In the binuclear iridium compound, different pyridine molecules swap places at different speeds, which seems to be related to how tightly they're attached to the iridium atoms.

Scientific Claim

The binuclear iridium complex (Cl)(H)(py)(μ-Cl)(μ-H)(κ-μ-NC5H4)Ir(H)(py)2 shows selective ligand exchange behavior, with pyridine ligands exchanging at different rates based on their bond lengths to iridium.

Original Statement

“The addition of pyridine-d5 to the 1H-labeled 4 under H2 at 273 K confirms this effect, with the order of ligand exchange based on the fall in the ortho proton site resonance intensities being δ 9.40 > δ 9.48 ≫ δ 9.33, as detailed in Figure 4. We note that the corresponding Ir–N bond lengths for these groups are 2.068(3), 2.072(3), and 2.152(3) Å, respectively, and fit with these observations.”

From 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

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 ligand exchange behavior and correlates it with bond lengths, which is appropriate for describing an association between structural features and exchange rates.

More Accurate Statement

“The binuclear iridium complex (Cl)(H)(py)(μ-Cl)(μ-H)(κ-μ-NC5H4)Ir(H)(py)2 is associated with selective ligand exchange behavior, with pyridine ligands exchanging at different rates based on their bond lengths to iridium.”

Evidence from Studies

Supporting (1)

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

In Vitro

2016 Nov 21

Contradicting (0)

No contradicting evidence found

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

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