Proton Carbon Correlation
Proton Carbon Correlation - Related Videos
09:40
Proton Exchange Membrane Fuel Cells
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2023
Source: Laboratories of Margaret Workman and Kimberly Frye - Depaul University The United States consumes a large amount of energy – the current rate is around 97.5 quadrillion BTUs annually. The vast majority (90%) of this energy comes from non-renewable fuel sources. This energy is used for electricity (39%), transportation (28%), industry (22%), and residential/commercial use (11%). As the world has a limited supply of these non-renewable sources, the United States (among others) is...
02:20
Correlations
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2020
Correlation means that there is a relationship between two or more variables (such as ice cream consumption and crime), but this relationship does not necessarily imply cause and effect. When two variables are correlated, it simply means that as one variable changes, so does the other. We can measure correlation by calculating a statistic known as a correlation coefficient. A correlation coefficient is a number from -1 to +1 that indicates the strength and direction of the relationship between...
07:38
Functional Characterization of Na+/H+ Exchangers of Intracellular Compartments Using Proton-killing Selection to Express Them at the Plasma Membrane
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Cited by 4 •
2015
The first part of this article shows how to select mutant cell lines expressing vesicular Na+/H+ exchangers at their plasma membrane. The second part provides protocols based on intracellular pH measurements and fast ion uptake, which are used to determine the ion selectivity and the kinetic parameters of these exchangers.
01:09
Correlation
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2023
In statistics, two variables are said to be correlated if the values of one variable are associated with the other variable. Depending on the relationship between two variables, correlation can be of three types– positive correlation, negative correlation, and zero correlation. Two variables, for example, a and b, are said to be positively correlated if both variables move in the same direction. In other words, a positive correlation exists between two variables, a and b, if: Variable a...
01:14
The Carbon Cycle
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2019
Carbon is the basis of all organic matter on Earth, and is recycled through the ecosystem in two primary processes: one in which carbon is exchanged among living organisms, and one in which carbon is cycled over long periods of time through fossilized organic remains, weathering of rocks, and volcanic activity. Human activities, including increased agricultural practices and the burning of fossil fuels, has greatly affected the balance of the natural carbon cycle. Biological Carbon Cycle All...
FAQs
Magnetization transfer occurs through scalar, or J, coupling between coupled ¹H and ¹³C nuclei. The transferred magnetization is represented in a two-dimensional spectrum as a cross-peak at the proton and carbon chemical shifts involved. Reading these paired positions allows a researcher to connect signals from the two dimensions and use those relationships during structural analysis.
HSQC emphasizes one-bond ¹H–¹³C correlations, whereas HMBC is designed to reveal longer-range correlations. This difference changes the structural information each experiment contributes: HSQC links a proton signal with the carbon directly coupled to it, while HMBC can extend connectivity information beyond a single bond. Choosing between them depends on whether direct or longer-range relationships are needed.
Cross-peak patterns help separate signals that appear similar by adding the second nucleus's chemical-shift coordinate. A proton signal can therefore be evaluated together with its associated carbon shift rather than in isolation. This paired information supports signal assignment and helps distinguish chemically similar environments when mapping an organic molecule.
The distribution of correlations can be used to map portions of a carbon framework and test whether proposed assignments are consistent with observed proton signals. One-bond and longer-range relationships provide complementary evidence, so the combined pattern can support structure elucidation rather than relying on a single resonance. This is especially useful for chemically complex organic compounds.
A proton-carbon correlation experiment produces a two-dimensional NMR spectrum in which one axis represents proton chemical shifts and the other carbon chemical shifts. Analysis focuses on locating cross-peaks and matching their coordinates to the corresponding resonances. Researchers then interpret direct or longer-range relationships according to the experiment used, building assignments from the observed correlations.
During reaction monitoring, assigned proton-carbon correlations provide a way to track signals associated with starting materials, products, or changing molecular environments. Comparing the observed relationships as a reaction proceeds can help organize spectral information and support interpretation of structural changes. The method is therefore useful when monitoring is part of chemical characterization.
For metabolite identification, paired proton and carbon information adds structural constraints beyond isolated signals. Correlations can help assign resonances and distinguish similar environments within a metabolite, supporting identification in samples where molecular signals may be complex. The same reasoning extends to pharmaceutical and natural-product characterization, where reliable assignments aid interpretation of molecular structures.
In pharmaceutical and natural-product chemistry, HSQC and HMBC can provide complementary connectivity evidence. Direct one-bond links help anchor assignments to individual carbon environments, while longer-range links can reveal additional framework relationships. This combined view is valuable for characterizing organic compounds whose carbon frameworks contain multiple similar or chemically complex environments.