This article presents general concepts that have guided important developments in our recent research progress regarding room-temperature phosphorescent dyes and their potential applications. We first elaborate the theoretical background for emissive metal complexes and the strategic design of the chelating C-linked 2-pyridylazolate ligands, followed by their feasibility in functionalization and modification in an aim to fine-tune the chemical and photophysical properties. Subsequently, incorporation of 2-pyridylazolate chromophores is illustrated in the synthesis of the highly emissive, charge-neutral Os, Ru, Ir, and Pt complexes. Insights into their photophysical properties are gained from spectroscopy, relaxation dynamics, and theoretical approaches, from which the lowest-lying excited states, competitive radiative decay, and radiationless processes are then analyzed in detail. In view of applications, their potentials for OLEDs have been evaluated. The results, in combination with the fundamental basis, give a conceptual design contributed to the future advances in the field of OLEDs.

Phosphorescent Dyes for Organic Light‐Emitting Diodes

https://ir.nctu.edu.tw:443/bitstream/11536/14006/1/000227156800006.pdf

New Dopant and Host Materials for Blue-Light-Emitting Phosphorescent Organic Electroluminescent Devices

Uncouplers of oxidative phosphorylation in mitochondria inhibit the coupling between the electron transport and phosphorylation reactions and thus inhibit ATP synthesis without affecting the respiratory chain and ATP synthase (H(+)-ATPase). Miscellaneous compounds are known to be uncouplers, but weakly acidic uncouplers are representative because they show very potent activities. The most potent uncouplers discovered so far are the hindered phenol SF 6847, and hydrophobic salicylanilide S-13, which are active in vitro at concentrations in the 10 nM range. For induction of uncoupling, an acid dissociable group, bulky hydrophobic moiety and strong electron-withdrawing group are required. Weakly acidic uncouplers are considered to produce uncoupling by their protonophoric action in the H(+)-impermeable mitochondrial membrane. For exerting these effects, the stability of the respective uncoupler anions in the hydrophobic membrane is very important. High stability is achieved by delocalization of the polar ionic charge through uncoupler (chemical)-specific mechanisms. Such an action of weakly acidic uncouplers is characteristic of the highly efficient membrane targeting action of a nonsite-specific type of bioactive compound.

Uncouplers of oxidative phosphorylation.

Insights into the role played by modified cinchona alkaloids in the Sharpless asymmetric dihydroxylation inspired studies of modified cinchona alkaloids as chiral organic catalysts that lead to the development of highly enantioselective alcoholyses for the desymmetrization, kinetic resolution, and dynamic kinetic resolution of cyclic anhydrides, cyanation of ketones, and 1,4-addition of thiols to cylic enones. These studies demonstrate the potential of modified cinchona alkaloids as broadly useful chiral organic catalysts for asymmetric synthesis.

Asymmetric Organic Catalysis with Modified Cinchona Alkaloids

The coordination chemistry of 4-substituted 3,5-di(2-pyridyl)-4H-1,2,4-triazoles and related ligands

Synthesis of 4-acyl-2-(acylamino)-.DELTA.2-1,3,4-thiadiazolines and 4-acyl-2-amino-.DELTA.2-1,3,4-thiadiazolines by acylation of thiosemicarbazones

Synthesis of the naphthalenecarboxylic acid derivative obtained from neocarzinostatin (NCS): A structure revision

1,2,4‐Triazoles. V. Nuclear magnetic resonance study of N‐Methyl derivatives of 1,2,4‐triazoles

Antithyroid activity of 2, 4-dihydro-3H-1, 2, 4-triazole-3-thiones and thiosemicarbazones was tested by measuring the uptake ratio of thyroid : serum (T/S) of 125I through the mouse thyroid. Substitution with an alkyl group at the 5-position of the triazole nucleus remarkably increased the activity but substitution at the N-2 and/or N-4 positions caused a significant decrease in the activity, indicating the necessity of unsubstituted thioureylene moiety for the antithyroid activity. Thiosemicarbazone derivatives which are an open ring structure of triazoles showed comparable antithyroid activities to those in a ring form, but one thiosemicarbazone showed a much higher toxicity than the corresponding ring form compound. This suggests that the ring structure is not essential for the activity but is necessary to reduce toxic effect. Of fourteen compounds tested, 5-methyl-2, 4-dihydro-3H-1, 2, 4-triazole-3-thione was the most potent antithyroid compound with low toxicity, with a potency tenfold that of propylthiouracil, a drug currently used.

Effect of 2,4-dihydro-3H-1,2,4-triazole-3-thiones and thiosemicarbazones on iodide uptake by the mouse thyroid: the relationship between their structure and anti-thyroid activity.

On the basis of ultraviolet (UV) and infrared (IR) evidence, 3-phenyl-1, 2, 4-triazolin-5-one and its N-methyl derivatives were all shown to exist as the oxo forms, except the 2-methyl derivative which existed as the hydroxy form. Similarly, UV data showed the predominance of the thione forms of 3-phenyl-1, 2, 4-triazoline-5-thione and its N-methyl derivatives. The syntheses of the N-methyl derivatives of the triazolines used in the present study were described.

Seiju Kubota

Papers

Synthesis of 4-acyl-2-(acylamino)-.DELTA.2-1,3,4-thiadiazolines and 4-acyl-2-amino-.DELTA.2-1,3,4-thiadiazolines by acylation of thiosemicarbazones

Synthesis of the naphthalenecarboxylic acid derivative obtained from neocarzinostatin (NCS): A structure revision

1,2,4‐Triazoles. V. Nuclear magnetic resonance study of N‐Methyl derivatives of 1,2,4‐triazoles

Effect of 2,4-dihydro-3H-1,2,4-triazole-3-thiones and thiosemicarbazones on iodide uptake by the mouse thyroid: the relationship between their structure and anti-thyroid activity.

1, 2, 4-Triazoles. III. The Tautomerism of 3-Phenyl-1, 2, 4-triazolin-5-one, 3-Phenyl-1, 2, 4-triazoline-5-thione and Their N-Methyl Derivatives