Vibrational spectra of specifically deuteriated 2,2′‐bipyridine complexes of Fe(II), Ru(II) and Os(II)

McClanahan, Stephen F.; Kincaid, James R.

doi:10.1002/jrs.1250150309

Cited by 27 publications

(17 citation statements)

References 44 publications

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“…At all wavelengths examined (which span both visible absorption bands), vibrational modes are observed at 1608, 1571, 1485, 1304, 1272, 1159, and 1029 cm −1 , which are assigned to pyridyl based vibrations by comparison with the Raman spectrum of [Fe(bpy) 3 ] 2+ (1608, 1565, 1492, 1322, 1278, 1175, 1026 cm −1 ). 29 The modes at 1464, 1375, 1304, 1288, 1228, and 1076 cm −1 are assigned as C−H vibrational modes of the alkyl amine backbone on the basis of the isotope shifts observed in the spectra of d 5 -1 ( Figure S19) in which the alkyl hydrogens are exchanged for deuterium. The 1608 cm −1 mode of 1 is more intense relative to the 1571 cm −1 mode at λ exc 355 and 400.8 nm (i.e., absorption band II), however, at λ exc 449 and 473 nm (i.e., absorption band I) the reverse is the case with the 1571 cm −1 mode more intense than the 1608 cm −1 mode.…”

Section: ■ Resultsmentioning

confidence: 99%

Ligand Exchange and Spin State Equilibria of Fe^II(N4Py) and Related Complexes in Aqueous Media

Draksharapu

Logtenberg

et al. 2011

Inorg. Chem.

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We report the characterization and solution chemistry of a series of Fe(II) complexes based on the pentadentate ligands N4Py (1,1-di(pyridin-2-yl)-N,N-bis(pyridin-2-ylmethyl)methanamine), MeN4Py (1,1-di(pyridin-2-yl)-N,N-bis(pyridin-2-ylmethyl)ethanamine), and the tetradentate ligand Bn-N3Py (N-benzyl-1,1-di(pyridin-2-yl)-N-(pyridin-2-ylmethyl)methanamine) ligands, i.e., [Fe(N4Py)(CH(3)CN)](ClO(4))(2) (1), [Fe(MeN4Py)(CH(3)CN)](ClO(4))(2) (2), and [Fe(Bn-N3Py)(CH(3)CN)(2)](ClO(4))(2) (3), respectively. Complexes 2 and 3 are characterized by X-ray crystallography, which indicates that they are low-spin Fe(II) complexes in the solid state. The solution properties of 1-3 are investigated using (1)H NMR, UV/vis absorption, and resonance Raman spectroscopies, cyclic voltammetry, and ESI-MS. These data confirm that in acetonitrile the complexes retain their solid-state structure, but in water immediate ligand exchange of the CH(3)CN ligand(s) for hydroxide or aqua ligands occurs with full dissociation of the polypyridyl ligand at low (<3) and high (>9) pH. pH jumping experiments confirm that over at least several minutes the ligand dissociation observed is fully reversible for complexes 1 and 2. In the pH range between 5 and 8, complexes 1 and 2 show an equilibrium between two different species. Furthermore, the aquated complexes show a spin equilibrium between low- and high-spin states with the equilibrium favoring the high-spin state for 1 but favoring the low-spin state for 2. Complex 3 forms only one species over the pH range 4-8, outside of which ligand dissociation occurs. The speciation analysis and the observation of an equilibrium between spin states in aqueous solution is proposed to be the origin of the effectiveness of complex 1 in cleaving DNA in water with (3)O(2) as terminal oxidant.

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Section: ■ Resultsmentioning

confidence: 99%

Ligand Exchange and Spin State Equilibria of Fe^II(N4Py) and Related Complexes in Aqueous Media

Draksharapu

Logtenberg

et al. 2011

Inorg. Chem.

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“…The syntheses of the [6,6 0 -d 2 ]-2,2 0 -bipyridine (22BPYd 2 ) 31 and [3,3 0 ,5,5 0 -d 4 ]-2,2 0 -bipyridine (22BPY-d 4 ) 8 samples have been already described. The 15 N-labelled molecule was synthesized by Merck, Sharpe and Dohme.…”

Section: Methodsmentioning

confidence: 99%

Ab initio and density functional study of the geometrical, electronic and vibrational properties of 2,2?-bipyridine

Ould-Moussa

Castellà-Ventura

Kassab

et al. 2000

J. Raman Spectrosc.

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“…51 The complexes Ru(bpy) 2 Cl 2 and Ru(d8bpy) 2 Cl 2 were prepared from RuCl 3 ÐH 2 O, bpy and d8bpy by literature methods. 52 [Ru(bpy) 2 (dpp)](PF 6 ) 2 , [Ru(d8bpy) 2 (dpp)](PF 6 ) 2 , [(bpy) 2 Ru(dpp)Ru(bpy) 2 ](PF 6 ) 4 and [(d8bpy) 2 Ru(dpp)Ru(d8 bpy) 2 ](PF 6 ) 4 were prepared from Ru(bpy) 2 Cl 2 , Ru(d8bpy) 2 Cl 2 and a stoichiometric amount of the dpp ligand, according to the method described by Braunstein et al 49 The sample was purified by repeated recrystallization from 1 : 1 water-ethanol solution and further purified on Sephadex CMC-25 ion-exchange resin as described by Denti et al 40 …”

Section: Preparation Of Compoundsmentioning

confidence: 99%

Resonance Raman and time‐resolved resonance Raman spectra of the monomeric and dimeric complexes of ruthenium(II) with 2,3‐bis(2‐pyridyl)pyrazine (dpp)

Su¹,

Kincaid²

2003

J Raman Spectroscopy

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The electronic absorption, resonance Raman (RR) and time-resolved resonance Raman (TR 3 ) spectra of the monomeric and dimeric complexes of ruthenium(II) with 2,3-bis(2-pyridyl)pyrazine (dpp) were measured, i.e. Ru(bpy) 2 dpp 2+ and Ru(bpy) 2 dppRu(bpy) 2 4+ , where bpy is 2,2 -bipyridine. In addition, in order to facilitate definitive assignments of the observed RR spectral parameters, the corresponding selectively labeled complexes employing perdeuterated bpy (d8bpy) were also prepared and studied. It is shown that using judiciously chosen excitation lines to acquire the RR spectra permits selective enhancement of vibrational features associated with specific molecular fragments of the complexes, facilitating structural characterization of ground states of each complex. In addition, the TR 3 spectrum of the monomeric complex yields vibrational signatures of its 3 MLCT state, which is consistent with polarization of electron density towards the pyrazyl fragment; corresponding studies of the dimeric complex failed to provide conclusive evidence for modes attributable to an anion radical fragment, presumably owing to lack of effective enhancement with the excitation lines available.

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Vibrational spectra of specifically deuteriated 2,2′‐bipyridine complexes of Fe(II), Ru(II) and Os(II)

Cited by 27 publications

References 44 publications

Ligand Exchange and Spin State Equilibria of Fe^II(N4Py) and Related Complexes in Aqueous Media

Ligand Exchange and Spin State Equilibria of Fe^II(N4Py) and Related Complexes in Aqueous Media

Ab initio and density functional study of the geometrical, electronic and vibrational properties of 2,2?-bipyridine

Resonance Raman and time‐resolved resonance Raman spectra of the monomeric and dimeric complexes of ruthenium(II) with 2,3‐bis(2‐pyridyl)pyrazine (dpp)

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Vibrational spectra of specifically deuteriated 2,2′‐bipyridine complexes of Fe(II), Ru(II) and Os(II)

Cited by 27 publications

References 44 publications

Ligand Exchange and Spin State Equilibria of FeII(N4Py) and Related Complexes in Aqueous Media

Ligand Exchange and Spin State Equilibria of FeII(N4Py) and Related Complexes in Aqueous Media

Ab initio and density functional study of the geometrical, electronic and vibrational properties of 2,2?-bipyridine

Resonance Raman and time‐resolved resonance Raman spectra of the monomeric and dimeric complexes of ruthenium(II) with 2,3‐bis(2‐pyridyl)pyrazine (dpp)

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Ligand Exchange and Spin State Equilibria of Fe^II(N4Py) and Related Complexes in Aqueous Media

Ligand Exchange and Spin State Equilibria of Fe^II(N4Py) and Related Complexes in Aqueous Media