When this iridium compound is used with special hydrogen gas, it can make NMR signals for pyridine much stronger—over 200 times stronger in some cases.

Scientific Claim

The iridium complex IrCl(H)2(COE)(py)2 shows hyperpolarization effects when exposed to parahydrogen, with ortho proton resonance of free pyridine showing >210-fold intensity gain at a 1:8 pyridine ratio and >500-fold at a 1:5.6 ratio.

Evidence Quality Assessment

Claim Status

appropriately stated

Study Design Support

Design supports claim

Appropriate Language Strength

association

Can only show association/correlation

Assessment Explanation

The study reports observed enhancement factors, which is appropriate for describing an association between the catalyst and hyperpolarization effects.

More Accurate Statement

“The iridium complex IrCl(H)2(COE)(py)2 is associated with hyperpolarization effects when exposed to parahydrogen, with ortho proton resonance of free pyridine showing >210-fold intensity gain at a 1:8 pyridine ratio and >500-fold at a 1:5.6 ratio.”

Source Excerpt

“When the initial ratio of 1 to py was 1:8, a >210-fold intensity gain in the ortho proton resonance of the free py signal is observed. This enhancement increases to >500-fold when the ligand ratio is 1:5.6 and can be increased further by warming to 313 K; sTable 4 contains data for nicotinamide, nicotine, 5-aminopyrimidine, and 3,5-lutudine to demonstrate scope.”

Evidence from Studies

Supporting Evidence (1)

Why it supports

The study reports specific enhancement factors for NMR signals when using different pyridine ratios with the iridium complex and parahydrogen. The source excerpt directly states the observed enhancement factors for free pyridine signals.

Score

Iridium Cyclooctene Complex That Forms a Hyperpolarization Transfer Catalyst before Converting to a Binuclear C–H Bond Activation Product Responsible for Hydrogen Isotope Exchange

Case Report

Supported

Source Study

Iridium Cyclooctene Complex That Forms a Hyperpolarization Transfer Catalyst before Converting to a Binuclear C–H Bond Activation Product Responsible for Hydrogen Isotope Exchange

Score: 4

DOI: 10.1021/acs.inorgchem.6b02560

Similar Assertions

A special iridium compound can make NMR signals much stronger for certain molecules like pyridine by using hydrogen gas, making it easier to detect these molecules in scientific tests.

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When this iridium compound is exposed to special hydrogen gas, its hydrogen atoms show enhanced signals in NMR tests, which is a sign of polarization transfer.

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The iridium compound has parts that move around quickly at room temperature, with pyridine molecules leaving at about 8 times per second and hydrogen atoms swapping positions about 3.6 times per second.

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The binuclear iridium compound can swap hydrogen atoms in pyridine molecules at specific rates, with the ortho position exchanging fastest.

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