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International audience; A multi-polydentate N-substituted oxamate ligand bearing an additional carboxylato group has been successfully reacted in solvothermal conditions to form the 2D coordination network (TMA) 3 [CuMn(paba) 2 (OAc)]•8H 2 O (1). This coordination network displays a brick-wall type morphology with, thanks to the augmented connectivity of the ligand, a lower than usual metal ion nuclearity for the building sub-unit. Temperature-dependent structural studies indicate that the layered structure undergoes dehydration at 90°C and remain stable up to 200°C. Magnetic characterizations show that 1 behaves as a ferrimagnet, with a Curie temperature of 2.8 K.

What happens when a C−H bond is forced to interact with unpaired pairs of electrons at a positively charged metal? Such interactions can be considered as “contra-electrostatic” H-bonds, which combine the familiar orbital interaction pattern characteristic for the covalent contribution to the conventional H-bonding with an unusual contra-electrostatic component. While electrostatics is strongly stabilizing component in the conventional C−H•••X bonds where X is an electronegative main group element, it is destabilizing in the C−H•••M contacts when M is Au(I), Ag(I), or Cu(I) of NHC−M−Cl systems. Such remarkable C−H•••M interaction became experimentally accessible within (α-ICyDMe)MCl, NHC−Metal complexes embedded into cyclodextrins. Computational analysis of the model systems suggests that the overall interaction energies are relatively insensitive to moderate variations in the directionality of interaction between a C−H bond and the metal center, indicating stereoelectronic promiscuity of fully filled set of d-orbitals. A combination of experimental and computational data demonstrates that metal encapsulation inside the cyclodextrin cavity forces the C−H bond to point toward the metal, and reveals a still attractive “contra-electrostatic” H-bonding interaction.

What happens when a C−H bond is forced to interact with unpaired pairs of electrons at a positively charged metal? Such interactions can be considered as “contra-electrostatic” H-bonds, which combine the familiar orbital interaction pattern characteristic for the covalent contribution to the conventional H-bonding with an unusual contra-electrostatic component. Whereas electrostatics is strongly stabilizing in the conventional C−H•••X bonds where X is an electronegative main group element, it is destabilizing in the C−H•••M contacts when M is Au(I), Ag(I), or Cu(I) of NHC−M−Cl systems. Such remarkable C−H•••M interaction became experimentally accessible within (a-ICyDMe)MCl, NHC−Metal complexes embedded into cyclodextrins. Computational analysis of the model systems suggests that the overall interaction energies are relatively insensitive to moderate variations in the directionality of interaction between a C−H bond and the metal center, indicating stereoelectronic promiscuity of fully filled set of d-orbitals. A combination of experimental and computational data demonstrates that metal encapsulation inside the cyclodextrin cavity forces the C−H bond to point toward the metal, and reveals a still attractive “contra-electrostatic” H-bonding interaction.

International audience; A new route to Martins spirosilanes has been devised. The original synthesis does not allow diversely substituted spirosilane derivatives to be synthesized, and thus their corresponding silicates. In this report, Martins spirosilanes bearing alkyl, aryl, halogen, alkoxy, and trifluoromethyl substituents on the aryl ring have been prepared through a versatile four-step route. Addition of fluoride onto these Lewis acids as a prototypical reaction with a nucleophile yielded a library of stable fluorosilicates. Both sets of compounds have been characterized by X-ray crystallograph

International audience; The first systems associating in a single molecule polyoxotungstates (POTs) and photochromic organic groups have been elaborated. Using the (TBA)4[PW11O39{Sn(C6H4I)}] precursor, two hybrid organic-inorganic species where a spiropyran derivative (SP) has been covalently grafted onto a {PW11Sn} fragment via a Sonogashira coupling have been successfully obtained. Alternatively, a complex containing a silicotungstate {PW11Si2} unit connected to two spiropyran entities has been characterized. The purity of these species has been assessed using several techniques, including 1H and 31P NMR spectroscopy, mass spectrometry, and electrochemical measurements. The optical properties of the hybrid materials have been investigated both in solution and in the solid state. These studies reveal that the grafting of SPs onto POTs does not significantly alter the photochromic behavior of the organic chromophore in solution. In contrast, these novel hybrid SP-POT materials display highly effective solid-state photochromism from neutral SP molecules initially nonphotochromic in the crystalline state. The photoresponses of the SP-POT systems in the solid state strongly depend on the nature and the number of grafted SP groups.

Mono- and bidentate ligands (5–8, 15–18, 20, 29–31) have been synthesized in which the phosphinyl group substitutes a (η5-cyclohexadienyl)Mn(CO)3 scaffold. In the case of one of the bidentate ligan...

A new series of polyoxometalate-based hybrids has been synthesized. These covalently linked organic-inorganic materials represent valuable elementary building blocks ready for postfunctionalization, using classical organic reactions and couplings. This approach is exemplified by the grafting of an organic chromophore via a Sonogashira coupling.

We report the first synthesis of π-bonded rhodio and iridio-o-benzoquinones [Cp*M(o-benzoquinone)] (M = Rh (3a); M = Ir (3b)) following a novel synthetic procedure. These compounds were fully characterized by spectroscopic methods; in particular the X-ray molecular structure of 3b was determined. Compounds 3a,b were used as chelating organometallic linkers for the design of a new family of chiral octahedral bimetallic complexes, 4−9. The X-ray molecular structure of [(bpy)2Ru(3b)][OTf]2 (5) is presented and shows that the organometallic linker 3b is chelating the ruthenium center. In particular, the carbocycle of the organometallic linker 3b adopts a η4-quinone form, where the Cp*Ir is also bonded to only four carbons. Further our strategy to design new assemblies with organometallic linkers is successfully achieved. These assemblies hold promise for new properties relative to those made from organic bidentate ligands.

The 3-(2'-imidazolyl)-1,5-dimethyl-6-oxoverdazyl radical (imvd(*)) and the corresponding tetrazane H3imvd were prepared and structurally characterized, the former as two different hydrates. Reaction of imvd(*) with [M(hfac)2] led to the formation of monometallic complexes [M(hfac)2(imvd(*))] (M = Ni and Mn). They were characterized by single-crystal X-ray diffraction. In the solid state, all four radical-containing compounds exhibit imidazole-oxoverdazyl pi stacking. Following the structural analysis, imvd(*) behaves as an antiferromagnetic (AF) coupled chain with J = -100 cm(-1) (H = -J summation operator SiS(i+1)). The magnetic behavior of [M(hfac)2(imvd(*))] complexes is interpreted with a four-coupled spin model with a metal ion radical intramolecular interaction (JMn = -62.5 cm(-1) and JNi = 193 cm(-1); H = -JSMSimvd) and an AF intermolecular interaction (JMn' = -12.6 cm(-1) and JNi' = -4.3 cm(-1)) related to imidazole-oxoverdazyl pi stacking.

Four new 1D coordination polymers have been constructed from [LCuIIMII] nodes connected by various spacers—the dianion of pyrazole-3,5-dicarboxylic acid (pzdc2−), the trianion of trimesic acid (trim3−), the tetracyanonickelate(II) anion ([Ni(CN)4]2−), and the dicyanamide anion (dca−) [MII = MnII, CoII, and L2− is the dianion of the Schiff-base resulting from the 2:1 condensation of 3-methoxysalicylaldehyde with 1,3-propanediamine, L2− = N,N′-propylene-bis-(3-methoxysalycilideneiminato)]: [LCuMn(pzdc)(CH3OH)(H2O)]·H2O (1), [LCuMn(trim)2/3(CH3OH)2/3(H2O)1/3]·0.66(H2O)·0.66(CH3OH) (2), [LCuCo(dca)2] (3), and [LCu(CH3OH)(H2O)Mn(NC)2Ni(CN)2]·(H2O)(CH3CN) (4). The fifth compound, [{CuL}K{LCu}{Ag(CN)2}] (5), was obtained by reacting [CuL] with K[Ag(CN)2]. The magnetic investigation of compounds 1, 2, and 4 reveals antiferromagnetic CuII−MnII intranode interactions (1, J = −48.9 cm−1; 2, J = −64.7 cm−1; and 4, J = −60.4 cm−1; H = −JSMnSCu), as well as weak internodes antiferromagnetic interactions (for compounds ...

The ruthenium-nitrido POM derivative [PW11O39{RuVIN}]4- has been synthesized by reaction between [PW11O39]7- and [RuVINCl5]2- or [RuVINCl4]-. Its molecular structure has been confirmed from multinuclear 31P and 183W NMR spectroscopy together with an EXAFS study, while the oxidation state of the ruthenium bearing the nitrido ligand has been inferred both from 183W NMR and XANES analysis at the Ru-K edge. The potential of [PW11O39{RuVIN}]4- in N-atom transfer reactions has been demonstrated through reaction with triphenylphosphine, which ultimately leads to the release of the bis(triphenylphosphane)iminium cation [PPh3=N=PPh3]+ through several intermediates, among which the phosphoraniminato derivative [PW11O39{RuVNPh3}]3- has been structurally characterized. Its unusual oxidation state is in accordance with its EPR spectrum.

New homo- and heterometallic, hexa- and pentanuclear complexes of formula {[Cu2(mpba)2(H2O)F][Cu(Me5dien)]4}(PF6)3·5H2O (1), {[Cu2(Me3mpba)2(H2O)2][Cu(Me5dien)]4}(ClO4)4·12H2O (2), {[Cu2(ppba)2][Cu(Me5dien)]4}(ClO4)4 (3), and [Ni(cyclam)]{[Cu2(mpba)2][Ni(cyclam)]3}(ClO4)4·6H2O (4) [mpba = 1,3-phenylenebis(oxamate), Me3mpba = 2,4,6-trimethyl-1,3-phenylenebis(oxamate), ppba = 1,4-phenylenebis(oxamate), Me5dien = N,N,N‘N‘ ‘,N‘ ‘-pentamethyldiethylenetriamine, and cyclam = 1,4,8,11-tetraazacyclotetradecane] have been synthesized through the use of the “complex-as-ligand/complex-as-metal” strategy. The structures of 1−3 consist of cationic CuII6 entities with an overall [2 × 2] ladder-type architecture which is made up of two oxamato-bridged CuII3 linear units connected through two m- or p-phenylenediamidate bridges between the two central copper atoms to give a binuclear metallacyclic core of the cyclophane-type. Complex 4 consists of cationic CuII2NiII3 entities with an incomplete [2 × 2] ladder-type archite...

Tris(bipyridine)ruthenium(II) is used as a templating agent to insert palladium(II) into three-dimensional oxalate-based networks. The templated-assembly of [Ru(bpy)(3)][Pd(2)(ox)(3)] (Pd(2)) and [Ru(bpy)(3)][PdMn(ox)(3)] (PdMn) is described. The latter compound is structurally characterized by powder X-ray diffraction and X-ray absorption spectroscopy. These techniques reveal an unusual 6-fold oxygen environment around the Pd(II) atoms with two short (2.02 Angstrom) and four long (2.17 Angstrom) Pd-O distances. As stated by magnetometry, this environment is associated with a triplet ground state (S = 1) of the palladium(II) ion: when the temperature is decreased, the chiMT product shows a monotonous decrease from 5.54 cm(3) K mol(-1) at 300 K, a value which is slightly lower than the one expected for independent paramagnetic Pd(II) (S = 1, g = 2) and Mn(II) (S = 5/2, g = 2) ions. This thermal variation is due to antiferromagnetic exchange interactions between the two spin bearers. Nevertheless, no long-range magnetic order is detected down to 2 K. These results are confirmed by an analysis of the [MII(C(2)O(4))(3)](4-) (M = Ni, Pd, Pt) complex and of a [Pd(II){mu-(C(2)O(4))Mn(II)(OH(2))(4)}(3)](2+) tetranuclear model using density functional theory.

A novel type of metalated phosphino ligands, [Cp*Ru(η6-arene-PPh2)][OTf] (2a−d-OTf), has been prepared in which the −PPh2 unit is attached to a metalated π-arene platform. This unique class of ligands 2a−d are converted to open-sided cationic gold complexes 3a−d upon treatment with [AuCl(tht)]. The structure of one of these compounds, [Cp*Ru(η6-C6H5−PPh2−Au-Cl)][OTf] (3a-OTf), was ascertained by single-crystal X-ray diffraction. Preliminary studies suggest that cationic complex 3a is active in metal-catalyzed cycloisomerization reactions.