Solid Rh crystals isomerize butene without dissolving
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.
Source
Solid-state molecular organometallic chemistry. Single-crystal to single-crystal reactivity and catalysis with light hydrocarbon substrates
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.
What they did
Authors used solid/gas substitution, X-ray, SSNMR, periodic DFT/GIPAW shifts, and compared 1-butene isomerization TOFs of octahedral vs hexagonal ethene polymorphs.
What they found
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.
The limits
What it doesn't show
Solution lifetimes are minutes; X-ray R-factors are high after SC-SC; industrial TON still far below silica-supported systems.
Key terms
- SMOM-Cat
- Solid-state molecular organometallic catalyst: a molecular crystal that catalyzes gas-phase reactions.
- σ-alkane complex
- Metal bound to C–H σ bonds of an alkane (here norbornane, NBA).
- Single-crystal to single-crystal (SC-SC)
- A reaction that preserves crystallinity so a new X-ray structure can be solved.
- [BArF4]–
- Bulky fluorinated borate anion that builds a cavity around the Rh cation.
- γ-agostic
- C–H···M interaction from a γ carbon, related to allyl-hydride isomerization TSs.
Flashcards
Research intelligence for this paper
See its role on concept claims, tensions it is part of, placement history, and related discoveries.
Quiz yourself
NBA in [1-NBA][BArF4] is best described as:
Common questions
What does NBA do?
Acts as a weakly bound token ligand that can be swapped for alkenes in the crystal.
Which polymorph is fastest?
Hexagonal porous [1-(ethene)2][BArF4]-Hex, TOF(90%) = 1160 h–1.
Can solution make the same species?
Often not as pure; many decompose within minutes when dissolved.
What is the pore volume of Hex?
About 25% solvent-accessible volume.
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