High resolution <sup>1</sup>H NMR spectra of 2,2′‐biquinoline

Drake, J. A. G.; Jones, D. W.

doi:10.1002/mrc.1270180110

Cited by 9 publications

(2 citation statements)

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“…In the 1 H NMR spectrum of 2,2′‐biquinoline the most downfield resonance is that of H3,3′, followed by that of H4,4′. The anti conformation assumed by the two quinolines in the free ligand brings N′ close to H3 (and N to H3′), and the deshielding of H3,3′ was attributed mainly to the electrostatic effect of the lone pairs (Figure ) . When symmetrically bound to diamagnetic octahedral metal centers, such as in Re(CO) 3 (bq)Br, the proton NMR spectrum of bq undergoes remarkable changes: the doublet of H8,8′ becomes the most downfield signal (Δ δ = 0.71 ppm), whereas that of H3,3′ is shifted to lower frequencies (Δ δ = –0.50 ppm ).…”

Section: Resultsmentioning

confidence: 99%

Photolabile Ru Model Complexes with Chelating Diimine Ligands for Light‐Triggered Drug Release

et al. 2018

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A series of water-soluble photolabile model complexes of the general formula [Ru([9]aneS 3 )(chel)(py)]Cl 2 ([9]aneS 3 = 1,4,7-trithiacyclononane, chel = chelating diimine) was prepared and fully characterized. The phototriggered release of pyridine with visible light as a function of the nature of the diimine {chel = 2,2′-bipyridine (6) 1,10-phenanthroline (7), 4,7-diphenil-1,10-phenanthroline (8), dipyrido-[3,2-a:2′,3′-c]-phenazine (dppz, 9), 2,2′-biquinoline (bq, 10)} was investigated. Our aim is to establish whether this type of complexes might be realistically used in the photo-uncaging strategy of photoactivated chemotherapy (PACT) in the future. Compounds 6-9 present a MLCT absorption in the blue region of the visible spectrum. When irradiated with light at 470 nm, they rapidly and quantitatively release the coordinated pyridine. Complex

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Section: Resultsmentioning

confidence: 99%

Photolabile Ru Model Complexes with Chelating Diimine Ligands for Light‐Triggered Drug Release

et al. 2018

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“…CH interactions with H-C(6') (H-C(2') in the case of 4), which has an appreciable deshielding effect [23]. The 'H-NMR spectrum of the free biquinoline was published by Draake and Jones [24], that of the complexed ligand shows quite different chemical shifts for some protons. At lowest field are the signals of H-C(4) and H-C(3) which can be distinguished with the help of NOE effects on H-C(5).…”

Section: (22'-biquinoline)bis[i-phenyl-ih-pyruzoluto-nc']rhodium(iimentioning

confidence: 98%

Complexes of Rhodium(III) with Two Chelating C⁁N Ligands and One Diimine Ligand

Maeder¹,

Zelewsky²,

Stœckli-Evans³

1992

Helvetica Chimica Acta

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The synthesis of two series of cyclometalated Rh"' compounds is described, namely of 5 dinuclear chlorobridged species [{Rh(CAN),}(p-C1),] A and of 15 mononuclear complexes [Rh(C/"),(Nr")]+ B; CAN stands for five different cyclometalating ligands, i.e. deprotonated phenylpyridine, deprotonated 2-(thienyl)pyridine, and three deprotonated 1-aryl-lH-pyrazoles, and NAN for six diimine ligands such as 2,2-bipyridine, 2,T-bi-1H-imidazole, and 2,2'-bipyrimidine. For (2,2'-bipyridine)bis[2-(thien-2-yl)pyridinato-~,C3']rhodium(III) chloride, an X-ray structure determination was carried out. In the other cases, 'H-NMR spectra established the configuration of the complexes. All mononuclear and dinuclear complexes show a C,C &-configuration. The UV/VIS-absorption bands at longest wavelength are most likely due to metal-to-ligand charge-transfer (MLCT) transitions, depending on the nature of the cyclometalating ligand CAN and on the diimine ligand NAN. The receptor orbital is in some cases on the cyclometalating ligand, in others on the diimine. All monomer complexes exhibit at least one reversible reduction wave in the cyclovoltammogram in dimethylformamide solutions, attributable to a ligand-cen- Introduction. -Complexes of transition metals comprising purely aromatic chelating ligands CAN recently found widespread interest as subjects of photochemical investigations [ 1-41. The strong ligand-field influence of the C-donor, combined with the possibility of n -back donation into the metallocycle, yields generally high-lying d-d excited states. Charge-transfer states, particularly interesting in photochemistry, become therewith often the lowest excited states.With the aim of tuning excited-state properties, in a way similar to the now well known case of tris(diimine)ruthenium(II) complexes [5], we prepared a series of 4d6 complexes with Rh"' as the central metal, having the general formula [Rh(CAN),(NAN)]'. Watts and coworkers [6] described some complexes of related structures. Two structural characterizations of Rh"' complexes, one with a single metallocycle [7], the other a dinuclear species with two metallocycles on each center [8], were recently reported. In the present paper, we describe the synthesis and give a complete characterization, including the configuration of the bis(cyclometa1ated) Rh"' complexes B, which contain the chelating hgands derived from 1-5 and the diimine ligands 6-11, and of some dimeric precursors A.

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Synthesis and high‐resolution ¹H NMR spectra of four dimethylaminated dipyridyl ketones

Jones

Pakdel

Hallas

et al. 1986

Magnetic Reson in Chemistry

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Four new dimethylaminated pyridoylpyridine intermediates, bis(3-dimethylamino-2-pyridyl) ketone (l), 6-dimethylamino-3-pyridyl epyridyl ketone (2), 6-dmethylamino-3-pyridyl 3-pyridyl ketone (3) and 6-dimethylamino-3-pyridyl 2-pyridyl ketone (4), have been synthesized and their lOOMHz 'H NMR spectra analysed iteratively as ABC, ABCX and ABXY spin systems. In 2-4 the H-5 shift ortho to the dimethylamino substituent is unaffected by the orientation of the pyridyl substituent, but H-4 and H-2 are increasingly deshielded in the sequence 2-4. In 3, when benzene-d6 replaces chloroform-d, as solvent, H-5' and H-4' in the umubstituted pyridyl ring suffer appreciable upfield shifts.

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High resolution ¹H NMR spectra of 2,2′‐biquinoline

Cited by 9 publications

References 9 publications

Photolabile Ru Model Complexes with Chelating Diimine Ligands for Light‐Triggered Drug Release

Photolabile Ru Model Complexes with Chelating Diimine Ligands for Light‐Triggered Drug Release

Complexes of Rhodium(III) with Two Chelating C⁁N Ligands and One Diimine Ligand

Synthesis and high‐resolution ¹H NMR spectra of four dimethylaminated dipyridyl ketones

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High resolution 1H NMR spectra of 2,2′‐biquinoline

Cited by 9 publications

References 9 publications

Photolabile Ru Model Complexes with Chelating Diimine Ligands for Light‐Triggered Drug Release

Photolabile Ru Model Complexes with Chelating Diimine Ligands for Light‐Triggered Drug Release

Complexes of Rhodium(III) with Two Chelating C⁁N Ligands and One Diimine Ligand

Synthesis and high‐resolution 1H NMR spectra of four dimethylaminated dipyridyl ketones

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High resolution ¹H NMR spectra of 2,2′‐biquinoline

Synthesis and high‐resolution ¹H NMR spectra of four dimethylaminated dipyridyl ketones