Steady‐State and Time‐Resolved Emission Studies of 6‐Methoxy Quinoline

Naik, L. R.; Kumar, H.M. Suresh; Inamdar, Sanjeev R.; Math, N N

doi:10.1081/sl-200062818

Cited by 21 publications

(9 citation statements)

References 10 publications

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“…Photobasicity has been characterized more recently than photoacidity, ,− and there are fewer applications of this phenomenon in reaction chemistry. Common examples of organic compounds that exhibit photobasicity include aromatic carboxylic acids (1-naphtholate) and azoles (quinoline), with the latter exhibiting a relatively high p K a * of 11.5, with Δp K a = 6.7 .…”

mentioning

confidence: 99%

Optical pK_a Control in a Bifunctional Iridium Complex

et al. 2019

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There are few ways to switch a catalyst's reactivity on or off, or change its selectivity, with external radiation; many of these involve photochemical activation of a catalyst. In the case of homogeneous late-transition-metal catalysts, the metal complex itself is frequently the chromophore involved in such reactivity switching. We show here a base-pendant ligand−metal bifunctional scaffold wherein a photobase, a compound that becomes more basic in the excited state (pK a < pK a *), is used to switch the proton acceptor ability on an active site of the complex. The system differs from those with metal-centered chromophores, because the photobase operates independently of the metal. While excellent progress has been made in photoacid chemistry, neither a photoacid nor a photobase has been designed into the structure of a transition-metal catalyst where the metal is not part of the chromophore. We find that quinoline is an efficient photobase that preserves its unique properties in the close proximity of an iridium center: the efficacy of the photobase (9.3 < pK a * < 12.4) in the iridium complex is unhindered relative to the free quinoline. We apply this notion to successful photodriven deprotonation of an aliphatic alcohol, thus showing the first case of metal-orthogonal optical pK a control in a transition-metal complex.

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confidence: 99%

Optical pK_a Control in a Bifunctional Iridium Complex

et al. 2019

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“…4). The emission spectrum of the free ligand exhibits two bands due to the existence of an acid-base equilibrium, as previously reported [24]. In this way, the band due to the protonated species is observed at 430 nm and that of the non-protonated one at 363 nm upon excitation with light of 300 nm [25].…”

Section: Luminescence Propertiesmentioning

confidence: 51%

“…This fact could be explained taking into account that the quinolinic nitrogen is bonded to the Hg(II) center, and for that reason the acid-base equilibrium is forbidden. The bands observed in the emission spectrum of the complex were assigned to the π-π* intraligand fluorescence [24,25].…”

Section: Luminescence Propertiesmentioning

confidence: 99%

Synthesis, crystal structure and physicochemical characterization of a Hg(II) complex with 6-methoxyquinoline as ligand

Villa-Pérez

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Payán-Aristizábal

et al. 2015

Zeitschrift Für Naturforschung B

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A new complex of Hg(II) with 6-methoxyquinoline (C 10 H 9 NO-6MQ) has been synthesized and characterized. The structure of the complex Hg(6MQ)Cl 2 was determined by single crystal X-ray diffraction. It crystallizes in the monoclinic space group P2 1 /c with a = 3.9139(3), b = 26.3400(2), c = 10.9090(9) Å, β = 89.833(6)°, V = 1124.6(1) Å 3 and Z = 4 molecules per unit cell. The coordination geometry of the mercury(II) center can be described as a distorted square pyramid formed by one nitrogen atom of the 6MQ and four chlorine atoms. Fourier transform infrared, Raman and UV/Vis spectroscopic studies have been carried out to characterize the compound, using theoretical calculations for the assignment of the experimentally observed bands. The thermal behavior was investigated by thermogravimetric analysis. The quantum yield of singlet molecular oxygen production Φ Δ was measured with steady-state methods in ethanol, using 9,10-dimethylanthracene (DMA) as actinometer and Bengal rose as reference photosensitizer. The resultant singlet molecular oxygen was detected indirectly by photooxidation reactions of DMA. The luminescence properties have also been studied.

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“…It is important to note that the acid or basic character can be modified in the excited state, the essentially non-bonding character of the orbitals can enhance one or other property, rendering the excited site more reactive [18,20,[36][37][38][39][40].…”

Section: Article In Pressmentioning

confidence: 99%