR-Untersuchungen des thermischen Abbaus von NH4Al(SO4)2·12H2O / 27Al-MAS-NMR Studies on the Thermolysis of NH4Al(SO4)2· 12H2O

Zeitschrift für Naturforschung B ◽

10.1515/znb-1991-1110 ◽

1991 ◽

Vol 46 (11) ◽

pp. 1515-1518 ◽

Cited By ~ 2

Author(s):

Gerhard Wegner ◽

Gert Blumenthal ◽

Dirk Müller ◽

Dirk-Henning Menz ◽

Antje Schmalstieg

Keyword(s):

Nmr Spectroscopy ◽

Structural Changes ◽

Chemical Shifts ◽

Mas Nmr ◽

Nmr Studies ◽

High Stage ◽

27Al Mas Nmr ◽

High Resolution Nmr ◽

First Time

Products of the thermolysis of NH4Al-alum were prepared under dried air and characterized by X-ray powder diffraction, thermogravimetry, and for the first time by solid-state 27Al-MAS-NMR spectroscopy. It was found, that high resolution NMR spectroscopy is applicable to follow up the thermal decomposition and to indicate even minor structural changes. 27Al-MAS-NMR spectra show peaks with characteristic chemical shifts for octahedral Al-units up to a high stage of thermolysis. During the decomposition of Al2(SO4)3 to γ-Al2O3 we again observed three-peak spectra with the specific signal at ≈ 35 ppm for penta-coordinated Al ions as recently proved for the thermolysis of AlCl3 · 6 H2O.

Download Full-text

Measurement of Long-Range Interatomic Distances by Solid-State Tritium-NMR Spectroscopy

Journal of the American Chemical Society ◽

10.1021/ja908915v ◽

2010 ◽

Vol 132 (6) ◽

pp. 1734-1735 ◽

Cited By ~ 8

Author(s):

Alexander K. L. Yuen ◽

Olivier Lafon ◽

Thibault Charpentier ◽

Myriam Roy ◽

Francine Brunet ◽

...

Keyword(s):

Solid State ◽

Nmr Spectroscopy ◽

Long Range ◽

Tritium Nmr ◽

Interatomic Distances

Download Full-text

Preparation, 1H and 13C NMR, and ab initio/IGLO study of mono-O-protonated deltic acid and theoretical investigation of di-, tri-, and tetra-O-protonated deltic acids

Canadian Journal of Chemistry ◽

10.1139/v98-166 ◽

1999 ◽

Vol 77 (5-6) ◽

pp. 525-529 ◽

Cited By ~ 2

Author(s):

GK Surya Prakash ◽

Golam Rasul ◽

George A Olah ◽

Ronghua Liu ◽

Thomas T Tidwell

Keyword(s):

Nmr Spectroscopy ◽

Ab Initio ◽

Theoretical Investigation ◽

13C Nmr ◽

Chemical Shifts ◽

1H And 13C Nmr ◽

Nmr Chemical Shifts ◽

Molar Solution ◽

Protonated Species ◽

C Nmr

The hitherto elusive mono-O-protonated deltic acid C3O3H3+ was prepared by protolysis of di-tert-butoxy deltate in FSO3H-SO2ClF and in FSO3H:SbF5 (Magic Acid; 1:1 molar solution) in SO2ClF as solvent at -78°C and was characterized by 1H and 13C NMR spectroscopy. The structure and NMR chemical shifts were also calculated by the ab initio/IGLO method. No NMR evidence was found for persistent di-O-protonated deltic acid under these conditions, although a limited equilibrium with the mono-O-protonated species can be involved. Di-, tri-, and tetra-O-protonated deltic acids were also studied by ab initio/IGLO method.Key words: protonated deltic acid, aromaticity, superacids, NMR spectroscopy, ab initio and IGLO calculations.

Download Full-text

Hexaethyl-2,4-dicarba-nido-hexaborane(8), Deprotonation and Complexation Studied by NMR Spectroscopy and Density Functional Theory (DFT) Calculations

Zeitschrift für Naturforschung B ◽

10.1515/znb-2004-0609 ◽

2004 ◽

Vol 59 (6) ◽

pp. 685-691 ◽

Cited By ~ 8

Author(s):

Bernd Wrackmeyer ◽

Hans-Jörg Schanz

Keyword(s):

Density Functional Theory ◽

Nmr Spectroscopy ◽

Density Functional ◽

Chemical Shifts ◽

Coupling Constants ◽

Analogous Reaction ◽

Sandwich Complex ◽

Dft Methods ◽

Functional Theory ◽

Nmr Data

Deprotonation of hexaethyl-2,4-dicarba-nido-borane(8) 2 leads first to the hexaethyl-2,4-dicarbanido- borate(1−) 3, and further deprotonation, using BuLi/KOtBu, gives the hexaethyl-2,4-dicarbanido- hexaborate(2−) 4. The reaction of 3 with FeCl2 affords the commo-ferracarborane [Fe(Et6-2,4- C2B4H)2] 5, and the analogous reaction of 4 leads to the anionic sandwich complex [Fe(Et6-2,4- C2B4)2]2− 6 which can be protonated to give 5. The complex 5 contains two hydrido ligands, each bridging the iron and two boron atoms. Reactions were monitored and the products were characterised by 11B NMR spectroscopy in solution. The geometries of the carboranes, the borates (all unsubstituted and permethyl-substituted) and the iron complexes (all unsubstituted) were optimised by DFT methods [B3LYP/6-311+G(d,p) or B3LYP/6-31+G(d)], and the relevant NMR data [chemical shifts δ11B, δ13C, δ57Fe, and coupling constants 1J(13C,1H), 1J(11B,1H), 1J(57Fe,1H), 1J(57Fe,11B)] were calculated at the same level of theory.

Download Full-text

ChemInform Abstract: NMR SPECTROSCOPY OF ORGANIC COMPOUNDS OF SELENIUM AND TELLURIUM. I. CHEMICAL SHIFTS OF CARBON-13 AND SELENIUM-77 IN ARYLSELENIDES AND NONADDITIVE EFFECT OF SUBSTITUENTS ON THE SHIELDING OF CARBON-13 NUCLEI OF THE AROMATIC RING

Chemischer Informationsdienst ◽

10.1002/chin.197921060 ◽

1979 ◽

Vol 10 (21) ◽

Author(s):

G. A. KALABIN ◽

D. F. KUSHNAREV ◽

G. A. CHMUTOVA ◽

L. V. KASHURNIKOVA

Keyword(s):

Nmr Spectroscopy ◽

Organic Compounds ◽

Aromatic Ring ◽

Chemical Shifts ◽

Effect Of Substituents

Download Full-text

Spin State Behavior of A Spin-Crossover Iron(II) Complex with N,N′-Disubstituted 2,6-bis(pyrazol-3-yl)pyridine: A Combined Study by X-ray Diffraction and NMR Spectroscopy

Crystals ◽

10.3390/cryst10090793 ◽

2020 ◽

Vol 10 (9) ◽

pp. 793

Author(s):

Elizaveta K. Melnikova ◽

Dmitry Yu. Aleshin ◽

Igor A. Nikovskiy ◽

Gleb L. Denisov ◽

Yulia V. Nelyubina

Keyword(s):

Nmr Spectroscopy ◽

Spin State ◽

Metal Ion ◽

Spin Crossover ◽

Molecular Design ◽

Chemical Shifts ◽

Variable Temperature ◽

High Spin State ◽

X Ray Diffraction ◽

X Ray

A series of three different solvatomorphs of a new iron(II) complex with N,N′-disubstituted 2,6-bis(pyrazol-3-yl)pyridine, including those with the same lattice solvent, has been identified by X-ray diffraction under the same crystallization conditions with the metal ion trapped in the different spin states. A thermally induced switching between them, however, occurs in a solution, as unambiguously confirmed by the Evans technique and an analysis of paramagnetic chemical shifts, both based on variable-temperature NMR spectroscopy. The observed stabilization of the high-spin state by an electron-donating substituent contributes to the controversial results for the iron(II) complexes of 2,6-bis(pyrazol-3-yl)pyridines, preventing ‘molecular’ design of their spin-crossover activity; the synthesized complex being only the fourth of the spin-crossover (SCO)-active kind with an N,N′-disubstituted ligand.

Download Full-text