Photosensitization via Dye Coordination:  A New Strategy to Synthesize Metal Nitrosyls That Release NO under Visible Light

Rose, Michael J.; Olmstead, Marilyn M.; Mascharak, Pradip K.

doi:10.1021/ja070247x

Cited by 77 publications

(83 citation statements)

References 14 publications

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“…The presence of trans-PPh 3 groups in both the complexes is consistent with the 31 P NMR spectroscopic data (vide infra). [15,16] In both the nitrosyl complexes, Ru-N NO distances [1.799(2) Å in 1a·CH 3 OH·2CH 2 Cl 2 ·H 2 O and 1.786(4) Å in 2a·2CH 2 Cl 2 ] were found to be longer than those reported, [17][18][19] which may be due to the trans effect of carbanion (C1). [4,6] However, this value was close to the value reported by Crutchley and coworkers.…”

Section: Introductionmentioning

confidence: 76%

Ruthenium(III) Cyclometalates Obtained by Site‐Specific Orthometallation and Their Reactivity with Nitric Oxide: Photoinduced Release and Estimation of NO Liberated from the Ruthenium Nitrosyl Complexes

Ghosh

Kumar

2012

Eur J Inorg Chem

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Cyclometalated RuIII complexes [Ru(LSB1)(PPh3)2Cl] (1), [LSB1H2 = 2‐(3‐nitrobenzylideneamino)phenol], and [Ru(LSB2)(PPh3)2Cl] (2), [LSB2H2 = 4‐methyl‐2‐(3‐nitrobenzylideneamino)phenol and H = dissociable protons], were synthesized by site‐specific orthometallation and characterized by spectroscopic and electrochemical studies. Complexes 1 and 2 were treated with in situ generated nitric oxide (NO), derived from an acidified nitrite solution, which afforded the ruthenium nitrosyl complexes [Ru(LSB3H)(PPh3)2(NO)Cl](ClO4) (1a) and [Ru(LBOX)(PPh3)2(NO)Cl](ClO4) (2a), respectively, [LSB3H2 = 4‐nitro‐2‐(3‐nitrobenzylideneamino)phenol, LBOXH = 5‐methyl‐7‐nitro‐2‐(3‐nitrophenyl)benzoxazole and H = dissociable protons]. Complexes 1a and 2a were found to be diamagnetic and were characterized by 1H NMR and 31P NMR spectral studies. Both 1a and 2a exhibited νNO in the range 1800–1835 cm–1 in the IR spectra. Molecular structures of σ‐aryl ruthenium nitrosyl complexes 1a·CH3OH·2CH2Cl2·H2O and 2a·2CH2Cl2 were determined by X‐ray crystallography. Nitrosylation at the metal centre, oxidative cyclization and ligand nitration were authenticated from the crystal structures. The redox properties of the metal centre were investigated. In both the nitrosyl complexes 1a and 2a, coordinated NO was found to be photolabile. The amount of photoreleased NO was estimated by using the Griess reagent and the data was compared with that obtained from sodium nitroprusside (SNP). The role of the nitro group in the ligand frame was discussed with regard to orthometallation, NO reactivity and photolability.

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Section: Introductionmentioning

confidence: 76%

Ruthenium(III) Cyclometalates Obtained by Site‐Specific Orthometallation and Their Reactivity with Nitric Oxide: Photoinduced Release and Estimation of NO Liberated from the Ruthenium Nitrosyl Complexes

Ghosh

Kumar

2012

Eur J Inorg Chem

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“…Although these alterations of the equatorial ligand frames of the Ru nitrosyls brought the λ max of the photobands into the visible region, their quantum yield values remained quite modest (φ 500 = 0.01-0.05), and hence the designed nitrosyls were not very effective in delivering high doses of NO to induce cytotoxic effects in malignant cells and pathogens. Additional photosensitization was achieved through direct coordination of dyes (as light-harvesting antennae) to these kinds of Ru nitrosyls in our later work [40]. For example, when the dye resorufin (Resf; ε 600 = 105 000 M −1 cm −1 ) was attached directly to the Ru centre, No loss of viability was observed with these cells in the dark.…”

Section: Photoactive Metal Nitrosyls Derived From Designed Ligandsmentioning

confidence: 92%

Light-triggered nitric oxide delivery to malignant sites and infection

Heilman

Mascharak

2013

Phil. Trans. R. Soc. A.

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The discovery of nitric oxide (NO) as a signalling molecule in various physiological and pathological pathways has spurred research in the design of exogenous NO donors as drugs. In recent years, metal nitrosyls (NO complexes of metals) have been investigated as NO-donating agents. Results from our laboratory during the past few years have demonstrated that metal nitrosyls derived from designed ligands can deliver NO under the total control of light of various frequencies. Careful incorporation of these photoactive nitrosyls into polymer matrices has afforded a set of nitrosylpolymer composites that can be used to make such NO delivery site-specific. The composite materials have shown excellent antineoplastic and antimicrobial actions in several in vitro experiments. This review highlights our key results in the context of recent developments in this area of NO donors that deliver NO on demand.

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“…These bands are assigned to dp (Ru) → p* (NO) (MLCT) 9 There is a red shift (max. 5 nm) of the band at 370 nm by ligands B (a-pic, 395; y-pic, 395; py, 390; and CH,CN, 368.)…”

Section: Uv and Visible Spectramentioning

confidence: 99%

“…Ruthenium nitrosyls are particularly attractive in this regard owing to their thermal stability and NO release upon exposure to light. [7][8][9] The NO release, in most of the octahedral ruthenium nitrosyls having {Ru II NO + } moiety, can be induced by one electron reduction by photolysis or PDT. In general, it has been found that NO release depends markedly on the p-acceptor strength of the ligand coordinated trans to NO and increase in plane ligand field strength.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization and Reaction of New Ruthenium Aromatic Thioamide Nitrosyls with some Nitrogen Donor Ligands

Singh¹

2016

Orient. J. Chem

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Reactions of LH=RCSNHCOOEt (R= 4-tolyl, 1-pyrrolyl, and 2-thiophenyl) with RuCl 3 . 3H 2 O and NO leads to the formation of diamagnetic compounds of the formula [L 2 Ru(NO)(Cl)J]. These compounds have been characterised by elemental analysis and IR, UV and Visible and magnetic measurements. The presence of (NO) at 1835-1855-cm -1 indicates a {Ru-NO} 6 configuration. The substitution of Cl bounded trans to NO by N-hetrocycles bases (a-picoline, y-picoline and or pyridine) and CH 3 CN has significant effect on the electronic properties of complexes.

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Photosensitization via Dye Coordination: A New Strategy to Synthesize Metal Nitrosyls That Release NO under Visible Light

Abstract: Direct coordination of the dye resorufin (Resf) to the ruthenium center photosensitizes the Ru−NO bond and improves NO photolability of the designed {Ru−NO}6 nitrosyl [(Me2bpb)Ru(NO)(Resf)] under visible light.

Cited by 77 publications

References 14 publications

Ruthenium(III) Cyclometalates Obtained by Site‐Specific Orthometallation and Their Reactivity with Nitric Oxide: Photoinduced Release and Estimation of NO Liberated from the Ruthenium Nitrosyl Complexes

Ruthenium(III) Cyclometalates Obtained by Site‐Specific Orthometallation and Their Reactivity with Nitric Oxide: Photoinduced Release and Estimation of NO Liberated from the Ruthenium Nitrosyl Complexes

Light-triggered nitric oxide delivery to malignant sites and infection

Synthesis, Characterization and Reaction of New Ruthenium Aromatic Thioamide Nitrosyls with some Nitrogen Donor Ligands

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