The Influence of Planarity and Rigidity on the Absorption and Fluorescence Parameters and Intersystem Crossing Rate Constant in Aromatic Molecules

Nijegorodov, N.; Downey, W. S.

doi:10.1021/j100073a011

Cited by 274 publications

(200 citation statements)

References 3 publications

(3 reference statements)

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“…The phosphorescence emission is expected to be very weak, 62 even not detectable 45 in perylene, and there is no observable transition to triplet state in terrylene. 63 Thus the k isc is very small and can be neglected.…”

Section: Nonradiative and Radiative Decay Ratesmentioning

confidence: 99%

Theoretical predictions of red and near-infrared strongly emitting X-annulated rylenes

Peng

Niu

Wang

et al. 2011

The Journal of Chemical Physics

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The optical properties of rylenes are extremely interesting because their emission colors can be tuned from blue to near-infrared by simply elongating the chain length. However, for conjugated chains, the dipole-allowed odd-parity 1B u excited state often lies above the dipole-forbidden evenparity 2A g state as the chain length increases, thus preventing any significant luminescence according to Kasha's rule. We systemically investigated the 1B u /2A g crossover behaviors with respect to the elongating rylene chain length with various quantum chemistry approaches, such as timedepended density functional theory (TDDFT), complete active space self-consistent field theory (CASSCF/CASPT2), multireference configuration interaction (MRCI)/Zerner's intermediate neglect of diatomic overlap (ZINDO), and MRCI/modified neglect of differential overlap. The calculated results by CASSCF/CASPT2 and MRCI/ZINDO are completely coherent: the optical active 1B u state lies below the dark B 3g or 2A g state for perylene and terrylene, which results in strong fluorescence; while a crossover to S 1 = 2A g occurs and leads to much weaker fluorescence for quaterrylene. Then we put forward a molecular design rule on how to recover fluorescence for the longer rylenes by introducing heteroatom bridges. Several heteroatom-annulated rylenes are designed theoretically, which are predicted to be strongly emissive in the red and near-infrared ranges. These are further confirmed by theoretical emission spectra as well as radiative and nonradiative decay rate calculations by using the vibration correlation function formalisms we developed earlier coupled with TDDFT.

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Section: Nonradiative and Radiative Decay Ratesmentioning

confidence: 99%

Theoretical predictions of red and near-infrared strongly emitting X-annulated rylenes

Peng

Niu

Wang

et al. 2011

The Journal of Chemical Physics

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“…It is known that rigid conjugate structures tend to generate strong fluorescence, 21,22 and that H + , OH -and H 2 O molecules in solution are capable of forming effective hydrogen bonds with the donor groups of a chromophore in the ground and excited states. 23 Therefore, L may form hydrogen bonds with H + , OH -and/or H 2 O in solution; L may also form intra-or intermolecular hydrogen bonds via its three phenolic and two alcoholic hydroxyl groups.…”

Section: Fluorescence Response Of L To Zinc(ii)mentioning

confidence: 99%

A phenol-based compartmental ligand as a potential chemosensor for zinc(ii) cations

Chen¹,

Cao²,

Wang³

et al. 2009

J. Braz. Chem. Soc.

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O ligante compartimental 2,6-bis(2-hidroxibenzil-2-hidroxietilamino) metil-4-metilfenol (L) foi sintetizado como um sensor químico em potencial para íons Zn 2+ . A base L coordena dois cátions Zn 2+ em metanol-água, formando um complexo dinuclear cuja formulação foi confirmada por espectrometria de massas com ionização por "electrospray" (ESI-MS) e pelo gráfico de Job. A fluorescência de L é notavelmente aumentada por Zn 2+ em comparação com os íons K + , Ca 2+ , Mg 2+ , Cu 2+ , Pb 2+ , Mn 2+ , Fe 3+ , Fe 2+ , Co 2+ , Cd 2+ e Ni 2+ . Isto se deve ao fato de que a complexação do íon Zn 2+ a L interrompe o processo de transferência eletrônica fotoinduzida e aumenta a rigidez do esqueleto molecular de L. Observou-se ainda que a fluorescência de L é fortemente dependente da acidez e da polaridade dos solventes. Este composto poderá ser utilizado como uma sonda sensível a íons Zn 2+ em solventes polares próticos, após uma modificação estrutural adequada.An "end-off"-type compartmental Lewis base, 2,6-bis(2-hydroxybenzyl-2-hydroxyethylamino) methyl-4-methylphenol (L), was synthesized as a potential chemosensor for Zn 2+ ions. L coordinates two Zn 2+ cations in methanol-water solution, forming a dinuclear complex whose formulation was confirmed by ESI-MS spectroscopy and Job's plot. The fluorescence of L is remarkably enhanced by Zn 2+ as compared with K + , Ca 2+ , Mg 2+ , Cu 2+ , Pb 2+ , Mn 2+ , Fe 3+ , Fe 2+ , Co 2+ , Cd 2+ and Ni 2+ ions. The fluorescence enhancement is attributed to the complexation of Zn 2+ with L, which interrupts the photoinduced electron transfer process and rigidifies the molecular skeleton of L. The fluorescence of L is greatly dependent on the acidity and polarity of the solvents. This compound may be used as a probe to sense Zn 2+ ion in polar protic solvents after proper modification.Keywords: chemosensor, fluorescence mechanism, phenol derivative, solvent effects, zinc(II) IntroductionZinc(II) ions play vital roles in a wide range of physiological processes. Deficiency or imbalance of Zn 2+ within the human body can lead to a variety of diseases. 1 Hence the development of selective zinc chemosensors is of great importance for tracking the Zn 2+ status in biological systems. 2 Fluorescence chemosensors based on photoinduced electron transfer (PET), 3 intramolecular charge transfer (ICT), 4 excited-state intramolecular proton transfer (ESIPT), 5 and fluorescence resonance energy transfer (FRET) mechanisms have been developed for this purpose in the past years. 2,6-10 Nevertheless, none of them completely satisfies the criteria for a biosystemoriented chemosensor. Therefore, efforts to design novel zinc probes are still needed.Structural factors, such as molecular rigidity, could produce significant influence on the fluorescence efficiency of a chemosensor. An increase in planarity and a decrease in torsion may benefit the chemosensor to enhance its fluorescence. 11 As a metal ion binds to a chemosensor, the molecular rigidity is enhanced and the above mentioned transfer processes are poss...

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“…ElSherif reported a series of palladium complexes that show antibacterial activities against S. pyogenes and E. coli bacteria at different concentrations 1, 2.5, and 5 mg/mL in DMSO in which the activities were smaller in the complexes than in ligands. 30 Also the results obtained for 1-2 and HL1-L2 show better antibacterial activities compared to the platinum(II) and palladium(II) complexes based on Schiff bases.…”

mentioning

confidence: 90%

The Effect of Electron-withdrawing Group Functionalization on Antibacterial and Catalytic Activity of Palladium(II) Complexes

Feng¹,

Yang²,

Ye³

et al. 2014

Bulletin of the Korean Chemical Society

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The design, synthesis, and structural characterization of two new palladium complexes based on Schiff base ligands is reported; [Pd(L1) 2 ] (1) and [Pd(L2) -diethylbenzenamine], which are obtained by functionalizing Schiff base ligands with or without electron-withdrawing groups. Both compounds are mononuclear structures. Comparisons are made to the compounds 1 and 2 to analyze and understand the effect of electron-withdrawing groups. Antibacterial activity studies indicate the electron-withdrawing groups on Schiff base ligands enhance antibacterial activity. Catalytic activity, however, is reduced due to the enhanced steric-hindrance of the electron-withdrawing groups. Electronic absorption and emission properties of HL1, L2, 1 and 2 are also reported.

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The Influence of Planarity and Rigidity on the Absorption and Fluorescence Parameters and Intersystem Crossing Rate Constant in Aromatic Molecules

Cited by 274 publications

References 3 publications

Theoretical predictions of red and near-infrared strongly emitting X-annulated rylenes

Theoretical predictions of red and near-infrared strongly emitting X-annulated rylenes

A phenol-based compartmental ligand as a potential chemosensor for zinc(ii) cations

The Effect of Electron-withdrawing Group Functionalization on Antibacterial and Catalytic Activity of Palladium(II) Complexes

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