Jean Sala Pala

Novel Infinite Three‐Dimensional Networks with Highly Conjugated Polynitrile Ligands: Syntheses, Crystal Structures, and Magnetic Properties of [Cu{C[C(CN)2]3}(H2O)2]n and [Cu{C[C(CN)2]3}(en)]n (en=NH2CH2CH2NH2)

An unprecedented coordination mode for the highly conjugated cyanocarbanion [C{C(CN)2}3]2− (1) is observed in the title complexes. This ligand employs four of its six CN groups in a μ4-η4 bridging mode to form two unique three-dimensional polymers.

Molecular assemblies based on tricyanomethanide units and copper(II) ions

Abstract New co-ordination polymers of formulae [Cu(tcm) 2 (tn)] ( 1 ) and [Cu(tcm)(tn) 2 ](tcm) ( 2 ) (tcm − =tricyanomethanide and tn=1,3-diaminopropane) have been synthesised and characterised by X-ray crystallography and magnetic measurements. For compound 1 , the Cu(II) ion presents an elongated and distorted CuN 4 N 1 N 1 octahedron generated by one chelating tn ligand and by four μ 2 -bridging tcm − ligands. The molecular arrangement of 1 can be described as a monodimensional chain of a ladder-like structure in which the Cu⋯Cu distance (7.5157(4) A) through the tcm − ligand forming the sides is significantly shorter than the corresponding distance observed through that providing the rung (7.7455(4) A). For compound 2 , the Cu(II) ion presents a centrosymmetric elongated CuN 4 N 2 octahedron; the equatorial plane is generated by two chelating tn ligands and the two axial positions are filled by two weakly co-ordinated equivalent tcm − units acting as μ 2 -bridging ligands. This leads to a monodimensional polymer in which the intrachain Cu⋯Cu distance is 9.1062(2) A. Magnetic measurements, performed in the temperature range 2–300 K for both compounds, show weak antiferromagnetic interactions for compound 1 while compound 2 obeys a Curie law. The difference between the magnetic behaviours can be explained from the larger intrachain Cu⋯Cu separation in 2 than in 1 .

Comparison of the properties of the 1,1,2,4,5,5-hexacyano-3-aza-penta-1,4-dienide[(NC)2CC(CN)NC(CN)C(CN)2] unit as anion and as ligand. Crystal structures of (Et4N)(C10N7) and [{Ag(C10N7)}∞]

Abstract The previously reported compounds, Et 4 N(C 10 N 7 ), 1 , and [{Ag(C 10 N 7 )} ∞ ], 2 , have been structurally characterized by X-ray diffraction. The C 10 N 7 unit acts in 1 as a monoanion and in 2 as a sophisticated bridging ligand (via the nitrogen atoms of its four external cyanogroups) leading to a structure with two crystallographically distinct silver cations. The first one has an usual pseudo-tetrahedral coordination, the second one presents an unexpected square planar coordination which is discussed. The geometry of the organic fragment is only slightly modified upon coordination: in both cases, the C 10 N 7 unit is essentially planar with central CN bond lengths of 1.317(4) and 1.334(4) A in 1 , 1.33(1) and 1.34(1) A in 2 and CNC angles of 128.3(3) in 1 and 129.2(9)° in 2 . In benzonitrile solutions, the C 10 N 7 anion shows two one electron diffusion-controlled reversible reduction rocesses, the first one leading to the radical species [(C 10 N 7 )] 2− characterized by ESR.

{[CuII(tn)]2[FeII(CN)6]}·KCl·5H2O (tn = 1,3-diaminopropane): a two-dimensional bimetallic layered material with “Cu4Fe3” defective cubane units

The new two-dimensional coordination compound {[CuII(tn)]2[FeII(CN)6]}·KCl·5H2O (1) (tn=1,3-diaminopropane), generated by six –Fe–CN–Cu– bridges, shows weak ferromagnetic interactions between the nearest Cu(II) ions through the diamagnetic [Fe(CN)6]4− anion.

Pentacyanopropenide group as ligand in organometallic chemistry. Crystal structure and electrochemical studies of (Et4N)[W(CO)5{(C(CN)2C(CN)C(CN)2}]

Abstract The title complex has been obtained by reaction of the tetraethylammonium pentacyanopropenide with tungsten hexacarbonyl in acetone. Its crystal structure involves discrete [W(CO)5{C3(CN)5}]− anions in which the organic fragment is N-coordinated via one of the nitrogen atoms of a cyano group borne by one of the terminal carbon atoms of the allylic skeleton. The anion presents a distorted octahedral coordination with a W–N bond length [2.168(5) A] considerably longer than the W–C bond lengths [cis-W–C in the range 1.998(7)–2.068(4) A; trans-W–C 1.962(7) A]. Cyclic voltammograms of this complex, recorded in CH2Cl2 and CH3CN (Bu4NPF6 0.1 M), display a quasi-reversible reduction and irreversible oxidation waves.

Synthesis and characterisation of new binuclear oxo-vanadium(IV) complexes with a bis(bidentate)oxalate bridge. Crystal structures of the cationic and anionic complexes [V2O2(C2O4)(H2O)6]Cl2·4Bu4NCl·H2O and [FeCp*2]2[Et4N]2[V2O2(C2O4)(NCS)6]

Abstract The new oxalate–vanadyl compounds [V2O2(C2O4)(H2O)6]Cl2·4Bu4NCl·H2O (1) (Bu=C4H9) and [Et4N]4[V2O2(C2O4)(NCS)6] (2′) (Et=C2H5) have been synthesized starting from V2O5 and VOSO4·5H2O, respectively. Metathesis of 2′ with [FeCp*2]BF4 (Cp*=C5(CH3)5) gave a partial substitution of the cations affording [FeCp*2]2[Et4N]2[V2O2(C2O4)(NCS)6] (2). The X-ray structures of 1 and 2 have been determined. In both complexes, which crystallise in the monoclinic space group P21/c, the centrosymmetric binuclear vanadium species present a bis(bidentate)oxalate ligand and an almost planar [V2O2(C2O4)X2] unit (X=O(H2O) for 1 and N(NCS) for 2) with two VO groups located in trans positions in the equatorial plane. In both cases, the strong VO terminal bond (1.569(7) in 1, 1.580(7) A in 2) has a strong trans influence which is slightly greater in the cation of 1 than in the anion of 2. Magnetic susceptibility measurements indicate weak antiferromagnetic pairwise interactions for 1, 2 and 2′.

Synthesis and crystal structure of a new salt of the complex anion [(TCNQ)3]2− [Mo2(μ2-S2)2 (S2CNME2)4] (TCNQ)3

Abstract The reaction of compounds [Mo 2 (μ 2 -S 2 ) 2 (S 2 CNR 2 ) 4 ](BF 4 ) 2 ( 1 ) (a R = Me, b R= Et) with 2 equiv. of LiTCNQ in methanol results in the formation of complexes [Mo 2 (μ 2 -S 2 ) 2 (S 2 CNR 2 ) 4 ](TCNQ) 2 ( 2 ). Further reaction of 2 with TCNQ yields the derivatives [Mo 2 (μ 2 -S 2 ) 2 (S 2 CNR 2 ) 4 ](TCNQ) 3 ( 3 ). Compounds 2 and 3 were characterized fully by microanalytical, IR and electron spin resonance studies. The single crystal structure of the green product 3a ·2 CH 3 CN was determined by X-ray diffraction methods. The TCNQ units form centrosymmetrical trimers with a slipped conformation and an interplanar distance of 3.16 A. In the [(TCNQ) 3 ] 2− anion, the bond lengths agree with an almost complete delocalization of the charge between three essentially identical TCNQ units. The trimers stack with an intertrimer distance of 3.56 A. The centrosymmetric dinuclear cation is characterized by an MoMo distance of 2.817(2) A in agreement with a metal-metal single bond. The molybdedum atoms are bridged by two μ 2 -S 2 2 ligands which presnet a quite normal bridge distances S-S of 2.001 ( 2 ) A.

Unendliche dreidimensionale Netze mit hochkonjugierten Polynitrilliganden: Strukturen und magnetische Eigenschaften von [{Cu{C[C(CN)2]3}(H2O)2}n] und [{Cu{C[C(CN)2]3}(en)}n] (en=NH2CH2CH2NH2)

Ein neuartiger Koordinationsmodus des hochkonjugierten Cyancarbanions [C{C(CN)2}3]2−1 wurde bei den Titelkomplexen festgestellt. Dieser Ligand setzt vier seiner sechs CN-Gruppen in einem μ4-η4-Verbruckungsmodus ein und bildet dadurch einzigartige dreidimensionale Polymere.

Unprecedented reactivity of a Schiff base ligand in the co-ordination sphere of copper(I) complex towards β-diketones. Synthesis and X-ray characterisation of a new copper(I) complex

The reactions of the copper(I) derivative [CuL(THF)(CH 3 CN)]PF 6 ( 1 ), in which L is the di-imine/pyridine ligand 2,6-bis[1-(2,6-diisopropylphenylimino)ethyl]pyridine, with different β-diketones (2,4-pentanedione (acacH), 1,3-diphenyl-1,3-propanedione (dbm)) yielded the new Cu(I) salt [CuL′ 2 ]PF 6 ( 2 ) (L′: 2-[acetyl]-6-[1-(2,6-diisopropylphenylimino)ethyl]pyridine). These reactions of β-diketones with a di-imine/pyridine ligand co-ordinated to a Cu(I) centre constitute the first example of a partial hydrolysis of such a Schiff base within the inner sphere of a Cu centre. Compound 2 ·acaH has been characterised by X-ray crystallography.

New coordination polymers with a 2,2-dicyano-1-ethoxyethenolate (dcne−) bridging ligand: syntheses, structural characterisation and magnetic properties of [M(dcne)2(H2O)2] (M = MnII, FeII, CoII, NiII and ZnII) and [Cu(dcne)2(H2O)]

New polymeric materials [M(dcne)2(H2O)2] with M = MnII (1), FeII (2), CoII (3), NiII (4) and ZnII (5) and [Cu(dcne)2(H2O)] (6) (dcne− = [(CN)2CC(O)OEt)]− = 2,2-dicyano-1-ethoxyethenolate anion) have been synthesised and characterised by infrared spectroscopy, X-ray crystallography and magnetic measurements. In these compounds, each organic ligand acts in a bridging mode with its two nitrogen atoms bound to two different metal cations. In compounds 1–5, each metal cation has a pseudo-octahedral cis-MN4O2 environment with four nitrogen atoms from four different organic ligands and two oxygen atoms from two water molecules. In compound 6, only one water molecule is coordinated and each copper(II) cation presents a CuN4O distorted trigonal bipyramid environment with a perfectly planar CuN2O equatorial plane. In all compounds the molecular arrangement involves 12-membered M(dcne)2M dimetallacycles that share a M atom forming chains running along the [101] direction with alternated, almost orthogonal, dimetallacycles. The intra-chain M⋯M distances (7.4270(2) A in 3, 7.4628(2) A in 5 and 7.2299(3) A in 6) are longer than the inter-chain ones (6.0430(4) A in 3, 6.0907(3) A in 5 and 5.9648(5) A in 6). The chains are connected by hydrogen bonds between the coordinated water molecules and the terminal oxygen atom of the organic ligand, giving rise to a 3D structure. Magnetic measurements show very weak antiferromagnetic coupling between metal centres that can be satisfactorily reproduced with a regular antiferromagnetic classical spin chain model.