Nitrous oxide as diazo transfer reagent.

Nitrous oxide, commonly known as "laughing gas", is formed as a by-product in several industrial processes. It is also readily available by thermal decomposition of ammonium nitrate. Traditionally, the chemical valorization of NO is achieved oxidation chemistry, where NO acts as a selective oxygen atom transfer reagent.

Metal-Mediated Synthesis of a Mixed Arduengo-Fischer Carbodicarbene Ligand.

Carbodicarbenes are strong C-donor ligands, which have found numerous applications in organometallic and main group element chemistry. Herein, we report a structurally distinct carbodicarbene ligand, which is formed by dinitrogenative coupling of a Fischer carbene complex with an N-heterocyclic diazoolefin. The resulting carbonyl complex serves as a stable source for the mixed Arduengo-Fischer carbodicarbene ligand.

Nanogels with Metal-Organic Cages as Functional Crosslinks.

A dinuclear metal-organic cage with four acrylate side chains was prepared by self-assembly. Precipitation polymerization of the cage with N-isopropylacrylamide yielded a thermoresponsive nanogel. The host properties of the cage were retained within the gel matrix, endowing the nanogel with the capability to serve as a sorbent for chloride ions in water.

Molecular imine cages with π-basic Au(pyrazolate) faces.

One tetrahedral and two trigonal prismatic cages with π-basic Au(pyrazolate) faces were obtained by connection of pre-formed gold complexes dynamic covalent imine chemistry. The parallel arrangement of the Au(pyrazolate) complexes in the prismatic cages augments the interaction with π-acids, as demonstrated by the encapsulation of polyhalogenated aromatic compounds. The tetrahedral cage was found to act as a potent receptor for fullerenes.

Orientational Self-Sorting in Octahedral Palladium Cages: Scope and Limitations of the " Rule".

Octahedral coordination cages of the general formula [PdL](BF) were obtained by combining [Pd(CHCN)](BF) with heteroditopic N-donor ligands. Four different ligands were employed. These ligands have 3-pyridyl donor groups at one end and 4-pyridyl, imidazolyl, or triazolyl donor groups at the other end.

Synthesis and Reactivity of an Anionic Diazoolefin.

Bent (hetero)allenes such as carbodicarbenes and carbodiphosphoranes can act as neutral C-donor ligands, and diverse applications in coordination chemistry have been reported. N-Heterocyclic diazoolefins are heterocumulenes, which can function in a similar fashion as L-type ligands. Herein, we describe the synthesis and the reactivity of an anionic diazoolefin.

A five-stranded heterometallic helicate.

A penta-stranded helicate was obtained by combining [Pd(CHCN)](BF) with La(NO) and a polydentate ligand. The helicate displays low symmetry, both in solution and in the solid state. A dynamic interconversion between the penta-stranded helicate and a symmetrical, four-stranded helicate was achieved by adjustment of the metal-to-ligand ratio.

Construction of Pd-based coordination cages with three geometrically distinct ligands.

Three different dipyridyl ligands were combined with [Pd(CHCN)](BF) to give mixtures of homo- and/or heteroleptic coordination cages. The three ligands were chosen so that one ligand shows a parallel orientation of the coordinate vectors, the second ligand a bent angle of 60°, and the third ligand a bent angle of 120°. We have identified ligand mixtures that give rise to integrative self-sorting, and we have characterized a heterotrileptic [PdLL'L''] cage by single crystal X-ray crystallography.

Head-to-Tail Dimerization of N-Heterocyclic Diazoolefins.

The head-to-tail dimerization of N-heterocyclic diazoolefins is described. The products of these formal (3+3) cycloaddition reactions are strongly reducing quinoidal tetrazines. Oxidation of the tetrazines occurs in a stepwise fashion, and we were able to isolate a stable radical cation and diamagnetic dications.

The acid-mediated isomerization of iridium(III) complexes with cyclometalated NHC ligands: kinetic thermodynamic control.

The isomerization of iridium(III) complexes with metalated N-heterocyclic carbene (NHC) ligands was studied. The isomers of complexes with 1-phenyl-3-methylbenzimidazolin-2-ylidene or 1-phenyl-3-benzylbenzimidazolin-2-ylidene ligands are transformed cleanly into the isomers when solutions of the complexes are treated with first HNTf and then NEt. The transformation can be accomplished within a few minutes and the side product (NEtH)(NTf) is easy to separate.

Synthetic Receptors with Micromolar Affinity for Chloride in Water.

A water-soluble coordination cage was obtained by reaction of Pd(NO ) with a 1,3-di(pyridin-3-yl)benzene ligand featuring a short PEG chain. The cavity of the metal-organic cage contains one nitrate anion, which is readily replaced by chloride. The apparent association constant for chloride binding in buffered aqueous solution is K =1.

Bonding and Reactivity in Terminal versus Bridging Arenide Complexes of Thorium Acting as Th Synthons.

Thorium redox chemistry is extremely scarce due to the high stability of Th . Here we report two unique examples of thorium arenide complexes prepared by reduction of a Th -siloxide complex in presence of naphthalene, the mononuclear arenide complex [K(OSi(O Bu) ) Th(η -C H )] (1) and the inverse-sandwich complex [K(OSi(O Bu) ) Th] (μ-η ,η -C H )] (2). The electrons stored in these complexes allow the reduction of a broad range of substrates (N O, AdN , CO , HBBN).

Synthesis and Reactivity of a Terminal 1-Alkynyl Triazene.

1-Alkynyl triazenes are versatile reagents in synthetic organic chemistry, but the structural diversity of this compound class has so far been limited. Herein, we describe the synthesis of a terminal 1-alkynyl triazene. Subsequent functionalization allows the preparation of 1-alkynyl triazenes with a range of functional groups including esters, alcohols, cyanides, phosphonates, and amides.

Copper Complexes with Diazoolefin Ligands and their Photochemical Conversion into Alkenylidene Complexes.

Homometallic copper complexes with alkenylidene ligands are discussed as intermediates in catalysis but the isolation of such complexes has remained elusive. Herein, we report the structural characterization of copper complexes with bridging and terminal alkenylidene ligands. The compounds were obtained by irradiation of Cu complexes with N-heterocyclic diazoolefin ligands.

Orientational self-sorting in cuboctahedral Pd cages.

Cuboctahedral coordination cages of the general formula [PdL] (L = low-symmetry ligand) were analyzed theoretically and experimentally. With 350 696 potential isomers, the structural space of these assemblies is vast. Orientational self-sorting refers to the preferential formation of particular isomers within the pool of potential structures.

Fluorinated Tetraarylethenes: Universal Tags for the Synthesis of Solid State Luminogens.

The aggregation-induced emission properties of tetraarylethenes (TAEs) have led to numerous applications in chemistry, biology, and materials science. Herein, we describe two fluorinated tetraarylethenes, which can be employed as universal tags for the synthesis of solid state luminogens. The tags are accessible in one or two steps from commercially available starting materials.

Acid-base-induced → isomerization of luminescent iridium(iii) complexes.

Luminescent Ir(C^N) complexes (C^N = cyclometalated arylpyridine ligand) exist in the form of two stable isomers with distinct photophysical and electrochemical properties: and . Herein, we show that -Ir(C^N) complexes can be converted into the thermodynamically less stable forms by a consecutive reaction with first acid and then base. The chemically induced isomerization is fast, quantitative, and stereoselective, and it can be inversed by light.

Chemo- and regio-divergent access to fluorinated 1-alkyl and 1-acyl triazenes from alkynyl triazenes.

The 1,1,2,2-tetrafluoroethylene unit is prevalent in bioactive molecules and functional materials. Despite being in principle a straightforward strategy to access this motif, the direct tetrafluorination of alkynes involves very hazardous or inconvenient reagents. Therefore, safer and convenient alternatives are sought after.

A Mesoionic Diselenolene Anion and the Corresponding Radical Dianion.

Dichalcogenolenes are archetypal redox non-innocent ligands with numerous applications. Herein, a diselenolene ligand with fundamentally different electronic properties is described. A mesoionic diselenolene was prepared by selenation of a C2-protected imidazolium salt.

LiBF -Induced Rearrangement and Desymmetrization of a Palladium-Ligand Assembly.

Thirteen palladium-ligand assemblies with different structures and topologies were investigated for the ability to bind lithium ions. In one case, the addition of LiBF resulted in a profound structural rearrangement, converting a dincluclear [Pd L ] complex into a low-symmetry [Pd L ] assembly with two binding pockets for solvated LiBF ion pairs. The rearrangement could only be induced by Li , indicating highly specific host-guest interactions.

Vanadium complexes with N-heterocyclic vinylidene ligands.

The preparation and the structural characterization of vanadium complexes with terminal and bridging N-heterocyclic vinylidene ligands is reported. The synthesis of the complexes was enabled by utilization of diazoolefins as ligand precursors. Structural data and theoretical results show that N-heterocyclic vinylidenes can act as 6e donor ligands, leading to strong metal-carbon interactions.

Synthesis of Four-Membered BN Heterocycles by the Borylation of Triazenes.

Borylated triazenes were synthesized by the dehydrocoupling of triazenes with 9-borabicyclo(3.3.1)nonane, by the condensation of triazenes with BEt, or by the reaction of sodium triazenides with dialkyl- or diarylboron halides.

Nitrous oxide as a diazo transfer reagent: the synthesis of triazolopyridines.

Nitrous oxide is a potential diazo transfer reagent, but its applications in organic chemistry are scarce. Here, we show that triazolopyridines and triazoloquinolines are formed in the reactions of metallated 2-alkylpyridines or 2-alkylquinolines with NO. The reactions can be performed under mild conditions and give synthetically interesting triazoles in moderate to good yields.

Synthesis, structural characterization, and coordination chemistry of imidazole-based alkylidene ketenes.

Alkylidene ketenes typically display high intrinsic reactivity, impeding isolation on a preparative scale. Herein, we report the synthesis of alkylidene ketenes by reaction of imidazole-based diazoolefins with carbon monoxide. The good thermal stability of these heterocumulenes allows for characterization by single crystal X-ray diffraction.