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Upstream product

• 504-24-5 4-aminopyridine 
• 81-84-5 1,8-Naphthalic anhydride 

Relevant academic research and scientific papers

Assessment of the electronic structure of a triruthenium acetate-pyridylnaphthalimide cluster

A synthetic route for attaining the combination of an electroactive unit with the chromophore N-(4-pyridyl)-1,8-naphthalimide (NI-py) was developed, yielding the trinuclear ruthenium cluster [Ru3O(CH3COO)6(NI-py)3]PF6 (1). Due to the presence of one unpaired electron in the [Ru3O(CH3COO)6]+ unit, 1H NMR analysis showed paramagnetic shifts in the NI-py hydrogens by displacing, for example, hydrogen ortho to the N-heteroatom in the free ligand from 8.83 ppm to 0.73 ppm in the coordinated ligand. The electronic spectrum of 1 showed absorption at 696 nm (metal-to-metal transitions of the [Ru3O(CH3COO)6] unit), and a band at 334 nm, assigned to cluster-NI-py charge transfer superimposed with the low energy π → π* NI transitions. The latter band did not show any shifts upon coordination or change in the formal charge of the [Ru3O(CH3COO)6] core, suggesting that the electronic states involved in these transitions are not perturbed significantly upon complexation. However, the comparison of both NI-py and complex luminescence spectra indicated that the metal unit can quench NI-py fluorescence. The computational calculations confirmed the electronic delocalization over the [Ru3O(CH3COO)6]+ core in the ground state and the superposition of both NI-py π → π* and the CLCT bands. A film, assembled on a FTO electrode surface by adsorption, showed the redox pair [Ru3O(CH3COO)6]+1/0 at 0.365 V vs. SHE, which is in accordance with the NI-py strong π -acid character. This film was electrochromic, being blue for [Ru3O(CH3COO)6(NI-py)3]+ and yellow for [Ru3O(CH3COO)6(NI-py)3]0.

The Role of Blue-Emissive 1,8-Naphthalimidopyridine N-Oxide in Sensitizing EuIII Photoluminescence in Dimeric Hexafluoroacetylacetonate Complexes

Two new fluorescence molecules incorporating coordinated pyridine N-oxide (PyNO) and the blue-emitting 1,8-naphthalimide (NI) chromophores, 4-(1,8-naphthalimido)pyridine N-oxide (4-NIPyNO) and 3-(1,8-naphthalimido)pyridine N-oxide (3-NIPyNO), are designed and used as ancillary ligands for constructing mixed-ligand tris(β-diketonate) lanthanide complexes, Ln2(hfa)6(4-NIPyNO)2 and Ln2(hfa)6(3-NIPyNO)3 (Ln = Eu, Gd; hfa = hexafluoroacetylacetone). Single-crystal X-ray diffraction crystallography analyses reveal that all the complexes adopt dimeric dinuclear structures; in each case, two LnIII ions from Ln(hfa)3 moieties are bridged by the oxygen atoms of the N-oxide groups of 4-NIPyNO and 3-NIPyNO. The luminescence quantum yield experiment reveals that the introduction of the ancillary ligands results in the EuIII ions having luminescence enhancement about 13 times greater than that from hydrated Eu(hfa)3(H2O)2. The detailed photophysical determinations are carried out to gain insight into the roles of the NIPyNO ligands in enhancing EuIII luminescence. By investigating the ligand-centered emission, it is found that both the singlet states (S) and the triplet states (T) are responsible for the energy transfer from the NIPyNO ligands to the metal center; in particular, the energy-transfer efficiencies of the singlet states reach up to 63 % and 71 % for Eu2(hfa)6(4-NIPyNO)2 and Eu2(hfa)6(3-NIPyNO)3, respectively. This auxiliary-ligand designing strategy enables the use of the blue-emitting chromophore as a sensitizer of the luminescence from EuIII ions.

Matrix screening of substituted N-aryl-1,8-naphthalimides reveals new dual fluorescent dyes and unusually bright pyridine derivatives

A 3 × 14 matrix of substituted N-aryl-1,8-naphthalimides was synthesized for the evaluation and discovery of dual fluorescence. Because of their unique photophysical properties, these dual fluorescent systems represent an exception to the widely studied T