N-Heterocycle-coordinated -iodanes as IBX alternatives for alcohol oxidations.

We report the synthesis of novel N-coordinated -iodanes as a unique class of hypervalent iodine compounds. X-ray diffraction analysis revealed their intriguing (pseudo)cyclic structure, showcasing distinctive N⋯I-secondary bonding interactions. We demonstrate the generation of reactive diacetoxy derivatives, which exhibits remarkable efficacy in alcohol oxidation reactions.

Synthesis of phosphate stabilised iodanes and their application in intramolecular aryl migrations.

A diverse set of hydroxy-benzo[]iodadioxaphosphinine oxides and derived diaryl iodonium salts are prepared and two examples are characterized by X-ray crystallography, featuring an out-of-plane geometry of the hypervalent bond for both compound classes. Treatment of the phosphate-stabilized diaryliodonium salts with Ca(OH) results in an efficient base-induced intramolecular aryl migration under aqueous conditions, yielding iodo-substituted diaryl ethers with yields up to 94%. Our findings highlight the synthetic potential of this previously underexplored compound class in organic transformations.

Cationic dinuclear complexes [M(PCP)-Cl][GaCl] of the group 10 elements. metallophilic interactions and catalytic dehydrogenation of MeNHBH.

The facile synthesis of the cationic dinuclear group 10 complexes [M(PCP)-Cl] (M = Ni, Pd, Pt) by transmetallation from a simple Ga precursor is reported (PCP = 2,6-(PhP)CH). Their use for the catalysed dehydrogenation of MeNHBH shows that Ni has a higher reactivity than Pt, whereas Pd is inactive.

Oxidation of benzylic alcohols to carbonyls using -heterocyclic stabilized λ-iodanes.

We present -heterocycle-stabilized iodanes (NHIs) as suitable reagents for the mild oxidation of activated alcohols. Two different protocols, both involving activation by chloride additives, were used to synthesize benzylic ketones and aldehydes without overoxidation in up to 97% yield. Based on MS experiments an activated hydroxy(chloro)iodane is proposed as the reactive intermediate.

En Route to a Molecular Terminal Tin Oxide.

In the pursuit of terminal tin chalcogenides, heteroleptic stannylenes bearing terphenyl- and hexamethyldisilazide ligands were reacted with carbodiimides to yield the respective guanidinato complexes. Further supported by quantum chemical calculations, this revealed that the -propyl-substituted derivative provides the maximum steric protection achievable. Oxidation with elemental selenium produced monomeric terminal tin selenides with four-coordinate tin centers.

Boosting quantum yields and circularly polarized luminescence of penta- and hexahelicenes by doping with two BN-groups.

The incorporation of boron-nitrogen (BN) units into polycyclic aromatic hydrocarbons (PAHs) as an isoelectronic replacement of two carbon atoms can significantly improve their optical properties, while the geometries are mostly retained. We report the first non-π-extended penta- and hexahelicenes comprising two aromatic 1,2-azaborinine rings. Comparing them with their all-carbon analogs regarding structural, spectral and (chir)optical properties allowed us to quantify the impact of the heteroatoms.

Synthesis and crystal structure of bis-(9-mesityl-9,10-di-hydro-10-aza-9-borabenzo[]quinolinato-κ,)zinc(II).

The title compound, [Zn(CHBN)] ( ), is an overall uncharged chelate that consists of two units of an N-deprotonated 10-aza-9-borabenzo[]quinoline ligand () per Zn center. It was synthesized in two steps by treating the protonated ligand with lithium bis-(tri-methyl-sil-yl)amide and further conversion with di-ethyl-zinc. Its asymmetric unit comprises one fragment; the mol-ecule is completed by application of inversion symmetry at Zn.

A Photomechanical Film in which Liquid Crystal Design Shifts the Absorption into the Visible Light Range.

Liquid crystalline polymer networks (LCN) with azobenzene monomers bend reversibly under UV-light irradiation, combining photomechanical and photothermal effects. However, the harmful nature of UV-light limits their use in biology and soft robotics. Although visible light-absorbing tetra-ortho-fluoro-substituted azobenzenes exist, liquid crystalline monomers have never been prepared.

Nickel and Palladium Complexes of a PP(O)P Pincer Ligand Based upon a -Substituted Acenaphthyl Scaffold and a Secondary Phosphine Oxide.

A PP(O)P pincer ligand based upon a -substituted acenaphthyl (Ace) scaffold and a secondary phosphine oxide, (5-PhP-Ace-6-)P(O)H, was prepared and fully characterized including a neutron diffraction study. The reaction with [Ni(HO)]Cl and PdCl produced ionic metal(II) complexes [κ-,,((5-PhP-Ace-6-)P(OH))MCl]Cl, which upon addition of EtN gave rise to zwitterionic metal(II) complexes κ-,,((5-PhP-Ace-6-)P(O))MCl (M = Ni, Pd). The reaction with Ni(COD) (COD = cyclooctadiene) provided the η-cyclooctenyl Ni(II) complex κ-,,((5-PhP-Ace-6-)P(O))Ni(η-CH).

Improvement in the Palladium-Catalyzed Miyaura Borylation Reaction by Optimization of the Base: Scope and Mechanistic Study.

Aryl boronic acids and esters are important building blocks in API synthesis. The palladium-catalyzed Suzuki-Miyaura borylation is the most common method for their preparation. This paper describes an improvement of the current reaction conditions.

Sila-Ibuprofen.

The synthesis, characterization, biological activity, and toxicology of sila-ibuprofen, a silicon derivative of the most common nonsteroidal anti-inflammatory drug, is reported. The key improvements compared with ibuprofen are a four times higher solubility in physiological media and a lower melting enthalpy, which are attributed to the carbon-silicon switch. The improved solubility is of interest for postsurgical intravenous administration.

Selective Hydrogenation of α,β-Unsaturated Aldehydes and Ketones by Air-Stable Ruthenium NNS Complexes.

The selective hydrogenation of the carbonyl functionality of α,β-unsaturated aldehydes and ketones is catalysed by ruthenium dichloride complexes bearing a tridentate NNS ligand as well as triphenylphosphine. The tridentate ligand backbone is flexible, as evidenced by the equilibrium observed in solution between the cis- and trans-isomers of the dichloride precatalysts, as well as crystal structures of several of these complexes. The complexes are activated by base in the presence of hydrogen and readily hydrogenate carbonyl functionalities under mild conditions.