Sulfur functionalized diamondoid phosphines enable building nanocomposites interfacing sp-carbon and gold nanolayers.

Interfacing metal frameworks with carbon-based materials is attractive for the bottom-up construction of nanocomposite functional materials. The stepwise layering of difunctionalized diamantanes and gold metal from physical and chemical vapor deposition for the preparation of nanocomposites inverts the conventional preparation of metal-organic frameworks (MOFs) and self-assemblies, where the metal is introduced first, and this method delivers metal surfaces with modified properties originating from the sp-carbon core. However, appropriate diamondoid candidates for such an approach are rare.

Tetrazo[1,2-b]indazoles: Straightforward Access to Nitrogen-Rich Polyaromatics from s-Tetrazines.

The straightforward access to a new class of aza-polyaromatics is reported. Starting from readily available fluorinated s-tetrazine, a cyclization process with azide leads to the formation of an unprecedented tetrazo[1,2-b]indazole or a bis-tetrazo[1,2-b]indazole (cis and trans conformers). Based on the new nitrogen core, further N-directed palladium-catalyzed ortho-C-H bond functionalization allows the introduction of halides or acetates.

The Hydrogen-Storage Challenge: Nanoparticles for Metal-Catalyzed Ammonia Borane Dehydrogenation.

Dihydrogen is one of the sustainable energy vectors envisioned for the future. However, the rapidly reversible and secure storage of large quantities of hydrogen is still a technological and scientific challenge. In this context, this review proposes a recent state-of-the-art on H production capacities from the dehydrogenation reaction of ammonia borane (and selected related amine-boranes) as a safer solid source of H by hydrolysis (or solvolysis), catalyzed by nanoparticle-based systems.

Coordination Chemistry of a Bis(Tetrazine) Tweezer: A Case of Host-Guest Behavior with Silver Salts.

The carbon-carbon cross-coupling of phenyl -tetrazine (Tz) units at their -phenyl positions allows the formation of constrained bis(tetrazines) with original tweezer structures. In these compounds, the face-to-face positioning of the central tetrazine cores is reinforced by π-stacking of the electron-poor nitrogen-containing heteroaromatic moieties. The resulting tetra-aromatic structure can be used as a weak coordinating ligand with cationic silver.

Cyclopropenylidenephosphoranes: Rearrangement to Azetidinylidene-Methylphosphoniums.

Attempts at preparing cyclopropenylphosphonium salts by P-quaternization of α-aminophosphines with bisdiisopropylaminocyclopropenium tetrafluoroborate led to azetidin-2-ylidene methylphosphoniums as unexpected isomers, in 57-85% yields. The basic structure of the products is discussed on the basis of X-ray crystallography analysis. The unprecedented 3 → 4 ring expansion process is argued to be driven by an ambivalent aromatic vs antiaromatic character (or loss of aromaticity) of the primary phosphonium product.

Bridge-Clamp Bis(tetrazine)s with [N] π-Stacking Interactions and Azido-s-Aryl Tetrazines: Two Classes of Doubly Clickable Tetrazines.

Click chemistry at a tetrazine core is useful for bioorthogonal labeling and crosslinking. Introduced here are two new classes of doubly clickable s-aryl tetrazines synthesized by Cu-catalyzed cross-coupling. Homocoupling of o-brominated s-aryl tetrazines leads to bis(tetrazine)s structurally characterized by tetrazine cores arranged face-to-face.

Diamondoid Nanostructures as sp -Carbon-Based Gas Sensors.

Diamondoids, sp -hybridized nanometer-sized diamond-like hydrocarbons (nanodiamonds), difunctionalized with hydroxy and primary phosphine oxide groups, enable the assembly of the first sp -C-based chemical sensors by vapor deposition. Both pristine nanodiamonds and palladium nanolayered composites can be used to detect toxic NO and NH gases. This carbon-based gas sensor technology allows reversible NO detection down to 50 ppb and NH detection at 25-100 ppm concentration with fast response and recovery processes at 100 °C.

Transition-Metal-Free α-Vinylation of Enolizable Ketones with β-Bromostyrenes.

An α-vinylation of enolizable ketones has been developed by using β-bromostyrenes and a KO tBu/NMP system. β,γ-Unsaturated ketones of E configuration were obtained in excellent yield and selectivity. Further synthetic possibilities are highlighted by one-pot functionalization via trapping of intermediate dienolates with alkyl, allyl, benzyl, and propargyl halides to generate quaternary centers.

Phosphenium Versus Pro-Phosphide Character of P-tert-butyl-dicyclopropeniophosphine: Zwitterionic Palladate Complexes of a Dicationic Phosphido Ligand.

With the view to enhancing the unique coordinating ability of the known phenyl-tetrakis(diisopropylamino)dicyclopropeniophosphine (Ph-DCP), replacement of the phenyl substituent by a tert-butyl substituent was envisaged. Both α-dicationic R-DCP phosphines, with R = Ph and Bu, were prepared in 54%-55% yield by substitution of RPCl with two equivalents of bis(diisopropylamino)-dicyclopropenylidene (BAC) and metathesis with NaBF. This method is implicitly consistent with the representation of R-DCPs as BAC-phosphenium adducts.