Asymmetric Transfer Hydrogenation of -Difluorocyclopropenyl Ketones: The Synthesis and Functionalization of Enantioenriched -Difluorocyclopropyl Ketones.

The asymmetric transfer hydrogenation of -difluorocyclopropenyl ketones, catalyzed by a Noyori-Ikariya ruthenium complex, was developed to access substituted optically enriched -disubstituted -difluorocyclopropyl ketones, and the value of these latter building blocks was illustrated by the synthesis of heterocycles fused to the difluorocyclopropyl moiety.

Cobalt-Catalyzed Bis-Borylation of Quinolines: The Importance of the Cobalt Triplet State.

We report herein a mild stereo- and regioselective dearomatization of quinolines using the simple low valent HCo(N )(PPh ) complex that exhibits labile ligands. Conditions to form selectively, at room temperature, high-valued 1,4-bis-borylated tetrahydroquinolines from simple starting heteroaromatic compounds have been developed. The efficient and selective functionalization of a large scope of quinolines bearing various electron-donating or electron-withdrawing substituents is presented, as well as the post-modification of the resulting C-B bond.

Bond-Dissociation Energies to Probe Pyridine Electronic Effects on Organogold(III) Complexes: From Methodological Developments to Application in π-Backdonation Investigation and Catalysis.

In this work, we report on the synthesis of several organogold(III) complexes based on 4,4'-diterbutylbiphenyl (C^C) and 2,6-bis(4-terbutylphenyl)pyridine (C^N^C) ligands and bond with variously substituted pyridine ligands (pyrR). Altogether, 33 complexes have been prepared and studied with mass spectrometry using higher-energy collision dissociation (HCD) in an Orbitrap mass spectrometer. A complete methodology including the kinetic modeling of the dissociation process based on the Rice-Ramsperger-Kassel-Marcus (RRKM) statistical method is proposed to obtain critical energies of the pyrR loss for all complexes.

-Heterocyclic Carbene Copper (I) Complexes Incorporating Pyrene Chromophore: Synthesis, Crystal Structure, and Luminescent Properties.

Luminescent -heterocyclic carbene chloride copper (I) complexes incorporating pyrene chromophore (1-Pyrenyl-NHC-R)-Cu-Cl, (, ) have been prepared and fully characterized. Two complexes were prepared with R = methyl () and R = naphthyl groups () at the nitrogen center of the carbene unit to tune their electronic properties. The molecular structures of and have been elucidated by X-ray diffraction and confirm the formation of the target compounds.

1,6-Naphthyridin-7(6)-ones: synthesis and optical properties.

Efficient synthesis of original 1,6-naphthyridin-7(6)-ones and their optical properties are described. Their powerful fluorescence properties including dual fluorescence, solvatochromism, acidochromism, large Stokes shifts and high quantum yields, suitable for biological applications or as luminescent devices in materials science, are evidenced.

Hydrido-Cobalt Complexes for the Chemo- and Regioselective 1,2-Silylative Dearomatization of -Heteroarenes.

We describe an efficient regio- and chemoselective dearomatization of -heteroarenes using hydrido-cobalt catalysts. Reactions were performed under mild conditions on a wide range of -heteroarenes leading exclusively to the silyl-1,2-dihydroheteroarene. Various quinolines and pyridines bearing electron-donating and electron-withdrawing substituents are compatible with this methodology.

Rational Design of Mono- and Bi-Nuclear Cyclometalated Ir(III) Complexes Containing Di-Pyridylamine Motifs: Synthesis, Structure, and Luminescent Properties.

Heteroleptic cyclometalated iridium (III) complexes (-) containing di-pyridylamine motifs were prepared in a stepwise fashion. The presence of the di-pyridylamine ligands tunes their electronic and optical properties, generating blue phosphorescent emitters at room temperature. Herein we describe the synthesis of the mononuclear iridium complexes [Ir(ppy)(DPA)][OTf] (), (ppy = phenylpyridine; DPA = Dipyridylamine) and [Ir(ppy)(DPA-PhI)][OTf] (), (DPA-PhI = Dipyridylamino-phenyliodide).

Molecular Magnetic Materials Based on {Co (Tp*)(CN) } Cyanidometallate: Combined Magnetic, Structural and Co NMR Study.

The cyanidocobaltate of formula fac-PPh [Co ( Tp)(CN) ] ⋅ CH CN (1) has been used as a metalloligand to prepare polynuclear magnetic complexes ( Tp=hydrotris(3,5-dimethylpyrazol-1-yl)borate). The association of 1 with in situ prepared [Fe (bik) (MeCN) ](OTf) (bik=bis(1-methylimidazol-2-yl)ketone) leads to a molecular square of formula {[Co {( Tp)}(CN) ] [Fe (bik) ] }(OTf)  ⋅ 4MeCN ⋅ 2H O (2), whereas the self-assembly of 1 with preformed cluster [Co (OH )(piv) (Hpiv) ] in MeCN leads to the two-dimensional network of formula {[Co (piv) ] [Co ( Tp)(CN) ]  ⋅ 2CH CN} (3). These compounds were structurally characterized via single crystal X-ray analysis and their spectroscopic (FTIR, UV-Vis and Co NMR) properties and magnetic behaviours were also investigated.

Cyclometalated Rhodium and Iridium Complexes Containing Masked Catecholates: Synthesis, Structure, Electrochemistry, and Luminescence Properties.

Two neutral cyclometalated rhodium and iridium coordination assemblies [(F2ppy)M(η-Cat)], M = Rh, () and M = Ir, () (F2ppy: 2,4-difluorophenylpyridine), displaying a masked catecholate (η-Cat = η-O∧O) are described. The catecholate ligand is π-bonded to an organometallic Cp*Ru(II) moiety. The latter brings stability to the whole system in solution and suppresses the formation of the related paramagnetic semiquinone complex.

[(C C)Au(N N)] Complexes as a New Family of Anticancer Candidates: Synthesis, Characterization and Exploration of the Antiproliferative Properties.

A library of eleven cationic gold(III) complexes of the general formula [(C C)Au(N N)] when C C is either biphenyl or 4,4'-ditertbutyldiphenyl and N N is a bipyridine, phenanthroline or dipyridylamine derivative have been synthesized and characterized. Contrasting effects on the viability of the triple negative breast cancer cells MDA-MB-231 was observed from a preliminary screening. The antiproliferative activity of the seven most active complexes were further assayed on a larger panel of human cancer cells as well as on non-cancerous cells for comparison.

Novel luminescent benzopyranothiophene- and BODIPY-derived aroylhydrazonic ligands and their dicopper(II) complexes: syntheses, antiproliferative activity and cellular uptake studies.

Two novel unsymmetrical binucleating aroylhydrazonic ligands and four dicopper(II) complexes carrying fluorescent benzopyranothiophene (BPT) or boron dipyrromethene (BODIPY) entities were synthesized and fully characterized. Complex 1, derived from the BPT-containing ligand HL1, had its crystal structure elucidated through X-ray diffraction measurements. The absorption and fluorescence profiles of all the compounds obtained were discussed.

Indolizy Carbene Ligand. Evaluation of Electronic Properties and Applications in Asymmetric Gold(I) Catalysis.

We report herein a new family of carbene ligands based on an indolizine-ylidene (Indolizy) moiety. The corresponding gold(I) complexes are easily obtained from the gold(I)-promoted cyclization of allenylpyridine precursors. Evaluation of the electronic properties by experimental methods and also by DFT calculations confirms strong σ-donating and π-accepting properties of these ligands.

Phenyl Silicates with Substituted Catecholate Ligands: Synthesis, Structural Studies and Reactivity.

While the generation of aryl radicals by photoredox catalysis under reductive conditions is well documented, it has remained challenging under an oxidative pathway. Because of the easy photo-oxidation of alkyl bis-catecholato silicates, a general study of phenyl silicates bearing substituted catecholate ligands has been achieved. The newly synthesized phenyl silicates have been fully characterized, and their reactivity has been explored.

A Solvent-free, Catalyst-free Formal [3+3] Cycloaddition Dearomatization Strategy: Towards New Fluorophores for Biomolecules Labelling.

A general, sustainable dearomatization reaction for nitrogen-containing heterocycles was developed. Under solvent free conditions and without catalyst, the biorenewable methyl coumalate (MC) reacted as an efficient C partner to convert nine types of basic aromatic rings into their pyrido[1,2-a] fused derivatives in good to excellent yields. The fluorescence properties of some of the products were harnessed to conjugate fluorescent tags to bovine serum albumin (BSA) and immunoglobulin G.

Isoxazole-Derived Aroylhydrazones and Their Dinuclear Copper(II) Complexes Show Antiproliferative Activity on Breast Cancer Cells with a Potentially Alternative Mechanism Of Action.

This paper reports the design, synthesis and cytotoxicity studies of two new isoxazole-derived aroylhydrazone ligands and their dinuclear copper(II) complexes. Compounds were fully characterized by various spectroscopic and analytical techniques. The molecular structures of four derivatives were confirmed by X-ray crystallography.

Electron Transfer in the Cs⊂{Mn Fe } Cubic Switch: A Soluble Molecular Model of the MnFe Prussian-Blue Analogues.

A mixed-valence {Mn Mn Fe Fe } cyanide-bridged molecular cube hosting a caesium cation, Cs⊂{Mn Fe }, was synthesized and structurally characterized by X-ray diffraction. Cyclic-voltammetry measurements show that its electronic state can be switched between five different redox states, which results in a remarkable electrochromic effect. Magnetic measurements on fresh samples point to the occurrence of a spin-state change near room temperature, which could be ascribed to a metal-to-metal electron transfer converting the {Fe -CN-Mn } pair into a {Fe -CN-Mn } pair.

Extra hydrogen bonding interactions by peripheral indole groups stabilize benzene-1,3,5-tricarboxamide helical assemblies.

Benzene-1,3,5-tricarboxamide monomers derived from alkyl esters of tryptophan (BTA Trp) self-assemble into helices with an inner threefold hydrogen bond network surrounded by a second network involving the indole N-H groups. As a consequence of this extra stabilization of its helical assemblies, BTA Trp forms more viscous solutions than a range of ester and alkyl BTAs.

Unique Class of Enantiopure N-Heterocyclic Carbene Half-Sandwich Iridium(III) Complexes with Stable Configurations: Probing Five-Membered versus Six-Membered Iridacycles.

A unique class of enantiopure N-heterocyclic carbene half-sandwich iridium complexes is reported. These compounds display stable configurations at the metal center, as demonstrated by their chiroptical properties. Remarkably, because of the nature of the naphthalimide molecule, two regioisomers containing five-membered [( R)-2a and ( S)-2a] and six-membered [( R)-2b and ( S)-2b] iridacycles were obtained.

Capturing a Square Planar Gold(III) Complex Inside a Platinum Nanocage: A Combined Experimental and Theoretical Study.

A novel synthetic procedure was set up to gain access to platinum coordination cages PtL, which are less investigated compared to their palladium counterparts. This PtL nanocage exhibits an adequate cavity for guest encapsulation. Indeed, the Au(III) metal complex [Au(bdt)] (bdt = benzene-1,2-dithiolate) was successfully captured inside the cavity, in contrast to the analogous palladium cage which failed to host the gold complex.

Radical Germylzincation of α-Heteroatom-Substituted Alkynes.

The regio- and stereoselective addition of germanium and zinc across the C-C triple bond of nitrogen-, sulfur-, oxygen-, and phosphorus-substituted terminal and internal alkynes is achieved by reaction with a combination of RGeH and EtZn. Diagnostic experiments support a radical-chain mechanism and the β-zincated vinylgermanes that show exceptional stability are characterized by NMR spectroscopy and X-ray crystallography. The unique feature of this new radical germylzincation reaction is that the C(sp)-Zn bond formed remains available for subsequent in situ Cu(I)- or Pd(0)-mediated C-C or C-heteroatom bond formation with retention of the double bond geometry.

Cyclometalated N-heterocyclic carbene iridium(iii) complexes with naphthalimide chromophores: a novel class of phosphorescent heteroleptic compounds.

A series of cyclometalated N-heterocyclic carbene complexes of the general formula [Ir(C^N)(C^C:)] has been prepared. Two sets of compounds were designed, those where (C^C:) represents a bidentate naphthalimide-substituted imidazolylidene ligand and (C^N) = ppy (3a), F2ppy (4a), bzq (5a) and those where (C^C:) represents a naphthalimide-substituted benzimidazolylidene ligand and (C^N) = ppy (3b), F2ppy (4b), bzq (5b). The naphthalimide-imidazole and naphthalimide-benzimidazole ligands 1a,b and the related imidazolium and benzimidazolium salts 2a,b were also prepared and fully characterized.

Chiral two bladed ML metallamacrocycles: design, structures and solution behavior.

Chiral two bladed complexes of [Co(L)][BF] (1) and [Zn(L)][BF] (2) containing an atropoisomeric semi-rigid bidentate ligand L were synthesized and characterized. They are obtained as homochiral species but in a racemic mixture via a ligand self-sorting mechanism. These enantiomers can be differentiated in solution using optically active anions.

Link between Affinity and Cu(II) Binding Sites to Amyloid-β Peptides Evaluated by a New Water-Soluble UV-Visible Ratiometric Dye with a Moderate Cu(II) Affinity.

Being able to easily determine the Cu(II) affinity for biomolecules of moderate affinity is important. Such biomolecules include amyloidogenic peptides, such as the well-known amyloid-β peptide involved in Alzheimer's disease. Here, we report the synthesis of a new water-soluble ratiometric Cu(II) dye with a moderate affinity (10 M at pH 7.

Tuning the structure of 1,3,5-benzene tricarboxamide self-assemblies through stereochemistry.

A heterochiral 1,3,5-benzene tricarboxamide (BTA) monomer, derived from valine dodecyl ester, forms long rods in cyclohexane whilst its homochiral analogue assembles into dimers only at the same concentration. This highly original assembly behaviour is related to the destabilization of the dimeric structure containing the two heterochiral monomers as corroborated by a combined experimental and computational study.

Single ion magnets based on lanthanoid polyoxomolybdate complexes.

Polyoxometalate (POM) chemistry has recently offered excellent examples of single ion magnets (SIMs) and molecular spin qubits. Compared with conventional coordination compounds, POMs provide rigid and highly symmetric coordination sites. However, all POM-based SIMs reported to date exhibit a very limited range of possibilities for chemical processability.