Asymmetric Heteroleptic Ir(III) Phosphorescent Complexes with Aromatic Selenide and Selenophene Groups: Synthesis and Photophysical, Electrochemical, and Electrophosphorescent Behaviors.

With the aim of evaluating the potential of selenium-containing groups in developing electroluminescent (EL) materials, a series of asymmetric heteroleptic Ir(III) phosphorescent complexes (Ir-Se0F, Ir-Se1F, Ir-Se2F, and Ir-Se3F) have been synthesized by using 2-selenophenylpyridine and one ppy-type (ppy = 2-phenylpyridine) ligand with a fluorinated selenide group. To the best of our knowledge, these complexes represent unprecedented examples of asymmetric heteroleptic Ir(III) phosphorescent emitters bearing selenium-containing groups. Natural transition orbital (NTO) analysis based on optimized geometries of the first triplet state (T1) have shown that the phosphorescent emissions of these Ir(III) complexes dominantly show 3π-π* features of the 2-selenophenylpyridine ligand with slight metal to ligand charge transfer (MLCT) contribution. In comparison with their symmetric parent complex Ir-Se with two 2-selenophenylpyridine ligands, these asymmetric heteroleptic Ir(III) phosphorescent complexes can show much higher phosphorescent quantum yields (ΦP) of ca. 0.90. Both the hole- and electron-trapping ability of these Ir(III) phosphorescent complexes can be enhanced by selenophene and fluorinated selenide groups to improve their EL efficiencies. The EL abilities of these asymmetric heteroleptic Ir(III) phosphorescent emitters fall in the order Ir-Se3F > Ir-Se2F > Ir-Se1F > Ir-Se0F. The highest EL efficiencies have been achieved by Ir-Se3F in the solution-processed OLEDs with external quantum efficiency (ηext), current efficiency (ηL), and power efficiency (ηP) of 19.9%, 65.6 cd A-1, and 57.3 lm W-1, respectively. These encouraging EL results clearly indicate the great potential of selenium-containing groups in developing high-performance Ir(III) phosphorescent emitters.

Synthesis and antifungal activity of ethers, alcohols, and iodohydrin derivatives of sclareol against phytopathogenic fungi in vitro.

This study synthesized 20 sclareol derivatives. The antifungal activities of these derivatives were evaluated in vitro against five phytopathogenic fungi using the mycelium growth rate method. Among all the tested compounds, compound 16 with one iodine atom and three hydroxyl groups displayed higher fungicidal activities against all the tested phytopathogenic fungi than precursor sclareol. Compound 16 also showed more pronounced antifungal activities against Curvularia lunata (IC50=12.09 µg/mL) and Alternaria brassicae (IC50=14.47 µg/mL) than the positive control, a commercial agricultural fungicide thiabendazole.

Highly efficient iridium-catalyzed asymmetric hydrogenation of unprotected ß-enamine esters.

A highly efficient and enantioselective hydrogenation of unprotected ß-enamine esters catalyzed by Ir-(S,S)-f-Binaphane complex has been developed. This methodology provides straightforward access to free ß-amino acids in high yields with excellent enantioselectivities up to 97% ee and high reactivities (TON > 5000).

The synthesis of cyclometalated platinum(II) complexes with benzoaryl-pyridines as C

A series of (C^N)Pt(acac)-type complexes has been successfully synthesized with a benzo[b]furan, benzo[b]thiophene, benzo[b]selenophene, or benzo[b]tellurophene group in the benzoaryl-pyridine ligand. Using X-ray crystallography, the chemical structures of the complexes with benzo[b]selenophene and benzo[b]tellurophene groups have been clearly revealed. The photophysical, electrochemical, and electroluminescent (EL) behaviors of these (C^N)Pt(acac)-type complexes have been fully characterized. Furthermore, both time-dependent functional theory (TD-DFT) and natural transition orbital (NTO) theoretical results have been obtained to gain insight into the absorption and emission features. It has been shown that both the absorption bands with the lowest energy and the phosphorescence emission behaviors are dominated by the benzoaryl-pyridine cyclometalating ligand. Importantly, the effects of the group VIA atoms on the properties of these (C^N)Pt(acac)-type complexes have been revealed. Owing to the rareness of (C^N)Pt(acac)-type complexes with benzo[b]selenophene and benzo[b]tellurophene groups, their EL abilities have been characterized using solution-processed organic light-emitting diodes (OLEDs). The optimized red OLEDs with the complex bearing a benzo[b]selenophene unit show a maximum external quantum efficiency (ηext) of 6.3%, current efficiency (ηL) of 10.5 cd A-1, and power efficiency (ηP) of 9.1 lm W-1, while the EL device with the complex bearing a benzo[b]tellurophene unit can give deep-red emission at ca. 636 nm with ηext of 6.3%, ηL of 6.5 cd A-1, and ηP of 5.8 lm W-1. This research not only provides novel (C^N)Pt(acac)-type complexes, but also furnishes critical information regarding the photophysical and EL behavior of these new complexes.

Synthesis and Antifungal Activities of Drimane-Amide Derivatives from Sclareol.

AIM AND OBJECTIVE: Plant diseases are caused by fungal pathogens lead to severe economic losses in many agriculture crops. And the increasing resistance of many fungi to commonly used antifungal agents necessitates the discovery and development of new fungicides. So this study was focused on synthesizing novel skeleton compounds to effectively control plant diseases. MATERIALS AND METHODS: A series of drimane-amide derivatives were designed, synthesized by aminolysis reaction of amine with intermediate sclareolide which was prepared from sclareol. The structures of all the synthesized compounds were confirmed using 1H NMR, 13C NMR, and HRMS (ESI) spectroscopic data. Their in vitro antifungal activity were preliminarily evaluated by using the mycelium growth rate method against five phytopathogenic fungi: Botrytis cinerea, Glomerella cingulata, Alternaria alternate, Alternaria brassicae, and Fusarium graminearum. RESULTS: 23 target compounds were successfully obtained in yields of 52-95%. Compounds A2 and A3 displayed favorable inhibitory potency against B. cinerea, G. cingulata and A. brassicae with IC50 values ranging from 3.18 to 10.48 µg/mL. These two compounds displayed higher fungicidal activity than sclareol against all the tested phytopathogenic fungi, and were more effective than the positive control thiabendazole against A. alternate and A. brassicae. The structure-activity relationship studies of compounds A1-10 indicated that both the position and type of substituent on the phenyl ring had significant effects on antifungal activity. CONCLUSION: The drimane-amide derivatives A2 and A3 were the most promising derivatives and should be selected as new templates for the potential antifungal agents.

Synthesis and Biological Evaluation of Hexahydropyrrolo[2,3-b]Indole Derivatives as Fungicides against Phytopathogenic Fungi.

Eighteen hexahydropyrrolo[2,3-b]indole derivatives were synthesized and evaluated their in vitro antifungal activities against five phytopathogenic fungal strains through the mycelium growth rate method. Analysis of the structure-activity relationship on these synthesized compounds revealed that the introduction of benzyl or substituted benzyl group at the C-3a or N-8 position of the pyrroloindoline scaffold conferred higher antifungal activity against all tested phytopathogenic fungi than compound 4a (both C-3a and N-8 positions are prenyl groups). Especially, compound 4r, among all the tested compounds, showed the most effective antifungal activity against Fusarium coeruleum, and Fusarium graminearum with IC50 values of 4.61 and 5.02 µg/mL, respectively. Moreover, all synthesized compounds 4a-4r displayed higher activities against Curvularia lunata than the positive control thiabendazole, a commercial agricultural fungicide.

Supported ruthenium-carbene catalyst on ionic magnetic nanoparticles for olefin metathesis.

The Grubbs-Hoveyda ruthenium-carbene complex has been covalently immobilized on ionic magnetic nanoparticles utilizing an imidazolium salt linker. The supported catalyst exhibited excellent catalytic activity for ring-closing metathesis (RCM) and cross-metathesis (CM) in the presence of less than 1 mol % of ruthenium. The catalysts can easily be recovered magnetically and reused up to seven times with minimal leaching of ruthenium species.