η 1 -silolyl-FeCp(CO) 2 complexes. Is there a way to sila-ferrocene?

Fekete, Csaba; Mokrai, Réka; Bombicz, Petra; Nyulászi, László; Kovács, I.

doi:10.1016/j.jorganchem.2015.09.023

Cited by 5 publications

(8 citation statements)

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“…[23] Similarly, compounds 2-5 show triplet resonances in the 29 Si{ 1 H} NMR spectra and all the chemical modifications (oxidation, sulfurization, alkylation, complexation) at the phosphorus centers lead to a downfield shift compared to silole 1 (Table 1). The changes in the 29 Si{ 1 H} NMR spectra are in line with those observed in the 31 P{ 1 H} NMR investigations, however, the changes are less pronounced. The 2 J P,Si coupling constants in compounds 1-5 are in the range of 3 J P,Si values reported for β-silyl phospholes (2-20 Hz).…”

Section: Heteronuclear Nmr Studiessupporting

confidence: 82%

“…[29,30] 1 H and 13 C NMR resonances are observed in the typical regions reported for similar compounds. [23,24,31]…”

Section: Heteronuclear Nmr Studiesmentioning

confidence: 99%

“…The bond lengths in the silole core are similar to those previously described for silacyclopentadiene rings. [31,33] In each of the five-membered rings 1, 2, 3 and 5 the Si-C(α) bond lengths are around 1.88 Å, a typical value for single bonds. [34] The C(α)-C(β) bond lengths are significantly shorter than the ones between the C(β) and C(β′) centers [e.g.…”

Section: Structural Studiesmentioning

confidence: 99%

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Phosphanyl‐Substituted Siloles: Synthesis, Optical and Electrochemical Studies and Computations

et al. 2020

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In this paper, we report the synthesis and characterization of a series of phosphanyl-substituted siloles. The chemical modification (oxidation, sulfurization, alkylation and complexation) results in a change in the energy levels of frontier orbitals, which has been studied by UV/Vis absorption spectroscopy and electrochemistry. Significantly, despite their high "s" Scheme 1. Synthesis of phosphanyl-functionalized siloles 1-5 (Naphth: naphthalenide, THT: tetrahydrothiophene).

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Section: Heteronuclear Nmr Studiessupporting

confidence: 82%

“…[29,30] 1 H and 13 C NMR resonances are observed in the typical regions reported for similar compounds. [23,24,31]…”

Section: Heteronuclear Nmr Studiesmentioning

confidence: 99%

Section: Structural Studiesmentioning

confidence: 99%

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Phosphanyl‐Substituted Siloles: Synthesis, Optical and Electrochemical Studies and Computations

et al. 2020

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“…While in 1,1-bissilol 4 (Fig. 3) the average Si-C distance is 1.885 Å 15 (typical single bond range is 1.87-1.89 Å), 16a the ring Si-C bonds in 3 (1.796(5) and 1.784(5) Å) are significantly shorter exhibiting considerable double bond (SiQC typically 1.70-1.76 Å) 16b character, despite the usual lengthening of the bonds in anionic compounds. The enhanced SiQC character is not surprising, and C-silyl-substitution at the SiQC bond is known to have a stabilizing effect.…”

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confidence: 92%

Planar lithium silolide: aromaticity, with significant contribution of non-classical resonance structures

et al. 2017

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The first planar lithium silolide characterized by X-ray crystallography is reported. The structural data, NMR and DFT results reveal high aromatic character, with the unusual dominance of non-classical resonance structures.The cyclopentadienide ion is a textbook example for a planar aromatic compound alongside benzene. 1a The replacement of a carbon atom by silicon results in the silacyclopentadienyl (silolide) anion, 1b-f for which the planarity and the apparently related aromaticity are far from being trivial. the structural similarity for the isoelectronic silolide anion is also expected. Computational studies have also predicted that silolide is pyramidal; 5 however, even with the non-planar silicone a moderate aromaticity was reported for the parent compound, 5a furthermore the presence of the countercation has a flattening effect on silicon. 5 A noteworthy feature of the calculated planar silolide structure was the equalization of the C-C distances, the Cb-Cb 0 bond being slightly (by 0.008 Å) shorter than Ca-Cb. Accordingly, for the planar silolide the ''b'' resonance structure had larger (30%) weight than the classical ''a'' (17%) according to a natural resonance theory (NRT) study (Fig. 1 Si and upfield in 13 C NMR) with respect to the neutral precursor disilane was attributed to cyclic delocalization. 7 Unfortunately, for this particular silolide, no X-ray structure could be obtained, The situation is further complicated by the fact that for 1-Me-tetraphenylsilolide the dimerization of the anion was reported, yielding tricyclic systems with a central 1,3-disilacyclobutane ring. 8While no planar silolide has been reported to date, Sekiguchi's 1,2,3-trisilacyclopentadienide and 1,2-disila-3-germacyclopentadienide anions have been shown to exhibit planar X-ray structures with equalized bond lengths, and with 29 Si NMR data indicating aromaticity.9 Furthermore, nearly planar transition metal (Zr, Hf or Ru) complexed silolides were also synthetized. 10In a computational search for planar silolide anions we revealed that due to the charge stabilizing effect, p-acceptor SiH 3 groups at the a carbons enhance the planarity and aromaticity of the naked silolide ring considerably. 5d This effect was already noted on the related phosphole with SiH 3 11 and BH 2 12 substituents, and the charge stabilizing effect was also shown in the case of the silyl-substituted stannole dianion. 13Furthermore, the a-silyl groups enhanced the relative weight of the b type resonance structure. 5d Z 5 -Coordination of the Li Fig. 1 Resonance structures for planar heteroaromatic five membered rings, with different heteroelements. E can be S, PR, or SiR À (R:H, alkyl, aryl, etc.). The numbering of the ring atoms is shown on resonance structure a.

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“…We report the molecular and crystal structures of the complexes, and their attempted transformation (by heating or UV irradiation) to the metallocenes. The reason for the increased stability of these carbonyl complexes can be attributed to the increased σ-electron donating behaviour of the silicon to the central Fe, while the aromaticity of the silolyl ligand seems to have less influence [6].…”

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confidence: 99%