Influence of triphosphine ligand coordination geometry in Mn(I) hydride complexes [(PPP)(CO)MnH] on their kinetic hydricity.

Octahedral Mn(I) complexes bearing tridentate donor ligands [(LL'L'')(CO)MnX] have recently emerged as major players in catalytic (de)hydrogenation processes. While most of these systems are still based on structurally rigid pincer scaffolds imposing a meridional coordination mode, for some more flexible tridentate ligands a facial arrangement of donor moieties becomes possible. Accordingly, the geometry of the corresponding Mn(I) hydrides [(LL'L'')(CO)MnH] directly involved in the catalytic processes, namely the nature of the donor extremity located in the -position of the hydride (CO and L for - and -configurations, respectively) may influence their hydride transfer ability.

Pyrazolate phenylethynide: direct exchange of the anionic bridging ligand in a cyclic trinuclear silver complex.

Cyclic trinuclear Ag(I) pyrazolate interacts with phenylacetylene forming a mix-ligand complex in which one pyrazolate ligand is changed to phenylethynide. The CC fragment coordinates only to two silver(I) atoms one carbon atom demonstrating unique μ-η σ-coordination with close Ag-C bond lengths and Ag-C-C angles. The complex exhibits blue emission under UV irradiation.

Synthesis of CF-Containing Spiro-[Indene-Proline] Derivatives via Rh(III)-Catalyzed C-H Activation/Annulation.

An efficient method of accessing new CF-containing spiro-[indene-proline] derivatives has been developed based on a Cp*Rh(III)-catalyzed tandem C-H activation/[3+2]-annulation reaction of 5-aryl-2-(trifluoromethyl)-3,4-dihydro-2-pyrrole-2-carboxylates with alkynes. An important feature of this spiro annulation process is the feasibility of dehydroproline moiety to act as a directing group in the selective activation of the aromatic C-H bond.

Synthesis of Functionalized Isoquinolone Derivatives via Rh(III)-Catalyzed [4+2]-Annulation of Benzamides with Internal Acetylene-Containing α-CF-α-Amino Carboxylates.

A convenient pathway to a new series of α-CF-substituted α-amino acid derivatives bearing pharmacophore isoquinolone core in their backbone has been developed. The method is based on [4+2]-annulation of (pivaloyloxy) aryl amides with orthogonally protected internal acetylene-containing α-amino carboxylates under Rh(III)-catalysis. The target annulation products can be easily transformed into valuable isoquinoline derivatives via a successive aromatization/cross-coupling operation.

Synthesis of Functionalized Azepines via Cu(I)-Catalyzed Tandem Amination/Cyclization Reaction of Fluorinated Allenynes.

An efficient method for the selective preparation of trifluoromethyl-substituted azepin-2-carboxylates and their phosphorous analogues has been developed via Cu(I)-catalyzed tandem amination/cyclization reaction of functionalized allenynes with primary and secondary amines.

Lossen rearrangement by Rh(III)-catalyzed C-H activation/annulation of aryl hydroxamates with alkynes: access to quinolone-containing amino acid derivatives.

A convenient and robust method for the preparation of new CF-containing 2-quinolones has been developed a Rh(III)-catalyzed C-H activation/Lossen rearrangement/annulation cascade of -pivaloyloxy-arylamides with internal alkynes bearing an α-CF-α-amino acid moiety on the triple bond. This work expands the scope of valuable products that are available through C-H activation/annulation reactions of arylamides in organic synthesis.

Thiophene-based water-soluble fullerene derivatives as highly potent antiherpetic pharmaceuticals.

Here we report the Friedel-Crafts arylation of chlorofullerenes C60Cl6 and C70Cl8 with thiophene-based methyl esters. While C60Cl6 formed expected Cs-C60R5Cl products, C70Cl8 demonstrated a tendency for both substitution of chlorine atoms and addition of an extra thiophene unit, thus forming Cs-C70R8 and C1-C70R9H compounds. The synthesized water-soluble C60 and C70 fullerene derivatives with thiophene-based addends demonstrated high activity against a broad range of viruses, including human immunodeficiency virus, influenza virus, cytomegalovirus, and herpes simplex virus.

Direct arylation of CCl and CCl with carboxylic acids: a synthetic avenue to water-soluble fullerene derivatives with promising antiviral activity.

We report unprecedented Friedel-Crafts arylation of chlorofullerenes C60Cl6 and C70Cl8 with unprotected carboxylic acids as an efficient single-step synthesis of the inherently stable water-soluble fullerene derivatives. Using this method, a series of previously unaccessible compounds was obtained without chromatographic purification in almost quantitative yields. Promising anti-HIV activity comparable to characteristics of commercial drugs was demonstrated for some of these compounds.

Diversion of the Arbuzov reaction: alkylation of C-Cl instead of phosphonic ester formation on the fullerene cage.

We report an "inversed" Arbuzov reaction of the fullerene derivatives CArCl with trialkyl phosphites P(OR) producing alkylated fullerene derivatives CArR (R = Me, Et, iPr, nBu) with almost quantitative yields. This reaction provides a convenient synthetic route for the preparation of a large variety of functionalized fullerene derivatives with tailored properties, e.g.

Exploitation of knowledge databases in the synthesis of zinc(II) malonates with photo-sensitive and photo-insensitive ,'-containing linkers.

Photoinitiated solid-state reactions are known to affect the physical properties of coordination polymers, such as fluorescence and sorption behaviour, and also afford extraordinary architectures ( three-periodic structures with polyorganic ligands). However, the construction of novel photo-sensitive coordination polymers requires an understanding of the factors which govern the mutual disposition of reactive fragments. A series of zinc(II) malonate complexes with 1,2-bis(pyridin-4-yl)ethylene and its photo-insensitive analogues has been synthesized for the purpose of systematic analysis of their underlying nets and mutual disposition of -donor ligands.

Structure elucidation of sweet-tasting cycloartane-type saponins from ginseng oolong tea and Abrus precatorius L. leaves.

The composition of ginseng oolong a widely used tea product was investigated. A new sweet-tasting cycloartane-type saponin 3β-O-[β-D-glucuronopyranosyl(1→2)]-β-D-6-acetylglucopyranosyl)-(20S,22S)-3β,22-dihydroxy-9,19-cyclolanost-24-en-26,29-oic acid (9), along with five new compounds, was identified in the methanolic extract of the ginseng oolong tea. Structural elucidation was conducted by spectroscopic methods, including 1D- and 2D-NMR, HR-MS, HPLC-LITMS/MS.

Stereoselective synthesis of novel adamantane derivatives with high potency against rimantadine-resistant influenza A virus strains.

A series of (R)- and (S)-isomers of new adamantane-substituted heterocycles (1,3-oxazinan-2-one, piperidine-2,4-dione, piperidine-2-one and piperidine) with potent activity against rimantadine-resistant strains of influenza A virus were synthesized through the transformation of adamantyl-substituted N-Boc-homoallylamines 8 into piperidine-2,4-diones 11 through the cyclic bromourethanes 9 and key intermediate enol esters 10. Biological assays of the prepared compounds were performed on the rimantadine-resistant S31N mutated strains of influenza A - A/California/7/2009(H1N1)pdm09 and modern pandemic strain A/IIV-Orenburg/29-L/2016(H1N1)pdm09. The most potent compounds were both enantiomers of the enol ester 10 displaying IC = 7.

Distorted commo-Cobaltacarboranes Based on the 5,6-Dicarba-nido-decaborane(12): The First Bimetal Cobalt-Copper Zwitterion-Containing Cluster with Four (B-H)···Cu Bonds Not Showing Fluxional Behavior in Solution.

Treatment of a recently reported complex [PhP][closo,nido-CoH(2,4-CBH)(7,8-CBH)] (1) either by HO in acetone or NaH in THF leads to the loss of both the bridging and terminal hydrides yielding the diamagnetic salt of an anionic commo-cobaltacarborane [PhP][Co(2,4-isonido-CBH)] (2) with the {CoCB}-cluster units adopting a distorted skeletal geometry of the isonido-type. The anionic commo complex 2 reacts with in situ generated cationic [CuPPh] species to give stable copper-cobalt zwitterion [PhPCu][Co(2,4-isonido-CBH)] (3) with four two-electron, three-center (B-H)···Cu bonds, and exhibits no fluxional behavior in solution. Complex 3, at the same time, in CHCl in the presence of 2-fold excess of PPh readily converts to a new anionic species [(PhP)Cu][Co(2,4-isonido-CBH)] (4) which retains initial isonido geometry.

The Role of Weak Interactions in Strong Intermolecular M···Cl Complexes of Coinage Metal Pyrazolates: Spectroscopic and DFT Study.

The nondestructive reversible complexation of the macrocyclic group 11 metal pyrazolates {[3,5-(CF3)2Pz]M}3 (M = Cu(I), Ag(I)) to the halogen atom X = Cl, Br of η(3)-allyliron tricarbonyl halides (η(3)-2-R-C3H4)Fe(CO)3X is revealed by the variable-temperature spectroscopic (IR, NMR) study combined with density functional theory calculations. The composition of all complexes at room temperature is determined as 1:1. In the case of the [AgL]3 macrocycle, complexes 1:2 are observed at low temperature (<260 K).

Tungsten carbonyl σ-complexes with charge-compensated nido-carboranyl thioether ligands.

Charge-compensated nido-carboranyl thioether ligands [7-MeS-10-Me2S-7,8-C2B9H10] and [7,8-(MeS)2-10-Me2S-7,8-C2B9H9] were prepared and fully characterized. They readily react with labile tungsten carbonyls to give σ-complexes - mono-substituted (CO)5W[7-MeS-10-Me2S-7,8-C2B9H10-κ(1)-S(1)] and (CO)5W[7,8-(MeS)2-10-Me2S-7,8-C2B9H9-κ(1)-S(1)] and chelate (CO)4W[7,8-(MeS)2-10-Me2S-7,8-C2B9H9-κ(2)-S(1),S(2)]. The synthesized metallocomplexes were characterized by multinuclear NMR spectroscopy and single crystal X-ray diffraction.

Photoinduced guest transformation promotes translocation of guest from hydroxypropyl-β-cyclodextrin to cucurbit[7]uril.

We report that three-component systems comprising styryl dyes (1 or 2) and two hosts (hydroxypropyl-β-cyclodextrin (HP-β-CD) and cucurbit[7]uril (CB[7])) undergo photoinduced transformation and translocation of the styryl guest from the cavity of HP-β-CD to CB[7]. We find that the protonation of guest trans-1 or the addition of Ba(2+) as competitor for CB[7] triggers dissociation of the container-guest complexes.

Synthesis and the structure of 8-tetrahydrofuronium and 8-tetrahydropyronium derivatives of iron bis(dicarbollide)(-I) and their cleavage reactions.

8-Tetrahydrofuronium and 8-tetrahydropyronium derivatives of iron bis(dicarbollide)(-I) were synthesized. Their reactions of ring cleavage by MeOH, N3(-), amines and 1,2-bis(diphenylphosphino)ethane were investigated. 8-Tetrahydrofuronium iron bis(dicarbollide)(-I) was found to be more active in these reactions in comparison with 8-tetrahydropyronium and 8-dioxonium species, respectively.

An unusual conversion of paramagnetic [3-Cl-3,3,8-{Ph2P(CH2)nPPh-µ-(C6H4-ortho)}-1,2-(CH3)2-closo-3,1,2-RuIIIC2B9H8] (n=3 and 4) to form the first 18-electron P-phenylene ortho-cycloboronated closo-ruthenacarboranes with a dioxygen ligand.

Treatment of [3-Cl-3,3,8-[Ph2P(CH2)nPPh-µ-(C6H4-ortho)]-1,2-Me2-closo-3,1,2-RuIIIC2B9H8] (1, n=3; 2, n=4) with an excess of KOH in a 1:1 benzene/methanol mixture at room temperature in air affords new dioxygen closo-ruthenacarborane complexes [3-(η2-O2)-3,3,8-[Ph2P(CH2)nPPh-µ-(C6H4-ortho)]-1,2-Me2-closo-3,1,2-RuIIIC2B9H8] (3, n=3) and (4, n=4) in 42.5% and 45.8% yield respectively.

Regiospecific C-N photocyclization of 2-styrylquinolines.

Regiospecific C-N photocyclization of 2-styrylquinolines resulting in formation of potentially biologically active quino[1,2-a]quinolizinium derivatives was investigated. The presence of strong electron-donating groups in the phenyl ring reveals to be a crucial factor managing photocyclization effectiveness. Introduction of a crown ether moiety allows changing the photoreaction parameters by means of complexation with Mg(ClO4)2.

A new approach to the synthesis of functional derivatives of nido-carborane: alkylation of [9-MeS-nido-7,8-C2B9H11]⁻.

A series of asymmetrically substituted sulfonium derivatives of nido-carborane [9-R(Me)S-nido-7,8-C2B9H11] (R = Et, Pr, Bu, Bn, CH=CH2, CH2CH=CH2, CH2C≡CH, CH=C=CH2) were prepared by alkylation of the 9-methylthio-nido-7,8-carborane. The synthesized compounds are the first examples of diastereomers combining nido-carborane and sulfonium chiral centers.

Peculiarities of the complexation of copper and silver adducts of a 3,5-bis(trifluoromethyl)pyrazolate ligand with organoiron compounds.

Interaction of the copper, {[3,5-(CF(3))(2)Pz]Cu}(3), and silver, {[3,5-(CF(3))(2)Pz]Ag}(3), macrocycles [3,5-(CF(3))(2)Pz = 3,5-bis(trifluoromethyl)pyrazolate] with cyclooctatetraeneiron tricarbonyl, (cot)Fe(CO)(3), was investigated by IR and NMR spectroscopy for the first time. The formation of 1:1 complexes was observed at low temperatures in hexane. The composition of the complexes (1:1) and their thermodynamic characteristics in hexane and dichloromethane were determined.