C. Miravitlles

Copper complexes with a pyrazole derivative ligand. Crystal structure of tetrakis{[(3,5-bis(pyridin-2-yl)pyrazolate)-(aqua)copper(II) nitrate monohydrate}

Abstract Reaction of the pyrazole-derived ligand 3,5-bis(pyridin-2-yl)pyrazole (bpypz) with Cu(NO3)2, CuCl2 and CuBr2 yields polynuclear copper(II) compounds with remarkable structural and magnetic properties. The magnetic behaviour was studied by fitting the experimental data with a dimer and tetramer magnetic model. Strong antiferromagnetic exchange interactions were found in all cases. The molecular structure of the nitrate compound was solved by X-ray diffraction methods. The compound is tetranuclear, orthorhombic, space group Fddd, a = 18.572(4), b = 23.816(8), c = 27.337(9) A, V= 12092 A3, Z = 8.

Anionic 2,4,6-trinitrophenylpalladium(II) complexes. Crystal structure of cis-[PdCl2{2,4,-C6H2(NO2)3}{S(O)Me2}]−

Abstract Treatment of [(PhCH2)PPh3]2[Pd2Cl4(μ-Cl)2] with HgR2 (R = 2,4,6-trinitrophenyl) ( 1 2 ) in refluxing acetone gives [(PhCH2)PPh3]2[Pd2R2Cl2(μ-Cl)2]-·2Me2CO (1). Reaction of 1 with an excess of NaX gives [(PhCH2)PPh3]2[Pd2R2-X2(μ-X)2][X = Br (2), I (3)]. Reactions of 1 or 2 with dimethylsulfoxide give the complexes cis-[(PhCH2)PPh3][Pd(R)X2{S(O)Me2}] (X = Cl (4) or Br (5)). An X-ray diffraction study of complex 4 has revealed a square-planar coordination around the palladium atom, with mutually cis chloro ligands and a S-bonded coordination of dimethylsulfoxide. The shortest Pd-O distances (2.911 and 2.910 A) are too long to imply intramolecular coordination.

Free radicals as clathrate hosts: crystal and molecular structure of 1: 1 perchlorotriphenylmethyl radical–benzene

The perchlorotriphenylmethyl radical (2) acts as a clathrate host for benzene, halogenobenzenes, and 1,4-dioxane giving inclusion compounds with different stabilities; the structure of (2)·C6H6, established by X-ray diffraction, shows the guest molecules located in channels between the hosts.

The structures of vulgarin and its isomers : —A reinvestigation

Abstract The green parts of Artemisia rehan , Chiov (Asteraceae) were found to contain vulgarin. The 1 H and 13 C NMR spectra of vulgarin and 4- epi vulgarin were unambiguously assigned based on COSY and 1 H- 13 C correlation experiments and an X-ray investigation settled the configuration. Furthermore, the compounds barrelin and judaicin were proved to be identical with vulgarin.

The 1:1-adduct of chlorotriphenyltin with 2',6'-dimethoxyflavone : a potential fungicide

The 1∶1 adduct of chlorotriphenyltin with 2′,6′-dimethoxyflavone, (C35H29O4ClSn)Mr=667.78, crystallizes in the triclinic space groupP1 with the following data:a-9.094(2),b=12.369(3),c=14.674(3) Å, α=74.78(2), β=77.00(2), γ=73.06(3)°,V=1503.8(4) Å3,Z=2, Mo-Kα, μ=9, 8 cm−1,Dc=1.475 g cm−3, F(000)=676,T=293K. The structure was solved by direct-methods and has been refined to a finalR value (l>3σ(I)) of 0.0301. The flavone coordinates to the tin atom through the carbonyl oxygen atom. The metal center exhibits a trigonal bipyramidal configuration with the three phenyl groups in equatorial positions.

An unusual β-diketone coordination mode. Crystal structure of bis(1,3-bis(2-hydroxyphenyl)-1,3-propanedione)tetrakispyridine dimanganese(III)

Abstract An unusual β-diketone coordination mode is reported here for the first time. A dinuclear Mn(III) compound is obtained by reaction, in open atmosphere and basic medium, of a mononuclear, β- diketone like complex of the trinucleating ligand 1,3-bis(2-hydroxyphenyl)-1,3-propanedione with a Mn(II) salt. The aforementioned molecule is a potentially trinucleating ligand with three coordination sites: the most reactive is the central β-diketone moiety, while the outer are the less reactive. In the Mn(III) complex both metal ions are occupying the two outer sites. The compound bis(1,3-bis(2- hydroxyphenyl)-1,3-propanedione)tetrakispyridine dimanganese(III), C50H38N4O8Mn2, is monoclinic, space group P21/n, a=16.093(5), b=17.062(4), c=31.449(6) A, β=93.09(2)°, V=8622.7 A3, Z=8, Dx=1.44 Mg m−3, μ(Mo Kα)=6.20 cm−1 4516 final data for 259 refined parameters. R=0.076, Rw= 0.081. MnMn distance in the dinuclear compound is 5.295(2) A.

Synthesis and structural study of complexes of nickel(II) with 4-amino-2,6-dimethyl-5-oxo-3-thioxo-2,3,4,5-tetrahydro-l,2,4-tria-zine

Abstract Bis-ligand nickel(II) complexes with 4-amino-2,6-dimethyl-5-oxo-3-thioxo-2,3,4,5-tetrahydro-1,2,4-tria-zine have been prepared by reaction between the triazine and the corresponding nickel salt in the 2:1 molar ratio, respectively. Conductance, magnetic, and infrared and visible spectroscopy data have been used for structural assignments. Pseudooctahedral structures are proposed for the complexes with the triazine molecule acting either as a monodentate N-donor ligand or a bidentate N- and S-donor ligand. An X-ray structural determination carried out with [Ni(triazine)2(H2O)2](ClO4)2 shows that the triazine acts as a bidentate ligand via the 4-amino nitrogen and the 3-thioxo sulfur (Ni-S=2.377 A; Ni-N=2.079 A) and the two H2O molecules complete the hexacoordination of nickel(II) (Ni-O=2.135 A).

Synthesis, molecular structure and magnetic properties of di-μ-hydroxo-bis-(bis(1,3-bis(2-hydroxyphenyl)-1,3-propanedione)chromium(III)) bistoluene

Abstract The title compound [Cr2(bhppH2)4(OH)2]·2C7H8 has been synthesized and isolated by chromatographic techniques from the reaction between 1,3-bis(2- hydroxyphenyl)-l,3-propanedione (bhppH3) and Cr(NO3)3·9H2O. Well formed single crystals were grown from toluene solutions and characterized by X-ray diffraction methods being triclinic, space group P 1 , with a = 12.692(2), b = 13.423(2), c = 21.983(4) A, α= 102.24(1), β = 92.04(1), γ = 115.72(1)°, V= 3.262(6) A3, Z = 2, Dx = 1.370 g cm−3 and μ = 3.9 cm−1, F(000) = 1.396. Magnetic susceptibilities were measured from 50 down to 4.2 K and fitted using the simplest Hamiltonian for exchange coupled systems = −2JS1S2. The best results were obtained with J=−4.1 cm−1 and g= 1.85. These values are compared with the Glerup, Hodgson and Pedersen (GHP) model.

2′,6′-Dimethoxyflavone as an Aid to the Crystallization of Benzoic Acids and X-Ray Structure of the Inclusion Compound with 2,4,6-Trimethoxybenzoic Acid

The crystal structure of the inclusion compound formed between 2′-6′-dimethoxyflavone and 2,4,6-trimethoxybenzoic acid has been investigated by single-crystal X-ray analysis. The compound crystallizes in the triclinic system, space group P-1, as do inclusion compounds with acetic, propionic, and bromoacetic acids. However, the larger 2,4,6-trimethoxybenzoic acid molecule induces a layered structure.

7-Hydroxy-2-(2,3,4-trimethoxyphenyl)-4H-1-benzopyran-4-one: (7-hydroxy-2',3',4'-trimethoxyflavone)

Abstract7-Hydroxy-2′,3′,4′-trimethoxyflavone, (C18H16O6),Mr=328.32 crystallizes in the orthorhombic system, space groupPbna, with the following crystal data:a=8.853(2),b=12.870(2),c=26.293(3)Å,V=2996(1)Å3,Z=8, MoKα, μ=0.67 cm−1,Dc=1.454 g·cm−3,F(000)=1376,T=294K. The structure was solved by direct-methods and has been refined by full-matrix least-squares methods to a finalR value (F>σ(F)) of 0.0496. The molecule is not planar, the dihedral angle between the phenyl ring and the fused ring system is 27.3°. There are no intramolecular hydrogen bonds, but intermolecular short hydrogen contacts exist between hydroxyl hydrogen and carbonyl oxygen atoms.