Shih-Ching Chuang

High‐Performance and Highly Durable Inverted Organic Photovoltaics Embedding Solution‐Processable Vanadium Oxides as an Interfacial Hole‐Transporting Layer

Inverted OPV devices based on sol-gel derived vanadium oxides (VOx ) as an interfacial layer are demonstrated. The VOx shows excellent characteristics as a hole-transporting and protecting layer. The constructed devices exhibit enhanced performance with the studied polymers and are highly durable under accelerated conditions for long time periods.

One-Pot Synthesis of Highly Substituted Polyheteroaromatic Compounds by Rhodium(III)-Catalyzed Multiple CH Activation and Annulation**

A new method for the synthesis of highly substituted naphthyridine-based polyheteroaromatic compounds in high yields proceeds through rhodium(III)-catalyzed multiple C-H bond cleavage and C-C and C-N bond formation in a one-pot process. Such highly substituted polyheteroaromatic compounds have attracted much attention because of their unique π-conjugation, which make them suitable materials for organic semiconductors and luminescent materials. Furthermore, a possible mechanism, which involves multiple chelation-assisted ortho C-H activation, alkyne insertion, and reductive elimination, is proposed for this transformation.

Palladium-Catalyzed Oxidative Insertion of Carbon Monoxide to N-Sulfonyl-2-aminobiaryls through C-H Bond Activation: Access to Bioactive Phenanthridinone Derivatives in One Pot

Palladium-catalyzed oxidative carbonylation of N-sulfonyl-2-aminobiaryls through C-H bond activation and C-C, C-N bond formation under TFA-free and milder conditions has been developed. The reaction tolerates a variety of substrates and provides biologically important phenanthridinone derivatives in yields up to 94%.

Demonstration of a Chemical Transformation Inside a Fullerene. The Reversible Conversion of the Allotropes of H2@C60

The interconversion of the two allotropes of the hydrogen molecule (para-H2 and ortho-H2) incarcerated inside the fullerene C60 is reported (oH2@C60 and pH2@C60, respectively). For conversion, oH2@C60 was adsorbed at the external surface of the zeolite NaY and immersed into liquid oxygen at 77 K. Equilibrium was reached in less than 0.5 h. Rapid removal of oxygen provides a sample of enriched pH2@C60 that is stable for many days in the absence of paramagnetic catalysts (half-life approximately 15 days). Enriched pH2@C60 is nonvolatile and soluble in organic solvents. At room temperature in the presence of a paramagnetic catalyst (dissolved O2 or the nitroxide Tempo) a slow back conversion into oH2@C60 was observed by 1H NMR. A bimolecular rate constant for conversion of pH2@C60 to oH2@C60 using Tempo of kTempo approximately 4 x 10-5 M-1 s-1 was observed, which is approximately 3 orders of magnitudes slower than that for dissolved pH2 in organic solvents which is not protected by the C60 shell.

One pot synthesis of bioactive benzopyranones through palladium-catalyzed C–H activation and CO insertion into 2-arylphenols

Palladium-catalyzed oxidative carbonylation of 2-arylphenols through C-H bond activation and C-C and C-O bond formation under acid-base free and mild conditions has been developed. The reaction tolerates a variety of substrates and provides biologically important benzopyranone derivatives in up to 87% isolated yield.

Annulation of Benzamides with [60]Fullerene through Palladium(II)-Catalyzed C-H Bond Activation

Palladium-catalyzed heteroannulation of N-substituted benzamides with [60]fullerene, which proceeds through direct sp(2) C-H bond activation to form 7-membered ring pallada-intermediate with C(60), led to formation of [60]fulleroisoquinolinones in moderate to good yields (8-64% based on recovered C(60)). A plausible reaction pathway is proposed.

Tricyclohexylphosphine-Catalyzed Cycloaddition of Enynoates with [60]Fullerene and the Application of Cyclopentenofullerenes as n-Type Materials in Organic Photovoltaics

The tricyclohexylphosphine-catalyzed [3 + 2] cycloaddition of (E)-alkyl 5-substituted phenylpent-4-en-2-ynoates with [60]fullerene was studied. This reaction undergoes an initial 1,3-addition of phosphines toward the α-carbons of enynoates. Subsequent cycloaddition of the generated 1,3-dipoles with [60]fullerene and elimination of tricyclohexylphosphines resulted in cyclopentenofullerenes in 20-43% yields. The isolated cyclopentenofullerenes were observed to serve as n-type materials in organic photovoltaics, providing a maximum average power conversion efficiency of 3.79 ± 0.29% upon embedding with P3HT in the active layer.

Fine tuning of the orifice size of an open-cage fullerene by placing selenium in the rim: insertion/release of molecular hydrogen

A newly synthesized open-cage fullerene containing selenium in the rim of the 13-membered-ring orifice allows milder conditions for hydrogen insertion, and the rate for hydrogen release is ca. three times faster than its sulfur analogue.

Fullerene Derivatives Incorporating Phosphoramidous Ylide and Phosphoramidate: Synthesis and Property

The reaction of dimethyl acetylenedicarboxylate (DMAD) with C(60) in the presence of hexamethylphosphorous triamide (HMPT) or hexaethylphosphorus triamide (HEPT) results in fullerene derivatives incorporating HMPT or HEPT ylides. The ylide derivatives exhibit unusual electronic absorptions in the visible region (435-660 nm), likely due to the presence of the ylide moiety. Electrochemical studies revealed that the first reductive potential of these compounds was more negative relative to those of both C(60) (DeltaE = 130 mV) and a simple Bingel adduct (DeltaE = 90 mV). A phosphoramidate side product, which resulted from the addition of HMPT or HEPT to C(60) followed by hydrolysis, exhibited a featureless absorption spectrum in the visible region and a more negative first reductive potential (DeltaE = 70 mV) relative to that of C(60).

Multicomponent Reactions of Phosphines, Diynedioates, and Aryl Aldehydes Generated Furans Appending Reactive Phosphorus Ylides through Cumulated Trienoates as Key Intermediates: A Phosphine α‑Addition-δ-Evolvement of an Anion Pathway

Multicomponent reactions of phosphines, diynedioates, and aryl aldehydes have been demonstrated, providing trisubstituted furans appending reactive phosphorus ylides, through cumulated trienoates as key intermediates. The proposed trienoate intermediates, 1,5-dipolar species formed via nucleophilic α-attack of phosphines toward diynedioates (α-addition-δ-evolvement of an anion, abbreviated αAδE), undergo addition to aryl aldehydes followed by 5-endo-dig cyclization, proton transfer, and resonance to give trisubstituted furans. Furthermore, the phosphorus ylides are oxidized to α-keto ester furans and utilized as Wittig reagents.