Catalysis
Solid Rh crystals isomerize butene without dissolving
Open access · cc by · source: Europe PMC
A crystalline Rh σ-alkane complex swaps NBA for alkenes in the solid state and the porous ethene polymorph isomerizes 1-butene with high TOF.
Study at a glance
- Design
- Other — Solid/gas SC-SC organometallic substitutions and polymorphic catalysis of 1-butene isomerization
- N
- Solid-state organometallic materials — no sample N
- Population
- Molecular organometallic crystals ([1-NBA]/[BArF4] ethene polymorphs)
- Outcome
- SC-SC reactivity and TOF differences between porous hexagonal and octahedral polymorphs
Structured fields used in claim comparison tables when every cited study has a complete layer.
Key findings
NBA is a token ligand; SC-SC ethene substitution gives an octahedral anion cage. The hexagonal porous polymorph (25% void) reaches TOF(90%) = 1160 h–1 versus 20–29 h–1 for nonporous crystals.
Methodology
Authors used solid/gas substitution, X-ray, SSNMR, periodic DFT/GIPAW shifts, and compared 1-butene isomerization TOFs of octahedral vs hexagonal ethene polymorphs.
Limitations
Solution lifetimes are minutes; X-ray R-factors are high after SC-SC; industrial TON still far below silica-supported systems.
How this study connects
Role on claims
Each row is a claim on a concept or method page where this paper supports, challenges, or qualifies the statement. Roles are hand-checked — not a model guess.
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Evidence for the claim as stated.
A crystalline Rh σ-alkane complex swaps NBA for alkenes in the solid state and the porous ethene polymorph isomerizes 1-butene with high TOF.
Evidence for the claim as stated.
Single-crystal-to-single-crystal XRD can watch a lattice stay crystalline while catalysis turns over. In solid rhodium organometallics, ethene substitution of a token NBA ligand gives an octahedral anion cage; the hexagonal porous polymorph (25% void) reaches TOF(90%) = 1160 h⁻¹ versus 20–29 h⁻¹ for nonporous crystals. Solution lifetimes are minutes, post-substitution R-factors are high, and industrial TON still trails silica-supported systems.
Evidence for the claim as stated.
XRD can show a lattice that is not the working catalyst. The rhodium hexagonal polymorph's 25% void tracks a 1160 versus 20–29 h⁻¹ TOF split, but post-SC-SC R-factors are already high. On carbon-supported Pt, the particles XRD/TEM size (the 6.7 nm mode) are the ORR-active population, not the leftover 1.8 nm primaries. Structure of what was synthesised is not automatically structure of what turns over.
Evidence for the claim as stated.
Open questions
Tensions this paper is part of
From concept pages' “where studies disagree.” Disagreement means the same question; scope means different assays, populations, or outcomes.
XRD can show a lattice that is not the working catalyst. The rhodium hexagonal polymorph's 25% void tracks a 1160 versus 20–29 h⁻¹ TOF split, but post-SC-SC R-factors are already high. On carbon-supported Pt, the particles XRD/TEM size (the 6.7 nm mode) are the ORR-active population, not the leftover 1.8 nm primaries. Structure of what was synthesised is not automatically structure of what turns over.
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