Intramolecular Phosphinyl-Zincation of Alkynes: A Powerful Entry to Benzophosphole Oxides.

Upon reacting ortho-alkynylated secondary arylphosphine oxides with EtZn, we discovered that P(O)─H activation is followed upon gentle heating by phosphinyl-zincation. This unprecedented transformation stands as a phosphorus version of the silyl and germyl-zincation of alkynes recently shown to give modular access to elaborated tri and tetra-substituted alkenes. The cyclic vinyl-zinc derivative resulting from intramolecular phosphinyl-zincation was characterized by multi-nuclear NMR spectroscopy.

Impact of isomerism on the photoproduction of carbon monoxide and singlet oxygen by visible-light absorbing rhenium(I) photoCORMs.

Photoactive rhenium(I) complexes have high therapeutic potential, particularly in the fight against cancer and antibiotic-resistant bacteria. They have the particularity of combining several modes of action, including photogeneration of carbon monoxide (CO) and singlet oxygen. However, their design is still to be improved.

Photoinduced modulation of the oxidation state of dibenzothiophene S-oxide molecules on an insulating substrate.

On-surface chemistry aims to overcome the limitations of conventional in-solution synthesis by taking advantage of the confinement in two dimensions to master highly ordered covalent structures with tailored properties. So far, most of the reported work is conducted on metal substrates and relies on unconventional mechanisms, thereby precluding a direct transposition of well-established organic reactions from solutions to surfaces. In addition, the intrinsic properties and reactivity of metal substrates often limit the activation methods available to trigger on-surface reactions, and photoinduced processes are especially difficult to handle due to quenching of the adsorbed precursor molecules.

Photo-release of acetonitrile in ruthenium(II) complexes with various substituted terpyridine ligands.

The photo-release of acetonitrile is investigated in a series of ruthenium(II) complexes of the general formula [Ru(R-phtpy)(acac)(MeCN)](PF) (phtpy stands for 4'-phenyl-2,2':6',2''-terpyridine, and R = EtN, MeN, MeO, Me, H, NO). The experimental quantum yields of photo-release ( = MeCN released/photons absorbed) increases with the donating capability of R, with values ranging from = 0 (NO) to = 0.05 (EtN).

Confinement-supported aurophilic interaction.

An anionic cyclotricatechylene cage (H) is shown (NMR, mass spectrometry and X-ray diffraction) to encapsulate cationic Au(I) complexes. As a result, an unprecedented bimetallic Au(I) complex (GG@H) has been characterized, in which confinement supports aurophilic interaction, even without bridging ligands.

Insertion of Nitriles Into a Gold(III)/Carbene Bond: A Direct and Powerful Entry to Imino-Substituted Carbenes.

Strikingly, very little is known so far about reactive gold(III) carbenes. They have been proposed as key intermediates in a few reactions but remain chemical curiosities. Taking into account the enhanced electrophilicity of cationic Au(III) carbene complexes, we were intrigued by their reactivity with nitriles.

Phosphine→Borane-Functionalized Pyrenes and Anthracenes.

The functionalization of polycyclic aromatic hydrocarbons (PAHs) with N→B Lewis pairs, so-called borylative fusion, has recently emerged as a simple and powerful means to modulate their electronic and photophysical properties thanks to the extension of the π system. Herein, we considered a new class of PAHs appended with phosphine→borane Lewis pairs and investigated pyrene as well as anthracene derivatives. In these compounds, strong P→B interactions are enforced geometrically, but the π-system is not extended.

New Sulfenate Sources for Double Pallado-Catalyzed Cross-Coupling Reaction: Application in Symmetrical Biarylsulfoxide Synthesis, and Evidence of TADF Properties.

Tetrahydro-4-thiopyran-4-one 1-oxide and sulfinyl-di--butylpropionate were reported as sources of bis-sulfenate anion and applied in a double pallado-catalyzed cross-coupling reaction for the synthesis of symmetrical biarylsulfoxides, tolerating a large array of electronic properties and bulkiness. The photophysical properties of a biarylsulfoxide have been explored, demonstrating an unreported TADF phenomenon on sulfoxide-containing scaffolds.

Catechol/-benzoquinone exchange at gold(iii).

Although gold(iii) chemistry has tremendously progressed in the past 2 decades, gold(iii) catecholate complexes remain extremely scarce and underdeveloped. Upon preparation and full characterization of P^C-cyclometalated gold(iii) complexes, we serendipitously uncovered an intriguing catechol exchange process at gold(iii). Electron-rich catecholates turned out to be readily displaced by electron-poor -benzoquinones.

Colloidal Bimetallic RuNi Particles and their Behaviour in Catalytic Quinoline Hydrogenation.

Colloidal metal nanoparticles exhibit interesting catalytic properties for the hydrogenation of (hetero)arenes. Catalysts based on precious metals, such as Ru and Rh, promote this reaction efficiently under mild reaction conditions. In contrast, heterogeneous catalysts based on earth-abundant metals can selectively hydrogenate (hetero)arenes but require harsher reaction conditions.

Dinuclear tricarbonylrhenium(I) complexes: impact of regioisomerism on the photoluminescence properties.

Dinuclear Re(I) complexes have proportionally been much less studied than mononuclear analogues. In particular, very little information is available about their solid-state emission properties. In this work, two structural isomers of dinuclear complexes (Bi-Re-metaPhe and Bi-Re-paraPhe), which differ by the relative position of the coordination spheres on a central phenyl ring, were synthesized and compared with each other and with the parent mononuclear compound (Mono-Re-Phe), from a theoretical and experimental point of view.

Reactivity of the phosphaethynolate anion with stabilized carbocations: mechanistic studies and synthetic applications.

The reactivity of sodium phosphaethynolate Na(OCP) towards various Mayr's reference electrophiles was investigated using conventional UV-visible and laser-flash photolysis techniques. The kinetic data, along with density functional theory (DFT) calculations, enabled the first experimental quantification of the phosphorus nucleophilicity of [OCP]. Product studies of these reactions demonstrate the formation of secondary as well as tertiary phosphines.

Pentafluorophenyl Copper-Biarylsulfoxide Complexes: Synthesis and Photoreactivity.

Pentafluorophenyl copper(I)-biarylsulfoxide complexes, existing as [Cu(CF)]L, both in solution and in the solid state, were prepared and thoroughly characterized. Subsequently, the photochemistry of the complexes was explored, showing inherent photoreactivity of the biarylsulfoxide moiety within the coordination sphere of the copper. Photoinduced cross-coupling reactions between the anthryl moiety of bis-anthracenylsulfoxide and pentafluorobenzene, and synthesis of CuO (cuprite), were demonstrated.

2-Cyanopropan-2-yl versus 1-Cyanocyclohex-1-yl Leaving Group: Comparing Reactivities of Symmetrical Trithiocarbonates in RAFT Polymerization.

This study introduces bis(1-cyanocyclohex-1-yl)trithiocarbonate (TTC-bCCH) as a novel trithiocarbonate chain transfer agent and compares its reactivity with the previously described bis(2-cyanopropan-2-yl)trithiocarbonate (TTC-bCP) for the reversible addition-fragmentation chain transfer (RAFT) polymerization of styrene (St), n-butyl acrylate (nBA), and methyl methacrylate (MMA). Significant findings include the effective control of M and low dispersities from the onset of polymerization of St and nBA showing swift addition-fragmentation kinetics, leading to similar behaviors between the two RAFT agents. In contrast, a fourfold decrease of the chain transfer constant to MMA is established for TTC-bCCH over TTC-bCP.

Ruthenium nitrosyl complexes with NO release capability: the use of fluorene as an antenna.

A ruthenium nitrosyl complex of formula [Ru(fluorene(C6)CHO-terpy)(bipy)(NO)] (AC) in which fluorene(C6) is the 9,9-dihexylfluorene, terpy the 2,2';6',2''-terpyridine, and bipy the 2,2'-bipyridine is presented with its related [Ru(MeO-terpy)(bipy)(NO)] (C) and 9,9-dihexylfluorene 2-hydroxymethylfluorene (A) building blocks. The reference complex C undergoes NO release capabilities under irradiation at = 365 nm. The effect of the introduction of the fluorescent A antenna within the resulting AC complex is discussed both experimentally and theoretically.

1,2,3-Triazol-5-ylidene- 1,2,3-triazole-based tricarbonylrhenium(I) complexes: influence of a mesoionic carbene ligand on the electronic and biological properties.

The tricarbonylrhenium complexes that incorporate a mesoionic carbene ligand represent an emerging and promising class of molecules, the solid-state optical properties of which have rarely been investigated. The aim of this comprehensive study is to compare three of these complexes with their 1,2,3-triazole-based analogues. The Hirshfeld surface analysis of the crystallographic data revealed that the triazolylidene derivatives are more prone to π-π interactions than their 1,2,3-triazole-based counterparts.

Synthesis, characterization, and inhibition effects of a novel eugenol derivative bearing pyrrole functionalities on the corrosion of mild steel in a HCl acid solution.

Semi-synthetic modifications of natural products have yielded numerous anti-cancer drugs, antimicrobials, and corrosion inhibitors. In this study, eugenol, a natural product, was synthetically modified to generate a novel heterocyclic compound: pyrrole, which forms crystals. The latter is the outcome of the condensation reaction between eugenol hydrazide and 2,5-hexanedione, conducted under reflux ethanol conditions, without a catalyst, achieving a 96% yield.

Photorelease of Nitric Oxide (NO) in Mono- and Bimetallic Ruthenium Nitrosyl Complexes: A Photokinetic Investigation with a Two-Step Model.

Two monometallic and three bimetallic ruthenium acetonitrile (RuMeCN) complexes are presented and fully characterized. All of them are built from the same skeleton [FTRu(bpy)(MeCN)], in which FT is a fluorenyl-substituted terpyridine ligand and bpy is the 2,2'-bipyridine. The crystal structure of [FTRu(bpy)(MeCN)](PF) is presented.

Ligand-Enabled Oxidative Fluorination of Gold(I) and Light-Induced Aryl-F Coupling at Gold(III).

MeDalphos Au(I) complexes featuring aryl, alkynyl, and alkyl groups readily react with electrophilic fluorinating reagents such as -fluorobenzenesulfonimide and Selectfluor. The ensuing [(MeDalphos)Au(R)F] complexes have been isolated and characterized by multinuclear NMR spectroscopy as well as X-ray diffraction. They adopt a square-planar contra-thermodynamic structure, with F to N.

Chemo-selective Stille-type coupling of acyl-chlorides upon phosphine-borane Au(i) catalysis.

Phosphine-boranes do not promote oxidative addition of acyl chlorides to gold, but the phosphine-borane gold triflimide complex [PrP(-CH)BCy]AuNTf was found to catalyze the coupling of acyl chlorides and aryl stannanes. The reaction involves aryl/chloride-bridged dinuclear gold(i) complexes as key intermediates, as substantiated by spectroscopic and crystallographic analyses. Similar to Pd(0)/Pd(ii)-catalyzed Stille coupling with phosphine-borane ligands, the gold-catalyzed variant shows complete chemoselectivity for acyl chlorides over aryl iodides and bromides, enabling straightforward access to halogenated aryl ketones.

Carboranylphosphines: B9-Substituted Derivatives with Enhanced Reactivity for Anchoring to Dendrimers.

Invited for the cover of this issue are the groups and colleagues of Anne-Marie Caminade at the CNRS and University of Toulouse, Evamarie Hey-Hawkins at Leipzig University, and Agustí Lledós from the Autonomous University of Barcelona. The image depicts birds crowned by a carborane competing for access to food, to illustrate the steric hindrance encountered when grafting carboranes to dendrimers (artwork by Dr. Christoph Selg).

Stannylenes and Germylenes Stabilized by Tetradentate Bis(amidine) Ligands with a Rigid Naphthalene Backbone.

An unusual series of germylenes and stannylenes stabilized by new tetradentate bis(amidine) ligands RNC(R')N-linker-NC(R')NR with a rigid naphthalene backbone has been prepared by protonolysis reaction of Lappert's metallylenes [M(HMDS)] (M = Ge or Sn). Germylenes and stannylenes were fully characterized by NMR spectroscopy and X-ray diffraction analysis. DFT calculations have been performed to clarify the structural and electronic properties associated with tetradentate bis(amidine) ligands.

Carboranylphosphines: B9-Substituted Derivatives with Enhanced Reactivity for the Anchoring to Dendrimers.

Several ortho-carboranes bearing a phenoxy or a phenylamino group in the B9 position were prepared employing various protection and deprotection strategies. Following established protocols, dendritic compounds were synthesized from a hexachlorocyclotriphosphazene or thiophosphoryl chloride core, and possible anchoring options for the B9-substituted ortho-carboranes were investigated experimentally and theoretically (DFT). Furthermore, 1- or 1,2-phosphanyl-substituted carborane derivatives were obtained.

Acetylacetonate Ruthenium Nitrosyls: A Gateway to Nitric Oxide Release in Water under Near-Infrared Excitation by Two-Photon Absorption.

A fundamental challenge for phototriggered therapies is to obtain robust molecular frameworks that can withstand biological media. Photoactivatable nitric oxide (NO) releasing molecules (photoNORMs) based on ruthenium nitrosyl (RuNO) complexes are among the most studied systems due to several appealing features that make them attractive for therapeutic applications. Nevertheless, the propensity of the NO ligand to be attacked by nucleophiles frequently manifests as significant instability in water for this class of photoNORMs.

Synthesis and structures of homoleptic germylenes and stannylenes with sulfonimidamide ligands.

An unusual series of germylenes and stannylenes with homoleptic symmetric and unsymmetric -substituted sulfonimidamide ligands PhSO(NiPr)(NHiPr) 1 and PhSO(NMes)(NHiPr) 2 have been prepared by protonolysis reaction of Lappert's metallylenes [M(HMDS)] (M = Ge or Sn) with two equivalents of the appropriate sulfonimidamide. The homoleptic germylenes [PhSO(NiPr)]Ge 3 and [PhSO(NMes)(NiPr)]Ge 4, and stannylenes [PhSO(NiPr)]Sn 5 and [PhSO(NMes)(NiPr)]Sn 6 were fully characterized by NMR spectroscopy and by X-ray diffraction analysis. DFT calculations have been performed to understand the electronic properties brought by the sulfonimidamide ligand.