Publications by authors named "Christophe Desmarets"

Developing chiral plasmonic nanostructures represents a significant scientific challenge due to their multidisciplinary potential. Observations have revealed that the dichroic behavior of metal plasmons changes when chiral molecules are present in the system, offering promising applications in various fields such as nano-optics, asymmetric catalysis, polarization-sensitive photochemistry and molecular detection. In this study, we explored the synthesis of plasmonic gold nanoparticles and the role of cysteine in their chiroplasmonic properties.

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The design and synthesis of a supramolecular square composed of polyoxometalate-based hybrid donors and ethylenediamine palladium(II) nodes are reported. The structure of the metallomacrocycle scaffold was inferred by diffusion NMR, small-angle X-ray scattering (SAXS), and molecular modeling. The metallomacrocycle scaffold that contains negatively and positively charged subunits can further self-assemble owing to a competition between the solvation energy of the discrete species and intermolecular electrostatic interactions.

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2,2'-(Ethylenedioxy)bis(ethylamine)-functionalized graphene quantum dots (GQDs) were prepared under mild conditions from graphene oxide (GO) via oxidative fragmentation. The as-prepared GQDs have an average diameter of ca. 4 nm, possess good colloidal stability, and emit strong green-yellow light with a photoluminescence (PL) quantum yield of 22% upon excitation at 375 nm.

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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.

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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.

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A novel palladium-based metallacage was self-assembled. This nanocage displayed two complementary effects that operate in synergy for guest encapsulation. Indeed, a metal complex, [Pt(NO2)4](2-), was hosted inside the cavity, as demonstrated by solution NMR studies.

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Metallosupramolecular cages of the general formulas [M₂(L)₄][X]₄ can be self-assembled in good yields, where M = Pd, X = NO₃, L = (); M = Pd, X = OTf, L = (); M = Pt, X = OTf, L = (); M = Pd, X = OTf, L = (); = 1,3-bis(pyridin-3-ylethynyl)-5-methoxybenzene; and = 2,6-(pyridin-3-ylethynyl)- 4-methoxyaniline, respectively. These cages have been fully characterized using ¹H, C NMR, elemental analysis, IR spectroscopy, and electrospray mass spectrometry. Additionally the molecular structure of [Pd₂()₄][OTf]₄ () was confirmed using single crystal X-ray diffraction.

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The self-assembly of two novel metallosupramolecular complexes of the general formulas [L2M2(CH3CN)4][BF4]4 (M = Co, 1a; M = Ni, 1b), where L stands for the tetradentate ligand 3,5-bis[4-(2,2'-dipyridylamino)phenylacetylenyl]toluene, is reported together with their molecular structures ascertained by single-crystal X-ray diffraction studies. Complexes 1a and 1b are isostructural and show the formation of dinuclear meso-helicates with the two octahedral metal centers displaying respectively Δ and Λ configurations. These meso-helicates display large nanocavities with metal---metal separation distance of >2 nm; furthermore, π-π-stacking occurs among individual units to form one-dimensional (1D) polymers which further autoassemble in another direction through π-π contacts among neighboring chains to generate a two-dimensional (2D) network with regular nanocavities.

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A dinuclear cobalt capsule [PF(6) subset(CH(3)CN)(2)(Co(2)L(4))][PF(6)](3) (2), (L = bis-benzimidazole-1,3-phenylene) has been prepared using a self-assembly approach. This unique class of cage is perfectly designed to encapsulate weakly coordinated anions, i.e.

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Luminescent cyclometalated rhodium(III) and iridium(III) complexes of the general formula [M(ppy) 2(N (wedge)N)][PF 6], with N (wedge)N = Hcmbpy = 4-carboxy-4'-methyl-2,2'-bipyridine and M = Rh ( 1), Ir ( 2) and N (wedge)N = H 2dcbpy = 4,4'-dicarboxy-2,2'-bipyridine and M = Rh ( 3), Ir ( 4), were prepared in high yields and fully characterized. The X-ray molecular structure of the monocarboxylic iridium complex [Ir(ppy) 2(Hcmbpy)][PF 6] ( 2) was also determined. The photophysical properties of these compounds were studied and showed that the photoluminescence of rhodium complexes 1 and 3 and iridium complexes 2 and 4 originates from intraligand charge-transfer (ILCT) and metal-to-ligand charge-transfer/ligand-centered MLCT/LC excited states, respectively.

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We report the anion-templated syntheses of a variety of supramolecular assemblies of Co(II). Remarkably in the presence of a weakly coordinating ion such as BF(4) (-), a discrete three-dimensional cage [BF(4) subset(BF(4))(2)Co(2)(L(1))(4)][BF(4)] (2) is formed with three coordinated BF(4) (-) ions, a rare example in supramolecular chemistry (L(1)=di(benzimidazole)-1,4-phenylene). Switching to stronger coordinating ions, such as NO(3) (-) or Cl(-), a one-dimensional coordination polymer [[Co(L(1))(NO(3))(2)](n)] (3) and a metallomacrocycle [Co(2)(L(1))(2)(Cl)(4)] (5) were formed, respectively.

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Naphthidines 2 were prepared by nickel-catalyzed amination of 1-chloronaphthalene followed by oxidative homocoupling of 1-naphthalene amines 1 using titanium(IV) tetrachloride. The electronic and magnetic properties of materials 2 were investigated by cyclic voltammetry and other electrochemical techniques, EPR and UV-visible spectroscopies, and magnetic susceptibility. It was demonstrated that compounds 2 could be easily and reversibly oxidized via a two-electron-transfer reaction into their bis(radical cation) 2(2.

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A general and simple nickel-catalyzed coupling of aryl chlorides and amines is reported. The scope and limitations of the coupling process using Ni(0), 1,3-bis(2,6-diisopropylphenyl)dihydroimidazol-2-ylidene, and NaO-t-Bu as base were investigated. Secondary cyclic and acyclic amines and anilines provided the arylamine coupling products in good to excellent yields.

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