Pushing the limits of electron donation for -chelating ligands an alliance of phosphonium ylide and anionic abnormal NHC.

The grafting of a -(CH)PR moiety on an NHC ligand backbone in the Mn(I) complex [Cp(CO)Mn(IMes)] followed by double deprotonation opens a route to bidentate ligands with extreme electron-donating character. Such remarkable electronic properties can even allow intramolecular sp C-H functionalization in typically inert square-planar Rh(I) dicarbonyl complexes.

Phosphine-NHC-Phosphonium Ylide Pincer Ligand: Complexation with Pd(II) and Unconventional -Coordination of the Ylide Moiety.

An efficient synthesis of two pincer preligands [PhPCH(R)ImCHCHCHPPh]X (R = H, X = OTf; R = Ph, X = BF) was developed. Subsequent reactions with PdCl and an excess of CsCO led to the formation of highly stable cationic metalated Pd(II) complexes [(,,,)Pd]X exhibiting phosphine, NHC, phosphonium ylide, and σ-aryl donor extremities. The protonation of one of the latter complexes with R = H affords the Pd(II) complex [(,,)Pd(MeCN)](OTf) bearing an unprecedented nonsymmetrical NHC core pincer scaffold with a 5,6-chelating framework.

Trinuclear Cyanido-Bridged [Cr Fe] Complexes: To Be or not to Be a Single-Molecule Magnet, a Matter of Straightness.

Trinuclear systems of formula [{Cr(L )(CN) } M(H L )] (M=Mn and Fe , L stands for pentadentate ligands) were prepared in order to assess the influence of the bending of the apical M-N≡C linkages on the magnetic anisotropy of the Fe derivatives and in turn on their Single-Molecule Magnet (SMM) behaviors. The cyanido-bridged [Cr M] derivatives were obtained by assembling trans-dicyanido Cr complex [Cr(L )(CN) ] and divalent pentagonal bipyramid complexes [M (H L )] with various R substituents (R=NH , cyclohexyl, S,S-mandelic) imparting different steric demand to the central moiety of the complexes. A comparative examination of the structural and magnetic properties showed an obvious effect of the deviation from straightness of the M-N≡C alignment on the slow relaxation of the magnetization exhibited by the [Cr Fe] complexes.

Direct Access to Palladium(II) Complexes Based on Anionic ,,-Phosphonium Ylide Core Pincer Ligand.

The reaction of readily available imidazolium-phosphonium salt [MesIm(CH)PPh](OTf) with PdCl in the presence of an excess of CsCO afforded selectively in one step the cationic Pd(II) complex [(,,)Pd(NCMe)](OTf) exhibiting an LX-type NHC-ylide-aryl ,,-pincer ligand via formal triple C-H bond activation. The replacement of labile MeCN in the latter by CNBu and CO fragments allowed to estimate the overall electronic properties of this phosphonium ylide core pincer scaffold incorporating three different carbon-based donor ends by IR spectroscopy, cyclic voltammetry, and molecular orbital analysis, revealing its significantly higher electron-rich character compared to the structurally close NHC core pincer system with two phosphonium ylide extremities. The pincer complex [(,,)Pd(CO)](OTf) represents a rare example of Pd(II) carbonyl species stable at room temperature and characterized by X-ray diffraction analysis.

Carbo-mer of Barrelene: A Rigid 3D-Carbon-Expanded Molecular Barrel.

After extensive studies of 1D and 2D skeletal carbo-mers based on C π-conjugating dialkynylbutatriene units (DABs: ∼C≡C-(R)C=C=C=C(R)-C≡C∼) bridging sp or sp centers in carbo-butene, carbo-xylylene or carbo-benzene derivatives, 3D versions are envisaged through carbo-barrelenes and partially reduced derivatives thereof where two or three DAB blades span a bridge between sp carbinol vertices or ether thereof. For R=Ph, stable representatives were synthesized through a pivotal [6]pericyclynedione, and extensively characterized by spectroscopic, electrochemical and crystallographic methods. Density functional theory calculations allow detailed analysis of structural and electronic features of the 7 Å high C barrel-shaped molecules, and show that they can behave as cages for ionic species.

Differential vector competence of Ornithodoros soft ticks for African swine fever virus: What if it involves more than just crossing organic barriers in ticks?

Background: Several species of soft ticks in genus Ornithodoros are known vectors and reservoirs of African swine fever virus (ASFV). However, the underlying mechanisms of vector competence for ASFV across Ornithodoros species remain to be fully understood. To that end, this study compared ASFV replication and dissemination as well as virus vertical transmission to descendants between Ornithodoros moubata, O.

Update of the Culicoides (Diptera: Ceratopogonidae) species checklist from Algeria with 10 new records.

Background: The Culicoides fauna of Algeria has been historically investigated, leading to the description of many new species by Kieffer in the 1920s, Clastrier in the 1950s or Callot in the 1960s and to a comprehensive inventory by Szadziewski in the 1980s. The emergence of bluetongue in the late 1990s enhanced Culicoides collections made in the country over the last two decades, but information remained mostly unpublished. The aim of this study is therefore to provide a comprehensive and updated checklist of Culicoides biting midge species in Algeria.

The tree that hides the forest: cryptic diversity and phylogenetic relationships in the Palaearctic vector Obsoletus/Scoticus Complex (Diptera: Ceratopogonidae) at the European level.

Background: Culicoides obsoletus is an abundant and widely distributed Holarctic biting midge species, involved in the transmission of bluetongue virus (BTV) and Schmallenberg virus (SBV) to wild and domestic ruminants. Females of this vector species are often reported jointly with two morphologically very close species, C. scoticus and C.

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.

NHC Core Phosphonium Ylide-based Palladium(II) Pincer Complexes: The Second Ylide Extremity Makes the Difference.

The coordinating properties of N-heterocyclic carbene (NHC) (A), phenolate (B), and phosphonium ylide (C) moieties were investigated systematically through the preparation of a family of NHC, phosphonium ylide-based pincer ligands, where the third donor extremity can be either an NHC, a phenolate, or a phosphonium ylide. The overall donor character of such ligands [NHC(ABC)] ( + + = 2) was analyzed by comparison of the molecular orbitals (energy and shape), oxidation potentials (), and IR ν and ν stretching frequencies of their isostructural pincer Pd(II) complexes [NHC(ABC)PdL][OTf] (L = NCCH, CO, or CNBu). The three categories of pincer complexes based on phosphonium ylides were easily obtained by acidic treatment of their highly stable -metalated Pd(II) precursors prepared in a single step from readily available N-phosphonio-substituted imidazolium salts.

Core carbo-mer of an Extended Tetrathiafulvalene: Redox-Controlled Reversible Conversion to a carbo-Benzenic Dication.

carbo-Benzene is an aromatic molecule devised by inserting C units within each C-C bond of the benzene molecule. By integrating the corresponding carbo-quinoid core as bridging unit in a π-extended tetrathiafulvalene (exTTF), it is shown that a carbo-benzene ring can be reversibly formed by electrochemical reduction or oxidation. The so-called carbo-exTTF molecule was thus experimentally prepared and studied by UV-visible absorption spectroscopy and cyclic voltammetry, as well as by X-ray crystallography and by scanning tunneling microscopy (STM) on a surface of highly oriented pyrolytic graphite (HOPG).

Modelling temporal dynamics of Culicoides Latreille (Diptera: Ceratopogonidae) populations on Reunion Island (Indian Ocean), vectors of viruses of veterinary importance.

Background: Reunion Island regularly faces outbreaks of epizootic haemorrhagic disease (EHD) and bluetongue (BT), two viral diseases transmitted by haematophagous midges of the genus Culicoides (Diptera: Ceratopogonidae) to ruminants. To date, five species of Culicoides are recorded in Reunion Island in which the first two are proven vector species: Culicoides bolitinos, C. imicola, C.

Visible Light Induced Rhodium(I)-Catalyzed C-H Borylation.

An efficient visible light induced rhodium(I)-catalyzed regioselective borylation of aromatic C-H bonds is reported. The photocatalytic system is based on a single NHC-Rh complex capable of both harvesting visible light and enabling the bond breaking/forming at room temperature. The chelating nature of the NHC-carboxylate ligand was critical to ensure the stability of the Rh complex and to provide excellent photocatalytic activities.

Phosphine-NHC Manganese Hydrogenation Catalyst Exhibiting a Non-Classical Metal-Ligand Cooperative H Activation Mode.

Deprotonation of the Mn NHC-phosphine complex fac-[MnBr(CO) (κ P,C-Ph PCH NHC)] (2) under a H atmosphere readily gives the hydride fac-[MnH(CO) (κ P,C-Ph PCH NHC)] (3) via the intermediacy of the highly reactive 18-e NHC-phosphinomethanide complex fac-[Mn(CO) (κ P,C,C-Ph PCHNHC)] (6 a). DFT calculations revealed that the preferred reaction mechanism involves the unsaturated 16-e mangana-substituted phosphonium ylide complex fac-[Mn(CO) (κ P,C-Ph P=CHNHC)] (6 b) as key intermediate able to activate H via a non-classical mode of metal-ligand cooperation implying a formal λ -P-λ -P phosphorus valence change. Complex 2 is shown to be one of the most efficient pre-catalysts for ketone hydrogenation in the Mn series reported to date (TON up to 6200).

Palladium(ii) pincer complexes of a C,C,C-NHC, diphosphonium bis(ylide) ligand.

A new family of pincer palladium(ii) complexes bearing an electron-rich C,C,C-NHC, diphosphonium bis(ylide) ligand of LX-type was prepared through the dual N-functionalization of 1H-imidazole by (3-bromopropyl)triphenylphosphonium bromide. Selected basic conditions allowed the sequential coordination of the NHC and phosphonium ylide moieties to Pd(ii). This strategy led to an original ortho-metallated complex where the Pd center is bonded to four carbon atoms of three different natures: carbenic (sp), arylic (sp), and chiral ylidic (sp).

Effects of the Exchange Coupling on Dynamic Properties in a Series of CoGdCo Complexes.

Reaction of 2-hydroxy3-methoxybenzaldehyde ( o-vanillin) with 1,1,1-tris(aminomethyl)ethane, Me-C(CHNH), or with N, N', N''-trimethylphosphorothioic trihydrazide, P(S)[NMe-NH], yields two tripodal LH and LH ligands which are able to give cationic heterotrinuclear [LCoGdCoL] or [LCoGdCoL] complexes. The Co ions are coordinated to these deprotonated ligands in the inner NO site, while the Gd ion is linked to three deprotonated phenoxo oxygen atoms of two anionic [LCo] or [LCo] units. Air oxidation of these trinuclear complexes does not yield complexes associating Co and Gd ions.

Methinylogation Approach in Chiral Pharmacophore Design: from Alkynyl- to Allenyl-carbinol Warheads against Tumor Cells.

Extension of a structure-activity relationship study of the antitumor cytotoxicity of lipidic dialkynylcarbinols (DACs) is envisaged by formal methinylogation of one of the ethyndiyl moieties of the DAC warhead into the corresponding allenylalkynylcarbinol (AllAC) counterpart. External AllACs were directly obtained by methinylation of the parent DACs with formaldehyde in either the racemic or scalemic series. Isomers containing external progargyl and propynyl motifs were also prepared.

Crystal structure of -poly[[[di-chlorido-copper(II)]-{μ--butyl -methyl--[4-(6-{[4-(pyridin-2-yl-κ)-1-1,2,3-triazol-1-yl-κ]meth-yl}-1,3-benzo-thia-zol-2-yl)phen-yl]carbamato}] aceto-nitrile monosolvate].

In the title coordination polymer, {[CuCl(CHNOS)]·CHCN} , the copper(II) ion is fivefold coordinated, with an almost perfect square-pyramidal coordination sphere. In the equatorial plane, it is ligated to a pyridine N atom and an N atom of the triazole unit and to two Cl ions, while the apical position is occupied by the carbonyl O atom of the -butyl carbamate group. In the crystal, the polymer chains propagate in the [11-1] direction, with the aceto-nitrile solvent mol-ecules linked to the chain by C-H⋯N hydrogen bonds.

Steric/π-Electronic Insulation of the carbo-Benzene Ring: Dramatic Effects of tert-Butyl versus Phenyl Crowns on Geometric, Chromophoric, Redox, and Magnetic Properties.

Hexa-tert-butyl-carbo-benzene (C tBu ) and three phenylated counterparts (C tBu Ph ; m=4, 2) have been synthesized. The peralkylated version (m=6) provides experimental access to intrinsic features of the insulated C core independently from the influence of π-conjugated substituent. Over the series, structural, spectroscopic, and electrochemical properties are compared with those of the hexaphenylated reference (m=0).

Carbo-biphenyls and Carbo-terphenyls: Oligo(phenylene ethynylene) Ring Carbo-mers.

Ring carbo-mers of oligo(phenylene ethynylene)s (OPEn, n=0-2), made of C -catenated C carbo-benzene rings, have been synthesized and characterized by NMR and UV-vis spectroscopy, crystallography and voltammetry. Analyses of crystal and DFT-optimized structures show that the C rings preserve their individual aromatic character according to structural and magnetic criteria (NICS indices). Carbo-terphenyls (n=2) are reversibly reduced at ca.

Crystal structure of tetra-aqua-bis-(1,3-dimethyl-2,6-dioxo-7-purin-7-ido-κ)cobalt(II).

The title complex, [Co(CHNO)(HO)], comprises mononuclear mol-ecules consisting of a Co ion, two deprotonated theophylline ligands (systematic name: 1,3-dimethyl-7-purine-2,6-dione) and four coordinating water mol-ecules. The Co atom lies on an inversion centre and has a slightly distorted octa-hedral coordination environment, with two N atoms of two -oriented theophylline ligands and the O atoms of four water mol-ecules. An intra-molecular hydrogen bond stabilizes this conformation.

The Forgotten Nitroaromatic Phosphines as Weakly Donating P-ligands: An N-Aryl-benzimidazolyl Series in RhCl(CO) Complexes.

The coordination chemistry of a priori weakly σ-donating nitroaromatic phosphines is addressed through a series of nitro-substituted (N-phenyl-benzimidazol-1-yl)diphenylphosphines in Rh complexes. From a set of seven such phosphines L=L (x, y, z=0 or 1=number of NO substituents at the 5, 6 and N-Ph para positions, respectively), including the non-nitrated parent L and its dicationic N-methyl counterpart L ', three LRhCl(COD) and seven L RhCl(CO) complexes have been obtained in 72-95 % yield. Despite of a cis orientation of the L and CO ligands, the C=O IR stretching frequency ν varies in the expected sense, from 1967±1 cm for L to 1978±1 cm for L , and 2005 cm for L '.