Photochemical nitrosyl linkage isomerism/metastable states

Bitterwolf, Thomas E.

doi:10.1016/j.ccr.2005.12.016

Cited by 94 publications

(84 citation statements)

References 98 publications

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“…[10] For example, sodium nitroprusside and many of its derivatives feature isomerization of the bound nitrosyl ligand, but only in the solid state at low temperature. [17,18] Heilweil, Webster, Burkey and co-workers have reported one such example in their studies of ultrafast photochromic organometallic compounds. [19] Picosecond transient absorption data for the S-bonded isomer are shown in Figure 2.…”

Section: (Pic)]mentioning

confidence: 97%

Two‐Color Reversible Switching in a Photochromic Ruthenium Sulfoxide Complex

McClure

Rack

2009

Angew Chem Int Ed

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Reversible, external triggering of molecules between two ground states is central to the operation of modern molecular machines. [1][2][3] A desirable trigger is light, as it provides an ample amount of energy in a short burst of time. Although light is commonly employed for the formation of many different types of metastable states, [4][5][6][7][8] in practice it is difficult to employ light to regenerate the initial ground state. The enthalpic and entropic factors that favor the photochemical generation of the metastable state from the ground state must necessarily be disfavored for the opposing photochemical reaction. Moreover, the photoproduct often reverts to the ground state thermally. Irradiation of photochromic compounds yields metastable states that exhibit distinct electronic structures compared to their ground states.[9] Whilst a number of organic photochromic compounds feature reversible or two-color photoswitching between metastable and ground states, such reactivity is rare in transition metal complexes.[10]Herein, we report our findings on a ruthenium sulfoxide complex that features two-color photochromism.The complex [Ru(bpy) 2 (pySO)](PF 6 ) 2 (bpy = 2,2'-bipyridine, pySO = 2-(isopropylsulfinylmethyl)pyridine) was prepared from reaction of cis-[Ru(bpy) 2 Cl 2 ] with pySO. The structure and formulation of the complex was verified by oneand-two-dimensional 1 H NMR, IR spectroscopy, and elemental analysis. The 1 H NMR spectrum is consistent with the presence of two isomers, which are most likely diastereomers, as both the ruthenium and sulfur centers are chiral. Elemental analysis of the isomeric mixture supports this assignment. The lowest-energy transition in the electronic spectrum occurs at 370 nm (e = 7250 cm À1 m À1 ) and is assigned to a Ru dp!bpy p* charge-transfer transition based on its energy and intensity (Figure 1). This transition is similar to that observed for other chelating S-bonded sulfoxides.[11] Furthermore, the structurally characterized complex [Ru(bpy) 2 (py)(dmso)] 2+ (dmso = dimethylsulfoxide), which has no chelation, features a maximum absorbance at 400 nm for the S-bonded isomer.[12]Therefore, the chelate complex exhibits an additional 2000 cm À1 of stabilization relative to the non-chelate form. White light irradiation of [Ru(bpy) 2 (pySO)]2+ in propylene carbonate solution results in a decrease in the absorbance at 370 nm concomitant with an increase at 472 nm (Figure 1, inset). In accord with other ruthenium sulfoxide complexes, [13] the spectral changes indicate an intramolecular S!O isomerization, with an isosbestic point at 408 nm. However, the observed spectral changes are muted in comparison to these other complexes. We questioned whether or not this spectrum represented a photostationary state. Accordingly, irradiation of this solution with 355 nm light resulted in a more pronounced absorbance at 472 nm (quantum efficiency F S!O = 0.11(2)). This value is similar to that of the Obonded isomer of [Ru(bpy) 2 (py)(dmso)] 2+ (476 nm) [12] and [Ru(bpy) 2 (pic)] + (483...

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Section: (Pic)]mentioning

confidence: 97%

Two‐Color Reversible Switching in a Photochromic Ruthenium Sulfoxide Complex

McClure

Rack

2009

Angew Chem Int Ed

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“…charge transfer processes or isomerisation reactions ( [1][2][3][4][5] and references therein). In this manner structures and chemical complexes become accessible which cannot be realized by standard synthetic methods.…”

Section: Introductionmentioning

confidence: 99%

Neutron photocrystallography: simulation and experiment

Schefer¹,

Schaniel²,

Petřı́ček³

et al. 2008

Zeitschrift Für Kristallographie - Crystalline Materials

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Abstract.The investigation of light-induced structural changes by diffractive methods has improved significantly in the last two decades. We present here the case of neutron photocrystallography for which we have built a special experimental setup at the single crystal neutron diffractometer TriCS at the Swiss Spallation Neutron Source SINQ. We illustrate the progress of the method on the example of the structural determination of photoinduced nitrosyl linkage-isomers in Na 2 [Fe(CN) 5 NO]⋅2H 2 O. The in-situ determination of the population of the light-induced linkage isomers by optical transmission measurements enhances the reliability of such structural investigations considerably. Additionally we present a new simulation tool within the program package JANA2006 which allows to plan a photocrystallographic experiment thoroughly since the required q-range, the minimally needed population of the photoinduced species, as well as the necessary counting statistics for a successful single crystal diffraction experiment can be evaluated in advance.

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“…73 These metastable states are populated when samples are irradiated at low temperature with light of the appropriate wavelength, and they are deactivated to the stable ground state (GS) isomer by red de-excitation or by thermal decay. 74,75 The ruthenium nitrosyl complexes for which long-lived metastable states were observed include K 2 37,38 In order to understand the influence of different equatorial ligands on the electronic structure of the Ru-NO chemical bonding, and thus on the reactivity of the coordinated NO, we propose an investigation into the nature of the chemical bond Ru-NO, considering tetraamine and tetraazamacrocycles as equatorial ligands, prior to and after the {RuNO} 6 to {RuNO} 7 core reduction. This investigation might not only provide a better comprehension of the differences but might also be helpful in designing new ruthenium nitrosyl complexes with potential biological applications.…”

Section: Introductionmentioning

confidence: 99%

The nature of Ru–NO bonds in ruthenium tetraazamacrocycle nitrosyl complexes—a computational study

et al. 2012

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2012The nature of Ru-NO bonds in ruthenium tetraazamacrocycle nitrosyl complexes-a computational study DALTON TRANSACTIONS, CAMBRIDGE, v. 41, n. 24, Ruthenium complexes including nitrosyl or nitrite complexes are particularly interesting because they can not only scavenge but also release nitric oxide in a controlled manner, regulating the NO-level in vivo.The judicious choice of ligands attached to the [RuNO] core has been shown to be a suitable strategy to modulate NO reactivity in these complexes. In order to understand the influence of different equatorial ligands on the electronic structure of the Ru-NO chemical bonding, and thus on the reactivity of the coordinated NO, we propose an investigation of the nature of the Ru-NO chemical bond by means of energy decomposition analysis (EDA), considering tetraamine and tetraazamacrocycles as equatorial ligands, prior to and after the reduction of the {RuNO} 6 moiety by one electron. This investigation provides a deep insight into the Ru-NO bonding situation, which is fundamental in designing new ruthenium nitrosyl complexes with potential biological applications.

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Photochemical nitrosyl linkage isomerism/metastable states

Cited by 94 publications

References 98 publications

Two‐Color Reversible Switching in a Photochromic Ruthenium Sulfoxide Complex

Two‐Color Reversible Switching in a Photochromic Ruthenium Sulfoxide Complex

Neutron photocrystallography: simulation and experiment

The nature of Ru–NO bonds in ruthenium tetraazamacrocycle nitrosyl complexes—a computational study

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