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Sydnones are heterocyclic compounds which display important biological activities, including their abilities to react in 1,3-dipolar additions for applications in the development of new prodrugs. Capitalizing on our preliminary work on the mechanosynthesis of sydnones, an extension of this work to two related families of molecules, diarylsydnones and iminosydnones is reported. A ball-milling approach towards the synthesis of diaryl sydnones was developed, a necessary step for the synthesis of potential sydnone-based ligands of metal complexes. A mechanochemistry-based synthesis of iminosydnones was optimized, including the preparation of active pharmaceutical ingredients (API) related to feprosidnine, linsidomine, mesocarb and molsidomine. This work demonstrated that the ball-milling procedures were efficient and time saving through avoiding purification steps, and reduced the use of organic solvents.

The synthesis of a new biobased aromatic diisocyanate derived from lignocellulosic raw material, namely guaiacol and vanillyl alcohol, through phosgene-free routes offers the prospect of greener approaches for isocyanate production and the polyurethane industry. Indeed, bisguaiacol F diisocyanate (BGI) was obtained via a three-step process from readily available bisguaiacol F (BGF), involving conversion of aromatic amine into aromatic isocyanate. The unusual metal-free conversion of BGF to bisguaiacol F diamine (BGA) was performed by a two-step approach: a) the Williamson-type alkylation of BGF and then b) the base-promoted Smiles rearrangement of bis O-Alkylated BGF. In order to improve the sustainability of this process, the first step was realized under solvent-free mechanochemical conditions, and the second step was performed using two different activating methods: thermal and microwave. The thermal process provided an isolated BGA yield of ca. 70%. Microwave activation proved to be an interesting alternative, although a lower yield (32%) of the desired BGA was achieved. Finally, the diisocyanate synthesis was performed via a phosgene-free/room temperature protocol using di-tert-butyl dicarbonate in presence of a catalytic amount of 4-dimethylaminopyridine (DMAP). Two polyurethane thermosets were designed and synthesized using the aromatic diisocyanates, biobased BGI and petrochemical-based methylene diphenyl diisocyanate (MDI), by a solvent-free two-step polymerization process, and their thermo-chemical properties were evaluated. These preliminary results suggest that BGI could be potentially used as a fully biobased surrogate for MDI.

We have focused our attention on alternative synthetic approaches for nucleotides and dinucleotides, that simplifies purification and/or improves sustainability. On one hand, we developed a liquid-...

International audience; In line with recent clinical trials demonstrating that ondansetron, a 5-HT3 receptor (5-HT3R) antagonist, ameliorates cognitive deficits of schizophrenia and the known procognitive effects of 5-HT6 receptor (5-HT6R) antagonists, we applied the hybridization strategy to design dual-acting 5-HT3/5-HT6R antagonists. We identified the first-in-class compound FPPQ, which behaves as a 5-HT3R antagonist and a neutral antagonist 5-HT6R of the Gs pathway. FPPQ shows selectivity over 87 targets and decent brain penetration. Likewise, FPPQ inhibits phencyclidine (PCP)-induced hyperactivity and displays procognitive properties in the novel object recognition task. In contrast to FPPQ, neither 5-HT6R inverse agonist SB399885 nor neutral 5-HT6R antagonist CPPQ reversed (PCP)-induced hyperactivity. Thus, combination of 5-HT3R antagonism and 5-HT6R antagonism, exemplified by FPPQ, contributes to alleviating the positive-like symptoms. Present findings reveal critical structural features useful in a rational polypharmacological approach to target 5-HT3/5-HT6 receptors and encourage further studies on dual-acting 5-HT3/5-HT6R antagonists for the treatment of psychiatric disorders.

The complex pathophysiology of depression, together with the limits of currently available antidepressants, has resulted in the continuous quest for alternative therapeutic strategies. Numerous findings suggest that pharmacological blockade of α2-adrenoceptor might be beneficial for the treatment of depressive symptoms by increasing both norepinephrine and serotonin levels in certain brain areas. Moreover, the antidepressant properties of 5-HT7 receptor antagonists have been widely demonstrated in a large set of animal models. Considering the potential therapeutic advantages in targeting both α2-adrenoceptors and 5-HT7 receptors, we designed a small series of arylsulfonamide derivatives of (dihydrobenzofuranoxy)ethyl piperidines as dually active ligands. Following green chemistry principles, the designed compounds were synthesized entirely using a sustainable mechanochemical approach. The identified compound 8 behaved as a potent α2A/5-HT7 receptor antagonist and displayed moderate-to-high selectivity over α1-adrenoceptor subtypes and selected serotonin and dopaminergic receptors. Finally, compound 8 improved performance of mice in the forced swim test, displaying similar potency to the reference drug mirtazapine.

The diverse signaling pathways engaged by serotonin type 6 receptor (5-HT

Serotonin type 6 receptor (5-HT6R) has gained particular interest as a promising target for treating cognitive deficits, given the positive effects of its antagonists in a wide range of memory impairment paradigms. Herein, we report on degradation of the 1H-pyrrolo[3,2-c]quinoline scaffold to provide the 2-phenyl-1H-pyrrole-3-carboxamide, which is devoid of canonical indole-like skeleton and retains recognition of 5-HT6R. This modification has changed the compound’s activity at 5-HT6R-operated signaling pathways from neutral antagonism to inverse agonism. The study identified compound 27 that behaves as an inverse agonist of the 5-HT6R at the Gs and Cdk5 signaling pathways. Compound 27 showed high selectivity and metabolic stability and was brain penetrant. Finally, 27 reversed scopolamine-induced memory decline in the novel object recognition test and exhibited procognitive properties in the attentional set-shifting task in rats. In light of these findings, 27 might be considered for further evaluation as a new cognition-enhancing agent, while 2-phenyl-1H-pyrrole-3-carboxamide might be used as a template for designing 5-HT6R inverse agonists.

International audience; (R)-1,2-Diaminobicyclo[2.2.2]octane was used as a starting material for the preparation, in solution or in a ball mill, of a salen ligand. Five metal salen complexes were prepared in high yield and their cytotoxic activities were evaluated against the Human Colon cancer HCT116 cell lines. The original manganese salen complex displayed the highest activity with a potency 16 fold higher than that of cisplatin, demonstrating the benefit of the bridging backbone compared to other salen systems. An alternative preparation route for this complex by mechanochemistry was also performed.

International audience; The diverse signaling pathways engaged by serotonin type 6 receptor (5-HT6R) together with its high constitutive activity suggests different types of pharmacological interventions for the treatment of CNS disorders. Nonphysiological activation of mTOR kinase by constitutively active 5-HT6R under neuropathic pain conditions focused our attention on the possible repurposing of 5-HT6R inverse agonists as a strategy to treat painful symptoms associated with neuropathies of different etiologies. Herein, we report the identification of compound 33 derived from the library of 2-aryl-1H-pyrrole-3-carboxamides as a potential analgesic agent. Compound 33 behaves as a potent 5-HT6R inverse agonist at Gs, Cdk5, and mTOR signaling. Preliminary ADME/Tox studies revealed preferential distribution of 33 to the CNS and placed it in the low-risk safety space. Finally, compound 33 dose-dependently reduced tactile allodynia in spinal nerve ligation (SNL)-induced neuropathic rats.

International audience; Serotonin type 6 receptor (5-HT6R) has gained particular interest as a promising target for treating cognitive deficits, given the positive effects of its antagonists in a wide range of memory impairment paradigms. Herein, we report on degradation of the 1H-pyrrolo[3,2-c]quinoline scaffold to provide the 2-phenyl-1H-pyrrole-3-carboxamide, which is devoid of canonical indole-like skeleton and retains recognition of 5-HT6R. This modification has changed the compound's activity at 5-HT6R-operated signaling pathways from neutral antagonism to inverse agonism. The study identified compound 27 that behaves as an inverse agonist of the 5-HT6R at the Gs and Cdk5 signaling pathways. Compound 27 showed high selectivity and metabolic stability and was brain penetrant. Finally, 27 reversed scopolamine-induced memory decline in the novel object recognition test and exhibited procognitive properties in the attentional set-shifting task in rats. In light of these findings, 27 might be considered for further evaluation as a new cognition-enhancing agent, while 2-phenyl-1H-pyrrole-3-carboxamide might be used as a template for designing 5-HT6R inverse agonists.

The use of ball-mills enabled the straightforward synthesis of a variety of silver(I) complexes featuring challenging NHC ligands. Sterically hindered including electron-poor or with very low solubility imidazolium salts were grinded with silver(I) oxide to furnish heteroleptic or homoleptic complexes in high yield and short reaction times. The synthesis of heteroleptic bis-NHC silver(I) complexes was also performed for the first time in a ball-mill. The efficiency and rapidity of the mechanochemical approach enabled the generation of a library of unprecedented NHC silver complexes, which cytotoxicity on HCT116 colorectal cancer cell line was evaluated providing a rare example of medicinal mechanochemistry. The cationic silver complexes were found more potent than the neutral analogues, with IC50 values down to 21 nM, 256 times more potent than cisplatin.; The use of ball-mills enabled the straightforward synthesis of a variety of silver(I) complexes featuring challenging NHC ligands. Sterically hindered including electron-poor or with very low solubility imidazolium salts were grinded with silver(I) oxide to furnish heteroleptic or homoleptic complexes in high yield and short reaction times. The synthesis of heteroleptic bis-NHC silver(I) complexes was also performed for the first time in a ball-mill. The efficiency and rapidity of the mechanochemical approach enabled the generation of a library of unprecedented NHC silver complexes, which cytotoxicity on HCT116 colorectal cancer cell line was evaluated providing a rare example of medicinal mechanochemistry. The cationic silver complexes were found more potent than the neutral analogues, with IC50 values down to 21 nM, 256 times more potent than cisplatin.

International audience; A solvent-assisted mechanochemical approach to access symmetrical and mixed dinucleoside 5,5'-polyphosphates is reported. Under ball-milling conditions, nucleoside 5'-monophosphates are quantitatively activated using N,N'-carbonyldiimidazole into their phosphorimidazolide derivatives. The addition of a nucleoside 5'-mono, di or triphosphate directly leads to the formation of the corresponding dinucleotides. Benefits of the reported one-pot method include the use of unprotected nucleotides in their sodium or acid form, activation by the eco-friendly N,N'-carbonyldiimidazole, non-dry conditions, short reaction time, high conversion rates and easy setup and purification. This work offers new perspectives for the synthesis of nucleotide conjugates and analogues, combining the phosphorimidazolide approach and milling conditions.

Recently, ball milling has become an excellent tool in synthetic organic chemistry as it offers several advantages over classical batch synthesis. Here, an efficient and sustainable mechanochemical procedure was developed to obtain PZ-1361, a potent and selective 5-HT7 receptor antagonist, with significant antidepressant properties in rodents. The elaborated protocol limited the use of organic solvents, reduced the excess of the alkylating agent, and enabled to avoid column chromatography purification of intermediates and the final compound.

International audience; Unusual high-cluster (Cu 9) cage phenylsilsesquioxanes were obtained via complexation of in situ Cu II ,Nasilsesquioxane species formed with phenanthroline and neocuproine. In the first case, phenanthroline, acting as "a silent ligand" (not participating in the composition of the final product), favors the formation of an unprecedented cagelike phenylsilsesquioxane of Cu 9 Na 6 nuclearity, 1. In the second case, neocuproine ligands withdraws two Cu ions from the metallasilsesquioxane matrix, producing two cationic fragments Cu + (neocuproine) 2. The remaining metallasilsesquioxane is rearranged into an anionic cage of Cu 9 Na 4 nuclearity, finalizing the formation of a specific ionic complex, 2. The impressive molecular architecture of both types of complexes, e.g., the presence of different (cyclic/acyclic) types of silsesquioxane ligands, was established by single-crystal X-ray diffraction studies. Compound 1 was revealed to be highly active in the oxidative amidation of benzylic alcohol and the catalyst loading could be reduced down to 100 ppm of Cu. Catalytic studies of compound 1 demonstrated its high activity in hydroperoxidation of alkanes with H 2 O 2 and oxidation of alcohols to ketones with tert-BuOOH.

International audience; 1,3-Di(benzyloxy)imidazol-2-ylidenes (or NOHCs) possess structures related to N-heterocyclic carbenes (NHCs), with potentially useful applications including the stabilization of metals. In order to prepare NOHC metal complexes, a multi-step synthesis involving mechanochemistry, and making use of ball-milling, was designed. A library of unprecedented NHOC metal complexes were tested for their cytotoxic activities against HCT116 colorectal cancer cell line. The tests demonstrated that the studied complexes displayed a similar activity, comparable with that one exhibited by the ligand. However, a remarkable activity was found in the case of silver complex 5 with an IC50 value of 0.75 μM, comparable to that of doxorubicin.

The recently described homoleptic cationic [Ag(IPr)2]PF6 [IPr = 1,3-bis(2,6-diisopropylphenyl)imidazolylidene] complex proved to be a versatile and highly efficient catalyst for the production of propargylamines by using the A3-coupling reaction. The reaction conditions were equally applicable to aliphatic and aromatic aldehydes and alkynes, including highly hindered aromatic aldehydes. Progargylamines were prepared in short reaction times with low catalyst loadings by using MeOH as a low-toxicity solvent. In addition, the catalyst was stable enough to support continuous-flow conditions, which showed that the reaction conditions are scalable.

International audience; The use of ball mills enabled the efficient mechanosynthesis of a variety of N-aryl,N-alkyl imidazolium salts and of corresponding NHC silver(I) complexes. Transmetalation with ruthenium via mechanochemistry allowed the rapid access (from 1.5 min to 1 h) to complexes having a similar structure to Noels-type precatalysts. Evaluation of the complexes in the ring-opening metathesis polymerization of norbornene in different solvent, including nontoxic ones, showed a high catalytic activity for one of them, comparable to that of the Noels catalyst.

International audience; A mechanochemical procedure was developed to obtain PZ-1361, a potent and selective 5-HT 7 receptor antagonist, with antidepressant properties in rodents. The elaborated protocol offered several advantages over classical batch synthesis, including improvement of the overall yield (from 34% to 64%), reduction of reaction time (from 60 to 5.5 h), limitation of the use of toxic solvents, and the formation of byproducts. This approach represents a rare example of the synthesis of biologically active compounds exclusively performed using mechanochemical reactions .

International audience; Two cage copper(II)silsesquioxanes, namely, tricopper complex (PhSiO 1.5) 8 (CuO) 3 (TMEDA) 2 *(MeCN) 3 Cu-1 and hexacopper complex (MeSiO 1,5) 12 (CuO) 6 (Py) 6 *TMEDA Cu-2 were synthesized (in 30% and 16% yield, respectively) via TMEDA-assisted reactions (TMEDA ¼ tetramethylethylenediamine). Structural features of both products were established by X-ray diffraction study. Complexes Cu-1 and Cu-2, along with some Cu(II)-silsesquioxanes reported earlier, were evaluated for the first time as precatalysts for the homogeneous Chan-Evans-Lam (CEL) O-arylation of benzoic acids (the highest yield of phenylbenzoic ester was 84%). Observed catalytic activity was superior to reference catalyst Cu(OAc) 2 *H 2 O. Finally, an application of coppersilsesquioxanes allowed to observe the first example of CO CEL coupling under microwave activation characterized by (i) reduced loading of copper, (ii) low amount of added base, (iii) minimization of the time of reaction.

The use of ball-mills enabled the efficient mechanosynthesis of a variety of N-aryl,N-alkyl imidazolium salts and of corresponding NHC-silver(I) complexes. Transmetalation with ruthenium via mechanochemistry allowed the rapid access (1.5 min to 1 h) to complexes having a similar structure to Noels-type precatalysts. Evaluation of the complexes in the Ring-Opening Metathesis Polymerization of norbornene in different solvent, including non-toxic ones, showed a high catalytic activity for one of them, comparable to the one of Noels catalyst.

International audience; Sydnones are mesioionic compounds studied for years for their versatile reactivity in substitution reactions, sydnone-alkyne or sydnone-alkene cycloaddition reactions. This perspective article focuses on the use of sydnones in coordination complexes, either through a metalation on one of the carbons of the sydnone ring, its modification to obtain polydentate ligands, or its use as a polar moiety that could influence the properties of the final complex. Such compounds are valuable either from a synthetic point of view or for their biological properties.

International audience; We have developed original one-pot and protecting group-free approaches, which are also userfriendly and reliable, to synthesize nucleotides and derivatives starting from nucleoside 5'-monophosphates. Both methods present convenient setup , i.e., non-dry solvents and reagents, substrates in their sodium or acid form, and commercially available and cheap phosphorus reagents as sodium and potassium salts.

In light of the multifactorial origin of neurodegenerative disorders and some body of evidence indicating that pharmacological blockade of serotonin 5-HT

International audience; A simple and versatile strategy of synthesis of cage metallagermaniumsesquioxanes is demonstrated for isolation of Cu 6-based phenylgermsesquioxanes 1e6. Structure of newly synthesized coppergermsesquioxanes was established by single-crystal X-ray diffraction analysis. General principle of these cages' topology implies the presence of two linear Cu 3 fragments, coordinated by three pairs of ligands. These are: (i) cyclic germsesquioxanes [PhGeO 1,5 ] 5 , products 1e6, (ii) 1,10-phenanthrolines, (1, 3e5) or 2,2'bipyridines, (2, 6), (or and (iii) OX species (X ¼ H, 1e2, CH 3 , 3, H and C 2 H 5 O, 4, HCO, 5, CH 3 CO, 6). Appearance of non-expected species (formiate for 5, acetate for 6), resulted from corresponding alcohols used as reaction media, points at easyness of oxidation processes in the conditions of such selfassembling reactions. Catalytic tests showed high activity of complexes 1 and 2 as precatalysts in homogeneous oxidations of alkanes (cyclohexane, methylcyclohexane, n-heptane, cis-1,2dimethylcyclohexane with hydrogen peroxide in acetonitrile solution. Hydroxyl radicals take part in the reaction. The same complexes catalyze oxidation of alcohols (cyclohexanol, 2-heptanol, 1phenylethanol) to corresponding ketones with tert-butyl hydroperoxide in almost 100% yield. With the addition of various alkyl ammonium salts, complex 2 could also furnish corresponding amides in high yield.

Mechanical forces induced by ball-milling agitation enabled the highly efficient and widely applicable synthesis of Cu–carbene complexes from N,N-diaryl-imidazolium salts and metallic copper. The required amount of gaseous dioxygen and insoluble copper could be reduced down to stoichiometric quantities, while reaction rates clearly outperformed those obtained in solution. Utilisation of Cu(0) as the copper source enabled the application of this approach to a wide array of N,N-diaryl-imidazolium salts (Cl−, BF4− and PF6−) that transferred their counter anion directly to the organometallic complexes. Cu–NHC complexes could be produced in excellent yields, including utilisation of highly challenging substrates. In addition, five unprecedented organometallic complexes are reported.

International audience; A silver-catalyzed cycloisomerization reaction of a series of o-alkynylbenzohydroxamic acids is reported. Several 5-exo-dig and 6-endo-dig modes of cyclization were observed with the nitrogen or oxygen atoms of the amide group acting as nucleophiles. The selectivity was strongly dependent on the silver salt used and on the presence of triphenylphosphine as an additive. Indeed, while the use of Ag2O at room temperature allowed the isolation of isobenzofuran-1-one oximes (7 compounds, 48–92% yield), [Ag(Im)]n with the concomitant addition of 2 equiv of PPh3 led to a switch in selectivity and to a family of isoindolin-1-ones (10 compounds, 59–87%).

International audience; Sydnones are mesioionic compounds studied for years for their versatile reactivity in substitution reactions, sydnone-alkyne or sydnone-alkene cycloaddition reactions. This perspective article focuses on the use of sydnones in coordination complexes, either through a metalation on one of the carbons of the sydnone ring, its modification to obtain polydentate ligands, or its use as a polar moiety that could influence the properties of the final complex. Such compounds are valuable either from a synthetic point of view or for their biological properties.

International audience; Unprecedented germanium-based sesquioxane exhibits an extremely high nuclearity (Cu 42 Ge 24 Na 4) and unusual encapsulation features. The compound demonstrated a high catalytic activity in the oxidative amidation of alcohols, with cost-effective catalyst loading down to 400 ppm of copper, and in the oxidation of cyclohexane and other alkanes with H 2 O 2 in acetonitrile in the presence of nitric acid. Selectivity parameters and the mode of dependence of initial cyclohexane oxidation rate on initial concentration of the hydrocarbon indicate that the reaction occurs with the participation of hydroxyl radicals and alkyl hydroperoxides are formed as the main primary product. Alcohols have been transformed into the corresponding ketones by the catalytic oxidation with tert-butyl hydroperoxide.

Unusual high-cluster (Cu

International audience; The absence of solvent, associated with intensive mechanical agitation, allowed the first mechanosynthesis of high-value silver(I)-carbenec omplexes and the corresponding N,N-dialkylimidazolium precursors. This procedure gave outstanding results in terms of yield and reactiont ime, when compared to solution-based conditions previously described in literature, and was generalized to unprecedented compounds. Silver(I)-carbene complexes could either be obtainedf rom N,N-dialkylimidazolium salts or directly from imidazole and alkyl halides in ao ne-pot two-step procedure withouti solating the imidazolium intermediate. Additionally,a ne fficient one-pot three-step sequence, including imidazole alkylation, silver metalation, andtransmetalationi sr eported.

The authors gratefully acknowledge the Royal Society (University Research Fellowship to CSJC), the CNRS (Centre National de la Recherche Scientifique) and l'Université de Montpellier for funding. In this short review, we focus on the synthesis and applications of new phosphite-bearing ruthenium complexes in olefin metathesis. These complexes were designed to take advantage of a known synergistic effect between strong σ-donating NHC ligands and π-acidic phosphites. The resulting catalysts display higher stability compared to their phosphine-containing congeners. A comparative summary of their use in ring-closing metathesis, cross metathesis and ring-opening metathesis polymerization is presented as well as DFT calculations describing our mechanistic understanding. Postprint

The transmetalation of bimetallic copper-sodium silsesquioxane cages, namely, [(PhSiO1.5 )10 (CuO)2 (NaO0.5 )2 ] ("Cooling Tower"; 1), [(PhSiO1.5 )12 (CuO)4 (NaO0.5 )4 ] ("Globule"; 2), and [(PhSiO1.5 )6 (CuO)4 (NaO0.5 )4 (PhSiO1.5 )6 ] ("Sandwich"; 3), resulted in the generation of three types of hexanuclear cylinder-like copper silsesqui- oxanes, [(PhSiO1.5 )12 (CuO)6 (C4 H9 OH)2 (C2 H5 OH)6 ] (4), [(PhSiO1.5 )12 (CuO)6 (C4 H8 O2 )4 (PhCN)2 (MeOH)4 ] (5), and [(PhSiO1.5 )12 (CuO)6 (NaCl)(C4 H8 O2 )12 (H2 O)2 ] (6). The products show a prominent "solvating system-structure" dependency, as determined by X-ray diffraction. Topological analysis of cages 1-6 was also performed. In addition, DFT theory was used to examine the structures of the Cooling Tower and Cylinder compounds, as well as the spin density distributions. Compounds 1, 2, and 5 were applied as catalysts for the direct oxidation of alcohols and amines into the corresponding amides. Compound 6 is an excellent catalyst in the oxidation reactions of benzene and alcohols.

Herein is described a mechanochemical one-pot two-step procedure giving access to various NHC (N-heterocyclic carbene) precursors. This original approach enabled the production of the widely used IPr·HCl, IMes·HCl, Io-Tol·HCl and ICy·HCl in much better yields than conventional solvent-based procedures, while the environmental impact was drastically reduced.

International audience; A new representative of an unusual family of metallagermaniumsesquioxanes, namely the heterometallic cagelike phenylgermsesquioxane (PhGeO 2) 12 Cu 2 Fe 5 (O)OH-(PhGe) 2 O 5 (bipy) 2 (2), was synthesized and structurally characterized. Fe(III) ions of the complex are coordinated by oxa ligands: (i) cyclic (PhGeO 2) 12 and acyclic (Ph 2 Ge 2 O 5) germoxanolates and (ii) O 2− and (iii) HO − moieties. In turn, Cu(II) ions are coordinated by both oxa (germoxanolates) and aza ligands (2,2′-bipyridines). This "hetero-type" of ligation gives in sum an attractive pagoda-like molecular architecture of the complex 2. Product 2 showed a high catalytic activity in the oxidation of alkanes to the corresponding alkyl hydroperoxides (in yields up to 30%) and alcohols (in yields up to 100%) and in the oxidative formation of benzamides from alcohols (catalyst loading down to 0.4 mol % in Cu/Fe).

Herein, we describe an approach to cage metallasilsesquioxanes by self-assembly with 1,2-bis(diphenylphosphino)ethane as a key reactant. This approach allowed us to achieve a unique family of complexes that includes anionic tetra- and nonanuclear cage copper(II) sodium silsesquioxane and cationic copper(I) 1,2-bis(diphenylphosphino)ethane components. Additional representatives of this intriguing metallasilsesquioxane family (Cu9Na6 and Cu9Na3Cs3) were obtained through the replacement of the original ethanol-based reaction medium by DMSO. The fascinating structural peculiarities of all products were established by using XRD and topological studies. Initial tests for the application of the synthesized complexes as catalysts revealed their very high activity in the homogeneous oxidation of alkanes and alcohols to produce alkyl hydroperoxides, ketones, and amides.

The synthesis, composition, and catalytic properties of a new family of hexanuclear Cu(II)-based phenylsilsesquioxanes are described here. Structural studies of 17 synthesized compounds revealed the general principle underlying their molecular topology: viz., a central metal oxide layer consisting of two Cu

International audience; Herein, we report the synthesis of zirconium metal-organic frameworks by a mechanochemical route. The frameworks are obtained by the coordination of a zirconium cluster with the biphenyldicarboxylic acid linker to obtain UiO-67 or with the iso-structural 2,20 -bipyridine-5,50 -dicarboxylic acid to access to a functional MOF (UiO-67-bpy). In a second mechanochemical reaction, it has been possible to coordinate by post-synthetic modification a copper salt on each bipyridine site (UiO-67-bpy-Cu). Both materials exhibit crystallinity and porosity (up to 750 m$^2$ /g) showing the possibility to get access to elaborated materials in a cleaner way than the classical solvothermal route in DMF.

Two types of heterometallic (Fe(III),Na) silsesquioxanes [Ph5Si5O10]2[Ph10Si10O21]Fe6(O2‒)2Na7(H3O+)(MeOH)2(MeCN)4.5.1.25(MeCN), I, and [Ph5Si5O10]2[Ph4Si4O8]2Fe6Na6(O2‒)3(MeCN)8.5(H2O)8.44, II, were obtained and characterized. X-Ray studies established distinctive structures of both products, with pair of Fe(III)-O-based triangles surrounded by siloxanolate ligands, giving fascinating cage architectures. Complex II proved to be catalytically active in the formation of amides from alcohols and amines, thus becoming a rare example of metallasilsesquioxanes performing homogeneous catalysis. Benzene, cyclohexane and other alkanes, as well as alcohols, can be oxidized in acetonitrile solution to phenol, the corresponding alkyl hydroperoxides and ketones, respectively, by hydrogen peroxide in air in the presence of catalytic amounts of complex II and trifluoroacetic acid. Thus, the cyclohexane oxidation at 20 °C gave oxygenates in very high for alkanes yield (48% based on alkane). The kinetic behaviour of the system indicates that the mechanism includes the formation of hydroxyl radicals generated from hydrogen peroxide in its interaction with diiron species. The latter are formed via monomerization of starting hexairon complex with further dimerization of the monomers.

The amide bond is an essential unit in many drugs and polymers. The catalyzed oxidation of alcohols and amines is an effective method to form amides with limited undesired waste. Herein, we demonstrate the beneficial effect of microwave activation for this reaction. The benzamides were directly formed from alcohols and amine hydrochloride salts in short reaction times with yields up to 84 % and TOFs (turnover frequencies) up to 33.6 h–1. Among the examined transition metals, only nontoxic and inexpensive FeCl2·4H2O together with caffeine as a stabilizing ligand provided a uniquely efficient catalytic system for the transformation. Natural sources of caffeine were also evaluated under the amidation conditions.

The synthesis, characterization, and catalytic activity of two new complexes, 2a,b, featuring a sterically demanding NHC and two different phosphites are described. Complexes 2a,b display a mutually trans arrangement of the π-acidic phosphite and the strong σ-donor SIPr ligand (SIPr = N,N′-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene). The synergy between the phosphite and the NHC ligand was revealed in the RCM of challenging substrates leading to tetrasubstituted olefins where, in comparison to their phosphine-containing analogues, 2a,b allowed higher conversions of these challenging substrates.

A series of Pd dimers bearing an N-heterocyclic carbene ligand was studied in the Mizoroki–Heck reaction. [Pd(μ-Cl)Cl(SIPr)]2 (SIPr = {N,N′-bis[2,6-(diisopropyl)phenyl]imidazolidin-2-ylidene}) was shown to be highly efficient in this cross-coupling for a range of aryl and heterocyclic bromides, with low palladium loading (20–200 ppm).

International audience; The synthesis, composition, and catalytic properties of a new family of hexanuclear Cu(II)-based phenylsilsesquioxanes are described here. Structural studies of 17 synthesized compounds revealed the general principle underlying their molecular topology: viz., a central metal oxide layer consisting of two Cu 3 trimers is coordinated by two cyclic [PhSiO 1.5 ] 5 siloxanolate ligands to form a skewed sandwich architecture with the composition [(PhSiO 1.5) 10 (CuO) 6 ] 2+. In addition to this O ligation by the siloxanolate rings, two opposite copper ions are additionally coordinated by the nitrogen atoms of corresponding N ligand(s), such as 2,2′-bipyridine (compounds 1−9), 1,10-phenanthroline (compounds 10−13), mixed 1,10-phenanthroline/2,2′-bipyridine (compound 14), or bathophenanthroline (compounds 15−17). Finally, the charge balance is maintained by two HO − (compounds 1−7, 10−13, and 15−17), two H 3 CO − (compound 8), or two CH 3 COO − (compounds 9 and 14) anions. Complexes 1 and 10 exhibited a high activity in the oxidative amidation oxidation of alcohols. Compounds 1, 10, and 15 are very efficient homogeneous catalysts in the oxidation of alkanes and alcohols with peroxides.

International audience; A user-friendly and solvent-free mechanosynthetic strategy allowed light-sensitive silver(I) complexesfeaturing N,N-diaryl N-heterocyclic carbenes (NHC), including challenging and sterically hinderedligands, to be yielded efficiently. The first transmetalations using ball-milling to obtain palladium andcopper NHC complexes were performed. A convenient one-pot two-step metalation/transmetalationprocedure was also realized.