Dye-tethered ruthenium nitrosyls containing planar dicarboxamide tetradentate N4 ligands: effects of in-plane ligand twist on NO photolability.
To examine the steric effects of the in-plane ligands in dye-sensitized {RuNO}(6) nitrosyls on their NO photolability, two new ligands, namely, 1,2-Bis(pyridine-2-carboxamido)-4,5-dimethoxybenzene (H(2)(OMe)(2)bpb) and 1,2-Bis(Isoquinoline-1-carboxamido)-4,5-dimethoxybenzene (H(2)(OMe)(2)IQ1, H's are dissociable carboxamide protons) have been designed and synthesized. The syntheses and spectroscopic properties of {RuNO}(6) nitrosyls derived from these two ligands, namely, [((OMe)(2)bpb)Ru(NO)(Cl)] (4-Cl), [((OMe)(2)IQ1)Ru(NO)(Cl)] (5-Cl), [((OMe)(2)bpb)Ru(NO)(Resf)] (4-Resf), and [((OMe)(2)IQ1)Ru(NO)(Resf)] (5-Resf), are reported. The structures of 5-Cl, 4-Resf, and 5-Resf have been determined by X-ray crystallography. Removal of the in-plane ligand twist in the quinoline-based R(2)bQb(2-) ligand frame (because of steric interactions between the extended quinoline ring systems) in both R(2)bpb(2-) and R(2)IQ1(2-) (pyridine and 1-isoquinoline rings, respectively, instead of quinoline rings in the equatorial plane) results in enhanced solution stability, as well as higher quantum yield values for NO photorelease upon exposure to 500 nm light. Both dye-tethered {RuNO}(6) nitrosyls 4-Resf and 5-Resf exhibit greater sensitivity to visible light compared to the chloro-bound species 4-Cl and 5-Cl. In addition, the dye-tethered nitrosyls are fluorescent and hence can be used as trackable NO donors in cellular studies.
Department of Chemistry and Biochemistry, University of California, Santa Cruz, California 95064, USA.
Nicole L
NL
Fry
Brandon J
BJ
Heilman
Pradip K
PK
Mascharak
D001554:Benzene / Q000737:chemistry; D018360:Crystallography, X-Ray; D005456:Fluorescent Dyes / Q000737:chemistry; D008024:Ligands; D008027:Light; D015394:Molecular Structure; D058990:Molecular Targeted Therapy; D009369:Neoplasms / Q000188:drug therapy; D009569:Nitric Oxide / Q000737:chemistry* / Q000627:therapeutic use; D009603:Nitroso Compounds / Q000138:chemical synthesis* / Q000627:therapeutic use; D010078:Oxazines / Q000737:chemistry; D010777:Photochemistry / Q000379:methods; D010782:Photolysis; D011725:Pyridines / Q000737:chemistry; D012428:Ruthenium / Q000737:chemistry
D005456:Fluorescent Dyes; D008024:Ligands; D009603:Nitroso Compounds; D010078:Oxazines; D011725:Pyridines; D009569:Nitric Oxide; C014180:resorufin; D012428:Ruthenium; D001554:Benzene