Metal-betaine interactions. IV. Crystal structures of trans-tetraaquabis(betaine)nickel(II) nitrate and trans-diaquatetrakis(pyridine betaine)cobalt(II) bis[trichloro(pyridine betaine)cobaltate(II)]

Two transition metal(II) complexes of betaine (Me₃N⁺CH₂COO^–, designated as BET) and pyridine betaine (C₅H₅N⁺CH₂COO^–, pyBET) have been prepared and investigated by X-ray crystallography and infrared spectroscopy. [Ni(BET)₂(H₂O)₄] (NO₃)₂ (1), (R _F=0.054 for 2518 observed MoK data) comprises slightly distorted octahedral [Ni(BET)₂(H₂O)₄]²⁺ cations in which the Ni(II) atom is centrosymmetrically coordinated by four aqua ligands and twotrans-related unidentate BET ligands, and the uncoordinated carboxy oxygens form intramolecular hydrogen bonds with the aqua ligands. [Co(pyBET)₄(H₂O)₂]·2[Co(pyBET)Cl₃] (2) (R _F=0.029 for 4696 observed data) consists of discrete octahedral [Co(pyBET)₄(H₂O)₂]²⁺ cations and tetrahedral [Co(pyBET)Cl₃]^– anions. In the centrosymmetric cation each of the twotrans-related aqua ligands form a pair of intramolecular hydrogen bonds with the uncoordinated oxygen atoms of two unidentate pyBET ligands. In the anion the cobalt atom is coordinated by one unidentate pyBET ligand and three chloro ligands.     

Metal-betaine interactions. I. Crystal structure of polymeric trans-diaquabis(pyridine betaine)manganese(II) dichloride

A new polymeric betaine complex of manganese(II), of stoichiometry [Mn(C₅H₅NCH₂COO)₂ (H₂O)₂]C1₂, has been prepared and characterized by infrared spectroscopy and X-ray crystallography. The complex exhibits strong carboxylate absorptions at 1624, 1396, 1384, and 715 cm^–1. The crystal structure has been refined toR _F =0.057 for 2342 observed (F ₀>6F ₀) MoK data. The complex consists of a packing ofsyn-anti carboxylate-bridged, one-dimensional polymeric chains running parallel to thea axis. Each Mn(II) atom is located at an inversion center, with aqua ligands occupying the trans positions in a slightly distorted octahedron. The chloride ions and aqua ligands are alternately linked by O-HCl hydrogen bonds into a (Cl^–·H₂O) zigzag chain also running parallel to thea axis.     

Crystal structures of isomorphous cadmium(II) and lead(II) oxalate trihydrates

The isomorphous cadmium(II) oxalate trihydrate (I) and lead(II) oxalate trihydrate (II) crystals belong to space groupP¯1 withZ=2. The crystallographic parameters for compoundI are:a=6.006(1),b=6.663(1),c=8.497(1)Å,a=74.76(1),=74.39(1), =80.94(1)°, andR=0.028 for 2643 observed MoK reflections; forII:a=6.008(1),b=6.671(1),c=8.493(1)Å,a=74.70(1),=74.33(1), =80.98(1)°, andR=0.065 for 4536 reflections. In the crystal structure, the metal atom is surrounded by seven oxygen atoms (including two aqua ligands) in the form of a distorted pentagonal bipyramid. The coordination polyhedra are interconnected through bridging oxalate groups to form a thick layer matching the (020) plane. Adjacent layers are further linked by hydrogen bonds involving both ligand and lattice water molecules to generate a three-dimensional network.On leave from Central Laboratory, Nankai University, Tianjin, China.     

Metal-betaine interactions. XXI. Crystal structures of lithium 3-carboxy-1-pyridinioacetate monohydrate and sodium 3-carboxy-1-pyridinioacetate tetrahydrate

Two hydrated alkali-metal salts of the betaine derivative 3-carboxy-1-pyridinioacetate, C₅H₄ (COOH)N⁺CH₂COO^–, have been prepared and investigated by X-ray crystallography. Lithium 3-carboxy-1-pyridinioacetate monohydrate (R _F =0.041 for 1144 observed MoK data) has a one-dimensional polymeric structure based on a centrosymmetric Li₂(acetato--O,O)2 dimeric unit with the Li ion coordinated additionally by an intra-dimer acetate oxygen atom and an aqua ligand molecule in a slightly distorted tetrahedral LiO₄ geometry [Li-O=1.908 (4)-1.976(4)Å]. Sodium 3-carboxy-1-pyridinioacetate tetrahydrate (R _F =0.054 for 1812 observed data) features parallel columns of edge-sharing NaO₆ octahedra linked into a layer by bridging aqua ligands and betaine ligands whose acetato and carboxylato groups function in the unidentate and-O modes, respectively, with Na-O distances ranging from 2.351(2) to 2.608(2)Å. All the water molecules and uncoordinated carboxy oxygen atoms are involved in hydrogen bonding in both crystal structures.     

Synthesis and crystal structures of quadruply carboxylate-bridged dimeric lanthanide(III) complexes of betaine

Three dimeric lanthanide(III) complexes, [Eu₂(bet)₈(H₂O)₄](CIO₄)₆ (1), [Tb₂(bet)₈(H₂O)₄](ClO₄)₆ (2), and [Eu₂(bet)₄(H₂O)₈] Cl₆·6H₂O (3) (bet = Me₃N⁺CH₂COO^–, trimethyl-aminoacetate), have been prepared and structurally characterized by X-ray crystallography. Complex 1 crystallizes in the monoclinic space group P2₁/c, with a = 11.7807(8), b = 27.757(5), c = 11.7980(8) Å, = 99.500(4)°, V = 3805.1(8) ų, and Z = 2. Complex 2 is isomorphous to complex 1, crystallizing in the monoclinic space group P2₁/c, with a = 11.7769(14), b = 27.725(3), c = 11.795(5) Å, = 99.668(14)°, V = 3797(2) ų, and Z = 2. Complex 3 crystallizes in the orthorhombic space group Pbca, with a = 12.5664(8), b = 17.8645(9), c = 22.2573(8) Å, V = 4996.6(4) ų and Z = 4. Both complexes 1 and 2 comprise quadruply carboxylate-O,O-bridged [M₂(bet)₄]⁶⁺ dimeric cores (M = Eu, Tb), and each metal ion is further coordinated by two terminal aqua ligands and two monodentate bet carboxylates to form a distorted square-antiprismatic coordination geometry. Complex 3 also has a [Eu₂(bet)₄]⁶⁺ core, in which two bet ligands act in the ¹:¹:₂ bridging fashion, and the other two bet ligands in the less common ²:¹:₂ bridging fashion, namely bridging-chelate mode. Each europium(III) ion in complex 3 is further coordinated by four water molecules to complete a monocapped square antiprism.     

Crystal and molecular structure of di-μ-chloro(dicyandiamide)cadmium(II)

The crystal structure of di--chloro(dicyandiamide)cadmium(II) has been determined and refined by Fourier and least-squares methods toR = 0·037 using three-dimensional X-ray data collected at room-temperature on a single-crystal automated diffractometer. Crystal data are as follows:a = 10·796(7),b = 8·933(5),c = 6·847(3) Å, = 99·9(1) °,Z = 4; space groupP2₁/n. The cadmium atom is surrounded by four chlorine (Cu-Cl = 2·572, 2·607, 2·630, 2·647 Å) and two nitrogen atoms (Cd-N (nitrilic) = 2·358 Å; Cd-N (guanidic) = 2·430 Å) so that the whole polyhedron appears as a slightly distorted octahedron. The chlorine atoms form bridges between adjacent metal atoms so that the coordination octahedra are linked in chains running along [001]. These chains are joined together by dicyandiamide bridges.The authors wish to thank Dr. A. Immirzi (Politecnico di Milano) for the use of his compter programmes.     

Preparation and crystal structure of diaquabis(1,8-naphthyridine-N-monoxide)nickel(II)nitrate

The title compound [Ni(napyo)₂(H₂O)₂](NO₃)₂ was formed by the reaction of nickel(II) nitrate with 1,8-naphthyridine-N-monoxide (napyo) in ethanol medium. The complex crystallizes in the monoclinic, space groupP2₁/n withZ=2. Lattice parameters are:a=7.160(2),b=11.713(3),c=11.830(2) Å,=95.11(3)°. The structure was determined from 1399 observed reflections and refined toR=0.061. The Ni atom shows a slightly distorted octahedral coordination, being bonded to two oxygen atoms and two nitrogen atoms of two napyo ligands and to two oxygen atoms of two water molecules.     

The conformation of pentaazamacrocyclics. I. Crystal structures of nickel (II) and copper (II) complexes of 1,4,7,11,14-pentaazacycloheptadecane

The crystal structures of [Ni(17-aneN₅)H₂O]Br₂·3H₂O (17-aneN₅=1,4,7,11,14-pentaazacycloheptadecane) and of [Cu(17-aneN₅)]CuBr₄ are reported. Diffraction data using MoK radiation were measured with a CAD-4 diffractometer and the structures refined by full-matrix least squares. The nickel compound has regular octahedral coordination with coordinated water completing the octahedron. The copper is approximately square-pyramidal with an apical Cu-N bond of 2.29(4) Å, compared to a mean bond length of 2.06(2) Å in the basal plane. As a result, the folding of the 17-membered macrocyclic rings is completely different in the two compounds.     

Crystal structures and magnetic properties of bipyridine copper(II) complexes

The synthesis, structure and magnetic properties of [Cu(diMe-bipy)Br₂] are reported (diMe-bipy=4,4-dimethyl 2,2-bipyridine). The complex has a polymeric structure composed of [Cu(diMebipy)Br₂] subunits linked via bridging bromine atoms. Each copper atom is hexacoordinated in a distorted octahedral coordination environment. Crystallographic data: monoclinic, space groupC2/c,Z=4, unit cell of dimensionsa=18.312(7),b=9.818(2),c=7.486(2)Å,=107.750(0)° at 293 K. The best fit of the magnetic susceptibility data by the uniform Heisenberg chain model forS=1/2 ions yields values for the exchange coupling constant of –0.46 cm^–1. The magnetic susceptibility of the dimeric [Cu(diMe-bipy)Cl₂]₂·0.5H₂O exhibits a maximum near 12 K that is indicative of an antiferromagnetic interaction between the two metal centers. The best fit of the experimental data by the Bleaney-Bowers equation was obtained withg=1.95 andJ=–6.99 cm^–1.     

Crystal structures and mesomorphic properties of Schiff base homologs and derivatives,and magnetic properties of their dimeric and dinuclear copper(II) complexes

Three N₂O₄ Schiff. base homologs, H₂L1 (n = 8), H₂L3 ((n = 9), and H₂L4 (n = 10) were obtained from the reactions of 2-HOC₆H₄CHO with H₂N(CH₂)_8-10NH₂, while a derivative of H₂L1, namely, H₂L2, was obtained from the reaction of 3,5-X₂-2-HOC₆H₂CHO (X = tert-butyl) with H₂N(CH₂)₈NH₂. The Schiff bases H₂L2 (triclinic; P-1), H₂L3 (monoclinic; C2/c), and H₂L4 (monoclinic; P21/c) were single crystals with low melting temperatures (less than 100°C). The homologs exhibited mesomorphisms, while the derivative was not mesomorphic and did not reform crystals from its melt. Copper(II) complexes of H₂L1, H₂L2 and H₂L4 were dimeric, while that of H₂L3 was dinuclear with chelating CH₃COO ligand. These complexes were paramagnetic with insignificant interactions between the copper(II) atoms and have high decomposition temperatures (T_dec = 268–304°C). Their melting temperatures (T_melt = 138.9–190.2°C) were higher than the corresponding Schiff bases, but they were not mesomorphic.     

Crystal structures of copper(II) compounds with racemic threonine

Crystals structures of two modifications of the copper(II) compound with racemic threonine Cu(D-Tre)(L-Tre) are determined by the electron diffraction technique. The unit cell parameters, space group, and number of formula units per unit cell for the crystals of two modifications are as follows: a = 11.10(3) Å b = 9.56(2) Å, c = 5.11(2) Å, γ = 92.6(2)°, space group P2₁/b, and Z = 2 (I); and a = 22.20(3) Å, b = 9.56(2) Å, c = 5.11(2) Å, γ = 92.6(2)°, space group C2₁/b, and Z = 4 (II). The structures are polytypic modifications of the same compound.     

Crystal growth,spectral, optical,thermal, luminescence and magnetic properties of blue light emitting diaquabis(hydrogenmalonato)cobalt(II)

Abstract

The single crystals of diaquabis(hydrogenmalonato)cobalt(II) were synthesized and grown using the slow evaporation of solutions method. The structure of the compound was obtained through single crystal XRD analyses and it belongs to P2₁/c space group of monoclinic system. The UV-vis absorption spectrum exhibits two peaks at 216 nm and 259?nm in the UV region and one peak at 524?nm in the visible region. Photoluminescence studies revealed emission of intense blue radiation. The thermal stability and decomposition stages have been investigated by TGA-DTA analysis. The magnetic measurements exposed that the compound exhibits antiferromagnetic behavior at low temperature.     

Crystal structure of bis[dihydrobis(3,5-dimethy-1-pyrazolyl)borato]cadmium(II)

The structure of [H₂B(3,5-Me₂pz)₂]₂Cd shows the four nitrogen donor atoms form a pseudotetrahedral arrangement about the cadmium(II). The intraligand N—Cd—N angles are restricted to an average of 91.4° by the chelate rings forcing the interligand N—Cd—N bond angles to average 119.4°. The Cd—N bond distances average 2.21 Å with a range of 0.04 Å. The crystal is in the triclinic space group, P with a = 7.6793(2) Å, b = 8.5992(2) Å, c = 25.0874(4) Å, = 91.0791(2)°, = 97.9769(4)°, = 110.2344(6)°, and Z = 2.     

Crystal structures of salicylideneguanylhydrazinium chloride and its copper(II) and cobalt(III) chloride complexes

The crystal structures of salicylideneguanylhydrazinium chloride hydrate hemiethanol solvate (I), salicylideneguanylhydrazinium trichloroaquacuprate(II) (II), and bis(salicylideneguanylhydrazino)cobalt(III) chloride trihydrate (III) are determined using X-ray diffraction. The structures of compounds I, II, and III are solved by direct methods and refined using the least-squares procedure in the anisotropic approximation for the non-hydrogen atoms to the final factors R = 0.0597, 0.0212, and 0.0283, respectively. In the structure of compound I, the monoprotonated molecules and chlorine ions linked by hydrogen bonds form layers aligned parallel to the (010) plane. In the structure of compound II, the salicylaldehyde guanylhydrazone cations and polymer chains consisting of trichloroaquacuprate(II) anions are joined by an extended three-dimensional network of hydrogen bonds. In the structure of compound III, the [Co(LH)₂]⁺ cations, chloride ions, and molecules of crystallization water are linked together by a similar network.     

Crystal structures of copper(II) nitrate,copper(II) chloride,and copper(II) perchlorate complexes with 2-formylpyridine semicarbazone

Compounds dinitrato(2-formylpyridinesemicarbazone)copper (I), dichloro(2-formylpyridinesemicarbazone) copper hemihydrate (II), and bis(2-formylpyridinesemicarbazone)copper(2+) perchlorate hydrate (III) are synthesized and their crystal structures are determined. In compounds I–III, the neutral 2-formylpyridine semicarbazone molecule (L) is tridentately attached to the copper atom via the N,N,O set of donor atoms. In compounds I and II, the Cu: L ratio is equal to 1: 1, whereas, in III, it is 1: 2. In complex I, the coordination sphere of the copper atom includes two nitrate ions with different structural functions in addition to the L ligand. The structure is built as a one-dimensional polymer in which the NO₃ bidentate group fulfills a bridging function. The coordination polyhedron of the copper(2+) atom can be considered a distorted tetragonal bipyramid (4 + 1 + 1). Compound II has an ionic structure in which the main element is the [CuLCl₂ · Cu(H₂O)LCl]⁺ dimer. In the dimer, the copper atoms are linked via one of the μ₂-bridging chlorine atoms. The coordination polyhedra of the central atoms of the Cu(H₂)LCl and CuLCl₂ complex fragments are tetragonal bipyramid and tetragonal pyramid, respectively. In compound III, the copper atom is octahedrally surrounded by two L ligands in the mer configuration.     

Crystal structures of three methylmercury(II) complexes with thiazolidine-2-thione

The crystal structures of three CH₃Hg⁺ complexes with 1,3-thiazolidine-2-thione (HT) are reported. The cationic [(CH₃Hg)HT]NO₃ complex is monoclinic, space group P2₁/c,a=7.158(14),b=10.156(7),c=13.472(12) Å,=108.21(4)°,Z=4. The structure was refined toR=0.045. The [(CH₃Hg)HT]⁺ cation contains a CH₃Hg⁺ group bonded to the exocyclic S atom of the ligand retaining its N-H proton. This proton is lost and the CH₃Hg⁺ group remains bonded to sulfur in the neutral [(CH₃Hg)T] compound (hexagonal, P6₃,a=13.502(8),c=6.984(7) Å,Z=6,R=0.027). The [(CH₃Hg)₂T]NO₃ compound (monoclinic, C2/c,a=25.200(10),b=7.029(6),c=17.946(8),=128.99(3)°,Z=8,R=0.047) contains complex cations in which the CH3Hg⁺ groups are bonded to N and the exocyclic S atom. This series of compounds shows that the exocyclic S atom is always the first target for the CH₃Hg⁺ group, which is also found to bind to nitrogen in the 2:1 compound. No coordination is observed with the endocyclic S site, which does not even participate in intermolecular H-bonding or HgS contacts in the solids.     

Crystal and molecular structures of trans-bis(acetonitrile)bis(bipyridine)ruthenium(II) perchlorate and trans-diamminebis(bipyridine)ruthenium(II) perchlorate

The structures of trans-[(MeCN)₂(bpy)₂Ru](ClO₄)₂(I) andtrans-[(NH₃)₂(bpy)₂Ru](ClO₄)₂(II) have been determined by single crystal X-ray diffraction methods. (I) forms monoclinic crystals in the space groupP2₁/c witha=8.399(2),b=10.406(2),c=15.590(3) Å,=93.78(2)° andZ=2 atT=293 K. The final refinement gaveR=0.040 for 2448 reflections withF _o ² >3(F _o ² ). (II) crystallizes in the triclinic space groupP¯1 witha=1.702(1),b=8.439(2),c=10.525(2) Å,=107.56(2),=104.63(1), =100.89(2)° andZ=1 atT=293 K. Refinement using 1878 reflections withF _o ² >3(F _o ² ) produced a finalR value of 0.036. Both of these structures have the ruthenium atom located on a crystallographic inversion center. The bipyridine ligands in both structures are in the bowed conformation as a means of circumventing the steric problems associated with the trans arrangement of the bipyridine ligands. The Ru-N(monodentate) distance is longer for the ammonia complex (2.106(3) Å) than for the acetonitrile complex (2.008(4) Å); there are no significant differences in the distances and angles of the two Ru(bpy)₂ frameworks.     

Crystal and molecular structures oftrans-dichloro-(ethylene) (4-methylpyridine)platinum(II) andtrans-dichloro(ethylene) (2,4,6-trimethylpyridine)platinum(II)

The crystal and molecular structures oftrans-[PtCl₂(C₂H₄)(4-MeC₅H₄N)] (I) andtrans-[PtCl₂(C₂H₄)(2,4,6-Me₃C₅H₂N)] (II) have been determined by single-crystal x-ray methods.I crystallizes in space groupP2₁/c witha= 4.991(1), b=21.658(3), c=10.675(3) Å, =110.17(2) °,Z=4;II is orthorhombic (Pbca) witha=10.295(6),b=12.393(8),c=20.370(10) Å,Z=8.Full-matrix least-squares refinements have given finalR factors of 0.053 (1520 reflections) forI and 0.042. (1412 reflections) forII. The intensities were recorded by counter methods, and only those reflections havingI>3(I) were used in the analyses.In both complexes, platinum is four-coordinate with the two chlorine atoms, the double bond of the ethylene, and the nitrogen atom of the substituted pyridine. The two structures are discussed in terms of the arrangement of the pyridine ligand with respect to the PtCl₂(C₂H₄) moiety.