Search results for "n ligands"
showing 10 items of 19 documents
Phosphasalen group IV metal complexes: synthesis, characterization and ring opening polymerization of lactide.
2020
International audience; We report the synthesis of a series of Zr and Ti complexes bearing phosphasalen which differs from salen by the incorporation of two P atoms in the ligand backbone. The reaction of phosphasalen proligands (1a-1c)H2 with Zr(CH2Ph)4 led to different products depending on the nature of the N,N-linker in the ligand. In case of ethylene-linked phosphasalen, octahedral Zr complex 2a formed as a single stereoisomer in trans geometry. With the phenylene linker, it was shown by dynamic NMR spectroscopy that complex 2b exists as a mixture of trans and cis-β isomers in solution, both enantiomers (Δ and Λ) of the cis-β isomer being in fast equilibrium with respect to the NMR tim…
The [Pd(bipy)]2+ “merry-go-round”: Insights into the lability of the Pd–N bond
2009
Abstract Two tripods (1 and 2) featuring pyrimidinyl pendant arms have been synthesized from 5-(1H-pyrazol-3-yl)-pyrimidine (5) and 1,3,5-tribromomethylbenzene derivatives. Reaction with three equivalents of [Pd(bipy)](NO3)2 to form a macrotricycle closed by palladium coordination unexpectedly afforded the mononuclear species [Pd(1)(bipy)]2+ and [Pd(2)(bipy)]2+. These complexes show fluxional behavior on the 1H NMR timescale, the [Pd(bipy)]2+ fragment hopping between the pyrimidinyl coordinating moieties. The ΔGc‡’s estimated by the coalescence method are temperature independent, which means that ΔSc‡ = 0. This indicates that the “merry-go-round” process of [Pd(bipy)]2+ occurs intramolecula…
Input of P, N-(phosphanyl, amino)-ferrocene hybrid derivatives in late transition metals catalysis
2018
International audience; Unequally functionalized ferrocenes give access to valuable hemilabile reactivity in catalytic reaction. We address the synthesis of hybrid (P, N)-ferrocenyl compounds for which recent catalytic breakthrough applications have been reported, transversely in late transition metals chemistry. Palladium, nickel, rhodium, iridium, and emerging iron and gold catalysis are illustrated from selected examples, which include CC bond formation from cross-coupling and polymerization, allylic substitution, cyanation, hydroformylation, CH arylation and silylation and hydrogenation reactions.
Photoinduced HS state in the first spin-crossover chain containing a cyanocarbanion as bridging ligand
2009
A new polymeric approach, based on cyanocarbanion ligands, for the design of spin crossover (SCO) compounds led us to the compound [Fe(abpt)2(tcpd)] (1) (tcpd^2 = (C[C(CN)2|3)^2 , abpt = 4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole) which has been characterised as the first SCO molecular chain involving a cyanocarbanion as bridging ligand. Gomez Garcia, Carlos Jose, Carlos.Gomez@uv.es
Ruthenium Metallodendrimers Based on Nitrile‐Functionalized Poly(alkylidene imine)s
2005
The preparation of the first- and second-generation of nitrile-functionalized 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-functionalize…
Preparation and Characterization of Novel Poly(alkylidenamine) Nitrile Ruthenium Metallodendrimers
2010
Complete functionalization of N,N,N',N'-[tetrakis(cyanoethyl)-hexamethylenediamine] [N≡C(CH 2 ) 2 ] 2 N(CH 2 ) 6 N[(CH 2 ) 2 -C≡N] 2 (4) and N,N,N',N'-(tetrakis(cyanoethoxypropyl)hexamethylenediamine] [N≡C(CH 2 ) 2 O(CH 2 ) 3 ] 2 N(CH 2 ) 6 N[(CH 2 ) 3 -O(CH 2 ) 2 C≡N] 2 (7) with the organometallic moiety [Ru(η 5 -C 5 H 5 )(PPh 3 ) 2 Cl] and the five-coordinate cis-[RuCl(dppe) 2 ]-[PF 6 ] [dppe = 1,2-bis(diphenylphosphanyl)ethane] was attained with good yield, respectively, by treating the metallo-fragment with the core in methanol (at room temperature and in presence of TIPF 6 as a chloride abstractor) and in 1,2-dichloroethane (under reflux). These novel nitrile-functionalized poly(alkyli…
Mono- and Binuclear Copper(II) and Nickel(II) Complexes with the 3,6-Bis(picolylamino)-1,2,4,5-Tetrazine Ligand
2021
Four new compounds of formulas [Cu(hfac)2(L)] (1), [Ni(hfac)2(L)] (2), [{Cu(hfac)2}2(µ-L)]·2CH3OH (3) and [{Ni(hfac)2}2(µ-L)]·2CH3CN (4) [Hhfac = hexafluoroacetylacetone and L = 3,6-bis(picolylamino)-1,2,4,5-tetrazine] have been prepared and their structures determined by X-ray diffraction on single crystals. Compounds 1 and 2 are isostructural mononuclear complexes where the metal ions [copper(II) (1) and nickel(II) (2)] are six-coordinated in distorted octahedral MN2O4 surroundings which are built by two bidentate hfac ligands plus another bidentate L molecule. This last ligand coordinates to the metal ions through the nitrogen atoms of the picolylamine fragment. Compounds 3 and 4 are cen…
Hepta- and tetra-nuclear copper(II) clusters self-assembled by cyano- and azacyano-carbanions
2015
International audience; Two polynuclear copper(II) complexes with hydroxido-bridging ligands and polycyanide units, [Cu{Cu(tn)}6(μ2-OH)2(μ3-OH)4Cl2](tcm)4Cl2·2H2O (1) and [{Cu(bpy)}4(OH)4(dca)2](dca)2·bpy·2H2O (2) (tn = NH2(CH2)3NH2; tcm− = [C(CN)3]−, bpy = 2,2′-bipyridyl, dca− = [N(CN)2]−) have been prepared by one-pot reactions. The structure of 1 consists of a centrosymmetric heptanuclear ion [Cu{Cu(tn)}6(μ2-OH)2(μ3-OH)4Cl2]6+. The tcm− and the halide anions which appear as counter-ions in the formula unit, play an important role in the stabilization of the complex since the hydrogen bonding between nitrogen atoms of the tcm− anion and halide anions, and hydrogen atoms of the terminal wa…
Resolution of β-aminophosphines with chiral cyclopalladated complexes
2005
Abstract Resolution of the racemic chiral β-aminophosphines Ph 2 PCH 2 CH(Ph)NH(Ar) ( L 1 for Ar = C 6 H 5 and L 2 for Ar = 2,6-C 6 H 3 i Pr 2 ) has been investigated by use of different cyclopalladated complexes as chiral agents. The resulting complexes afford diastereomeric adducts in a 1:1 ratio. After successive crystallizations from ethanol, a d.e. of 98% was achieved for one aminophosphine palladium complex, while no significant d.e. was obtained after crystallizations from chlorinated solvents. The X-ray structure analysis has pointed out intermolecular hydrogen interactions N–H⋯Cl between the P,N ligand and the chloride ion, which are responsible for the formation and stabilization …
Anion template effect and the polymerization degree
2005
Two 2D (M1 and M2) and one 1D (M3) metal‐organic frameworks (MOFs) have been prepared from pyridine functionalized tetradentate ligand tetrakis(nicotinoxymethyl)methane TNM with silver tetrafluoroborate, nickel chloride, and copper hexafluorophosphate. M1 manifests a previously unpresented mode of 4,4 threefold parallel interpenetration for 2D MOFs. Large channels (vdW diameter 9.4 Å) through eclipsed 2D layers of M2 were observed. While the open space percentage in the noninterpenetrated M2 was 38.0 %, the triple interpenetration of the sheets of M1 reduced the void to 10.8 %. With the same ligand and a similar, weakly coordinating anion as that in M1, the structure M3 was rendered one‐dim…