Substituent effect on Fermi resonance in p-substituted benzoyl chlorides

Ortiz, Elio Quiala; Bertrán, José Fernández; Ballester, Lourdes

doi:10.1016/0584-8539(71)80226-x

Cited by 13 publications

(3 citation statements)

References 8 publications

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“…The dip at 1580 cm −1 is originated by the Fermi resonance between the phenyl modes at this frequency, which couples with the ν(CO) mode. 106,107 Similar spectra were reported in the literature for other TiCl 4 /EB complexes. 89,108 Although the two strong ν(CO) bands occur at slightly different wavenumbers depending on the position of EB (e.g., trans to a bridged or to a terminal chlorine), all TiCl 4 /EB complexes do show a couple of strong absorption bands centered around 1550 cm −1 .…”

Section: Resultssupporting

confidence: 83%

“…Both bands owe a major part of their intensity to the ν̃(CO) vibrational mode, although formally the band at 1591 cm –1 is assigned to a phenyl vibration. The dip at 1580 cm –1 is originated by the Fermi resonance between the phenyl modes at this frequency, which couples with the ν̃(CO) mode. , Similar spectra were reported in the literature for other TiCl 4 /EB complexes. , …”

Section: Resultssupporting

confidence: 81%

“…These results give an additional clue toward the nonexistence of Ti 2 Cl 8 dimeric species in MgCl 2 -based Ziegler−Natta catalysts, even in the presence of the electron donors. At the same time, limited to ΔE ads values (i.e., total electron energy variations), the monomeric TiCl 4 EB adduct on the(107) surface stands as the most stable complex among those investigated in this work. It is worth noticing that the structure of these adducts is perfectly compatible with the Ti−Cl and Ti−ester average distances as determined by EXAFS in an early work 68.…”

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confidence: 91%

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Spectroscopic Evidences for TiCl₄/Donor Complexes on the Surface of MgCl₂-Supported Ziegler–Natta Catalysts

et al. 2018

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In this work, we have addressed the question of the location of electron donors (we chose ethylbenzoate, EB, for practical reasons) on the surface of MgCl2-supported Ziegler–Natta catalysts by synergistically coupling (a) an in situ investigation of the EB adsorption process by Fourier transform infrared spectroscopy, (b) an evaluation of the MgCl2 surfaces available for the adsorption of CO as a molecular probe at each step of the precatalyst synthesis and (c) an accurate quantum mechanical density functional theory (DFT-D) study of a few TiCl4/EB complexes. Our experimental data indicate that homogeneous-like TiCl4/EB complexes are formed, loosely bonded to the MgCl2 surfaces, as a consequence of a rather high mobility of the adsorbed EB and TiCl4. Our DFT-D computational results demonstrate that monomeric TiCl4(EB) and TiCl4(EB)2 complexes might indeed exist on different catalytically relevant MgCl2 surfaces (although steric repulsion does not allow reaching a full surface coverage), whose computed infrared spectra are highly compatible with the experimental ones. The whole set of data converge to a final scenario whereby the internal donor has the function to induce a certain mobility for TiCl4 simultaneously acting as a “surfactant”, in certain cases providing a particularly exposed TiCl4 species readily available for further reaction with the aluminum alkyl activator. The relevant role of the MgCl2 support in assisting the self-organization of the catalyst components clearly emerges.

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Section: Resultssupporting

confidence: 83%

Section: Resultssupporting

confidence: 81%

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confidence: 91%

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Spectroscopic Evidences for TiCl₄/Donor Complexes on the Surface of MgCl₂-Supported Ziegler–Natta Catalysts

et al. 2018

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Vibrational spectra, thermodynamic functions and barriers to internal rotation for isomeric trifluoromethylbenzoyl chlorides

Shanker

Yadav

Singh

et al. 1992

J Raman Spectroscopy

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The polarized Raman spectra (50-4OoO cm-') and IR spectra (180-4OoO cm-I) of 0-, in-and ptrifluoromethylbenzoy1 chlorides were recorded and all the 45 (Mu' + 15d') normal modes of vibration were assigned assuming C, symmetry. Consistent assignments for the internal modes of the COCi and CF, groups are proposed. Thermodynamic functions were computed and barriers to internal rotations for the COCl and CF, tops were determined, using the assigned vibrational frequencies and assumed structural parameters for the three isomers.

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Carbonyl Frequencies

Bellamy¹

1980

The Infrared Spectra of Complex Molecules

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Substituent effect on Fermi resonance in p-substituted benzoyl chlorides

Cited by 13 publications

References 8 publications

Spectroscopic Evidences for TiCl₄/Donor Complexes on the Surface of MgCl₂-Supported Ziegler–Natta Catalysts

Spectroscopic Evidences for TiCl₄/Donor Complexes on the Surface of MgCl₂-Supported Ziegler–Natta Catalysts

Vibrational spectra, thermodynamic functions and barriers to internal rotation for isomeric trifluoromethylbenzoyl chlorides

Carbonyl Frequencies

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Substituent effect on Fermi resonance in p-substituted benzoyl chlorides

Cited by 13 publications

References 8 publications

Spectroscopic Evidences for TiCl4/Donor Complexes on the Surface of MgCl2-Supported Ziegler–Natta Catalysts

Spectroscopic Evidences for TiCl4/Donor Complexes on the Surface of MgCl2-Supported Ziegler–Natta Catalysts

Vibrational spectra, thermodynamic functions and barriers to internal rotation for isomeric trifluoromethylbenzoyl chlorides

Carbonyl Frequencies

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Spectroscopic Evidences for TiCl₄/Donor Complexes on the Surface of MgCl₂-Supported Ziegler–Natta Catalysts

Spectroscopic Evidences for TiCl₄/Donor Complexes on the Surface of MgCl₂-Supported Ziegler–Natta Catalysts