Ethylenedibiguanide-a particularly interesting ligand in relation with the crystal structure of metal complexes

The structure of ethylenedibiguanide Mn(III) nitrate monohydrate has been determined using MoK radiation. The complex is triclinic:P¯1,a=9.412(2),b=11.452(3),c=8.635(1) Å,= 101.10(2)°,=102.45(2)° and=102.13(2)°. The structure was solved by the heavy-atom method, and refined by full-matrix least-squares to anR value of 0.024 for 3369 observed reflections. The disposition and nature of the metal-ligand bond in this and related compounds have been discussed. The crystal structure of the present compound is not in agreement with that proposed from chemical evidence.     

Dinuclear complex of rhodium(III) with an amine-phenol ligand: synthesis and X-ray crystal structure

A new rhodium(III) complex of an amine-phenol ligand N,NN-bis-(2-hydroxybenzyl)1,3-diaminopropane was synthesized and characterized by X-ray diffraction studies. Diffraction data were collected by the-2 scan method using MoK. radiation. The structure was solved by conventional methods resulting in a final R factor of 0.037 for 1954 independent reflections (F _o >2(F _o )). The structure consists of a dinuclear complex with two -hydroxy bridges between the two Rh atoms. The overall charge of the molecule is neutral due to deprotonation of all phenolic groups. Crystal data: triclinic, space groupP¯1,a=7.308(3)Å;b=9.586(3)Å,c=12.686(5)Å, =87.51(2), =88.28(2), =71.70(3)°,V=866.6(6)ų;Z=2.     

X-ray crystal structure of 2-styrylpyridine

We have crystallized the 2-styrylpyridine from the condensation reaction between the 2-methylpyridine with benzaldehyde in the formation of the model compound 2-styrylpyridine. The X-ray structure and NMR are currently reported. The main features of the structure is that is shows a localization of the double bonds rather than a delocalization of π electrons in an aromatic fashion.     

X-ray crystal structure of 2-styrylpyridine

We have crystallized the 2-styrylpyridine from the condensation reaction between the 2-methylpyridine with benzaldehyde in the formation of the model compound 2-styrylpyridine. The X-ray structure and NMR are currently reported. The main features of the structure is that is shows a localization of the double bonds rather than a delocalization of π electrons in an aromatic fashion.     

Palladium(II) complexes of N2O2 and N2S2 ligands: Syntheses and X-ray crystal structures

Palladium(II) complexes of an imine-thiophene ligand N,N bis(1-methylenethiophene)-1,3-diaminopropane and an amine-phenol ligand N,N-bis(2-hydroxybenzyl)1,3-diamino-2,2-dimethylpropane were synthesized by reacting K₂PdCl₄ with alcoholic solutions of the ligands. X-ray structures of the complexes were determined using data from a CAD-4 Nonius diffractometer (MoK radiation). The structures were solved by conventional methods resulting inR factors of 0.044 and 0.061 using 1841 and 2241 independent reflections, respectively. Crystal data: Complex I, orthorhombic, space groupPbca,a=11.323(2),b=14.819(2),c=23.873(3)Å,V=4006(1)ų,Z=8. Complex II: Space groupP2₁/c,a=9.169(2),b=31.920(4),c=8.902(6),=90.38(2)°,V=2605(1)ų.Z=4. Both complexes showed coordination of the ligands through the nitrogens only while the sulphur and the oxygen atoms were uncoordinated. Square planar coordination is completed bycis chloro ligands.Deceased.     

Photochemical synthesis and crystal structure of two potentially useful metal carbonyl complexes: pentacarbonyl(η2-cis-cyclooctene)-tungsten(0) and tetracarbonylbis(η2-cis-cyclooctene)tungsten(0)

W(CO)₅(C₈H₁₄) and W(CO)₄(C₈H₁₄)₂ were synthesized photochemically from W(CO)₆ andcis-cyclooctene with a respective yield of 71% and 18%. The compounds were characterized by NMR, IR and single X-ray crystallography. The IR spectra of the two compounds exhibited characteristic bands for the mono- and bis-substituted metal carbonyl complexes. In W(CO)₄(C₈H₁₄)₂, thecis-cyclooctene ligands are in atrans configuration with the double bonds perpendicular to each other. The two crystal structures were refined toR=0.040 for W(CO)₅(C₈H₁₄) and 0.025 for W(CO)₄(C₈H₁₄)₂. Although the tungsten-carbon (of the carbonyl groups) distances are very similar in both structures, the distances between the tungsten atom and the olefinic carbons are shorter in W(CO)₄(C₈H₁₄)₂, 2.36 Å, than in W(CO)₅(C₈H₁₄), 2.51 Å.     

1,4-Di-[2-phenyl-1-diazenyl]perhydro-1,4-diazepine: X-ray crystal structure

1,4-Di-[2-phenyl-1-diazenyl]perhydro-1,4-diazepine (1) has been synthesized by reaction of benzenediazonium chloride with homopiperazine (perhydro-1,4-diazepine). The crystal structure of 1 has been determined by single crystal X-ray diffraction analysis. The bis-triazene (1) adopts an extended conformation which precludes any close intramolecular interaction of the phenyl rings. The heterocyclic seven-membered ring adopts a chair conformation, with the triazene side chains occupying alternate axial and equatorial positions consistent with cis-geometry. Internal torsion angles of the seven-membered ring have been measured. The crystal packing is determined by short contacts between C=H groups of phenyl rings and nitrogens of triazene moieties and by van der Waals interactions, with no evidence for intermolecular – interactions. This work establishes the structure of the product of diazonium coupling with homopiperazine as 1,4-di[(E)-2-phenyl-1-diazenyl]perhydro-1,4-diazepine. Crystal data: 1 C₁₇H₂₀N₆, monoclinic, space group P2₁/n, a = 9.1838(5) Å, b = 12.1095(6) Å, c = 15.0081(8) Å, = 101.320(2), V = 1636.6(2) Å,³ for Z = 4.     

Ether cleavage of [2.2.2]cryptand: synthesis and X-ray crystal structure of [NH(CH2CH2I)3][I5]

Treatment of [2.2.2]cryptand1 in toluene with HI(g) has resulted in the formation of a twophase liquid clathrate solution from which the complex [NH(CH₂CH₂I)₃][I₅]2 has been isolated and crystallographically characterized. Crystal data for2: triclinic, space group $P\bar 1$ ,a=9.301(3) Å,b=10.419(3) Å,c=11.078(3) Å, α=90.20(2)^o, β=103.28(2)^o γ=96.50(2)^o,D _c =3.57g/cm³,Z=2,R _f =0.054,R _w =0.054. The salt is a product of an ether cleavage of the macrobicycle. The crystal structure of2 contains [NH(CH₂CH₂I)₃]⁺ ions and zigzag chains of [I₅]^? ions which self-assemble to form alternating layers, of cations and anions.     

TEM and X-ray investigations of defect structure of PbSnTe crystal

The Pb_0.8Sn_0.2Te single crystal grown by the Bridgman technique was examined by X-ray and TEM methods. The X-ray reflection topography revealed that the PbSnTe crystal consisted of monocrystallinic blocks with linear dimensions of 1–5 mm separated by low angle boundaries of tilt-twist character. “As grown” defects observed by TEM method have been identified as single perfect dislocations and dislocation pairs. A mean density of dislocations inside the crystal blocks was no more than 10³ cm⁻². Except “as grown” defects rows of mobile dislocations were observed. All of dislocations lines were characterized by the same type of Burgers vector, i.e. b = 1/2a〈110〉.     

The crystal structure of Zr2Se reinvestigated by electron crystallography and X-ray powder diffraction

The metal-rich compound Zr₂Se is of particular interest for electron crystallography, since it was one of the first examples that proved that heavy-atom structures can be solved via quasi-automatic direct methods from selected area electron diffraction intensities [1]. For this reason, Zr₂Se has been chosen as a model to discuss the possibilities and the limits of the quasi-kinematical approach that has been successfully used to determine this and related structures from high-resolution electron microscopy (HREM) images and selected area electron diffraction. In order to quantify the achievable accuracy of the electron crystallography techniques used, the corresponding structures are compared with results from structural analysis with X-ray powder data and with a model received from first-principles calculations. The latter structure was chosen in this study as a reference, since the calculations do not depend on experimental parameters. Analysis of the obtained result from electron diffraction structural analysis (EDSA) shows that the structural model is, on average, only off by 0.08 Å, despite the investigated crystal having an effective thickness of 286 Å. The corresponding result from Rietveld refinement with X-ray powder data agrees to within 0.04 Å with the structure from calculation and within 0.03 Å with the result from an earlier single crystal X-ray study [2].     

Aquadifluoro(1,10-phenanthroline)copper(II) dihydrate: X-ray crystal structure reveals strong hydrogen bonds between ligand fluoride and lattice water molecules

C₁₂H₁₄CuF₂N₂O₃,M=335.797, monoclinic, space groupP2₁/n,a=6.985(2),b=17.406(2),c=10.581(2) Å,=92.41(2)°,V=1285(1) ų,D _c =1.736 g cm^–3,Z=4,F(000)=684,(CuK)=27.0 cm^–1, =1.5418 Å,T=20°C, crystal dimensions=0.75×0.45×0.30 mm. The structure of the title compound shows it to be [Cu(phen)F₂(H₂O)]·2H₂O with pentacoordinate-square pyramidal Cu(II), short Cu-F bonds [1.890(4) and 1.891(4) Å], and short FH-O hydrogen bonds (ca. 2.68 Å) between the complex and lattice water molecule.     

Synthesis and X-ray crystal structure determination of N-p-methylphenyl-4-benzoyl-3,4-diphenyl-2-azetidinone

The title compound, C₂₉H₂₃NO₂, has been characterized by single-crystal X-ray diffraction at two different temperatures (303 K and 120 K) and wavelengths (MoK _α and CuK _α). The non-centrosymmetric hexagonal crystal structure contains four-membered planar β-lactam ring with an unusually long C-C bond. The β-lactam ring is almost planar.     

Infrared spectra of silver complexes with 2-aminopyridine and crystal structure of the 4:3 aminopyridine-silver nitrate compound

The 43 complex formed between 2-aminopyridine (ampy) and AgNO₃ belongs to the orthorhombic space groupPccn. The unit cell of dimensionsa=7.992(4),b=16.788(5),c=21.034(8) Å contains four formula units. The structure was refined on 998 nonzero reflections toR=0.038. The crystal contains the dimeric [Ag₃(ampy)₄]³⁺ cation. Two of the three independent Ag atoms are each coordinated to two ampy ligandsvia the heterocyclic nitrogen lone pair (mean Ag-N=2.18 Å), and the N-Ag-N angle in this [ampy-Ag-ampy]⁺ unit is 154.0°. By using the two available amino groups, the [ampy-Ag-ampy]⁺ unit acts as a bidentate ligand, and two such units related by a twofold axis achieve a roughly tetrahedral environment of NH₂ lone pairs about the third Ag atom (mean Ag-N=2.39 Å). The infrared spectra of [Ag₃(ampy)₄](NO₃)₃, [Ag(ampy)₂]ClO₄, [Ag₃(ampy-H)₂]NO₃, and [Ag₃(ampy-H)₂]ClO₄, and those of their amino-deuterated derivatives, are discussed. Diagnostic regions are proposed to identify coordinationvia the amino group and the heterocyclic nitrogen atom.     

Synthesis and crystal structure of Mn(II) and Zn(II) complexes with 1,3,5-tris(carboxymethoxyl)benzene ligand

Two complexes (H₂bipy)[M₂(TB)₂(H₂O)₈]·5H₂O (M = Mn 1, Zn 2) (bipy = 4,4′-bipyridine, H₃TB = 1,3,5-tris(carboxymethoxyl)benzene) were synthesized by the reaction of the corresponding metal salt with ligand H₃TB and 4,4′-bipy in an aqueous methanol solution at room temperature, respectively. Their structures were determined by single crystal X-ray diffraction analysis. Both complexes 1 and 2 crystallize in the triclinic space group with the crystal parameters of 1: a = 9.725(12) ?, b = 10.651(13) ?, c = 10.882(13) ?, α = 91.72(2)°, β = 96.41(2)°, γ = 97.72(2)°, V = 1109(2) ?³, Z = 1 and 2: a = 9.610(10) ?, b = 10.55(2) ?, c = 10.83(2) ?, α = 91.60(4)°, β = 95.32(2)°, γ = 97.73(4)°, V = 1082(3) ?³, Z = 1. Complexes 1 and 2 have the same dinuclear structure, in which each metal atom is six coordinated with distorted octahedral geometry by two oxygen atoms from two different TB³⁻ ligands and four ones from four coordinated water molecules. The dinuclear units are further linked by hydrogen bonding and π–π interactions to form the three-dimensional framework structure.     

X-ray crystal structure of (6-n-propyl-2-thiouracilato)(triethylphosphine)gold(I)

The crystal structure of the title compound [Et₃PAu(PTU)] is reported. There are two molecules in the asymmetric unit and each of the independent Au atoms exists in a linear geometry defined by a P atom of the phosphine ligand and a thiolate S atom derived from the thionucleobase; molecule 1: Au-P 2.255(5), Au-S 2.314(5)Å, P-Au-S 176.9(2)° and molecule 2: Au-P 2.249(5), Au-S 2.328(4)Å and P-Au-S 175.0(2)°. The lattice features weak AuAu contacts of 3.486(1)Å and hydrogen bonding interactions involving theOxo and N-H groups. Crystals are monoclinic, space groupP2₁/c with unit cell dimensions:a=21.445(2),b=8.931(2),c=17.956(3)Å;=96.09(1)° andZ=8. The structure was refined by a full-matrix least-squares procedure to finalR=0.053 using 2875 reflections withI3.0(I).     

Copper, a chemical Janus: two copper(II) complexes with different ligand in one single crystal

A chemical Janus, binuclear copper(II) complexes, {[Cu(TPA)Cl][Cu(BPA)Cl]}(ClO₄)₂ (TPA = Tris(2-pyridylmethyl) amine, BPA = bis-(2-pyridylmethyl)amine) containing two different ligands has been synthesized and characterized by X-ray single crystal analysis. Crystal data: triclinic, space group P1$sm, a = 12.529(3), b = 12.655(3), c = 13.458(3) Å, = 70.48(3), = 67.40(3), = 75.81(3)°, D _x = 1.648 mg m^–3, and Z = 2. The molecular structure shows that the binuclear copper complex consists of two positive cation and two perchlorate anions. The positive cations moieties have different ligands. Cu(1) is coordinated by four nitrogen atoms from TPA and one chloride atom, forming a square-pyramidal geometry, whereas the coordinate number of Cu(2) is four, three of which are from BPA, one from chloride. There are two weak bonds between the Cl(2a) ion and the Cu(2) ion (2.844 Å) and the distance of Cu(2)=O(13) is 2.750(9) Å.     

Synthesis,characterization and crystal structure of a novel 2D Cu(I) complex with flexible ligand

An exploration of the Cu(I)‐L system under hydrothermal conditions, has led to the isolation of a novel framework [Cu(I)(L)]_n ( 1 ) (L = bis(3,3‐dimethyl‐4,4‐dihydro‐1H‐pyrazol‐4‐yl)methane). Single‐crystal X‐ray analysis reveals that it crystallizes in the monoclinic, space group C2/c, a = 19.781(4) Å, b =11.026(3) Å, c = 16.339(4) Å, β = 127.186(3)°. The Cu ions are linked into an extended rainbow‐like chain via L molecules. Further, these adjacent chains are united together through hydrogen‐bonded interaction to a 2D layer. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Two new coordination polymers based on tartaric acid ligand: Syntheses,crystal structure and thermal stability

Two new coordination polymers [Cd₃(D-Tar)₃]_n (1) and [Pb(meso-Tar)]_n (2) (H₂Tar = tartaric acid) have been synthesized by hydrothermal reaction and characterized by single crystal X-ray diffraction analysis and IR spectra. 1 crystallizes in the C222₁ chiral space group and shows a 3D (4,4)-connected net with the (4.6.8⁴)₄(4.6².8².10)(4.6².8³)(4.6³.8²)(4.6³.8²)₄(4.8⁵)₂ topology. 2 possesses a 3D (4,4)-connected net with the (4³.6².8) topology. In addition, the thermogravimetric analyses (TGA) results for polymers are discussed.     

Unexpected crystallization and X-ray crystal structure of racemic 1-phenyl-2-(4-pyridyl)ethanol intermediate

We have isolated, by crystallization, the intermediate, 1-phenyl-2-(4-pyridyl)ethanol, from the condensation reaction of 4-methylpyridine with benzaldehyde in which the aim was to obtain the model compound 4-styrylpyridine in absence of a condensing agent. Single crystal X-ray analysis shows the formation of an intermolecular hydrogen bond O–H···N between the nitrogen atom of a pyridine group and the oxygen atom of the OH of the neighboring molecule, which helps to stabilize the crystal structure. Crystal structure determination clearly revealed that the solid is chiral and racemic, as expected. The title compound crystallizes in an orthorhombic system with a space group Pna2₁ with two pairs of R and S enantiomers in each crystal cell (a = 15.591(1) Å, b = 12.691(1) Å, and c = 5.589(1) Å). Spectroscopic NMR data gave evidence that the isolated compound is actually the alcohol just before the dehydration process that yields the double bond of the 4-styrylpyridine.     

Synthesis and crystal structure of a silver(I) complex with dithioether ligand

The reaction of the dithioether ligand, 2,3-bis(5-methyl-1,3,4-thiadiazole-2-thiomethyl) quinoxaline (L) with AgBF₄, leads to the formation of a novel complex {[AgL](BF₄)}_∞ 1, which has been characterized by single-crystal X-ray diffraction analysis: monoclinic, space group C2/c, with a = 20.316(7) ?, b = 12.401(4) ?, c = 18.039(6) ?, β = 108.404(6)° and V = 4312(3) ?³. The crystal structure of the complex consists of 1D {[AgL]⁺}_∞ cation chain and BF₄ ⁻ anions. In 1, the coordination geometry of Ag^I center can be best described as trigonal planar coordinated by three N from two distinct L ligands. The ligand is polydentate with one end adopting a bidentate conformation to chelate an Ag^I atom and the other end monodentate to bridge another Ag^I resulting in an infinite chain along b axis. There exist Ag⋯N weak coordination, π–π stacking and F⋯S weak interactions in the complex, and these weak interactions link the 1D complex into 3D supramolecular structure and further stabilize the crystal structure in the solid state.