Weakly interacting solvation spheres surrounding a calixarene-protected tetrairidium carbonyl cluster: contrasting effects on reactivity of alkane solvent and silica support
- Univ. of California, Davis, CA (United States); Univ. of California, Berkeley, CA (United States); DOE/OSTI
- Univ. of Alabama, Tuscaloosa, AL (United States)
- California Institute of Technology (CalTech), Pasadena, CA (United States)
- Univ. of California, Davis, CA (United States)
- Univ. of California, Berkeley, CA (United States)
The tetrairidium carbonyl cluster Ir4L3(CO)9 (L = tert-butyl-calix[4]arene(OPr)3(OCH2PPh2) (Ph = phenyl; Pr = propyl)) on a partially dehydroxylated silica support undergoes hydrogen activation at a rate and with a mechanism different from those pertaining to the cluster in alkane solution. These results are unobvious in view of the sterically bulky ligands protecting the cluster and the nearly identical CO band frequencies in the infrared spectra characterizing the supported and dissolved Ir4L3(CO)9, both before reaction and during reaction involving decarbonylation in the presence of either helium or H2 (and H2 reacted with the clusters to form hydrides with the same Ir–H band frequencies for clusters in alkane solvent and supported on silica). The initial rates of CO loss from the supported clusters in the presence of helium were the same as those in the presence of H2. In this work, the comparison demonstrates that the rate-determining step for hydride formation on the silica-supported cluster is CO dissociation. In contrast, the comparable dissociation of CO from the cluster in n-decane solution requires a higher temperature, 343 K, and is at least an order of magnitude slower than when the clusters were supported on silica. CO dissociation is not the rate-determining step for hydrogen activation on the cluster in n-decane, as the rate is influenced by reactant H2 as well.
- Research Organization:
- Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Univ. of California, Davis, CA (United States); Univ. of California, Oakland, CA (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE Office of Science (SC); USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- FG02-04ER15513; FG02-05ER15696
- OSTI ID:
- 1609503
- Alternate ID(s):
- OSTI ID: 1469718
- Journal Information:
- Dalton Transactions, Journal Name: Dalton Transactions Journal Issue: 38 Vol. 47; ISSN 1477-9226; ISSN ICHBD9
- Publisher:
- Royal Society of ChemistryCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Continuous Hydrogenation of Ethyl Levulinate to 1,4‐Pentanediol over 2.8Cu‐3.5Fe/SBA‐15 Catalyst at Low Loading: The Effect of Fe Doping
|
journal | July 2019 |
Similar Records
Dialing in single-site reactivity of a supported calixarene-protected tetrairidium cluster catalyst
MgO-supported tetrairidium clusters: Evidence of the metal-support interface structure from X-ray absorption spectroscopy
Cyclohexene hydrogenation catalyzed by MgO-supported tetrairidium clusters
Journal Article
·
Wed May 03 20:00:00 EDT 2017
· Chemical Science
·
OSTI ID:1429914
MgO-supported tetrairidium clusters: Evidence of the metal-support interface structure from X-ray absorption spectroscopy
Journal Article
·
Wed Feb 19 23:00:00 EST 1997
· Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical
·
OSTI ID:506625
Cyclohexene hydrogenation catalyzed by MgO-supported tetrairidium clusters
Journal Article
·
Sat Jul 01 00:00:00 EDT 1995
· Journal of Catalysis
·
OSTI ID:111028