scholarly journals Unexpectedly Long Lifetime of the Excited State of Benzothiadiazole Derivative and Its Adducts with Lewis Acids

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2030
Author(s):  
Taisiya S. Sukhikh ◽  
Radmir M. Khisamov ◽  
Sergey N. Konchenko
Keyword(s):  
Lewis Acids ◽  
Bromine Atom ◽  
Heavy Atom ◽  
Intersystem Crossing ◽  
Triplet States ◽  
X Ray Diffraction ◽  
X Ray ◽  
Singlet And Triplet States ◽  
Long Lifetime ◽  
Atom Effect

We report a study of photoluminescent properties of 4-bromo-7-(3-pyridylamino)-2,1,3-benzothiadiazole (Py-btd) and its novel Lewis adducts: (PyH-btd)2(ZnCl4) and [Cu2Cl2(Py-btd)2{PPO}2]·2C7H8 (PPO = tetraphenyldiphosphine monoxide), whose crystal structure was determined by X-ray diffraction analysis. Py-btd exhibits a lifetime of 9 microseconds indicating its phosphorescent nature, which is rare for purely organic compounds. This phenomenon arises from the heavy atom effect: the presence of a bromine atom in Py-btd promotes mixing of the singlet and triplet states to allow efficient singlet-to-triplet intersystem crossing. The Lewis adducts also feature a microsecond lifetime while emitting in a higher energy range than free Py-btd, which opens up the possibility to color-tune luminescence of benzothiadiazole derivatives.

Synthesis, Characterization, and Photophysics of a New Trinuclear Mercury(II) Complex of 1,3,5-Triethynylbenzene

2006 ◽  
Vol 59 (7) ◽  
pp. 434 ◽  
Author(s):  
Li Liu ◽  
Wai-Yeung Wong ◽  
Cheuk-Lam Ho
Keyword(s):  
Excited State ◽  
Photophysical Properties ◽  
Heavy Atom ◽  
High Energy ◽  
Intersystem Crossing ◽  
Spectroscopic Techniques ◽  
Triplet States ◽  
Ambient Conditions ◽  
Triplet Excited States ◽  
Atom Effect

A new trinuclear mercury(ii) complex of 1,3,5-triethynylbenzene [(MeHgC≡C)3(1,3,5-C6H3)] 1 was prepared in good yield by Hagihara’s dehydrohalogenation reaction of HgMeCl with [(HC≡C)3(1,3,5-C6H3)] under ambient conditions. This trimercury triacetylide complex’s structure was confirmed by common spectroscopic techniques and its photophysical properties were examined and compared with the isolobal gold(i) congener [{(PPh3)AuC≡C}3(1,3,5-C6H3)] 2. Our investigations indicate that the organic triplet emissions can be harvested by the heavy-atom effect of mercury which enables efficient intersystem crossing from the S1 singlet excited state to the T1 triplet excited state. The influence of Hg and Au centres on the phosphorescence efficiency and evolution of the lowest electronic singlet and triplet excited states is critically characterized. Both complexes 1 and 2 possess high-energy triplet states of 2.77–2.82 eV, in which the order of intersystem crossing rate follows the order Au > Hg.

External Heavy-Atom Effect via Orbital Interactions Revealed by Single-Crystal X-ray Diffraction

2016 ◽  
Vol 120 (29) ◽  
pp. 5791-5797 ◽  
Author(s):  
Xingxing Sun ◽  
Baicheng Zhang ◽  
Xinyang Li ◽  
Carl O. Trindle ◽  
Guoqing Zhang
Keyword(s):  
Single Crystal ◽  
Heavy Atom ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heavy Atom Effect ◽  
Orbital Interactions ◽  
Atom Effect

Isomorphous replacement in electron diffraction of wet crystals of rat hemoglobin

1983 ◽  
Vol 41 ◽  
pp. 446-447
Author(s):  
William F. Tivol ◽  
Murray Vernon King ◽  
D. F. Parsons
Keyword(s):  
Electron Diffraction ◽  
Heavy Atom ◽  
Isomorphous Substitution ◽  
X Ray Diffraction ◽  
Salt Solutions ◽  
X Ray ◽  
Isomorphous Replacement ◽  
Structure Factors ◽  
Diffraction Structure ◽  
The Mean

Feasibility of isomorphous substitution in electron diffraction is supported by a calculation of the mean alteration of the electron-diffraction structure factors for hemoglobin crystals caused by substituting two mercury atoms per molecule, following Green, Ingram & Perutz, but with allowance for the proportionality of f to Z3/4 for electron diffraction. This yields a mean net change in F of 12.5%, as contrasted with 22.8% for x-ray diffraction.Use of the hydration chamber in electron diffraction opens prospects for examining many proteins that yield only very thin crystals not suitable for x-ray diffraction. Examination in the wet state avoids treatments that could cause translocation of the heavy-atom labels or distortion of the crystal. Combined with low-fluence techniques, it enables study of the protein in a state as close to native as possible.We have undertaken a study of crystals of rat hemoglobin by electron diffraction in the wet state. Rat hemoglobin offers a certain advantage for hydration-chamber work over other hemoglobins in that it can be crystallized from distilled water instead of salt solutions.

Enhancement of Reverse Intersystem Crossing in Charge‐Transfer Molecule through Internal Heavy Atom Effect

2021 ◽  
pp. 2104646
Author(s):  
Hyung Suk Kim ◽  
Ja Yeon Lee ◽  
Seongjun Shin ◽  
Wonkyo Jeong ◽  
Sang Hoon Lee ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Heavy Atom ◽  
Intersystem Crossing ◽  
Heavy Atom Effect ◽  
Atom Effect

The Crystal and Molecular Structures of Two Modifications of cis-Dichloro-mer-tris-(dimethylphenylphosphine)hydridoiridium(III)

1988 ◽  
Vol 41 (3) ◽  
pp. 283 ◽  
Author(s):  
GB Robertson ◽  
PA Tucker
Keyword(s):  
Heavy Atom ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
X Ray ◽  
Bond Lengths ◽  
Metal Ligand ◽  
Ligand Bond

The structures of two crystalline modifications of mer -(Pme2Ph)3H-cis-Cl2IrIII, (1), have been determined from single-crystal X-ray diffraction data. Modification (A) is monoclinic, space group P21/c with a 12.635(1), b 30.605(3), c 14.992(2)Ǻ, β 110.01(2)° and Z = 8. Modification (B) is orthorhombic, space group Pbca with a 27.646(3), b 11.366(1), c 17.252(2)Ǻ and Z = 8. The structures were solved by conventional heavy atom techniques and refined by full-matrix least- squares analyses to conventional R values of 0.037 [(A), 8845 independent reflections] and 0.028 [(B), 5291 independent reflections]. Important bond lengths [Ǻ] are Ir -P(trans to Cl ) 2.249(1) av. (A) and 2.234(1) (B), Ir -P(trans to PMe2Ph) 2.339(2) av. (A) and 2.344(1), 2.352(1) (B), Ir-Cl (trans to H) 2.492(2), 2.518(2) (A) and 2.503(1) (B) and Ir-Cl (trans to PMe2Ph)2.452(2) av. (A) and 2.449(1)(B). Differences in chemically equivalent metal- ligand bond lengths emphasize the importance of non-bonded contacts in determining those lengths.

Depletion of singlet and triplet states of 1-amino-5, 6, 7, 8-tetrahydronaphthalene due to external heavy-atom perturbation

1986 ◽  
Vol 8 (5) ◽  
pp. 541-552 ◽  
Author(s):  
K. Chatterjee ◽  
S. Chakravorti ◽  
T. Ganguly ◽  
S. B. Banerjee
Keyword(s):  
Heavy Atom ◽  
Triplet States ◽  
Singlet And Triplet States

Löschung der Perylen-Fluoreszenz durch Ag+ -Ionen / Quenching of the Perylene Fluorescence by Ag+-Ions

1983 ◽  
Vol 38 (6) ◽  
pp. 698-700 ◽  
Author(s):  
H. Dreeskamp ◽  
A. Läufer ◽  
M. Zander
Keyword(s):  
Triplet State ◽  
Dynamic Process ◽  
Aromatic Compounds ◽  
Heavy Atom ◽  
Silver Ions ◽  
Intersystem Crossing ◽  
Fluid Solution ◽  
Long Wavelength ◽  
Wavelength Emission ◽  
Atom Effect

The fluorescence of perylene in fluid solution (λ0.0 = 440 nm) is quenched by silver ions in a dynamic process according to a Stern-Volmer kinetics (kq = 2 · 109 [1 • mol-1 · sec-1], in ethanol at 295 K). Simultaneously an unstructured long-wavelength emission (λmax ≈ 470 nm) appears which we assign to a perylene/Ag+ exciplex. A similar emission is observed when other polvcyclic aromatic compounds (PAC) are used, whose fluorescence as in the case of perylene is not easily quenched in an external heavy atom effect by iodopropane (kq ≦ 106). In these cases the excited PAC/Ag+ complex is long-lived enough to emit fluorescence since the intersystem crossing to the triplet system is slow due to the absence of an energetically favorable accepting triplet state

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