Search results for "Polynitrile"
showing 10 items of 10 documents
New planar polynitrile dianion and its first coordination polymer with unexpected short M⋯M contacts (tcno2−=[(NC)2CC(O)C(CN)2]2−)
2008
International audience; A new planar polynitrile dianion ([tcno]2− = [(NC)2CC(O)C(CN)2]2−) has been synthesized as its potassium salt, K2[tcno] (1). The crystallization of 1 by the slow evaporation of an aqueous solution at room temperature gave two types of colourless crystals having two different shapes [1-A: fine plates and 1-B: needles] for which the crystal structure determinations showed similar geometries for the polynitrile anion in both the structures. The combination of this novel dianion with Cu(II) led to the coordination complex [Cu(tcno)2(H2O)2] (2), which constitutes the first coordination complex of this dianion. The structure of 2 can be described as a coordination polymer …
Copper(II) complexes with 2,5-bis(2-pyridyl)pyrazine and 1,1,3,3-tetracyano-2-ethoxypropenide anion: Syntheses, crystal structures and magnetic prope…
2009
International audience; The copper(II) complexes of formula [Cu2(2,5-dpp)(H2O)4(CF3SO3)4] · 2H2O (1) and [Cu2(2,5-dpp)(H2O)2(tcnoet)4]n (2) [2,5-dpp = 2,5-bis(2-pyridyl)pyrazine and tcnoet− = 1,1,3,3-tetracyano-2-ethoxypropenide anion] have been prepared and their structures determined by X-ray crystallographic methods. Compound 1 is a dinuclear complex where the 2,5-dpp molecule acts as a bis-bidentate bridge between the two copper centers, the electroneutrality being achieved by four terminally bound triflate anions. Each copper(II) ion presents an elongated octahedral CuN2O4 environment with two nitrogen atoms from 2,5-dpp and two water molecules in the basal plane and two triflate-oxyge…
New coordination polymer based on a triply bridged dicarboxylate ligand: Synthesis, structure, and magnetic properties of the adipato complex [Cu4(bp…
2007
International audience; One-pot reaction of copper(II) chloride dihydrate CuCl2 · 2H2O with 2,2′-bipyridyl (bpy = C10H8N2) in the presence of sodium adipate Na2adip (adip2− = [O2C(CH2)4CO2]2−) and potassium 1,1,3,3-tetracyano-2-ethoxypropenide (tcnoet− = [(NC)2CC(OEt)C(CN)2]−) gives the new compound [Cu4(bpy)4(adip)3](tcnoet)2 · 2H2O (1), which was characterized by single crystal X-ray diffraction analysis. The Cu(II) metal ion presents an elongated square pyramidal CuN2O3 environment, with an oxygen atom in apical position and a base plane involving almost equivalent bond lengths. The structure can be described as a pseudo dinuclear species in which two Cu(bpy) units are triply bridged by …
Crystal structures of 2,2′-bipyridin-1-ium 1,1,3,3-tetracyano-2-ethoxyprop-2-en-1-ide and bis(2,2′-bipyridin-1-ium) 1,1,3,3-tetracyano-2-(dicyanometh…
2015
In each of the title compounds, the anion shows evidence of extensive electronic delocalization. A combination of N—H⋯N and X—H⋯N hydrogen bonds links the ions in (I) into a ribbon of alternating centrosymmetric (18) and (26) rings, and those in (II) into simple (7) chains of alternating cations and anion with further cations pendent from the chain.
Guidelines to design new spin crossover materials
2010
International audience; This review focuses on new families of spin crossover (SCO) complexes based on polynitrile anions as new anionic ligands or on polyazamacrocycles as neutral macrocyclic ligands. We have shown that the structural and electronic characteristics (original coordination modes and high electronic delocalization) of the polynitrile anions can be tuned by slight chemical modifications such as substitution of functional groups or variation of the negative charge to design new discrete or polymeric SCO systems.In our ongoing work on the design of new molecular systems based on new ligands that can be fine-tuned via chemical modifications, another promising way which has been r…
Polynitrile anions as ligands: From magnetic polymeric architectures to spin crossover materials
2010
International audience; The use of polynitrile anions as ligands (L) either alone or in combination with neutral co-ligands (L′) is a very promising and appealing strategy to get molecular architectures with different topologies and dimensionalities thanks to their ability to coordinate and bridge metal ions in many different ways. The presence of several potentially coordinating nitrile groups (or even other donor groups as –OH, –SH or –NH2), their rigidity and their electronic delocalization allow the synthesis of original magnetic high dimensional coordination polymers with transition metals ions. Furthermore, these ligands have shown coordinating and bridging capabilities in novel discr…
Polynitrile anions as ligands: Synthesis, structure and magnetic properties of a new three-dimensional coordination polymer with the 2-dicyanomethyle…
2005
cited By 12; International audience; Reaction between CuCl2 and K2tcpd (tcpd2- = C[C(CN)2]32- = 2-dicyanomethylenc-1,1,3,3-tetracyanopropanediide anion) in presence of the neutral ligand tn (1,3-diaminopropane) in aqueous solution yields the new compound [Cu(tn)(tcpd)] (1) which was characterized by X-ray crystallography. The crystal structure of 1 consists of one [Cu(tn)]2+ unit and one tcpd2- anion, both located on general positions. Each Cu atom presents an essentially octahedral coordination with four nitrogen atoms arising from four polynitrile ligands and two nitrogen atoms from the chelating tn ligand. Despite its six nitrile groups potentially bridging, the tcpd ligand acts with a μ…
A novel polynitrile ligand with different coordination modes: Synthesis, structure and magnetic properties of the series [M(tcnoprOH)2(H2O)2] (M=Mn, …
2008
International audience; A novel polynitrile ligand (tcnoprOH− = [(NC)2CC(OCH2CH2CH2OH)C(CN)2]−) with up to five potentially coordinating groups has been synthesized in a one-pot reaction from a cyclic acetal and malononitrile. The combination of this novel ligand with different transition metal ions has led to the synthesis of two different structural types with the same formula but with different coordination modes in the ligand. Mn(II) and Cu(II) lead to a μ2-N,O-coordinating mode in the series of compounds formulated as [M(N,O-tcnoprOH)2(H2O)2] (M = MnII (1) and CuII (2)), whereas Co(II) and, most probably Ni(II), lead to a μ2-N,N′-coordinating mode in [Co(N,N′-tcnoprOH)2(H2O)2] (3). Bot…
New coordination polymers based on a novel polynitrile ligand: Synthesis, structure and magnetic properties of the series [M(tcnoetOH)2(4,4′-bpy)(H2O…
2008
International audience; A novel polynitrile anionic ligand, tcnoetOH−(=[(NC)2CC(OCH2CH2OH)C(CN)2]−), has been synthesized by a one-pot reaction from a cyclic acetal and malononitrile. This ligand has been successfully used to prepare, with 4,4′-bpy as co-ligand, a novel series of coordination polymers formulated as [M(tcnoetOH)2(4,4′-bpy)(H2O)2] with M(II) = Fe (1), Co (2) and Ni (3). These isostructural compounds present a linear chain structure consisting of octahedrally coordinated metal ions bridged by trans 4,4′-bpy ligands. The coordination sphere of the metal ions is completed with two terminal tcnoetOH− ligand and two water molecules. The magnetic properties indicate that the three …
Crystal structure of [tris(4,4-bipyridine)]diium bis(1,1,3,3-tetracyano-2-ethoxypropenide) trihydrate
2016
In the title hydrated salt, which was obtained from the hydrothermal reaction between between potassium 1,1,3,3-tetracyano-2-ethoxypropenide and 4,4′-bipyridine in the presence of iron(II) sulfate heptahydrate, the ionic components are linked into a three-dimensional network by C—H⋯N hydrogen bonds.