Electronic structure control of Si-H bond activation by transition metals.2.Valence photoelectron spectra of (η5-C5H 4CH3)Mn(CO)2HSiPh3,(η 5-C5H4CH3)Mn(CO)2 HSiHPh2,and (η5-C5H4CH 3)

Dennis L Lichtenberger, Anjana Rai-Chaudhuri

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

The He I photoelectron spectra of (η5-C5H4CH3)Mn(CO) 2HSiHPh2, (η5-C5H4CH3)Mn(CO) 2HSiPh3, and (η5-C5H4CH3)Mn(CO) 2HSiFPh2 (Ph = C6H5) have been obtained in order to measure the nature and extent of Si-H bond interaction with the transition-metal center in these complexes. The principal electronic structure factors contributing to the addition of the Si-H bond to the transition metal involve the interaction of the Si-H σ and σ* orbitals with the metal. The extent of Si-H σ* interaction with the metal is obtained from the shape and splitting pattern of the metal-based ionization band. The electron distribution between the Si-H bond and the metal is indicated by the relative stabilities of the metal-based and ligand-based ionizations. It is found that the metal-based ionizations of these complexes reflect the formal d6 electron count at the metal center. Also, the small shifts of the valence ionizations reveal that the extent of electron charge density shift from the metal to the ligand is negligible. These observations show that the electronic structure of the Si-H interaction with the metal is in the initial stages of Si-H bond addition to the metal, before oxidative addition has become prevalent. The mechanism of interaction of the Si-H bond with the Mn center is predominantly through interaction of the filled Si-H σ-bonding orbital with empty metal orbitals. This contrasts with our previous photoelectron studies on (η5-C5H5)Mn(CO)2HSiCl 3, where the experimental data showed this compound to be a nearly complete oxidative addition product with formation of discrete Mn-H and Mn-Si bonds. The combination of the present study with the previous results demonstrates that complexes can be obtained that stabilize different stages of activation of the Si-H bond. These stages range from weak coordination of the Si-H bond to the metal to complete oxidative addition, depending on the substituents on the silicon atom.

Original languageEnglish (US)
Pages (from-to)2492-2497
Number of pages6
JournalJournal of the American Chemical Society
Volume112
Issue number7
StatePublished - Mar 28 1990

Fingerprint

Carbon Monoxide
Electron transitions
Photoelectrons
Electronic structure
Metals
Chemical activation
Ionization
Electrons
Transition metals
Ligands
Silicon
Charge density

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

@article{3b43b3aeb97745899925b5deaa72192c,
title = "Electronic structure control of Si-H bond activation by transition metals.2.Valence photoelectron spectra of (η5-C5H 4CH3)Mn(CO)2HSiPh3,(η 5-C5H4CH3)Mn(CO)2 HSiHPh2,and (η5-C5H4CH 3)",
abstract = "The He I photoelectron spectra of (η5-C5H4CH3)Mn(CO) 2HSiHPh2, (η5-C5H4CH3)Mn(CO) 2HSiPh3, and (η5-C5H4CH3)Mn(CO) 2HSiFPh2 (Ph = C6H5) have been obtained in order to measure the nature and extent of Si-H bond interaction with the transition-metal center in these complexes. The principal electronic structure factors contributing to the addition of the Si-H bond to the transition metal involve the interaction of the Si-H σ and σ* orbitals with the metal. The extent of Si-H σ* interaction with the metal is obtained from the shape and splitting pattern of the metal-based ionization band. The electron distribution between the Si-H bond and the metal is indicated by the relative stabilities of the metal-based and ligand-based ionizations. It is found that the metal-based ionizations of these complexes reflect the formal d6 electron count at the metal center. Also, the small shifts of the valence ionizations reveal that the extent of electron charge density shift from the metal to the ligand is negligible. These observations show that the electronic structure of the Si-H interaction with the metal is in the initial stages of Si-H bond addition to the metal, before oxidative addition has become prevalent. The mechanism of interaction of the Si-H bond with the Mn center is predominantly through interaction of the filled Si-H σ-bonding orbital with empty metal orbitals. This contrasts with our previous photoelectron studies on (η5-C5H5)Mn(CO)2HSiCl 3, where the experimental data showed this compound to be a nearly complete oxidative addition product with formation of discrete Mn-H and Mn-Si bonds. The combination of the present study with the previous results demonstrates that complexes can be obtained that stabilize different stages of activation of the Si-H bond. These stages range from weak coordination of the Si-H bond to the metal to complete oxidative addition, depending on the substituents on the silicon atom.",
author = "Lichtenberger, {Dennis L} and Anjana Rai-Chaudhuri",
year = "1990",
month = "3",
day = "28",
language = "English (US)",
volume = "112",
pages = "2492--2497",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "7",

}

TY - JOUR

T1 - Electronic structure control of Si-H bond activation by transition metals.2.Valence photoelectron spectra of (η5-C5H 4CH3)Mn(CO)2HSiPh3,(η 5-C5H4CH3)Mn(CO)2 HSiHPh2,and (η5-C5H4CH 3)

AU - Lichtenberger, Dennis L

AU - Rai-Chaudhuri, Anjana

PY - 1990/3/28

Y1 - 1990/3/28

N2 - The He I photoelectron spectra of (η5-C5H4CH3)Mn(CO) 2HSiHPh2, (η5-C5H4CH3)Mn(CO) 2HSiPh3, and (η5-C5H4CH3)Mn(CO) 2HSiFPh2 (Ph = C6H5) have been obtained in order to measure the nature and extent of Si-H bond interaction with the transition-metal center in these complexes. The principal electronic structure factors contributing to the addition of the Si-H bond to the transition metal involve the interaction of the Si-H σ and σ* orbitals with the metal. The extent of Si-H σ* interaction with the metal is obtained from the shape and splitting pattern of the metal-based ionization band. The electron distribution between the Si-H bond and the metal is indicated by the relative stabilities of the metal-based and ligand-based ionizations. It is found that the metal-based ionizations of these complexes reflect the formal d6 electron count at the metal center. Also, the small shifts of the valence ionizations reveal that the extent of electron charge density shift from the metal to the ligand is negligible. These observations show that the electronic structure of the Si-H interaction with the metal is in the initial stages of Si-H bond addition to the metal, before oxidative addition has become prevalent. The mechanism of interaction of the Si-H bond with the Mn center is predominantly through interaction of the filled Si-H σ-bonding orbital with empty metal orbitals. This contrasts with our previous photoelectron studies on (η5-C5H5)Mn(CO)2HSiCl 3, where the experimental data showed this compound to be a nearly complete oxidative addition product with formation of discrete Mn-H and Mn-Si bonds. The combination of the present study with the previous results demonstrates that complexes can be obtained that stabilize different stages of activation of the Si-H bond. These stages range from weak coordination of the Si-H bond to the metal to complete oxidative addition, depending on the substituents on the silicon atom.

AB - The He I photoelectron spectra of (η5-C5H4CH3)Mn(CO) 2HSiHPh2, (η5-C5H4CH3)Mn(CO) 2HSiPh3, and (η5-C5H4CH3)Mn(CO) 2HSiFPh2 (Ph = C6H5) have been obtained in order to measure the nature and extent of Si-H bond interaction with the transition-metal center in these complexes. The principal electronic structure factors contributing to the addition of the Si-H bond to the transition metal involve the interaction of the Si-H σ and σ* orbitals with the metal. The extent of Si-H σ* interaction with the metal is obtained from the shape and splitting pattern of the metal-based ionization band. The electron distribution between the Si-H bond and the metal is indicated by the relative stabilities of the metal-based and ligand-based ionizations. It is found that the metal-based ionizations of these complexes reflect the formal d6 electron count at the metal center. Also, the small shifts of the valence ionizations reveal that the extent of electron charge density shift from the metal to the ligand is negligible. These observations show that the electronic structure of the Si-H interaction with the metal is in the initial stages of Si-H bond addition to the metal, before oxidative addition has become prevalent. The mechanism of interaction of the Si-H bond with the Mn center is predominantly through interaction of the filled Si-H σ-bonding orbital with empty metal orbitals. This contrasts with our previous photoelectron studies on (η5-C5H5)Mn(CO)2HSiCl 3, where the experimental data showed this compound to be a nearly complete oxidative addition product with formation of discrete Mn-H and Mn-Si bonds. The combination of the present study with the previous results demonstrates that complexes can be obtained that stabilize different stages of activation of the Si-H bond. These stages range from weak coordination of the Si-H bond to the metal to complete oxidative addition, depending on the substituents on the silicon atom.

UR - http://www.scopus.com/inward/record.url?scp=5244247030&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=5244247030&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:5244247030

VL - 112

SP - 2492

EP - 2497

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 7

ER -