A study on the excitations of ligand-to-metal charge transfer in complexes Cp2MCl2 (Cp=π-C5H5, M=Ti, Zr, Hf) by density functional theory

Wang, Xiaojing; Lv, Chen; Endou, Akira; Kubo, Momoji; Miyamoto, Akira

doi:10.1016/s0022-328x(03)00475-3

Cited by 21 publications

(21 citation statements)

References 35 publications

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“…1(b)] the disappearance of this band, due to the loss of conjugation of the enone, demonstrating the complexation of the metal by the carbonyl group. In contrast, another absorption peak appears in the UV spectrum at 320 nm (ε max = 1360 mol −1 L cm −1 ), which may be attributed to a ligand‐to‐metal charge transfer from π type orbital of the pyrone ligand to the d 0 orbital of the zirconium 17. The low intensity of this band can be attributed to a low superposition between the metal and ligand orbitals 18, 19.…”

Section: Resultsmentioning

confidence: 97%

Synthesis of a new zirconium catalyst for ethylene polymerization

Fim

Machado

Sá

et al. 2008

J. Polym. Sci. A Polym. Chem.

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A novel complex dichlorobis(2‐ethyl‐3‐hydroxy‐4‐pyrone)zirconium(IV) (ZrCl2(ethylpyrone)2) was synthesized. Complexation of the pyrone ligand to the zirconium was confirmed by UV, 1H and 13C‐NMR, and electrochemical studies. NMR showed the presence of four isomers and density functional theory calculations indicated that the main isomer had a cis configuration. The catalyst was shown to be active in ethylene polymerization in the presence of the cocatalyst methylaluminoxane. The highest catalyst activity for the zirconium complex was achieved at Al/Zr = 2500, 70 °C and when a small concentration of catalyst was used (1 μmol). © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3830–3841, 2008

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Section: Resultsmentioning

confidence: 97%

Synthesis of a new zirconium catalyst for ethylene polymerization

Fim

Machado

Sá

et al. 2008

J. Polym. Sci. A Polym. Chem.

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“…Molecular orbital (MO) and experimental studies of bent metallocenes have been done by different research groups [21][22][23][24][25]. Nevertheless, topological analysis is needed for better understanding of the electronic nature of these important catalysts for olefin polymerization.…”

Section: Introductionmentioning

confidence: 99%

Topological study of bis(cyclopentadienyl) titanium and bent titanocenes

Firme

Pontes

Antunes³

2010

Chemical Physics Letters

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The electronic nature of ferrocene, titanocene and some bent titanocenes was analyzed by QTAIM. PBE1PBE-optimised geometrical data agreed well with X-ray diffraction data, this method being chosen to extract and analyze the wave functions of all studied metallocenes within the QTAIM framework. Within the studied metallocenes, the number of bond paths can be used as an indicative of their stability. The Ind 2 Ti(CH 3 ) 2 has less Ti-C bond paths than the Cp 2 Ti(CH 3 ) 2 as well as the Cp 2 Ti has less C-Mt bond paths than Cp 2 Fe. These results concords with the smaller stabilities of Ind 2 Ti(CH 3 ) 2 and Cp 2 Ti relative to their counterparts.

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“…44 The main advantage here is that ligandto-metal charge-transfer processes relate to excitations occurring in the visible optical region. 44 The main advantage here is that ligandto-metal charge-transfer processes relate to excitations occurring in the visible optical region.…”

Section: G Cp 2 Ticlmentioning

confidence: 99%

Time-dependent density-functional theory calculations of triplet-triplet absorption

Cronstrand¹,

Rinkevičius²,

Luo³

et al. 2005

The Journal of Chemical Physics

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We present density-functional theory calculations of triplet-triplet absorption by three different approaches based on time-dependent density-functional theory (DFT): unrestricted DFT linear response, open-shell restricted DFT linear response applied to the triplet state, and quadratic response with triplet excitations applied to the ground state. Comparison is also made with corresponding results obtained by Hartree-Fock and multiconfiguration self-consistent-field response theory. Two main conclusions concerning triplet-triplet transitions are drawn in this study: First, the very good agreement between unrestricted and restricted DFT results indicates that spin contamination of the triplet state is not a serious problem when computing triplet-triplet spectra of common organic molecules. Second, DFT response calculations of triplet-triplet transitions can be affected by triplet instability problems, especially for the combination of DFT quadratic response with functionals containing fractional exact Hartree-Fock exchange.

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A study on the excitations of ligand-to-metal charge transfer in complexes Cp2MCl2 (Cp=π-C5H5, M=Ti, Zr, Hf) by density functional theory

Cited by 21 publications

References 35 publications

Synthesis of a new zirconium catalyst for ethylene polymerization

Synthesis of a new zirconium catalyst for ethylene polymerization

Topological study of bis(cyclopentadienyl) titanium and bent titanocenes

Time-dependent density-functional theory calculations of triplet-triplet absorption

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