Multifunctional Cationic Iridium(III) Complexes Bearing 2‑Aryloxazolo[4,5‑<i>f</i>][1,10]phenanthroline (N^N) Ligand: Synthesis, Crystal Structure, Photophysics, Mechanochromic/Vapochromic Effects, and Reverse Saturable Absorption

A series of 2-aryloxazolo­[4,5-<i>f</i>]­[1,10]­phenanthroline ligands (N^N ligands) and their cationic iridium­(III) complexes (<b>1</b>–<b>11</b>, aryl = 4-NO₂-phenyl (<b>1</b>), 4-Br-phenyl (<b>2</b>), Ph (<b>3</b>), 4-NPh₂-phenyl (<b>4</b>), 4-NH₂-phenyl (<b>5</b>), pyridin-4-yl (<b>6</b>), naphthalen-1-yl (<b>7</b>), naphthalen-2-yl (<b>8</b>), phenanthren-9-yl (<b>9</b>), anthracen-9-yl (<b>10</b>), and pyren-1-yl (<b>11</b>)) were synthesized and characterized. By introducing different electron-donating or electron-withdrawing substituents at the 4-position of the 2-phenyl ring (<b>1</b>–<b>5</b>), or different aromatic substituents with varied degrees of π-conjugation (<b>6</b>–<b>11</b>) on oxazolo­[4,5-<i>f</i>]­[1,10]­phenanthroline ligand, we aim to understand the effects of terminal substituents at the N^N ligands on the photophysics of cationic Ir­(III) complexes using both spectroscopic methods and quantum chemistry calculations. Complexes with the 4-R-phenyl substituents adopted an almost coplanar structure with the oxazolo­[4,5-<i>f</i>]­[1,10]­phenanthroline motif, while the polycyclic aryl substituents (except for naphthalen-2-yl) were twisted away from the oxazolo­[4,5-<i>f</i>]­[1,10]­phenanthroline motif. All complexes possessed strong absorption bands below 350 nm that emanated from the ligand-localized ¹π,π*/¹ILCT (intraligand charge transfer) transitions, mixed with ¹LLCT (ligand-to-ligand charge transfer)/¹MLCT (metal-to-ligand charge transfer) transitions. At the range of 350–570 nm, all complexes exhibited moderately strong ¹ILCT/¹LLCT/¹MLCT transitions at 350−450 nm, and broad but very weak ³LLCT/³MLCT absorption at 450−570 nm. Most of the complexes demonstrated moderate to strong room temperature phosphorescence both in solution and in the solid state. Among them, complex <b>7</b> also manifested a drastic mechanochromic and vapochromic luminescence effect. Except for complexes <b>1</b> and <b>4</b> that contain NO₂ or NPh₂ substituent at the phenyl ring, respectively, all other complexes exhibited moderate to strong triplet excited-state absorption in the spectral region of 440–750 nm. Moderate to very strong reverse saturable absorption (RSA) of these complexes appeared at 532 nm for 4.1 ns laser pulses. The RSA strength followed the trend of <b>7</b> > <b>11</b> > <b>9</b> > <b>3</b> > <b>2</b> ≈ <b>4</b> > <b>5</b> ≈ <b>10</b> ≈ <b>6</b> ≈ <b>8</b> > <b>1</b>. The photophysical studies revealed that the different 2-aryl substituents on the oxazole ring impacted the singlet and triplet excited-state characteristics dramatically, which in turn notably influenced the RSA of these complexes

Palladium-Catalyzed Intramolecular Cyclization of Ynamides: Synthesis of 4‑Halo-oxazolones

A mild and efficient methodology involving Pd­(PPh₃)₄-catalyzed intramolecular cyclization of <i>N</i>-alkynyl alkyloxycarbamates with CuCl₂ or CuBr₂ for the synthesis of 4-halo-oxazolones was developed. This reaction exhibiting good functional tolerance provided a new, efficient, and rapid synthetic process to 4-halo-oxazolones. The resulting 4-halo-oxazolones can serve as great potential precursors for the 3,4,5-trisubstituted oxazolones via a Pd-catalyzed cross-coupling reaction

Residue Catalytic Cracking Process for Maximum Ethylene and Propylene Production

Effects of operating conditions on residue fluid catalytic cracking (RFCC) were studied in a pilot-scale FCC unit. Experimental results indicated that both high reaction severity and long residence time promoted the production of ethylene and propylene. A novel RFCC process for maximum ethylene and propylene (MEP) production was further proposed, which was characterized by high operating severity, application of olefin-selective catalyst, and stratified reprocessing of light gasoline and butenes. Simulation experiments of the MEP process demonstrated that both light cycle gasoline and recycled butenes were effectively converted; meanwhile, the semispent catalyst still retained sufficient activity to further crack residue feedstock. When treating Daqing AR, the MEP process yielded up to 8.85 wt % ethylene and 25.97 wt % propylene. In contrast, due to elevated catalyst activity in a second-stage riser, the two-stage riser MEP process produced more propylene and LPG at the expense of light oil. Also, ethylene yield was still up to a comparative level

Controlled Synthesis of 1,3,5-Oxadiazin-2-ones and Oxazolones through Regioselective Iodocyclization of Ynamides

Two efficient processes based on the iodocyclization of ynamides have been developed: (i) <i>N</i>-alkynyl <i>tert</i>-butyloxycarbamates were found to undergo a rare 6-<i>exo-dig</i> ring closure reaction affording 1,3,5-oxadiazin-2-ones by using acetonitrile as solvent; (ii) In the absence of acetonitrile, <i>N</i>-alkynyl <i>tert</i>-butyloxycarbamates could undergo 5-<i>endo-dig</i> cyclization providing oxazolones

The analysis workflow and the calculation of alpha diversity.

(A) Data acquisition and processing workflow. (B) Calculation and comparison of alpha diversity using Shannon and Simpson indices.</p

The co-occurrence correlation among ARGs.

(A) Healthy group. (B) PDAC group. Pearson correlation was used in this analysis.</p

Construction of the diagnostic model.

(A) Identification of the top 20 ARGs contributing the most to the model. (B) Evaluation of the accuracy of the diagnostic model.</p

The abundance of top 20 ARGs in each group and across all samples.

The abundance of top 20 ARGs in each group and across all samples.</p

Beta diversity and differential AGRs.

(A) Assessment of beta diversity based on Bray-Curtis distance and p-values calculated using Adnois. (B, C) Calculation of differentially abundant ARGs, with p-values adjusted using the Benjamini-Hochberg correction.</p

Competitive Adsorption-Assisted Formation of One-Dimensional Cobalt Nanochains with High CO Hydrogenation Activity

A dramatic morphology evolution from cobalt nanoparticles to one-dimensional cobalt nanochains have been found by the introduction of CO in the synthesis process. The competitive adsorption between oleylamine (OAm) and CO molecules on cobalt surface was analyzed by DFT calculations. The competitive adsorption provides an effective way to regulate the surface properties of cobalt nanoaparticles, thus adjusting the interactions between cobalt nanoparticles and leading the self-assembly formation of cobalt nanochains. The novel one-dimensional cobalt nanochains show superior activity for CO hydrogenation, thus providing a powerful strategy for the surface and morphology controlled synthesis of catalyst nanomaterials assisted by small molecules