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- Visible-light photolytic synthesis of multinuclear and dendritic iron-nitrile cationic complexesPublication . Ornelas, Cátia; Ruiz, Jaime; Rodrigues, João; Astruc, DidierMultinuclear and dendritic iron-nitrile piano-stool cationic complexes were synthesized in quantitative yield by a single-step synthesis involving visible-light photolysis of the complex [CpFe(eta(6)-toluene)][PF6]. This synthetic strategy was applied to mono-, bis- and tris-nitrile ligands and to new nitrile-terminated dendrimers containing 9, 27, and 81 tethers. All the synthesized products are deep red solids or red waxy products, highly stable to air and moisture. They were characterized by (1)H, (13)C, and (31)P NMR, elemental analysis, UV-vis spectroscopy, and cyclic voltammetry (single reversible oxidation wave to Fe(III)). Only the para-disubstituted arene dinitrile diiron complex shows two separated reversible waves indicating some electronic communication between the iron centers through the nitrile ligands.
- Organometallic syntheses of hexa and nonanitrile ligands and their ruthenium complexesPublication . Ornelas, Cátia; Ruiz, Jaime; Blais, Jean-Claude; Rodrigues, João; Astruc, DidierHexa- and nonanitrile ligands were synthesized by the known CpFe+-induced hexaallylation of hexamethylbenzene in [FeCp(η6-C6Me6)][PF6] and nonaallylation of mesitylene in [FeCp(η6-1,3,5-C6H3Me3)][PF6], respectively, followed by Pt-catalyzed regioselective hydrosilylation of the iron-free polyolefins using (chloromethyl)dimethylsilane and sodium iodide catalyzed Williamson coupling with p-hydroxybenzonitrile. The hexanitrile star was coordinated to the piano-stool ruthenium complex [RuCp(PPh3)2Cl] by substitution of the six ruthenium-bound chlorides with nitriles using TlPF6 to give the hexacationic hexaruthenium star complex, whereas the analogous metalation reaction partly failed, due to bulk constraint with the nonanitrile ligand. The strategy that involved lengthening of the tethers of the latter, however, successfully provided a nonacationic nonaruthenium complex.
- Synthesis, characterization and crystal structure of the bimetallic cyano-bridged [(η5-C5H5)(PPh3) 2Ru (μ-CN) Ru (PPh3) 2 (η5-C5H5)][PF6]Publication . Ornelas, Cátia; Gandum, Cláudia; Mesquita, José; Rodrigues, João; Garcia, M. Helena; Lopes, Nelson; Robalo, M. Paula; Nattinen, Kalle; Rissanen, Kari
- Ruthenium metallodendrimers based on Nitrile-functionalized Poly(alkylidene imine)sPublication . Ornelas, Cátia; Vertlib, Viatcheslav; Rodrigues, João; Rissanen, KariThe preparation of the first- and second-generation of nitrilefunctionalized poly(alkylidene imine) dendrimers with the organometallic ruthenium complex [Ru(η5-C5H5)(PPh3)2Cl] peripherally attached is described. The reaction of N,N -bis(cyanomethyl)piperazine (1), N,N -bis[N ,N -bis(cyanoethyl)aminoethyl]piperazine (2), or N,N,N ,N -tetrakis(cyanoethyl)ethylenediamine (3) with [Ru(η5-C5H5)(PPh3)2Cl] (4) in the presence of TlPF6 gives the new air-stable ruthenium metallodendrimers 5, 6, and 7, respectively. These stable metallodendrimers are easily prepared and represent a novel quantitative method to solidify and chromatographically purify the otherwise semi-liquid nitrile-functionalized poly(alkylidene imine) dendrimers. The compounds were fully characterized by IR and 1H, 13C, and 31P NMR spectroscopy, and mass spectrometry. These dendrimers represent the first example of the utilization of nitrile-functionalized poly(alkylidene imine)s as cores in the preparation of metallodendrimers.
- From simple monopyridine clusters [Mo6Br13(Py-R)][n-Bu4N] and hexapyridine clusters [Mo6X8(Py-R)6][OSO2CF3]4 (X = Br or I) to cluster-cored organometallic stars, dendrons, and dendrimersPublication . Méry, Denise; Plault, Lauriane; Ornelas, Cátia; Ruiz, Jaime; Nlate, Sylvain; Astruc, Didier; Blais, Jean-Claude; Rodrigues, João; Cordier, Stéphane; Kirakci, Kaplan; Perrin, ChristianeHexasubstitution of apical triflate ligands in the octahedral clusters [M]2[Mo6X8(CF3SO3)6] (M = n-Bu4N or Cs, X = Br or I) and monosubstitution in [n-Bu4N]2[Mo6Br13(CF3SO3)] was carried out in tetrahydrofuran at 60 degrees C with simple pyridines and then extended to organometallic pyridines, yielding cluster-cored stars, and to dendronic polyallyl- and polyferrocenylpyridines, yielding cluster-cored polyallyl and polyferrocenyl dendrimers and dendrons. The orange pyridine-substituted clusters, whose pyridine protons are deshielded in 1H NMR (a practical tool for characterization), are air-stable and thermally stable with simple pyridines, light- and air-sensitive with organometallic pyridines, and air-fragile and thermally fragile with large dendronized pyridines.
- Mo6Br8-Cluster-cored organometallic stars and dendrimersPublication . Méry, Denise; Ornelas, Cátia; Daniel, Marie-Christine; Ruiz, Jaime; Rodrigues, João; Astruc, Didier; Cordier, Stéphane; Kirakci, Kaplan; Perrin, ChristianeTheoctahedralmolybdenumcluster[n-Bu4N]2[Mo6Br8(CF3SO3)6]undergoessubstitutionofallsixterminaltriflateligands withtheorganometallicpyridineligands[RuCp(PPh3)2(g1-C2-4-pyridinyl)],1,and1-ferrocenyl-2-(4-pyridinyl)acetylene,5,to give the new light and air sensitive hexa-functionalized Mo6 clusters 4 and 7 respectively, and with the dendronic phenolate ligand p-NaO–C6H4C{CH2CH2CH2Si(Me)2Fc}3, 8, to give the air-sensitive Mo6-cluster-cored octadecylferrocenyl dendrimer 9 that discloses a single CV wave in CH2Cl2 and recognizes the biologically important adenosyl triphosphate di-anion (ATP2-). The organometallic pyridines 1 and 5 were also coordinated toAg+ to give the new trinuclearAgRu2 andAgFc2 cationic complexes 2 and 6 respectively for comparison of the structures and electronic delocalization with those of the clusters.