Crystal structure of bis-{1-[(E)-(2-meth-oxy-phen-yl)diazen-yl]naphthalen-2-olato-κ(3) O,N (2),O'}copper(II) containing an unknown solvate.

The title complex, [Cu(C17H13N2O2)2], crystallizes with two independent mol-ecules in the asymmetric unit. Each Cu(II) atom has a distorted ocahedral coordination environment defined by two N atoms and four O atoms from two tridentate 1-[(E)-(2-meth-oxy-phen-yl)diazen-yl]naphthalen-2-olate ligands. In the crystal, the two mol-ecules are linked via weak C-H⋯O hydrogen bonds which in turn stack parallel to [010]. A region of disordered electron density, most probably disordered methanol solvent molecules, was corrected for using the SQUEEZE routine in PLATON [Spek (2015). Acta Cryst. C71, 9-18]. Their formula mass and unit-cell characteristics were not taken into account during refinement.

(E)-1-[(2,4,6-Tri-bromo-phen-yl)diazen-yl]naphthalen-2-ol.

The title azo mol-ecule, C16H9Br3N2O, adopts a trans conformation with respect to the azo N=N double bond. An intra-molecular O-H⋯N hydrogen bond forms an S(6) ring motif. The dihedral angle between the naphthalene ring system and the benzene ring is 33.80 (16)°. In the crystal, mol-ecules are stacked in columns along the a axis by π-π inter-actions [centroid-centroid distances = 3.815 (3) and 3.990 (3) Å].

1-[(E)-2-(2-Hy-droxy-5-methyl-phen-yl)diazen-2-ium-1-yl]naphthalen-2-olate.

The title zwitterion, C17H14N2O2, crystallizes with two independent mol-ecules in the asymmetric unit, both of which are approximately planar, the dihedral angles between the benzene ring and the naphthalene ring system being 4.39 (12)° in one mol-ecule and 5.83 (12)° in the other, and show an E conformation with respect to the azo double bond. An intra-molecular N-H⋯O hydrogen bond in each molecule helps to establish their near planar conformation. In the crystal, mol-ecules are linked through O-H⋯O hydrogen bonds into infinite chains running along the a-axis direction. In addition, the chains are stacked along the b axis via π-π inter-actions between the benzene and the naphthalene rings of adjacent mol-ecules, the centroid-centroid distances being 3.722 (3) and 3.823 (4) Å.

(E)-1-(2-Phenyl-diazen-2-ium-1-yl)naph-thalen-2-olate.

In the title zwitterionic compound, C16H12N2O, the dihedral angle between the phenyl ring and the naphthalene ring system is 17.85 (8)°; an intra-molecular N-H⋯O hydrogen bond occurs. In the crystal, π-π stacking is observed between naphthalene ring systems of adjacent mol-ecules, the centroid-centroid distance being 3.6486 (11) Å.

(E)-1-(3-Formyl-phen-yl)-2-(2-oxidonaphthalen-1-yl)diazen-1-ium.

In the title zwitterion, C17H12N2O2, the dihedral angle between the benzene ring and naphthalene ring system is 11.76 (7)° and an intra-molecular N-H⋯O hydrogen bond exists. In the crystal, molecules are linked via pairs of C-H⋯O hydrogen bonds, forming inversion dimers.

Bis{1-[(E)-(2-chloro-phen-yl)diazen-yl]naphthalen-2-olato}copper(II).

The Cu(II) atom in the title compound, [Cu(C16H10ClN2O)2], is located on an inversion center and is tetra-coordinated by two N and two O atoms from two bidentate 1-[(E)-(2-chloro-phen-yl)diazen-yl]naphthalen-2-olate ligands, forming a square-planar complex. In the crystal, mol-ecules are linked via weak C-H⋯O and C-H⋯Cl hydrogen bonds, forming chains propagating along [010]. There are also π-π inter-actions present involving adjacent naphthalene rings [centroid-centroid distance = 3.661 (13) Å].

1-(3-Acetyl-phen-yl)-2-(2-oxidonaph-thalen-1-yl)diazen-1-ium.

The title compound, C18H14N2O2, crystallized with two independent zwitterion mol-ecules (A and B) in the asymmetric unit. They are both close to planar, the dihedral angle between the benzene ring and naphthalene ring system being 4.30 (9)° in A and 4.69 (9)° in B. Each mol-ecule has an E conformation with respect to the azo double bond. In each of the independent mol-ecules, an intra-molecular N-H⋯O hydrogen bond forms an S(6) ring motif. In the crystal, mol-ecules are linked via C-H⋯O hydrogen bonds, forming -A-A-A- and -B-B-B- chains parallel to one another and propagating along the a-axis direction. There are also π-π inter-actions between adjacent mol-ecules involving benzene and naphthalene rings [centroid-centroid distance of 3.626 (3) Šfor adjacent A mol-ecules and 3.652 (3) Šfor adjacent B mol-ecules].

1-(4-Hy-droxy-phen-yl)-2-(2-oxidonaphthalen-1-yl)diazen-1-ium methanol hemisolvate.

In the title compound, C16H12N2O2·0.5CH3OH, the H atom of the -OH group has been transfered to the N atom in the azo group, forming a zwitterion. Hence, there is an intra-molecular N-H⋯O, rather than an O-H⋯N, hydrogen bond in the mol-ecule. The mol-ecule is almost planar, the dihedral angle between the benzene ring and the mean plane of the naphthalene ring system being 4.51 (6)°. In the crystal, mol-ecules are linked to and bridged by O-H⋯O hydrogen bonds involving the methanol mol-ecule, which is located about a twofold rotation axis, and hence half-occupied, forming zigzag chains along [001]. Mol-ecules are also linked via C-H⋯π and π-π inter-actions, the latter involving adjacent benzene and naphthalene rings and having a centroid-centroid distance of 3.6616 (13) Å, forming a three-dimensional network.

Lanthanide(III) and actinide(III) complexes [M(BH4)2 (THF)5][BPh4] and [M(BH4)2(18-crown-6)][BPh4] (M = Nd, Ce, U): synthesis, crystal structure, and density functional theory investigation of the covalent contribution to metal-borohydride bonding.

Treatment of [M(BH4)3(THF)3] with NEt3HBPh4 in THF afforded the cationic complexes [M(BH4)2(THF)5][BPh4] [M = U (1), Nd (2), Ce (3)] which were transformed into [M(BH4)2(18-crown-6)][BPh4] [M = U (4), Nd (5), Ce (6)] in the presence of 18-crown-6; [U(BH4)2(18-thiacrown-6)][BPh4] (7) was obtained from 1 and 18-thiacrown-6 in tetrahydro-thiophene. Compounds 1, 3.C4H8S, 4.THF, 5, and 6.THF exhibit a penta- or hexagonal bipyramidal crystal structure with the two terdentate borohydride ligands in apical positions; the BH4 groups in the crystals of 7.C4H8S are in relative cis positions, and the thiacrown-ether presents a saddle shape, with two diametrically opposite sulfur atoms bound to uranium in trans positions. The crystal structures of these complexes, as well as those of previously reported [M(BH4)2(THF)5]+ cations, do not reveal any clear-cut lanthanide(III)/actinide(III) differentiation. The structural data obtained for [M(BH4)2(18-crown-6)]+ (M = U, Ce) by relativistic density functional theory (DFT) calculations are indicative of a small shortening of the U...B with respect to the Ce...B distance, which is accompanied by a lengthening of the U-Hb bonds and an opening of the Hb-B-Hb angle (Hb = bridging hydrogen atom of the eta3-BH4 ligand). The Mulliken population analysis and the natural bond orbital analysis indicate that the BH4 -->M(III) donation is greater for M = U than for M = Ce, as well as the overlap population of the M-Hb bond, thus showing a better interaction between the uranium 5f orbitals and the Hb atoms. The more covalent character of the B-H-U three-center two-electron bond was confirmed by the molecular orbital (MO) analysis. Three MOs represent the pi bonding interactions between U(III) and the three Hb atoms with significant 6d and 5f orbital contributions. These MOs in the cerium(III) complex exhibit a much lesser metallic weight with practically no participation of the 4f orbitals.

cis-Dichlorido[4,4,5,5-tetra-methyl-2-(2-pyrid-yl)-2-imidazoline-1-ox-yl]-palladium(II) tetra-hydro-furan hemi-solvate.

The asymmetric unit of the title complex, [PdCl(2)(C(12)H(16)N(3)O)]·0.5C(4)H(8)O, consists of one palladium complex in a general position and one half tetra-hydro-furan (THF) solvent mol-ecule, with the O atom lying on a twofold rotation axis. The Pd(II) atom is bound to one chelating imino nitroxide radical through two N atoms, one from the pyridyl ring and the other from the imidazoline ring. The coordination of the metal centre is completed by two Cl atoms in a cis configuration, leading to a quasi-square-planar coordination of the metal centre. The four atoms that define the Pd(II) coordination environment and the eight atoms that belong to the pyridylimine fragment are coplanar, with no deviation larger than 0.087 (5) Å. In the crystal structure, inter-molecular inter-actions shorter than the corresponding van der Waals radii sum are observed only between Pd(II) complexes, and no short contact is observed around the THF mol-ecule. Weak C-H⋯O and C-H⋯Cl inter-actions yield a two-dimensional network of complexes in the (101) plane.

Bonding behavior of Co(CO)(3)L (L = CO, PPh(3)) building blocks in platinum-cobalt carbonyl clusters.

The reaction of [Co(CO)(4)](-) with [Pt(2)Cl(mu-PPh(2))(PPh(3))(3)] (1:1 ratio), which was prepared in situ by reaction of aqueous HCl with the orthometalated complex [Pt(2)(mu-PPh(2))(mu-o-C(6)H(4)PPh(2))(PPh(3))(2)], afforded the deep green triangular cluster [Pt(2)Co(mu-PPh(2))(CO)(4)(PPh(3))(2)], 7. X-ray crystallographic analysis reveals that this new cluster contains two formally monoanionic fragments, PPh(2-) and Co(CO)(4-), that bridge a d(9)-d(9) Pt(I)-Pt(I) metal-metal bond. Whereas tetracarbonylcobaltate is generally bonded to only one metal center as a 2e donor ligand, it is best viewed here as a formally 4e donor anionic metalloligand. This model leads then to the usual 16e count for each Pt center and relates this metalloligand to other anionic bridging ligands, such as PPh(2-). A comparative EHMO bonding analysis of [Co(CO)(3)L](-) (L = CO, PR(3)) fragments is presented which takes into account the possible coordination geometries about cobalt, trigonal bipyramidal (with C(3v) local symmetry) or edge-capped tetrahedral when referring to the ligand polyhedron (with C(2v) or C(s) symmetry). The results support the description of this unusual bridging bonding mode.