Silicon-29 NMR investigation of silyl derivatives of the iron-group transition metals

Krentz, Richard; Pomeroy, Roland K.

doi:10.1021/ic00213a021

Cited by 72 publications

(26 citation statements)

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“…The 29 Si-NMR spectrum of compound 11 features four resonances for the cyclo-silyl ligand bonded at the metal atom ( [7] which is the expected trend for complexes of this type. [20] The 13 C-NMR data of 11 are in agreement with the proposed structure ( Table 2).…”

Section: Wϫx]supporting

confidence: 79%

Preparation, Characterization, and Properties of Various Novel Ionic Derivatives of Pentacarbonyltungsten

Palitzsch

Beyer

Böhme

et al. 1999

Eur. J. Inorg. Chem.

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Section: Wϫx]supporting

confidence: 79%

Preparation, Characterization, and Properties of Various Novel Ionic Derivatives of Pentacarbonyltungsten

Palitzsch

Beyer

Böhme

et al. 1999

Eur. J. Inorg. Chem.

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“…43,45,49 In PR 3 complexes there is an increase in the PR lengths in closely related complexes when the electron density increases at the metal center, which is consistent with this interpretation. 50 In 1M and 3M, however, there is no significant difference in the SiCl bond lengths in the two types of silyl ligands (Tables 4 and 6).…”

Section: (R 3 P)(oc) 4 Mru(co) 3 (Sicl 3 ) 2 (M ) Ru Os) Derivativessupporting

confidence: 70%

Complexes Containing Unbridged Dative Metal−Metal Bonds and the Strong Acceptor Ru(CO)₃(SiCl₃)₂ Moiety. Comments on the Transition Metal to Silicon Bond

et al. 1998

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Complexes of formula (R 3 P)(OC) 4 MRu(CO) 3 (SiCl 3 ) 2 (M ) Ru, Os) and (OC) 3 (Bu t NC) 2 MRu-(CO) 3 (SiCl 3 ) 2 (M ) Fe, Ru, Os) have been prepared from the reaction of cis-Ru(CO) 4 (SiCl 3 ) 2 and the appropriate donor molecule in solution at room temperature. The characterization of the complexes included the crystal structures of (Me 3 P)(OC) 4 MRu(CO) 3 (SiCl 3 ) 2 (M ) Ru, 1Ru; Os, 1Os) and the three M(CO) 3 (CNBu t ) 2 derivatives (3Fe, 3Ru, 3Os). All five structures reveal molecules with unbridged metal-metal bonds. The PMe 3 ligand is trans to the metal bond in 1M, whereas the isocyanide ligands are cis to this bond in 3M. The Bu t NC substituents have a cis configuration in 3Fe and 3Ru, but a trans arrangement in 3Os. Complexes 3Fe, 1Ru, and 3Ru are rare examples of structurally characterized compounds in which a first-row or second-row transition metal acts as the donor atom in a molecule containing an unbridged dative bond between two transition metals. The (OC) 3 (Bu t -NC) 2 FeRu(CO) 3 (SiCl 3 ) 2 derivative is unstable both in solution and the solid state and attempts to prepare similar complexes in which Fe acts as the donor atom were unsuccessful. In contrast to previous studies, the Ru(CO) 4 (PR 3 ) derivatives were reasonably stable. The RuSi lengths trans to the dative metal-metal bond (range 2.338(3)-2.357(2) Å) are considerably shorter than the RuSi lengths trans to the carbonyl ligand (range 2.399(5)-2.420(4) Å), whereas there is no significant difference between the SiCl lengths in the two types of SiCl 3 ligands in the five structures. These results are interpreted in terms of the trichlorosilyl ligand acting as a π acceptor ligand principally via the Si 3d orbitals.

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“…In case of complex 3 , the M–Si BCP is present only in the experimental ρ( r ), as symbolized by an open blue circle. Key: (a) ref ; (b) this work; (c) ref ; (d) ref ; (e) refs and ; (f) ref .…”

Section: Introductionmentioning

confidence: 99%

“…These nonclassical hydrosilane complexes can be considered as arrested intermediates along the oxidative addition pathway. 1−3 This is illustrated in Figure 1 by selected benchmark systems, where the σ-complex Cr-(CO) 5 SiH 2 Ph 2 (1) 4 and the classical silyl hydride Fe(CO) 4 H-(SiCl 3 ) (7) 5 represent the starting point and terminus of this process. The propagation along the oxidative addition pathway can then be considered as a continuum of electronic structures.…”

Section: Introductionmentioning

confidence: 99%

J(Si,H) Coupling Constants of Activated Si–H Bonds

et al. 2017

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We outline in this combined experimental and theoretical NMR study that sign and magnitude of J(Si,H) coupling constants provide reliable indicators to evaluate the extent of the oxidative addition of Si-H bonds in hydrosilane complexes. In combination with experimental electron density studies and MO analyses a simple structure-property relationship emerges: positive J(Si,H) coupling constants are observed in cases where M → L π-back-donation (M = transition metal; L = hydrosilane ligand) dominates. The corresponding complexes are located close to the terminus of the respective oxidative addition trajectory. In contrast negative J(Si,H) values signal the predominance of significant covalent Si-H interactions and the according complexes reside at an earlier stage of the oxidative addition reaction pathway. Hence, in nonclassical hydrosilane complexes such as CpTi(PMe)(HSiMeCl) (with n = 1-3) the sign of J(Si,H) changes from minus to plus with increasing number of chloro substituents n and maps the rising degree of oxidative addition. Accordingly, the sign and magnitude of J(Si,H) coupling constants can be employed to identify and characterize nonclassical hydrosilane species also in solution. These NMR studies might therefore help to reveal the salient control parameters of the Si-H bond activation process in transition-metal hydrosilane complexes which represent key intermediates for numerous metal-catalyzed Si-H bond activation processes. Furthermore, experimental high-resolution and high-pressure X-ray diffraction studies were undertaken to explore the close relationship between the topology of the electron density displayed by the η(Si-H)M units and their respective J(Si,H) couplings.

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Silicon-29 NMR investigation of silyl derivatives of the iron-group transition metals

Cited by 72 publications

References 3 publications

Preparation, Characterization, and Properties of Various Novel Ionic Derivatives of Pentacarbonyltungsten

Preparation, Characterization, and Properties of Various Novel Ionic Derivatives of Pentacarbonyltungsten

Complexes Containing Unbridged Dative Metal−Metal Bonds and the Strong Acceptor Ru(CO)₃(SiCl₃)₂ Moiety. Comments on the Transition Metal to Silicon Bond

J(Si,H) Coupling Constants of Activated Si–H Bonds

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Silicon-29 NMR investigation of silyl derivatives of the iron-group transition metals

Cited by 72 publications

References 3 publications

Preparation, Characterization, and Properties of Various Novel Ionic Derivatives of Pentacarbonyltungsten

Preparation, Characterization, and Properties of Various Novel Ionic Derivatives of Pentacarbonyltungsten

Complexes Containing Unbridged Dative Metal−Metal Bonds and the Strong Acceptor Ru(CO)3(SiCl3)2 Moiety. Comments on the Transition Metal to Silicon Bond

J(Si,H) Coupling Constants of Activated Si–H Bonds

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Complexes Containing Unbridged Dative Metal−Metal Bonds and the Strong Acceptor Ru(CO)₃(SiCl₃)₂ Moiety. Comments on the Transition Metal to Silicon Bond