Synthesis, Structure, and Photophysical Properties of Novel Ruthenium(II) Carboxypyridine Type Complexes

Norrby, Thomas; Börje, Anna; Åkermark, Björn; Hammarström, Leif; Alsins, Jan; Lashgari, K.; Norrestam, R.; Mårtensson, Jerker; Stenhagen, Gunnar

doi:10.1021/ic9705812

Cited by 79 publications

(86 citation statements)

References 66 publications

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“…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 nm; pic = 2-pyridinecarboxylate), [14] which feature N and O donors in the Ru II (bpy) 2 coordination sphere. The S-bonded and extracted O-bonded spectra (e 472nm = 6400 cm À1 m À1 ) are shown in Figure 1.…”

supporting

confidence: 74%

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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supporting

confidence: 74%

Two‐Color Reversible Switching in a Photochromic Ruthenium Sulfoxide Complex

McClure

Rack

2009

Angew Chem Int Ed

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“…The 1 H NMR spectrum of [Ru(pic)(bpy)2]Cl in a mixture of acetone-d6/CD3OD (1:1) was in agreement with that of [Ru(pic)(bpy)2](PF6) 4 ( Fig. S2 and Table S1), so that a Cl -and a…”

Section: Nn′)(dmso-s)2]supporting

confidence: 72%

“…These structural parameters of the pic ligand is a common feature of complexes with the pic and its analogues. 3,4 The dihedral angles between the pyridine planes within each bpy group are 3.7(1) for bpy-N1,N2 and 5.0(1) for bpy-N3,N4, and are smaller than those in PF6 salt (14.4(2) and 10.3(3) , respectively). 3 The torsion angles of C2-C1-C6-C7 (0.0(3) ) and C12-C11-C16-C17 (2.6(3) ) also reveal that both of the bpy ligands are planar.…”

Section: Pf6mentioning

confidence: 98%

“…[3][4][5] The crystal structure and 1 H NMR spectrum of [Ru(pic)(bpy)2](PF6) have been repotrted. 3,4 In the crystal structure, the dihedral angles between two pyridine rings within each 2,2′-bipyridyl ligand (10.3(3) and 14.4(2) ), are significantly larger than that in [Ru(bpy)3](PF6)2 (2.2(1) ). 6 Although a greater twisting of bpy ligands has not been noticed in the literature, 3 we take notice of the greater twisting and the hydrogen-bonding interactions between two oxygen atoms of a pic in a Ru(II) complex cation and 3,3′-protons of a bpy ligand in a neighboring complex cation; Fig.…”

Section: Nn′)(dmso-s)2]mentioning

confidence: 99%

“…One of the popular and typical Ru(II)N5O type complexes that includes a pic ligand is [Ru(pic)(bpy)2] + (bpy = 2,2′-bipyridine), which has been synthesized. [3][4][5] The crystal structure and 1 H NMR spectrum of [Ru(pic)(bpy)2](PF6) have been repotrted. 3,4 In the crystal structure, the dihedral angles between two pyridine rings within each 2,2′-bipyridyl ligand (10.3(3) and 14.4(2) ), are significantly larger than that in [Ru(bpy)3](PF6)2 (2.2(1) ).…”

mentioning

confidence: 99%

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Crystal Structure of (2-Picolinato)bis(2,2′-bipyridine)ruthenium(II) Chloride

Toyama

Nakayasu

Nagao

2017

X-ray Structure Analysis Online

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11The coordination chemistry of ruthenium(II) complexes with polypyridyl ligands has been an area of great interest, because of their redox properties and photochemistry. 1 We reported on the syntheses, crystal structures, and isomerization reactions of the ruthenium(II) complexes bearing a di-2-pyridyl ketone (dpk); trans(Cl),cis(S)-[RuCl2(dpk-κ 2 N,O)(dmso-S)2] and cis(Cl),cis(S)-[RuCl2(dpk-κ2 The crystal structure of the trans(Cl),cis(S)-isomer revealed that the oxygen of the ketone group on the dpk ligand was able to act as an effective donor atom to from a N,O-coordination mode, which was kinetically more favorable than the N,N mode, but was thermodynamically unstable. In view of the hemilabile coordination ability of the N,O bidentate ligand, the 2-picolinic acid (Hpic) has great interest for us. One of the popular and typical Ru(II)N5O type complexes that includes a pic ligand is [Ru(pic)(bpy)2] + (bpy = 2,2′-bipyridine), which has been synthesized. [3][4][5] The crystal structure and 1 H NMR spectrum of [Ru(pic)(bpy)2](PF6) have been repotrted. 3,4 In the crystal structure, the dihedral angles between two pyridine rings within each 2,2′-bipyridyl ligand (10.3(3) and 14.4(2) ), are significantly larger than that in [Ru(bpy)3](PF6)2 (2.2(1) ). 6Although a greater twisting of bpy ligands has not been noticed in the literature, 3 we take notice of the greater twisting and the hydrogen-bonding interactions between two oxygen atoms of a pic in a Ru(II) complex cation and 3,3′-protons of a bpy ligand in a neighboring complex cation; Fig. S1 in which the hydrogen-bonding diagram is drawn according to the CIF file of [Ru(pic)(bpy)2](PF6). That is to say, the four O···H-C interactions between two Ru(II) complex cations allow the cations to come close to each other so that the bpy ligands are twisted. Similar O···H-C interactions between two O atoms of a ClO4 -ion and 3,3′-protons of a bpy ligand in {(μ-H2L)[Ru(bpy)2]2}(ClO4)2 (H4L = 1,5-diamino-9,10-anthraquinone) have also been observed, 7 in which the dihedral angles of the bpy ligands (9.9 and 10.4 ) are similar to those in [Ru(pic)(bpy)2](PF6). We thus feel a great interest in the structure of [Ru(pic)(bpy)2] + with another counter anion. Warren et al. isolated the Cl salt by converting it from PF6 salt using the ion-exchange resin. 5 We directly isolated a Ru(II) complex as Cl salt, [Ru(pic)(bpy)2]Cl, from the reaction mixture, and determined the crystal structure, as shown in Fig. 1 To the homogeneous dark-purple hydrolysis solution, a solution of Hpic (1.1 mmol) in ethanol (20 mL) was added, and the mixture was refluxed for 3 h. While refluxing, the solution turned from dark-purple to wine-red. The resulting wine-red solution was evaporated to dryness under a vacuum, and the residue was dissolved in 2 mL of water. An aqueous solution of HCl (1 M, 2 mL) was added to precipitate a brown-red solid.The brown-red solid, [Ru(pic)(bpy)2]Cl was collected by filtration, washed with a small amount of cold water, and dried in vacuo (0.93 mmol, 96%). The 1 H NMR spectr...

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