Cyano-bridged heterodinuclear complexes of nickel(II) and palladium(II). A disordered structure for the linkage isomer [LPd-CN-NiL](ClO4)

1992 ◽  
Vol 70 (9) ◽  
pp. 2461-2467 ◽  
Author(s):  
Parimal Paul ◽  
Ramprasad Das ◽  
Kamalaksha Nag ◽  
Eric J. Gabe ◽  
Jean-Pierre Charland
Keyword(s):  
Direct Methods ◽  
The Other ◽  
Tridentate Ligand ◽  
Full Matrix ◽  
X Ray ◽  
Disordered Structure ◽  
Metal Atoms ◽  
Square Planar ◽  
C And N ◽  
Cyanide Bridge

The homodinuclear [M2L2μ(CN)](ClO4) complexes and the heterodinuclear [LPd-CN-NiL](ClO4) and [LNi-CN-PdL](ClO4) complexes of nickel(II) and palladium(II) have been synthesized with a tridentate ligand HL (methyl 2-[(2′-aminoethyl)amino]cyclopent-1-enedithiocarboxylate). In solution both the isomers dissociate, [LNi-CN-PdL]+ much more rapidly than [LPd-CN-NiL]+, and a steady state equilibrium between the [LPd-CN-NiL]+, [Pd2L2μ-(CN)]+, and [Ni2L2μ-(CN)]+ species is established. The isomer [LPd-CN-NiL]+ exhibits a band at 555 nm that is absent in the other isomer and homodinuclear complexes. The X-ray structure of [LPd-CN-NiL](ClO4) has been studied. Crystals of the compound are monoclinic, a = 8.964(2), b = 23.852(2), c = 14.096(2) Å, β = 105.92(1)°, Z = 4, space group P21/a. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.054 and Rw = 0.034 for 4426 reflections with I ≥ 2.5σ(I). The two metal centres are in a square-planar environment provided by the N2S donor set of the ligand and cyanide bridge, but the metal atoms as well as C and N atoms of μ-CN could not be distinguished due to disorder. An alternate stacking of Pd-CN-Ni and Ni-NC-Pd units has been proposed to explain the 1:1 occupancy of the atoms concerned.

Synthesis of meso-phenyl-4,6-dipyrrins, preparation of their Cu(II), Ni(II), and Zn(II) chelates, and structural characterization of bis[meso-phenyl-4,6-dipyrrinato]Ni(II)

1996 ◽  
Vol 74 (11) ◽  
pp. 2182-2193 ◽  
Author(s):  
Christian Brückner ◽  
Veranja Karunaratne ◽  
Steven J. Rettig ◽  
David Dolphin
Keyword(s):  
Dihedral Angle ◽  
Direct Methods ◽  
Metal Chelates ◽  
Central Metal ◽  
Full Matrix ◽  
X Ray ◽  
X Ray Crystallography ◽  
Transition Metal Chelates ◽  
Square Planar

meso-Phenyldipyrromethanes can be oxidized by 2,6-dicyano-3,5-dichloro-para-benzoquinone (DDQ) to the corresponding meso-phenyldipyrrins. As expected, these novel, stable bipyrrolic pigments readily form metal chelates with copper(II), nickel(II), and zinc(II). Their UV–VIS spectra are compared with a series of known alkyl-substituted dipyrrin chelates and, based on the UV–VIS spectral analysis, the dihedral angle between the two ligands in the bis[meso-phenyldipyrrinato]Ni(II) complex was calculated to be 42°. The molecular structure of this complex was determined by X-ray crystallography, essentially confirming the calculation. Crystals of C30H22N4Ni are orthorhombic, a = 17.156(3), b = 35.217(1), c = 7.886(1) Å, Z = 8, space group Fddd. The structure was solved by direct methods and refined by full-matrix least-squares procedures to R = 0.040 and Rw = 0.031 for 1058 reflections with I ≥ 3σ(F2). The central nickel is coordinated in a distorted square-planar fashion by four nitrogens. The pair of the planar dipyrrinato ligands enclose a dihedral angle of 38.5°. This is the lowest angle reported for nickel(II) complexes of this kind. As a result of this, and in sharp contrast to previously described nickel(II) dipyrrin chelates, the central metal is diamagnetic. Key words: meso-phenyldipyrromethanes, meso-phenyldipyrrins, meso-phenyldipyrrinato transition metal chelates, X-ray crystallography.

Complexes of 15-crown-5 and cyclohexano-15-crown-5 with lithium, sodium, and potassium phenoxide having macrocycle: salt ratios of 1:1 and 1:2. The crystal structures of two polymorphs of 15-crown-5•2LiOPh

1988 ◽  
Vol 66 (10) ◽  
pp. 2515-2523 ◽  
Author(s):  
Michael P. Murchie ◽  
John W. Bovenkamp ◽  
André Rodrigue ◽  
Kimberley A. Watson ◽  
Suzanne Fortier
Keyword(s):  
Crystal Structures ◽  
Direct Methods ◽  
The Other ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
Space Group ◽  
X Ray ◽  
Diffraction Structure ◽  
Structure Determinations ◽  
Sodium And Potassium

The syntheses, in ethereal solvents, of the complexes of 15-crown-5 and cyclohexano-15-crown-5 with lithium, sodium, and potassium phenoxide are described. The two macrocycles form complexes with lithium and sodium phenoxide with host:guest ratios of 1:2. Potassium phenoxide, however, was complexed by the two macrocycles to give products with macrocycle:salt ratios of 1:1. Crystals of 15-crown-5•2LiOPh were obtained for X-ray diffraction structure determinations. In fact, the crystal structures of two co-crystallizing polymorphs of this complex (1a and 1b) have been determined. Polymorph 1a crystallizes in space group [Formula: see text] with a = 11.386(4), b = 11.901(4), c = 10.654(4) Å, α = 106.53(3), β = 112.60(3), γ = 106.52(3)°, and Z = 2. Polymorph 1b crystallizes in space group P21/n with a = 15.355(4), b = 11.642(2), c = 13.595(6) Å, β = 104.56(3)°, and Z = 4. Both structures were solved by direct methods, and refined by full-matrix least-squares calculations to residuals, R, of 0.053 and 0.055 for polymorphs 1a and 1b, respectively. The structures of the two polymorphs differ only in the orientation of the phenoxides. The structures show a dimer, (15-crown-5•2LiOPh)2, which consists of an aggregate of four lithium phenoxide molecules complexed by two 15-crown-5 macrocycles. The two lithiums of each monomeric unit of this dimer have different crystallographic and chemical environments. One lithium is coordinated to all five oxygens of the macrocycle and to one of the phenoxide oxygens while the other lithium is coordinated to only one oxygen of the macrocycle and to three phenoxide oxygens.

Structural studies of organoboron compounds. LVI. 1-Benzyl-7-methyl-3,5-diphenyl-2,4,6-trioxa-1-azonia-3-bora-5-boratabicyclo[3.3.0]octane and 1,4,6,9-tetramethyl-2,7-diphenyl-3,8,11,12-tetraoxa-1,6-diazonia-2,7-diboratatricyclo[5.3.1.12,6]dodecane

1992 ◽  
Vol 70 (11) ◽  
pp. 2809-2817 ◽  
Author(s):  
Wolfgang Kliegel ◽  
Gottfried Lubkowitz ◽  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Solid State ◽  
Gas Phase ◽  
Phenylboronic Acid ◽  
Direct Methods ◽  
Structural Studies ◽  
Triclinic Space Group ◽  
Full Matrix ◽  
X Ray ◽  
Molar Ratios ◽  
New Type

The preparation of the N-(2-hydroxypropyl)-N-alkylhydroxylamines, 6a (R = CH3) and 6b (R = CH2Ph), and their reactions with phenylboronic acid are described. Regardless of the molar ratios of reactants employed, the reaction with 6b leads to the 1:2 condensate 1-benzyl-7-methyl-3,5-diphenyl-2,4,6-trioxa-1-azonia-3-bora-5-boratabicyclo[3.3.0]octane, 7, while that with 6a gives rise to the 1:1 condensate 1,4,6,9-tetramethyl-2,7-diphenyl-3,8,11,12-tetraoxa-1,6-diazonia-2,7-diboratatricyclo[5.3.1. 12,6]dodecane, 11 (the cyclic BONBON dimer of 4,6-dimethyl-2-phenyl-1,3-dioxa-4-aza-2-boracyclohexane, 9). Compounds 7 and 11 both crystallize in the triclinic space group [Formula: see text]: for 7; a = 13.126(1), b = 15.337(1), c = 10.9469(5) Å, α = 91.727(5), β = 104.647(5), γ = 72.922(7)°, Z = 4; and for 11; a = 9.0807(4), b = 9.1653(3), c = 6.4876(2) Å, α = 97.708(3), β = 108.830(3), γ = 89.188(4)°, Z = 1. The structures were solved by direct methods and were refined by full-matrix least-squares procedures to R = 0.038 and 0.032 for 5879 and 1827 reflections with I ≥ 3σ(F2), respectively. Compound 7 has the expected bicyclic pyroboronate structure, but represents the first reported N-substituted example of this type of compound. Bond lengths involving boron in 7 are (C) O—B(sp3) = 1.428(2) and 1.420(2), (B)O—B(sp3) = 1.472(2) and 1.468(2), N—B(sp3) = 1.737(2) and 1.762(2), C(phenyl)—B(sp3) = 1.588(2) and 1.584(2), (N)O—B(sp2) = 1.402(2) and 1.404(2), (B)O—B(sp2) = 1.331(2) and 1.329(2), C(phenyl)—B(sp2) = 1.555(3) and 1.553(2) Å. The X-ray analysis establishes a centrosymmetric, twofold N → B coordinated, dimeric structure in the solid state for 11 in which each B—O—N segment of a central six-membered BONBON ring is bridged by an O—C—C moiety. Compound 11 represents the first fully characterized example of a new type of "BONBON" compound. Bond distances involving the boron atom are (N)O—B = 1.465(1), (C)O—B = 1.428(1), N—B = 1.695(2), and C(phenyl)—B = 1.607(2) Å. Spectroscopic evidence indicates that in solution and in the gas phase this material exists predominantly as the monomer 9.

Structure and Stereochemistry of Adducts of Tris(dipivaloylmethanato)europium(III), Eu(dpm)3, with Some Dipolar Aprotic Unidentate O-Donors

2020 ◽  
Vol 73 (6) ◽  
pp. 455
Author(s):  
Eric J. Chan ◽  
Jack M. Harrowfield ◽  
Brian W. Skelton ◽  
Alexandre N. Sobolev ◽  
Allan H. White
Keyword(s):  
Single Crystal ◽  
Dimethyl Sulfoxide ◽  
The Other ◽  
Asymmetric Unit ◽  
X Ray ◽  
Metal Atoms ◽  
Oxygen Donor ◽  
Trigonal Prismatic

Single crystal X-ray structural characterisations are reported for adducts of the form [(L-O)Eu(O,O′-dpm)3] obtained by the crystallisation of tris(dipivaloylmethanato)europium(iii) (dpm=[HC(C(tBu).CO)2]−) from an array of dipolar aprotic oxygen-donor solvents L (L=N-methylpyrrolidinone (nmp), trimethylphosphate, (MeO)3PO, (tmp), hexamethylphosphoramide (hmpa), dimethylacetamide (dma), dimethyl sulfoxide (dmso), and the bidentate octamethylpyrophosphoramide (ompa). In all adducts, the resulting arrays contain seven-coordinate metal atoms, which adopt two different isomeric forms of the mono-capped trigonal prismatic stereochemistry, the L=dma and dmso adducts corresponding to one type, nmp and tmp the other. The adduct formed with ompa behaves as a pair of discrete metal environments bridged by the O-ompa-O′ ligand, thus; [(dpm-O,O′)3Eu(O-ompa-O′)Eu(O,O′-dpm)3], and is found in two forms, one in which both Eu environments is of the tmp type, the other of the dmso/dma type. In the hmpa adduct, the asymmetric unit of the structure is a disordered composite of both types. In none of the adducts is there any further solvation beyond coordination of a single L.

The Crystal and Molecular Structure of Pentane-2,4-dionato-(2,3,5,6-tetrahepto-2,3-dicarbomethoxo[2.2.1]bicycloheptadiene)rhodium(I), Rh(C5H7O2) (C7H6(CO2CH3)2)

1975 ◽  
Vol 53 (18) ◽  
pp. 2707-2713 ◽  
Author(s):  
Debbie Allen ◽  
Colin James Lyne Lock ◽  
Graham Turner ◽  
John Powell
Keyword(s):  
Crystal And Molecular Structure ◽  
Molecular Structures ◽  
Monoclinic Space Group ◽  
Intensity Data ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Square Planar ◽  
Rhodium Atom

The crystal and molecular structures of pentane-2,4-dionato-(2,3,5,6-tetrahapto-2,3-dicarbomethoxo[2.2.1]bicycloheptadienerhodium(I), Rh(C5H7O2)(C7H6(CO2CH3)2), have been measured by single crystal X-ray diffraction. The orange crystals are monoclinic, space group P21/c, Z = 4, a = 9.245(4), b = 9.003(4), c = 21.680(15) Å, β = 113.41(5)°. The calculated and observed densities are 1.645 and 1.642(5) respectively. Intensity data were collected on a Syntex [Formula: see text] diffractometer and a full matrix least squares refinement on 3010 observed reflections leads to a conventional R = 0.0660. The structure can be considered as a roughly square planar arrangement of ligands around the rhodium atom composed of two β-ketoenolate oxygen atoms (Rh—O, 2.037(5) and 2.025(5) Å ) and the centers of the two ethylenic groups. The Rh—C distances for the olefin group attached to the two carbomethoxo groups, 2.117(8), 2.108(8) Å, appear to be slightly larger than those for the other olefinic group, 2.087(7), 2.082(6), and the corresponding C=C distances of 1.375(10) and 1.410(9) Å are different at the 95% confidence level.

The crystal and molecular structure of 1,4-diphenyl-2,2′,3,3′,5,5′,6,6′-octamethylcyclo-1,4-diphospha-2,3,5,6-tetrasilahexane, a phosphorus–silicon heterocycle

1979 ◽  
Vol 57 (2) ◽  
pp. 174-179 ◽  
Author(s):  
A. Wallace Cordes ◽  
Paul F. Schubert ◽  
Richard T. Oakley
Keyword(s):  
Molecular Structure ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Chair Conformation ◽  
Monoclinic Space Group ◽  
Single Bond ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Bond Lengths

The crystal structure of 1,4-diphenyl-2,2′,3,3′,5,5′,6,6′-octamethylcyclo-1,4-diphospha-2,3,5,6-tetrasilahexane, (PhPSi2Me4)2, has been determined by single crystal X-ray diffraction. The crystals are monoclinic, space group P21/c, with a = 9.866(1), b = 11.921(1), and c = 11.324(2) Å, β = 104.31(1)°, Z = 2, and ρcalcd = 1.15 g/cm3. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.060 and Rw of 0.078, for 1173 reflections with intensities greater than 3σ. The (PhPSi2Me4)2 molecule lies on a crystallographic centre of symmetry, and the six-membered P2Si4 ring has a chair conformation with equatorial phenyl groups. The endocyclic angles at P (104.4(1)°) and Si (104.9(2)°) are intermediate between those found in cyclic hexaphosphine and hexasilane molecules, and the Si—Si and P—Si distances of 2.345(3) and 2.252(4) Å, respectively, correspond to single bond lengths, with no appreciable evidence for secondary pπ → dπ bonding between phosphorus and silicon. The Si—C (1.867(8) Å) and P—C (1.828(7) Å) bond lengths are also normal. The variations in the Si—P—C (101.6(2)°, 108.6(2)°), P—Si—C (range 106.2(3)–120.0(3)°), and Si—Si—C (range 105.8(3)–113.7(3)°) angles indicate that the positions of the exocyclic methyl and phenyl groups are influenced by both intra- and intermolecular steric forces.

The crystal structures of the 1:2 host:guest complexes of dicyclohexano-18-crown-6 (isomers A and B) with sodium and potassium phenoxide

1986 ◽  
Vol 64 (4) ◽  
pp. 816-823 ◽  
Author(s):  
Marie E. Fraser ◽  
Suzanne Fortier ◽  
André Rodrigue ◽  
John W. Bovenkamp
Keyword(s):  
Crown Ether ◽  
Crystal Structures ◽  
Metal Cation ◽  
Direct Methods ◽  
The Other ◽  
Full Matrix ◽  
Space Group ◽  
Elliptical Cavity ◽  
Cation Coordination ◽  
Sodium And Potassium

The crystal structures of the 1:2 host:guest complexes of dicyclohexano-18-crown-6 (isomer B) with potassium phenoxide and dicyclohexano-18-crown-6 (isomer A) with sodium phenoxide have been determined. The potassium phenoxide complex crystallizes in space group [Formula: see text] with a = 10.023(2), b = 11.238(2), c = 7.546(2) Å, α = 95.73(2), β = 103.04(2), γ = 92.03(2)°, and Z = 1. The sodium phenoxide complex crystallizes in space group P21/n with a = 19.185(12), b = 13.266(5), c = 13.038(5) Å, β = 96.55(4)°, and Z = 4. Both structures were solved by direct methods and refined by full matrix least-squares calculations to a residual, R, of 0.035. The host conformation as well as the metal cation coordination differ considerably in the two structures. In the potassium phenoxide complex, the two cations are related by symmetry and have, consequently, the same chemical environment. Each potassium is located approximately halfway between the plane formed by the crown ether oxygens and the phenoxide anions and is coordinated to four of the crown oxygens and to two phenoxide oxygens. The oxygens of the crown are found to outline an elliptical cavity and to lie approximately in a plane. In the sodium phenoxide complex, the two sodiums have different crystallographic and chemical environments. One sodium is coordinated to the six hexaether oxygens, with distances ranging from 2.36to2.84 Å, and to one of the phenoxide oxygens. The other sodium is coordinated to only one of the crown oxygens and to three of the phenoxide oxygens. The hexaether adopts a highly irregular conformation.

3-Methylpyridine complexes of cobalt(II) and nickel(II) hexafluorophosphate and hexafluoroarsenate. Crystal and molecular structure of Ni(H2O)2(3-CH3C5H4N)6(PF6)2

1983 ◽  
Vol 61 (7) ◽  
pp. 1651-1658 ◽  
Author(s):  
Raymond M. Morrison ◽  
Robert C. Thompson ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Hydrogen Atom ◽  
Water Molecule ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Water Molecules ◽  
Magnetic Studies ◽  
Full Matrix ◽  
Mild Conditions ◽  
Square Planar

Reaction of aqueous solutions containing CO2+ or Ni2+ and PF6−, or AsF6− with excess 3-methylpyridine yields crystals of compounds of composition M(H2O)2(3mpy)6(EF6)2. Blue crystals of diaquohexakis(3-methylpyridine)nickel(II) hexafluorophosphate, C36H46F12NiN6O2P2, are monoclinic, a = 10.497(1), b = 20.074(3), c = 21.836(5) Å, β = 103.93(2)°, Z = 4, space group Cc. The structure was determined with MoKα CAD4 diffractometer data by direct methods, and refined by full-matrix least-squares procedures to R = 0.048 for 2723 reflections with I ≥ 3σ(I). The structure consists of {Ni(3mpy)4[(OH2)(3mpy)]2}2+ cations and PF6− anions. The cation contains a NiN4O2 chromophore with water molecules occupying trans positions of a distorted octahedron about nickel. One additional 3-methylpyridine molecule is H-bonded to each of the water molecules with [Formula: see text] distances of 2.717(11) and 2.719(11) Å. Weak interaction of each water molecule via its second hydrogen atom with a PF6− ion is indicated by the positioning of the anions. The [Formula: see text] distances are 2.958(11) and 2.959(11) Å. Two other complexes of this type, where M is Ni and E is As and where M is Co and E is P, are reported here and on the basis of spectroscopic and magnetic studies are assigned structures similar to the Ni/P complex.Decomposition of the aquo complexes under mild conditions yields compounds of composition M(3mpy)4(EF6)2. Ni(3mpy)4(PF6)2 is assigned a square planar structure with weakly interacting PF6−, anions in axial positions. Both Co(3mpy)4(EF6)2 complexes, where E is P or As, have tetrahedral [Co(3mpy)4]2+ cations and non-coordinated anions.

X-Ray Absorption Study of Ti and Cr Reactions with Triazine and Polyimide

1993 ◽  
Vol 323 ◽  
Author(s):  
K. Konstadinidis ◽  
R. L. Opila ◽  
M. A. Marcus ◽  
K. Short ◽  
A. E. White ◽  
...  
Keyword(s):  
Fine Structure ◽  
Polymer Matrix ◽  
Model Compound ◽  
The Other ◽  
Absorption Study ◽  
X Ray ◽  
Buried Interfaces ◽  
Metal Atoms ◽  
Π Complex ◽  
X Ray Absorption

AbstractIn this paper we present results on the use of x-ray absorption spectroscopy and in particular extended x-ray absorption fine structure (EXAFS) to study non-destructively buried interfaces between polymers and metals. In particular we study the interaction between isolated metal atoms (Ti or Cr) and the surrounding polymer matrix (polyimide or triazine). The metal atoms have been introduced into the polymer matrix using ion-implantation. We find that Cr forms a π complex with the aromatic structures of polyimide and triazine in agreement with model compound and XPS data. Ti on the other hand seems to form Ti-O-C bonds with both polymers.

The methylgallium-2-carboxylatobenzimidazolato hexamer, [MeGa·C8H4N2O2]6·C6H6·(Me2C6H4)2; synthesis and X-ray crystal structure

1999 ◽  
Vol 77 (4) ◽  
pp. 434-438 ◽  
Author(s):  
Steven J Rettig ◽  
Alan Storr ◽  
James Trotter
Keyword(s):  
Crystal Structure ◽  
Carboxylic Acid ◽  
Room Temperature ◽  
Direct Methods ◽  
Membered Ring ◽  
Coordination Geometry ◽  
Temperature Reaction ◽  
Full Matrix ◽  
X Ray ◽  
Solvent Molecules

The room-temperature reaction of Me3Ga with benzimidazole 2-carboxylic acid in xylene solvent has yielded a novel crystalline hexameric gallium compound with "MeGa" moieties bridged by the doubly depronotated ligand precursor. Crystals of [MeGa(4,5-benzimidazolato-2-carboxylato)]6·(C6H6)·(m-Me2C6H4)2 are monoclinic, a = 18.091(2), b = 17.094(2), c = 13.2215(5) Å, Z = 2, space group C2/m. The structure was solved by direct methods and refined by full-matrix least-squares procedures to R (F, I [Formula: see text] 3σ(I)) = 0.064 (Rw (F2, all data) = 0.134). The hexameric Ga complex contains a six-membered ring of Ga atoms, bridged by the benzimidazolate ligands with the benzo rings projecting alternately above and below the Ga plane, thus forming a ball-shaped molecule. The complex could have ideal D3d symmetry, but it contains an encapsulated molecule of benzene, which distorts the regularity of the Ga6 hexagon, and reduces the symmetry of the complex to the crystallographically observed C2h. The coordination geometry at each of the two independent GaO2N2C centres approximates a trigonal bipyramid, with a N2C trigonal plane, and the O atoms above and below; average dimensions are Ga-O = 2.176(2), Ga-N = 1.973(3), Ga-C = 1.927(5) Å, O-Ga-O = 165°. The unit cell also contains four m-xylene solvent molecules (outside the molecular cage).Key words: gallium, crystal structure, benzene intercalate, benzimidazolecarboxylic acid.

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