L Ligands (l + ligand)

Distribution by Scientific Domains


Selected Abstracts


Oxidorhenium(V) Complexes of a Family of Bipyridine-Like Ligands Including Pyridyltriazines and Pyrazinyltriazine: Oxygen-Atom Transfer, Metal Redox and Correlations

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 11 2006
Samir Das
Abstract The title ligands (general abbreviation L) are bipyridine (bpy), its dimethyl (mbpy) and diphenyl (pbpy) derivatives, phenanthroline (phen), 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine (ppyt) and its dimethyl (mpyt) and pyrazinyl (ppzt) analogues. The concerned oxido complexes are [ReOCl3(L)],[ReOBr3(ppyt)] and [ReOBr3(ppzt)]. The chloro and bromo complexes of ppyt and ppzt were prepared by reacting these ligands with [ReOX3(AsPh3)2] (X = Cl, Br). The X-ray structures of [ReOCl3(ppyt)] and [ReOCl3(ppzt)] reveal that the ReCl3 fragment is meridionally disposed and that the L ligand is N,N -coordinated such that the pyridine/pyrazine nitrogen lies trans to the oxido oxygen atom. The Re,O lengths [1.656(10)/1.625(9) ] correspond to approximate triple bonding. The rate of oxygen-atom transfer from [ReOX3(L)] to triphenylphosphane in solution follows second-order kinetics and is associated with a large and negative entropy of activation (approx. ,30 cal,K,1,mol,1). The initial attack is believed to involve the phosphane lone pair and Re,O ,*-orbitals. Electron withdrawal from the ReVO moiety by varying X or L facilitates oxygen-atom transfer. Thus, the rates follow the orders Br < Cl; mbpy < bpy < phen < pbpy << mpyt < ppyt < ppzt. The reduction potential of the quasireversible ReVIO/ReVO couple displays similar trends and the logarithmic rate constant of oxygen-atom transfer is found to correlate linearly with the reduction potential. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source]


A novel 18-membered metallocycle in {2,5-bis[3-(1H -1,3-imidazol-1-ylmethyl)phenyl]-1,3,4-oxadiazole}dichloridocobalt(II)

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2010
Yan Wu
The title molecular complex, [CoCl2(C22H18N6O)], features a novel 18-membered Co-containing metallocycle. The CoII atom lies in a fairly regular tetrahedral geometry defined by two imidazole N-atom donors from one 2,5-bis[3-(1H -1,3-imidazol-1-ylmethyl)phenyl]-1,3,4-oxadiazole (L) ligand and two chloride anions. The coordinating orientation of the L ligand plays an important role in constructing the metallocycle complex. The complexes form a three-dimensional supramolecular assembly via nonclassical C,H...Cl and C,H...N hydrogen bonds and ,,, interactions. [source]


Bis(,-benzene-1,2-dicarboxylato)bis{aqua[2-(2-chloro-6-fluorophenyl)-1H -imidazo[4,5- f][1,10]phenanthroline]cadmium(II)} and its zinc(II) analogue

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009
Xiu-Yan Wang
In the isomorphous title compounds, [Cd2(C8H4O4)2(C19H10ClFN4)2(H2O)2] and [Zn2(C8H4O4)2(C19H10ClFN4)2(H2O)2], the CdII centre is seven-coordinated by two N atoms from one [2-(2-chloro-6-fluorophenyl)-1H -imidazo[4,5- f][1,10]phenanthroline (L) ligand, one water O atom and four carboxylate O atoms from two different benzene-1,2-dicarboxylate (1,2-bdc) ligands in a distorted pentagonal,bipyramidal coordination, while the ZnII centre is six-coordinated by two N atoms from one L ligand, one water O atom and three carboxylate O atoms from two different 1,2-bdc ligands in a distorted octahedral coordination. Each pair of adjacent metal centres is bridged by two 1,2-bdc ligands to form a dimeric structure. In the dimer, each L ligand coordinates one metal centre. The dimer is centrosymmetric, with a crystallographic inversion centre midway between the two metal centres. The aromatic interactions lead the dimers to form a two-dimensional supramolecular architecture. Finally, O,H...O and N,H...O hydrogen bonds reinforce the two-dimensional structures of the two compounds. [source]


catena -Poly[[aqua(11-chloropyrido[2,,3,:2,3]pyrimidino[5,6- f][1,10]phenanthroline-,2N4,N5)cadmium(II)]-,-benzene-1,4-dicarboxylato-,3O1,O1,:O4]: an inclined interpenetrating (6,3) network

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009
Zhi-Guo Kong
The asymmetric unit of the title compound, [Cd(C8H4O4)(C17H8ClN5)(H2O)]n, contains one CdII atom, two half benzene-1,4-dicarboxylate (1,4-bdc) anions, one 11-chloropyrido[2,,3,:2,3]pyrimidino[5,6- f][1,10]phenanthroline (L) ligand and one coordination water molecule. The 1,4-bdc ligands are on inversion centers at the centroids of the arene rings. The CdII atom is six-coordinated by two N atoms from one L ligand, three carboxylate O atoms from two different 1,4-bdc ligands and one water O atom in a distorted octahedral coordination sphere. Each CdII center is bridged by the 1,4-bdc dianions to give a one-dimensional chain. ,,, stacking interactions between L ligands of neighboring chains extend adjacent chains into a two-dimensional supramolecular (6,3) network. Neighboring (6,3) networks are interpenetrated in an unusual inclined mode, resulting in a three-dimensional framework. Additionally, the water,carboxylate O,H...O hydrogen bonds observed in the network consolidate the interpenetrating nets. [source]


Poly[(N,N -dimethylformamide-,O)(,3 -4,4,-ethylenedibenzoato-,5O,O,:O,:O,,,O,,,)(pyrazino[2,3- f][1,10]phenanthroline-,2N8,N9)lead(II)]

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2009
Qian Qiao
In the title PbII coordination polymer, [Pb(C16H10O4)(C14H8N4)(C3H7NO)]n, each PbII atom is eight-coordinated by two chelating N atoms from one pyrazino[2,3- f][1,10]phenanthroline (L) ligand, one dimethylformamide (DMF) O atom and five carboxylate O atoms from three different 4,4,-ethylenedibenzoate (eedb) ligands. The eedb dianions bridge neighbouring PbII centres through four typical Pb,O bonds and one longer Pb,O interaction to form a two-dimensional structure. The C atoms from the L and eedb ligands form C,H...O hydrogen bonds with the O atoms of eedb and DMF ligands, which further stabilize the structure. The title compound is the first PbII coordination polymer incorporating the L ligand. [source]


Three-Component Entanglements Consisting of Three Crescent-Shaped Bidentate Ligands Coordinated to an Octahedral Metal Centre

CHEMISTRY - A EUROPEAN JOURNAL, Issue 31 2007
Fabien Durola
Abstract 3,3,-Biisoquinoline ligands (biiq) L, bearing aromatic substituents on their 8 and 8, positions, have been used to generate interwoven systems consisting of three crescent-shaped ligands disposed around an octahedral metal centre. Mono-ligand complexes of the type [ReL(CO)3py]+ (py: pyridine) have also been prepared, leading to sterically non-hindering complexes in spite of the endotopic nature of the chelate used. The three-component entanglements have been prepared by using either FeII or RuII as gathering metal centre. The synthetic procedure is simple and efficient, affording fully characterised complexes as their PF6 or SbCl6 salts. X-ray crystallography clearly shows that the crescent-shaped ligands do not repel each other in the tris-chelate complexes. In an analogous way, the ReI complexes show open structures with no steric repulsion between the L ligand and the ancillary CO or py groups. The FeL3 or RuL3 compounds are very unusual in the sense that, contrary to all the other tris-bidentate chelate complexes made till now, the three organic components are tangled up, in a situation which will be very favourable to the formation of new non trivial topologies of the catenane type. [source]


Synthesis and structure of a new one-dimensional cobalt complex with dicyanamide and 4-picolyl choride bridges

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 4 2006
Hongxia Pei
Abstract The synthesis and structure of the 1D cobalt (II) complex, [Co(L)2(dca)2] (1) (dca = dicyanamide, C2N3,, L = 4-picolyl choride) is reported. Complex 1 crystallized in triclinic system, space group P -1, with cell dimensions of a = 7.291(2) , b = 7.481(2) , c = 9.007(3) , , =104.444(4), , = 96.971(4), , =102.618(4), V = 456.1(2) 3, Z = 1, Dc = 1.624 Mg/m3. In complex 1, Co (II) is 6-coordinated by N atoms of four dca ligands and two L ligands. The centrosymmetric CoN6 chromophore is an axially elongated octahedron that has Co-N distances ranging from 2.122(3) to 2.154(3) . ( 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]


Two Cobalt Compounds Based on Azide/Methoxy and Isonicotinate N -Oxide Ligands Exhibiting Ferromagnetic and Antiferromagnetic Interactions

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 28 2010
Fu-Chen Liu
Abstract Two new CoII complexes, [Co(OCH3)L] (1) and [Co3(N3)4(OCH3)2L2] (2) (L = isonicotinate N -oxide), were synthesized by solvothermal reaction and magnetically characterized. The cobalt ions in 1 and 2 all exhibit distorted octahedral coordination geometry. In 1, there is a ,11 -methoxy/syn,syn -carboxylate mixed coordinated cobalt chain with mixed coordination, and a 3D structure is formed by the chains linked through the L ligands. In 2, the alternating CoII chains that are formed by linking the double end-on azide-bridged trimers are connected by the L ligands to form a 2D layer. Magnetic studies revealed that ferromagnetic coupling exists between the CoII ions in 1, and 1 undergoes a ferromagnetic transition at 2.5 K, whereas alternating ferromagnetic (FM) and antiferromagnetic (AFM) interactions exist in the chain of 2. [source]


Lanthanide Complexes of Disulfoxide Ligands with Varied Configurations: Influence of Lanthanide Contraction on the Structures of the Complexes

EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 10 2005
Jian-Rong Li
Abstract Four new disulfoxide-LnIII complexes, [Ln(L)2(NO3)3]n {Ln = La (1), n = n; Ln = Gd (2), Dy (3) and Yb (4), n = 2}, have been prepared by the reaction of Ln(NO3)3nH2O with meso -1,3-bis(ethylsulfinyl)propane (meso - L) in methanol/triethylorthoformate, and their solid-state structures were characterized by IR spectroscopy, elemental analyses and X-ray diffraction. Complex 1 is a 1D double-bridged chain in which the LaIII ions are ten-coordinate and the L ligands adopt both meso and rac configurations, and a bis-monodentate bridging coordination mode. While complexes 2,4 have isostructural dinuclear structures, in which the LnIII ions are nine-coordinate and the ligands show two types of coordination fashions and configurations: bis-monodentate bridging with a meso -configuration, and monodentate coordination with a rac -configuration. The structural differences between 1 and 2,4 indicate the influence of lanthanide contraction on the complex structures. In addition, a change in configuration of the ligand occurs when it reacts with metal ions. ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source]


Poly[bis(,-benzene-1,4-dicarboxylato)bis[,-6-(4-pyridyl)-5H -imidazolo[4,5- f][1,10]phenanthroline]dilead(II)]: an interpenetrating ,-Po net

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2010
Zhan-Lin Xu
The asymmetric unit of the title compound, [Pb2(C8H4O4)2(C18H11N5)2]n, contains two PbII atoms, two benzene-1,4-dicarboxylate (1,4-bdc) dianions and two 6-(4-pyridyl)-5H -imidazolo[4,5- f][1,10]phenanthroline (L) ligands. Each PbII atom is eight-coordinated by three N atoms from two different L ligands and five carboxylate O atoms from three different 1,4-bdc dianions. The two 1,4-bdc dianions (1,4-bdc1 and 1,4-bdc2) show different coordination modes. Each 1,4-bdc1 coordinates to two PbII atoms in a chelating bis-bidentate mode. Each carboxylate group of the 1,4-bdc2 anion connects two PbII atoms in a chelating,bridging tridentate mode to form a dinuclear unit. Neighbouring dinuclear units are connected together by the aromatic backbone of the 1,4-bdc dianions and the L ligands into a three-dimensional six-connected ,-polonium framework. The most striking feature is that two identical three-dimensional single ,-polonium nets are interlocked with each other, thus leading directly to the formation of a twofold interpenetrated three-dimensional ,-polonium architecture. The framework is held together in part by strong N,H...O hydrogen bonds between the imidazole NH groups of the L ligands and the carboxylate O atoms of 1,4-bdc dianions within different ,-polonium nets. [source]


Poly[[{,4 -3-[(1H -1,2,4-triazol-1-yl)methyl]benzoato}zinc(II)] hemihydrate]: a novel two-dimensional framework formed by self-association of zinc(II) sulfate with 3-[(1H -1,2,4-triazol-1-yl)methyl]benzoic acid

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 6 2010
Li Duan
The title novel two-dimensional coordination polymer, {[Zn2(C10H8N3O2)4]H2O}n, features a {Zn2L2} bimetallic ring repeat unit {L is the 3-[(1H -1,2,4-triazol-1-yl)methyl]benzoate ligand}. Each ZnII cation of the bimetallic ring is further bonded to two other L ligands, resulting in a novel infinite two-dimensional network structure with two channels of different sizes. The crystallographically unique ZnII atom is thus six-coordinated in a distorted octahedral environment of four carboxylate O atoms and two triazole N atoms. Two of these networks interpenetrate in an orthogonal arrangement to form the full three-dimensional framework, with disordered water molecules located in the channels. [source]


catena -Poly[[aqua(11-chloropyrido[2,,3,:2,3]pyrimidino[5,6- f][1,10]phenanthroline-,2N4,N5)cadmium(II)]-,-benzene-1,4-dicarboxylato-,3O1,O1,:O4]: an inclined interpenetrating (6,3) network

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 12 2009
Zhi-Guo Kong
The asymmetric unit of the title compound, [Cd(C8H4O4)(C17H8ClN5)(H2O)]n, contains one CdII atom, two half benzene-1,4-dicarboxylate (1,4-bdc) anions, one 11-chloropyrido[2,,3,:2,3]pyrimidino[5,6- f][1,10]phenanthroline (L) ligand and one coordination water molecule. The 1,4-bdc ligands are on inversion centers at the centroids of the arene rings. The CdII atom is six-coordinated by two N atoms from one L ligand, three carboxylate O atoms from two different 1,4-bdc ligands and one water O atom in a distorted octahedral coordination sphere. Each CdII center is bridged by the 1,4-bdc dianions to give a one-dimensional chain. ,,, stacking interactions between L ligands of neighboring chains extend adjacent chains into a two-dimensional supramolecular (6,3) network. Neighboring (6,3) networks are interpenetrated in an unusual inclined mode, resulting in a three-dimensional framework. Additionally, the water,carboxylate O,H...O hydrogen bonds observed in the network consolidate the interpenetrating nets. [source]


Trans influence in a mer -octahedral triiodidolanthanide: triiodidotris(tetrahydrofuran-,O)ytterbium(III)

ACTA CRYSTALLOGRAPHICA SECTION C, Issue 11 2009
Thomas J. Emge
The structure of the six-coordinate title complex, [YbI3(C4H8O)3], is the first mer -octahedral form of an LnI3L3 lanthanide (Ln) compound with neutral L ligands, and is closely related to that of several of the seven-coordinate LnX3L4 series of compounds, where X = Cl, Br or I and L = tetrahydrofuran (THF), isopropanol, pyridine or water. A structural trans effect can be assigned to YbI3(THF)3, in contrast to the LnX3L4 compounds, where steric and crystal packing effects are significant. The Yb,I bond lengths are 2.9543,(4) and 2.9151,(6), for I trans and cis to I, respectively, and the Yb,O bond lengths are 2.299,(5) and 2.251,(3), for O trans and cis to I, respectively. The crystal packing allows for six contact distances as weak C,H...I interactions in the range 3.10,3.24,. The title molecule has a crystallographic twofold axis passing through a THF O atom, the trans I atom and the Yb atom. [source]