Evans Method with NMReady-60 for understanding 1H NMR of Paramagnetic Compounds

Evans Method with NMReady-60 for understanding 1H NMR of Paramagnetic Compounds

Due to the presence of unpaired d electrons in their metal ions, many transition metal complexes are paramagnetic. The unpaired electrons have a magnetic dipole moment due to their spin and act like tiny magnets, resulting in a small net attraction to an externally applied magnetic field. Unsurprisingly, the presence of paramagnetic ions has significant effects on both the chemical shift and lineshape of the 1H NMR spectrum of transition metal complexes, with the chemical shift range being much wider along with broadening of the signals.

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Unlocking the Key to Enzymes: Studying Enzyme Kinetics

Unlocking the Key to Enzymes: Studying Enzyme Kinetics

By virtue of its quantitative nature, NMR spectroscopy is increasingly becoming the method of choice to monitor a reaction and determine its kinetic parameters. We’ve demonstrated the ability of the NMReady-60 to monitor a reaction and subsequently extract kinetic parameters in a previous blog post. In this blog post, I’d like to show how the NMReady-60 can be used to study enzyme kinetics. Adapted from a Journal of Chemical Education article published by Olsen and Giles, the enzymatic hydrolysis of N-acetyl-DL-methionine by porcine acylase was studied.

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Spine disease? No, just a rigid backbone, but it keeps from flippin’ the ring!

Spine disease? No, just a rigid backbone, but it keeps from flippin’ the ring!

For this one I must begin with a little personal background information due to my special relationship to the scaffold of the target compound. During my diploma thesis I investigated gold(I) phosphine complexes as catalysts for the intermolecular hydroamidation of olefins.[1] I found that dinuclear gold complex showed superior reaction times and yields compared to mononuclear complexes, like Ph3PAuCl. This particular dinuclear complex [xantphos(AuCl)2] (1) was kicking the reaction of norbornene (2) and tosyl amide (3) and made my first academic publication possible (scheme 1).

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Nucleophilic Substitution Reactions and Benchtop NMR

Nucleophilic Substitution Reactions and Benchtop NMR

Nucleophilic substitution reactions are frequently performed as an experiment in undergraduate organic chemistry courses. Reactions taking place at saturated carbons are mainly classified as SN1 or SN2, where S stands for substitution, N for nucleophilic, and the number indicates the molecularity of the reaction (1 for a unimolecular process, 2 for a bimolecular process). In the SN2 reaction the attack of the nucleophile and elimination of the leaving group occur simultaneously in a concerted process and its rate is proportional to the concentration of both the alkyl halide and the nucleophile.

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To apodize or not to apodize - the age old question

To apodize or not to apodize - the age old question

Are you familiar with the Apodization tool in Mnova? Apodization (also referred to as Weighting or Windowing) literally translates to ‘cutting off the feet’ from the original Greek. In this case, the ‘feet’ are the leakage or wiggles that appears when the NMR signal rapidly decays to zero. As such, apodization can enhance the resolution or the sensitivity (S/N ratio) in the spectrum and even remove truncation artefacts after data has been collected. This function is particularly useful for spectra acquired on a benchtop NMR instrument due to the lower S/N ratio compared to spectra collected on high-field instruments.

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How strong was your coffee this morning?

How strong was your coffee this morning?

Who doesn’t want to start the day with a warm cup of coffee? Coffee has a stimulating effect on humans because of its caffeine content and for that reason it has become one of the most popular drinks in the world. Some clinical studies actually suggest that small amounts of caffeine everyday might be beneficial for adults. In this blog I am going to highlight an experiment done in collaboration with the Swager group at MIT using an organometallic complex to quantify the caffeine content in regular coffee without sample preparation!

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A bright application…

A bright application…

BODIPY dyes, which are boron difluoride compounds supported by dipyrrinato ligands, have gained recognition as being one of the more versatile fluorophores due to their superior photophysical properties.[1,2] BODIPY derivatives are used as stable functional dyes in several fields such as light harvesters, laser dyes, fluorescent switches, and biomolecular labels.[3-6] They gained popularity as biological probes due to the easy modification of the ligand framework, extension of the chromophore, and substitution of the fluorine atoms.6 Figure 1 shows some commercially available BODIPY dyes used as biological probes.

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To D2O or not to D2O?

To D2O or not to D2O?

In the average case one can simply dissolve an analyte in an appropriate deuterated solvent and acquire a simple 1D spectrum to obtain all the required structural information.  However, sometimes doing so may not provide you with all of the information you need!  It is not uncommon to encounter labile proton peaks in functional groups such as alcohols, amines, amides, and carboxylic acids. 

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The lightest metal with a heavyweight demand: Lithium

The lightest metal with a heavyweight demand: Lithium

Before the early 1950’s lithium was an ingredient found in Seven-up®; however, after concerns by the FDA it was removed from this popular beverage. Interestingly, about the same time it was found that lithium had antipsychotic properties, but it was only approved for human consumption in the 1970’s.[1] Despite being such a simple molecule lithium carbonate is still the most effective drug for the treatment of bipolar affective disorder! We don’t hear this side of the lithium history very often. In recent years this element has become very popular and its demand has increased considerably due to its widespread use in batteries for small electronic devices such as smart phones and laptops.[2]

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A watched pot never boils… how to monitor reactions the easy way!

A watched pot never boils… how to monitor reactions the easy way!

When monitoring reaction progress for determination of reaction kinetic parameters, NMR spectroscopy has increasingly become the method of choice. The ease in which one can calculate the concentration changes of a substrate being consumed or a product being formed over time, directly from peak integration are the reason behind this.

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