Electronic structure, spectroscopy, and photochemistry of group 8 metallocenes

Yamaguchi, Yoshikazu; Ding, Wei; Sanderson, Cynthia T.; Borden, Michelle L.; Morgan, Matthew J.; Kutal, Charles

doi:10.1016/j.ccr.2006.02.028

Cited by 134 publications

(114 citation statements)

References 29 publications

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“…Increase in the intensity of the absorption bands is as a result of mixing charge transfer character into the transition thus reducing the Laporte forbidden character. 76 The observed shifts of band maxima to higher energies in polar solvents point to presence of a polar ground state and nonpolar excited state in imines, i.e. compounds 3, 4 and 6-8.…”

Section: Solvatochromism Studiesmentioning

confidence: 93%

“…52,75, These spectral characteristics of the ferrocenyl-N -(pyridinylmethyl)anilines are attributed to the mixing of appreciable metal-to-ligand charge transfer (MLCT) character into their low-energy electronic excited states. 76 This MLCT contribution originate from vectorial displacement of electron density from the metal to the ligand. Conjugation between the p orbitals of the cyclopentadienyl, phenyl and pyridyl rings allows the transferred charge to be delocalized over several atoms, consequently stabilizing the MLCT excited state relative to the ground state and lowering the transition energy.…”

Section: Solvatochromism Studiesmentioning

confidence: 99%

“…Ordinarily, aromatic ligands/heterocyclic compounds are not strongly emissive at room temperature. 76 In addition, ferrocene does not show luminescence, because in its excited states, it undergoes very rapid electronic and vibrational relaxation to the ground state. 76 However, in solution at room temperature, all the compounds studied here show broad emission bands, with large stoke shifts averaging between 28-30 nm.…”

Section: Fluorescent Spectral Studiesmentioning

confidence: 99%

“…76 In addition, ferrocene does not show luminescence, because in its excited states, it undergoes very rapid electronic and vibrational relaxation to the ground state. 76 However, in solution at room temperature, all the compounds studied here show broad emission bands, with large stoke shifts averaging between 28-30 nm. This is indicative of molecular fluorescence with short-lived excited states as deduced from the stable emissions.…”

Section: Fluorescent Spectral Studiesmentioning

confidence: 99%

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Synthesis, physical and antimicrobial studies of ferrocenyl-N-(pyridinylmethylene)anilines and ferrocenyl-N-(pyridinylmethyl)anilines

2016

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Section: Solvatochromism Studiesmentioning

confidence: 93%

Section: Solvatochromism Studiesmentioning

confidence: 99%

Section: Fluorescent Spectral Studiesmentioning

confidence: 99%

Section: Fluorescent Spectral Studiesmentioning

confidence: 99%

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Synthesis, physical and antimicrobial studies of ferrocenyl-N-(pyridinylmethylene)anilines and ferrocenyl-N-(pyridinylmethyl)anilines

2016

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“…6,12 Based on ligand field theory, the low-energy peaks are assigned to be d−d transitions and the stronger absorptions to charge-transfer (CT) states. 15,21 Analysis of density differences and charge differences on Fe between ground and excited states reveals that low-and high-lying excited states involve similar amounts of charge transfer, so that the distinction between n d−d and CT transitions 21 is not justified.…”

Section: ■ Introductionmentioning

confidence: 99%

Quantitatively Correct UV-vis Spectrum of Ferrocene with TDB3LYP

Salzner

2013

J. Chem. Theory Comput.

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The ultraviolet−visible light (UV-vis) absorption spectrum of ferrocene is modeled with time-dependent density functional theory employing LSDA, BLYP, B3LYP, and CAM-B3LYP functionals in combination with 6-31G*, 6-31+G*, CC-PVTZ, and aug-CC-PVTZ basis sets. With the exception of LSDA, all functionals predict a reasonable Fe-CP distance of ∼1.67 Å. Diffuse functions are essential for the strongly allowed states at high energy but of lesser consequence for the visible range of the spectrum. Dipole forbidden states are examined with vibrationally excited structures, obtained from the normal modes of the infrared (IR) spectrum. Despite earlier claims, TDB3LYP predicts the UV−vis spectrum of ferrocene quantitatively correct. TDBLYP predicts a large number of spurious charge-transfer states, TDCAM-B3LYP and TDwB97XD are correct in the low-energy region but overestimate the energy of strongest peak of the spectrum by 0.8 eV. The amount of charge transfer involved in "d−d transitions" is equal to that in "charge-transfer states". ■ INTRODUCTIONFerrocene was discovered in 1951 1 and has revolutionized the views of chemists about how metals bind to organic π-systems. Its electronic structure and ultraviolet-visible light (UV-vis) absorption spectrum have become textbook 2 examples, and one would assume that not much new can be said about them. However, comparison between results obtained with timedependent density functional theory (TDDFT) by the author and theoretical data from the literature 3−15 revealed several discrepancies, which prompted the present investigation.Pure ferrocene is a very stable light orange powder, and the UV−vis absorption spectrum of ferrocene has been investigated in detail. 16−19 Upon cooling, the color changes from orange to lemon yellow. 16,17 The orange color stems from a dipoleforbidden absorption at 440 nm (2.81 eV) and a shoulder at 528 nm (2.34 eV), 16−18 both of which gain oscillator strength only through vibronic coupling. 8 Outside the visible range, a weak peak occurs at 324 nm (3.83 eV) and several relatively weak but allowed absorptions are present between 265 nm and 230 nm. The strongest absorption of ferrocene is observed at 202 nm (6.12 eV) in solution and 6.31 eV in the vapor phase. 16−19 The oscillator strength of this allowed absorption is 350 times stronger than that of the peak at 440 nm.B3LYP produces the structural parameters of ferrocene with errors of 2 pm or less, 20 and there is consensus that, in agreement with experiment, theory predicts the eclipsed form to be more stable than the staggered one. Several authors have cautioned, however, against using B3LYP for excited-state calculations of ferrocene. 6,10,12,15 Boulet et al., 6 Li et al., 10 and Scuppa et al. 12 promoted gradient-corrected pure DFT functionals, and Fromager et al. 15 promoted the rangeseparated CAM-B3LYP functional. In this investigation, TDDFT results with several functionals and different allelectron basis sets are analyzed. It is demonstrated that B3LYP works perfectly fine and that t...

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