Interference pattern of X-ray waves inside the crystal and its image in vacuum in double-field approximation (I)

The distribution of intensity of the interference field during simultaneous superposition of all the four Bloch waves in a two-mode case has been investigated. It is shown that the distribution of intensity of the total field in the upper layers of the crystal is of a periodic character in two mutually-perpendicular directions. In the lower layers, where the first field is absorbed, a sinusoidal distribution occurs only in the direction of the reciprocal lattice vector.     

X-ray crystal structure oftrans-dichlorobis(2,4,6-collidine)-copper(II)

The X-ray crystal structure oftrans-dichlorobis(2,4,6-collidine)copper(II) has been determined. Dark blue crystals of the complex crystallize in the monoclinic space group P2₁/c, with cell dimensionsa=7.527(3),b=14.732(4),c=7.951(4)Å and=92.79(9)°;V=880.6(6)ų andZ=2. 949 unique reflections withI _net>3(I) on refinement afforded values ofR=0.041 andR _w =0.048.     

X-ray crystal structure oftrans-dichlorobis(2,6-lutidine)palladium(II)

The X-ray structure oftrans-(2,6-lutidine)₂PdCl₂ has been determined. Golden orange crystals of the complex crystallize in the triclinic space group , with cell dimensionsa=7.6950(8),b=7.9705(10),c=8.0485(8)Å, =116.967(9), =113.343(8), and =93.836(9)°;V=385.18(7)ų andZ=2. 1336 unique reflections withI _net>3 (I) on refinement afforded values ofR=0.018 andR _w=0.023.     

X-ray crystal structure of tetraaquabis (xanthosinato)nickel(II) hexahydrate

The complex [Ni(XsH_–1)₂(H₂O)₄]·6H₂O (XsH_–1: xanthosinate) was isolated from the reaction of nickel carbonate with xanthosine in aqueous solution. The octahedral coordination is supported by the reflectance measurements. Single-crystal X-ray diffraction studies show that the crystals belong to the triclinic P1 space group, with a = 7.152(1), b = 8.830(1),c = 13.783(1) Å, = 82.024(1)°, = 86.155(1)°, = 70.900(1)°, and D = 1.643 mg/m³, forZ = 1. Nickel is six coordinate with four water molecules, and two N7 atoms from xanthosinato ligands. A complicated hydrogen-bonding network is present, all possible donors taking part in it.     

X-ray crystal structure of trans-bis(monoethanolamine) bis(saccharinato)nickel(II)

The crystal structure of trans-bis(monoethanolamine)bis(saccharinato)nickel(II), [Ni(C₇H₄NO₃S)₂(C₂H₇NO)₂], has been determined from X-ray diffraction data. The metal complex is monoclinic, with a = 11.0555(5), b = 8.9103(4), c = 11.3890(5) Å, = 105.0230(10)°, Z = 2, and space group P2_1/c . The structure consists of individual molecules. Two monoethanolamine molecules and two saccharinate anions coordinate the nickel atom forming a distorted octahedron. The monoethanolamine molecules act as a bidentate ligand and form five-membered trans chelate rings, which constitute the plane of the coordination octahedron, while two saccharinate ions behave as a monodentate ligand occupying the axial positions. Intermolecular hydrogen bonds link the molecules to form a three-dimensional infinite structure.     

X-ray crystal structure of a macrocyclic tetraamine nitrito nickel(II) complex

The compound [Ni(L)(²-NO₂)]ClO₄ (L = 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) has been synthesized and structurally characterized. It crystallizes in the monoclinic system, space group P2₁/c with a = 26.899(5), b = 8.476(2), c = 23.633(5) Å, = 115.12(13)°, V = 4878.6(17) ų, and Z = 4. Each nickel(II) ion has a six-coordinated bicapped square-pyramidal geometry with four secondary amines of the macrocycle and two oxygen atoms of the bidentate nitrito group. Electronic spectra and effective magnetic moment of the complex also exhibit a high-spin six-coordinated geometry.     

X-ray crystal structure oftrans-dinitratotetrapyridinezinc(II)-pyridine solvate,a clathrate compound

The X-ray structure oftrans-dinitratotetrapyridinezinc(II)·2 pyridine has been determined. Clear colorless crystals of the complex crystallize in the orthorhombic space group Ccca, with cell dimensionsa=12.108(3),b=14.966(7) andc=17.113(4)Å;V=3101.0(18)ų and Z=4. Unique reflections, 755, withI _net>3 (I) on refinement afforded values ofR=0.069 andR _w=0.075.     

X-ray crystal structure and spectroscopy of a pseudo-square pyramidal Cu(II) complex, trans-dinitratotetrakis (trans-4-styrylpyridine)copper(II)

Single crystals of the title Cu(II) complex, [Cu(stpy)₄(ONO₂)(ONO₂)] [stpy = trans-4-styryl-pyridine] have been prepared and characterized by elemental and thermal analyses, IR, electronic and EPR spectral measurements, and X-ray crystal structure determination. The complex crystallizes in the monoclinic space group P2₁/c with unit-cell parameters, a = 12.985(2), b = 22.865(8), c = 17.024(10) Å, = 112.29(3)°, and Z = 4. The structure consists of discrete monomeric units of [Cu(stpy)₄(ONO₂)(ONO₂)]. The equatorial positions of the Cu(II) polyhedron are occupied by nitrogen atoms of the four stpy ligands and the axial positions by the oxygens of two unidentate nitrate anions. One of these oxygens is at rather longer distance [2.609(3) Å] and may be considered to be semicoordinated. If this semibond is ignored, the coordination geometry lies closer to an idealized square pyramid than to the trigonal bipyramid geometry. IR spectra reveal nitrogen coordination from stpy and asymmetry in the monodentate oxygen binding of the two nitrate ligands. The optical reflectance band at 600 nm suggests pseudo-square-based pyramidal geometry around Cu(II). Well-resolved Cu(II) hyperfine features in the EPR spectra reveal the absence of exchange interactions between adjacent copper centers. Optical and EPR spectra of a methanolic solution of the complex indicate solvent interactions. Thermogravimetric analysis shows the complex to be stable up to 175°C.     

X-ray crystal and molecular structure of dichlorobis [2(1H)-pyridinethione-S]iron(II)

Attempts to prepare the mixed ligand complex, FeCl₂(pyS)(Ph₃P)₂ from the reaction of iron(III) chloride with 2(1H)-pyridinethione-S(HpyS) and triphenylphosphine(Ph₃P) in ethanol instead formed FeCl₂(HPyS)₂ characterized by X-ray crystallography. The structure was determined by the heavy atom method, using MoK diffractometer data, and refined by full-matrix least squares toR=0.049 for 1123 observed reflections. The molecule possesses twofold symmetry with a distorted tetrahedral geometry about the iron(II) center with S-Fe-S and Cl-Fe-Cl bond angles of 98.76(5)° and 115.79(5)° and Fe-S and Fe-Cl bond distances 2.345(1) Å and 2.288(1) Å, respectively. Hydrogen bonding between NH and chlorine atoms leads to a polymeric type structure of linked molecules running approximately parallel to thea axis.     

Synthesis,characterization, and X-ray crystal structure of tris(1,10-phenanthroline)nickel(II) perchlorate hemihydrate

The title compound was synthesized and characterized by conventional methods and its X-ray crystal structure was determined. The complex crystallizes in the monoclinic space group C2/c with eight formula units in a cell of dimensions:a=36.714(4),b=15.746(2),c=12.337(2) Å; =102.9(1)°. The structure is built up by alternate layers of octahedral [Ni(phen)₃]²⁺ cations and perchlorate anions with water molecules which run in the direction of thea axis nearly parallel to thebc plane.     

X-ray crystal structure of (1-methylthyminato)triethylphosphinegold(I)

The crystal structure of the title compound reveals that the gold atom exists in a linear geometry defined by a P atom [Au-P 2.223(6) Å] and the N(3) atom of the 1-methylthyminate nucleobase [Au-N(3) 2.06(2) Å] with a P-Au-N angle of 178.4(5)°. The crystal lattice is characterized by significant hydrogen bonding contacts involving both the carbonyl oxygen atoms and the solvent water molecule of crystallization. The crystals are monoclinic, space groupP2₁ with unit cell dimensionsa 8.037(1),b=11.329(2),c09.501(1) Å,=104.08(1)°,Z=2. The structure was refined to finalR=0.047 for 2069 reflections which satisfiedI3.0(itI).     

Synthesis,Characterization and X-ray Structures of 2,6-Diacetylpyridinebis(benzenesulfonylhydrazide) and its Zinc(II) Complex

Abstract  2,6-Diacetylpyridinebis(benzenesulfonylhydrazide) (2,6-DAPBSH) and its zinc(II) complex have been synthesized and characterized by X-ray crystallography. The ligand crystallizes in the monoclinic crystal system, space group Cc, with cell parameter = 16.808(2) Ǻ, b = 16.328(2) Ǻ, c = 8.2670(11) Ǻ, β = 91.869(9)°, while the zinc(II) complex crystallizes in the orthorhombic crystal system, space group Pbcn, with cell parameters a = 14.5927(3) Ǻ, b = 9.6502(2) Ǻ, c = 20.5610(5) Ǻ. The metal center is seven-coordinate, with an approximate pentagonal bipyramidal configuration of the chelating ligand and two apically coordinated DMSO molecules. Graphical Abstract  X-ray crystallographic study on the [2,6-diacetylpyridine—bis(benzenesulfonylhydrazonato-κ⁵ N′N′′N′′′O′O′′)]bis(dimethyl sulfoxide-κO)zinc(II) (Fig. 1) shows that the complex is a seven-coordinate, with an approximate pentagonal bipyramidal configuration where the ligand coordinates to the zinc(II) ion as a pentadentate chelate via the pyridine nitrogen atom, the two azomethine nitrogen atoms and the two sulfonyl oxygen atoms.      

Synthesis and crystal structure of thiosemicarbazide complexes of nickel(II) and copper(II)

Thiosemicarbazide complexes of nickel(II) [Ni(TSC)₂](HSal)₂ (I) and copper(II) [Cu(TSC)₂](HSal)₂ (Ia) (TSC is thiosemicarbazide and HSal is a salycilate anion), as well as complexes [Ni(TSC)₂](SO₄) · 2H₂O (II) and [Ni(TSC)₃]Cl₂ · H₂O (III), are synthesized and characterized by IR spectroscopy and X-ray diffraction. Monoclinic crystals I and Ia are isostructural; space group P2₁/n, Z = 2. Crystals II are monoclinic, space group P2₁/m, Z = 2. Crystals III are orthorhombic, space group Pbca, Z = 8. In I and Ia, two planar salycilate anions sandwich a planar centrosymmetric [Ni(TSC)₂]²⁺ cation to form a supermolecule. The cation and anions are additionally bound by hydrogen bonds. Other hydrogen bonds connect supermolecules into planar layers. In structure II, centrosymmetric [Ni(TSC)₂]²⁺ cations are connected by ??-stacking interactions into supramolecular ensembles of a specific type. The ensembles, water molecules, and (SO₄)^2? anions are bound in the crystal via hydrogen bonds. In the [Ni(TSC)₃]²⁺ cation of structure III, ligands coordinate the Ni atom by the bidentate chelate pattern with the formation of five-membered metallocycles. These metallocycles have an envelope conformation unlike those in I and II, which are planar. In III (unlike in analogous complexes), a meridional isomer of the coordination octahedron of the Ni atom is formed. Together with Cl1^? and Cl2^? anions, cations form supermolecules, which are packed into planar layers with a square-cellular structure. The layers are linked by hydrogen bonds formed by crystallization water molecules that are located between the layers.     

Catenated molecular pattern in the crystal structure of a copper(II) complex with pyrazine-2,6-dicarboxylic acid and chloride ligands

The crystals of catena-dichloro-(dihydrogen pyrazine-2,6-dicarboxylato-O,O′,N,-N′) copper(II) dihydrate Cu[H₂(2,6-PZDC)]Cl₂?2H₂O are monclinic, space group C2/c with a = 11.658(2) Å, b = 6.778(1) Å, c = 16.390(3) Å, β = 98.90(3)^°, and Z = 4. Two adjacent copper(II) ions are bridged by a fully protonated pyrazine-2,6-dicarboxylic acid molecule which uses for bridging its O,O′,N-bonding moiety on one side and a single hetero-ring nitrogen atom on the other. Two chloride ions in axial position complete the octahedral coordination around the metal ions with bond distances: Cu–N 2.027(3) ÅA, Cu–N′ 2.005(3) ÅA, Cu–Cl. 2.281(1) ÅA, and Cu–O 2.446(2) ÅA. Copper(II) ions are located in the center of symmetry and are coplanar with the ligand acid molecule forming flat molecular chains propagating in the direction of the b axis. Hydrogen bonds via solvation water molecule link the chains into molecular layers parallel to the ac plane. Weak van der Waals type interactions operate between the layers.     

Synthesis and crystal structure of bis(benzimidazolium) tetrahalocobaltate(II)

The crystal structures of benzimidazolium tetrahalocobaltates (HBz)₂[CoX₄] (X = Cl and Br) have been determined. The chloride salt is triclinic, P-1, with a = 7.670(3) Å, b = 8.307(3) Å, c = 15.730(2) Å, and = 87.37(3)°, = 84.99(3)°, = 67.72(2)°. The bromide salt is monoclinic, C2/c, with a = 15.568(2) Å, b = 8.063(3) Å, c = 5.762(2) Å and = 91.36(3)°. The structures of the two salts are closely related. Both the compounds contain isolated tetrahedral CoX₄ ^2– anions and benzimidazolium cations. In the chloride salt, three chloride ions are involved in strong hydrogen bonding while only two bromide ions participate in the bromide salt. The greater deviation from the ideal tetrahedral geometry in CoBr₄ ^2– can be related to the less extensive hydrogen-bonding network compared to the chloro complex.     

The X-ray crystal structures of three bis(cyclopentadienyl)titanium(IV) derivatives

The X-ray crystal structures of (aqua)bis(cyclopentadienyl)chlorotitanium(IV) trifluoromethanesulfonate, bis(aqua)bis(cyclopentadienyl)titanium(IV) bis(trifluoromethanesul-fonate) and bis(cyclopentadienyl)bis(trifluoromethanesulfonato)titanium(IV) show a pseudo-tetrahedral array of Cp ring centroids and oxygen or oxygen and chloride donors around titanium, and varied long-range packing motifs dependent on the availability of hydrogen bond acceptors within the lattice.     

Synthesis and X-ray crystal structure of a complex formed by reaction of 1,2-bis(2′-pyridylethynyl)benzene and mercury(II) chloride

The X-ray crystal structure of the complex formed between 1,2-bis(2′-pyridylethynyl) benzene and mercuric(II) chloride is described. The complex (C₄₀H₂₄Cl₆Hg₃N₄) crystallized in the triclinic space group P-1 with a=9.0414(6), b=9.4631(7), c=12.1134(9) ?, α=97.4680(10), β=94.8130(10), γ=105.4700(10)°. The structure reveals that the ligand is distorted from planarity to accommodate the mercury cation and a third mercuric chloride moiety is held between two ligand-mercury coordination complexes. The central mercury cation has octahedral coordination geometry surrounded by six chlorides while the other two mercury cations have distorted tetrahedral geometry each coordinated by two pyridyl nitrogen atoms and two chlorides.     

Synthesis and crystal structure of bis(2-methylbenzimidazolium) tetrahalocuprate(II)

The crystal structures of 2-methylbenzimidazolium tetrahalocuprates (H2-mebz)₂[CuX₄] (X = Cl and Br) have been detemined. The chloride salt is monoclinic, P2₁/c, with a = 8.540(2) Å, b = 16.591(2) Å, c = 14.303(3) Å, and = 98.69(2)°. The bromide salt is also monoclinic, P2₁/c, with a = 8.316(3) Å, b = 17.436(3) Å, c = 14.747(3) Å, and = 98.82(3)°. Both the compounds contain discrete distorted tetrahedral CuX₄ ^2– anions and almost planar 2-methylbenzimidazolium cations. In the chloride salt, three chloride ions are involved in hydrogen bonding instead of two bromide ions in the bromide salt.