In Situ NMR Investigations of Photocatalyzed Hydrogenations with Parahydrogen in the Presence of Metal Carbonyl Compounds of Group 6

1994 ◽  
Vol 33 (7) ◽  
pp. 755-757 ◽  
Author(s):  
Angelika Thomas ◽  
Mathias Haake ◽  
Friedrich-Wilhelm Grevels ◽  
Joachim Bargon
2012 ◽  
Vol 84 (11) ◽  
pp. 2233-2241 ◽  
Author(s):  
K. Geetharani ◽  
Shubhankar Kumar Bose ◽  
Sundargopal Ghosh

Heterometallic cubane-type clusters were synthesized from the reaction of group 6 and 8 metallaboranes using transition-metal carbonyl compounds. Structural and spectroscopic study revealed the existence of novel “capped-cubane” geometry. In addition, the crystal structure of these clusters distinctly confirms the presence of boride unit as one of the vertices. These clusters possess 60 cluster valence electrons (cve) and six metal–metal bonds. A plausible pathway for the formation of ruthenium-capped cubane has been described.


Author(s):  
Emilija Kohls ◽  
Matthias Stein

Metal carbonyl complexes are an important family of catalysts in homogeneous industrial processes. Their characteristic vibrational frequencies allow in situ tracking of catalytic progress. Structural assignment of intermedi-ates is often hampered by the lack of appropriate reference compounds. The calculation of carbonyl vibrational fre-quencies from first principles provides an alternative tool to identify such reactive intermediates. Scaling factors for computed vibrational carbonyl stretching frequencies were derived from a training set of 45 Rh-carbonyl complexes using the BP86 and B3LYP functionals. The systematic scaling of the computed C=O frequencies yields accurate calculation and assignment of the experimentally obtained 𝜈(CO) values. The vibrational scaling factors can be used to identify reaction intermediates of the industrially relevant Rh-catalyzed hydroformylation reaction. The absolute error between calculated and experimental spectra was significantly reduced and the experimental spectra were as-signed successfully.


2011 ◽  
Vol 50 (12) ◽  
pp. 5824-5832 ◽  
Author(s):  
K. Geetharani ◽  
Shubhankar Kumar Bose ◽  
Satyanarayan Sahoo ◽  
Babu Varghese ◽  
Shaikh M. Mobin ◽  
...  

1985 ◽  
Vol 4 (8) ◽  
pp. 1473-1475 ◽  
Author(s):  
Dorothy H. Gibson ◽  
Yekhlef S. El-Omrani

2021 ◽  
Vol 109 (4) ◽  
pp. 243-260 ◽  
Author(s):  
Yves Wittwer ◽  
Robert Eichler ◽  
Dominik Herrmann ◽  
Andreas Türler

Abstract A new setup named Fast On-line Reaction Apparatus (FORA) is presented which allows for the efficient investigation and optimization of metal carbonyl complex (MCC) formation reactions under various reaction conditions. The setup contains a 252Cf-source producing short-lived Mo, Tc, Ru and Rh isotopes at a rate of a few atoms per second by its 3% spontaneous fission decay branch. Those atoms are transformed within FORA in-situ into volatile metal carbonyl complexes (MCCs) by using CO-containing carrier gases. Here, the design, operation and performance of FORA is discussed, revealing it as a suitable setup for performing single-atom chemistry studies. The influence of various gas-additives, such as CO2, CH4, H2, Ar, O2, H2O and ambient air, on the formation and transport of MCCs was investigated. O2, H2O and air were found to harm the formation and transport of MCCs in FORA, with H2O being the most severe. An exception is Tc, for which about 130 ppmv of H2O caused an increased production and transport of volatile compounds. The other gas-additives were not influencing the formation and transport efficiency of MCCs. Using an older setup called Miss Piggy based on a similar working principle as FORA, it was additionally investigated if gas-additives are mostly affecting the formation or only the transport stability of MCCs. It was found that mostly formation is impacted, as MCCs appear to be much less sensitive to reacting with gas-additives in comparison to the bare Mo, Tc, Ru and Rh atoms.


Author(s):  
Anagha Sasikumar ◽  
Anouar Belhboub ◽  
Camille Bacon ◽  
Alexander C. Forse ◽  
John Griffin ◽  
...  

In situ NMR spectroscopy is a powerful technique to investigate charge storage mechanisms in carbon-based supercapacitors thanks to its ability to distinguish ionic and molecular species adsorbed in the porous...


1993 ◽  
Vol 447 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Ikhtiar Ahmed ◽  
Alan M. Bond ◽  
Ray Colton ◽  
Mandy Jurcevic ◽  
John C. Traeger ◽  
...  

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