ESR study of ordered Ti(III) clusters in frozen solutions

ESR spectra of thianatocopper(II) complexes with imidazole derivatives were studied in ethanolic solutions at 295 and 123 K. Axialsymmetric spectra, attributed to the monomeric complex units, were obtained for the frozen solutions. The bonding parameters were interpreted by using calculated g, Cu-hyperfine, and 14N-ligand hyperfine splitting values. The Cu-N bond parameters indicate a considerable delocalization of the unpaired electron. The values of the isotropic Cu-hyperfine splitting suggest that the deviations from the planar symmetry of the CuN4 units are due to tetrahedral perturbation of the ligand field.

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3D sub-nanometer analysis of glucose in an aqueous solution by cryo-atom probe tomography

Scientific Reports ◽

10.1038/s41598-021-90862-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

T. M. Schwarz ◽

C. A. Dietrich ◽

J. Ott ◽

E. M. Weikum ◽

R. Lawitzki ◽

...

Keyword(s):

Atom Probe Tomography ◽

Density Functional ◽

Chemical Characterization ◽

Analytical Techniques ◽

Atom Probe ◽

Characterization Methods ◽

Signal Deconvolution ◽

The Stability ◽

Frozen Solutions ◽

3D Volume

AbstractAtom Probe Tomography (APT) is currently a well-established technique to analyse the composition of solid materials including metals, semiconductors and ceramics with up to near-atomic resolution. Using an aqueous glucose solution, we now extended the technique to frozen solutions. While the mass signals of the common glucose fragments CxHy and CxOyHz overlap with (H2O)nH from water, we achieved stoichiometrically correct values via signal deconvolution. Density functional theory (DFT) calculations were performed to investigate the stability of the detected pyranose fragments. This paper demonstrates APT’s capabilities to achieve sub-nanometre resolution in tracing whole glucose molecules in a frozen solution by using cryogenic workflows. We use a solution of defined concentration to investigate the chemical resolution capabilities as a step toward the measurement of biological molecules. Due to the evaporation of nearly intact glucose molecules, their position within the measured 3D volume of the solution can be determined with sub-nanometre resolution. Our analyses take analytical techniques to a new level, since chemical characterization methods for cryogenically-frozen solutions or biological materials are limited.

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Structure and conformation of nitroxyl spin-label compounds in frozen solutions by electron nuclear double resonance spectroscopy

Applied Magnetic Resonance ◽

10.1007/bf03166701 ◽

1992 ◽

Vol 3 (2) ◽

pp. 321-331 ◽

Cited By ~ 1

Author(s):

D. Mustafi ◽

M. W. Makinen

Keyword(s):

Spin Label ◽

Double Resonance ◽

Resonance Spectroscopy ◽

Electron Nuclear Double Resonance ◽

Double Resonance Spectroscopy ◽

Frozen Solutions

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A calorimetric method for measuring ice in frozen solutions

Cryobiology ◽

10.1016/0011-2240(65)90072-6 ◽

1965 ◽

Vol 1 (5) ◽

pp. 317-323 ◽

Cited By ~ 16

Author(s):

R.J. Williams ◽

H.T. Meryman

Keyword(s):

Calorimetric Method ◽

Frozen Solutions

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PHOTOIONISATION AND BIPHOTONIC PROCESSES OF NUCLEIC ACIDS DERIVATIVES IN FROZEN SOLUTIONS

Photochemistry and Photobiology ◽

10.1111/j.1751-1097.1966.tb05767.x ◽

1966 ◽

Vol 5 (1) ◽

pp. 127-133 ◽

Cited By ~ 48

Author(s):

Claude Hélène ◽

René Santus ◽

Pierre Douzou

Keyword(s):

Nucleic Acids ◽

Frozen Solutions

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A 19F, 119Sn nuclear magnetic resonance and 119Sn Mössbauer study of the SnF2–MF–H2O system

Canadian Journal of Chemistry ◽

10.1139/v84-099 ◽

1984 ◽

Vol 62 (3) ◽

pp. 591-595 ◽

Cited By ~ 11

Author(s):

Thomas Birchall ◽

Georges Dénès

Keyword(s):

Nuclear Magnetic Resonance ◽

Spectroscopic Data ◽

Dominant Species ◽

Mössbauer Study ◽

Frozen Solution ◽

Nmr Data ◽

Mössbauer Measurements ◽

Mössbauer Parameters ◽

High Concentrations ◽

Frozen Solutions

19F and 119Sn nmr spectroscopy has been used to study the SnF2–MF–H2O (M = Li+, Na+, K+, Rb+, Cs+, and [NH4]+) system. The nmr data have been supplemented by frozen solution 119Sn Mössbauer measurements. The evidence suggests that the dominant species in the SnF2–H2O system is a hydrated stannous fluoride, probably SnF2•H2O having Mössbauer parameters of δ = 3.46 mm s−1 and Δ = 1.70 mm s−1. When F− is added to these solutions rapid F− exchange occurs with the hydrated SnF2 and the dominant species becomes [SnF3]−. The 119Sn nmr chemical shift of [SnF3]− is ~ −700 ppm from (CH3)4Sn. The 119Sn Mössbauer parameters for frozen solutions of [SnF3]− are δ = ~ 3.1 mm s−1 Δ = 1.9 mm s−1. These spectroscopic data are cation dependent. We could find no strong evidence for high concentrations of [Sn2F5]− in any of these solutions.

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Metallic condensation of Wannier-Mott impurity states in lithium-hexamethylphosphoramide glasses

Canadian Journal of Chemistry ◽

10.1139/v77-310 ◽

1977 ◽

Vol 55 (11) ◽

pp. 2258-2263 ◽

Cited By ~ 6

Author(s):

Peter P. Edwards ◽

Ron Catterall

Keyword(s):

Tight Binding ◽

Mott Transition ◽

Electron Interaction ◽

Metallic State ◽

Binding Model ◽

Impurity States ◽

Coulombic Repulsion ◽

Variational Form ◽

Frozen Solutions ◽

Good Agreement

A metal to non-metal (MNM) transition observed in frozen solutions of lithium in hexamethylphosphoramide (HMPA) was tentatively interpreted as a Mott transition in which localized Wannier-type impurity states were the source of electrons in the metallic state. In this paper this assertion is examined in greater detail by calculating critical densities (nc) on the basis of a scaled (variational) form of Mott's original criterion for the onset of localization in a dielectrically screened Coulomb potential, and also on the basis of the Hubbard tight-binding model. Mott's model for the transition is based upon the screening properties of a freely propagating gas of metallic electrons. In the Hubbard regime, however, the phenomenon is viewed from the tight-binding limit; the transition from localized to delocalized states occurs when the bandwidth (Δ) of a regular lattice of isolated centres exceeds the value of the intra-atomic Coulombic repulsion integral (U) associated with electron correlation.Both electron-gas (Mott) and tight-binding (Hubbard) approaches give calculated critical densities (5.6 × 1018, 3.2 × 1018 cm−3, respectively) in good agreement with the experimental value (∼3 × 1018 cm−3). These results therefore support the earlier suggestion that the MNM transition in frozen lithium-HMPA solutions is a Mott-transition associated with electron-interaction effects.

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