Upgrading heterogeneous Ni catalysts with thiol modification.

Precious metal catalysts are the cornerstone of many industrial processes. Replacing precious metal catalysts with earth-abundant metals is one of key challenges for the green and sustainable development of chemical industry. We report in this work a surprisingly effective strategy toward the development of cost-effective, air-stable, and efficient Ni catalysts by simple surface modification with thiols.

Solvent-mediated assembly of atom-precise gold-silver nanoclusters to semiconducting one-dimensional materials.

Bottom-up design of functional device components based on nanometer-sized building blocks relies on accurate control of their self-assembly behavior. Atom-precise metal nanoclusters are well-characterizable building blocks for designing tunable nanomaterials, but it has been challenging to achieve directed assembly to macroscopic functional cluster-based materials with highly anisotropic properties. Here, we discover a solvent-mediated assembly of 34-atom intermetallic gold-silver clusters protected by 20 1-ethynyladamantanes into 1D polymers with Ag-Au-Ag bonds between neighboring clusters as shown directly by the atomic structure from single-crystal X-ray diffraction analysis.

Solubility-Driven Isolation of a Metastable Nonagold Cluster with Body-Centered Cubic Structure.

The conventional synthetic methodology for atomically precise gold nanoclusters by using reduction in solution offers only the thermodynamically most stable nanoclusters. Herein, a solubility-driven isolation strategy is reported to access a metastable gold cluster. The cluster, with the composition of [Au (PPh ) ] (1), displays an unusual, nearly perfect body-centered cubic (bcc) structure.

Methylamine-Dimer-Induced Phase Transition toward MAPbI Films and High-Efficiency Perovskite Solar Modules.

Perovskite films prepared with CHNH molecules under ambient conditions have led to rapid fabrication of perovskite solar cells (PSCs), but there remains a lack of mechanistic studies and inconsistencies with operability in their production. Here the crystal structure of CHNH-CHNHPbI was analyzed to involve hydrogen bonds (CHNH···CHNH) and has guided the facile, reproducible preparation of high-quality perovskite films under ambient conditions. Hydrogen bonds within CHNH···CHNH dimers were found in the CHNH-CHNHPbI intermediates, accompanied by 1D-PbI chains (δ-phase).

Synthesis of α,β-Unsaturated Amidines through Gold-Catalyzed Intermolecular Reaction of Azides with Ynamides.

A concise and flexible synthesis of α,β-unsaturated amidines via gold-catalyzed intermolecular ynamide amination/carbene 1,2-shift between ynamides and benzylic azides has been developed. Under mild reaction conditions, various α,β-unsaturated amidines were obtained in mostly good yields, thus providing an efficient and atom-economic way for the construction of valuable α,β-unsaturated amidines.

Gold-Catalyzed Intermolecular Ynamide Amination-Initiated Aza-Nazarov Cyclization: Access to Functionalized 2-Aminopyrroles.

A novel gold-catalyzed intermolecular ynamide amination-initiated aza-Nazarov cyclization has been developed, allowing the facile and efficient synthesis of various 2-aminopyrroles in moderate to good yields. Furthermore, a mechanistic rationale for this tandem sequence, especially for the observed high regioselectivity, is also well supported by DFT (density functional theory) computations. The high flexibility, broad substrate scope, and mild nature of this reaction render it a viable alternative for the construction of 2-aminopyrroles.

Gold-Catalyzed Tandem Cycloisomerization-Halogenation of Chiral Homopropargyl Sulfonamides.

Two new gold-catalyzed tandem cycloisomerization-halogenation reactions of chiral homopropargyl sulfonamides have been developed. Various enantioenriched 3,3-diiodopyrrolidin-2-ols and 3-fluoropyrrolidin-2-ols were obtained in moderate-to-good yields with excellent enantio- and diastereoselectivity.

Synthesis of α,β-Unsaturated N-Sulfonyl Imides through Zinc-Catalyzed Intermolecular Oxidation of N-Sulfonyl Ynamides.

A novel zinc-catalyzed intermolecular oxidation of N-sulfonyl ynamides has been developed. A variety of functionalized α,β-unsaturated N-sulfonyl imides are readily accessed by utilizing this approach, thus providing a viable alternative to synthetically useful α,β-unsaturated imides. Importantly, the reaction is proposed to proceed by a vinyligous E2-type elimination pathway, but not metal carbene pathway.