Sonochemical preparation of pure t-LaVO4 nanoparticles with the aid of tris(acetylacetonato)lanthanum hydrate as a novel precursor.

Herein a simple and fast method is introduced for the synthesis of lanthanum orthovanadate (LaVO4) nanoparticles under ultrasound irradiation. The effect of tris(acetylacetonato)lanthanum hydrate ([La(acac)3·3H2O]) and La(OAc)3 as two different precursors on the morphology and phase purity of LaVO4 was investigated. To optimum the particle size of the products, sonication time and the kind of surfactants have been changed. The as-synthesized products were characterized by XRD, FT-IR, SEM, TEM, and EDS. Based on the obtained results, it was found that the size and shape of the sonochemically formed LaVO4 nanoparticles were dramatically dependent on the sonication time, type of surfactant and lanthanum precursor. According to the XRD results, it was observed that pure tetragonal phase lanthanum orthovanadate (t-LaVO4) could be obtained only by using [La(acac)3·3H2O] as precursor under ultrasound irradiation for 30 min. On the other hand, monoclinic phase lanthanum orthovanadate (m-LaVO4) with poor crystallinity has been produced by vigorous stirring at room temperature without sonication.

{µ-2-[(3-Amino-2,2-dimethyl-prop-yl)imino-meth-yl]-6-meth-oxy-phenolato-1:2κ(5)O(1),O(6):N,N',O(1)}{2-[(3-amino-2,2-dimethyl-prop-yl)imino-meth-yl]-6-meth-oxy-phenolato-1κ(3)N,N',O(1)}-µ-azido-1:2κ(2)N:N-azido-2κN-methanol-2κO-dinickel(II).

Two distinct coordination geometries are found in the binuclear title complex, [Ni(2)(C(13)H(19)N(2)O(2))(2)(N(3))(2)(CH(3)OH)], as one Schiff base ligand is penta-dentate, coordinating via the anti-cipated oxide O, imine N and amine N atoms (as for the second, tridentate, ligand) but the oxide O is bridging and coordination also occurs through the meth-oxy O atom. The Ni(II) atoms are linked by a µ(2)-oxide atom and one end of a µ(2)-azide ligand, forming an Ni(2)ON core. The coordination geometry for the Ni(II) atom coordinated by the tridentate ligand is completed by the meth-oxy O atom derived from the penta-dentate ligand, with the resulting N(3)O(3) donor set defining a fac octa-hedron. The second Ni(II) atom has its cis-octa-hedral N(4)O(2) coordination geometry completed by the imine N and amine N atoms of the penta-dentate Schiff base ligand, a terminally coordinated azide N and a methanol O atom. The arrangement is stabilized by an intra-molecular hydrogen bond between the methanol H and the oxide O atom. Linear supra-molecular chains along the a axis are formed in the crystal packing whereby two amine H atoms from different amine atoms hydrogen bond to the terminal N atom of the monodentate azide ligand.

Di-µ-azido-κ(4)N:N-bis-({2-[(3-amino-2,2-dimethyl-prop-yl)imino-meth-yl]-6-meth-oxy-phenolato-1κ(3)N,N',O(1)}copper(II)).

The complete mol-ecule of the title complex, [Cu(2)(C(13)H(19)N(2)O(2))(2)(N(3))(2)], is generated by the application of a centre of inversion. The central Cu(2)N(2) core is a rhombus as the µ(2)-azide ligands bridge in an asymmetric fashion. Each Cu(II) atom is also coordinated by a monoanionic tridentate Schiff base ligand via the anti-cipated oxide O, imine N and amine N atoms. The resulting N(4)O coordination geometry is based on a square pyramid. No specific inter-molecular inter-actions are noted in the crystal packing, but the amine H atoms form intra-molecular N-H⋯O(oxide)/N(azide) hydrogen bonds.

catena-Poly[[lead(II)-bis-(µ(2)-quinolin-8-ol-ato)-κN,O:O;κO:N,O] N,N-di-methyl-formamide hemisolvate].

The asymmetric unit of the title compound, {[Pb(C(9)H(6)NO)(2)]·0.5C(3)H(7)NO}(n), comprises Pb(quinolate)(2) and half a dimethyl-formamide mol-ecule (which is disordered about a centre of inversion). The quinolate ligands N,O-chelate to a Pb(II) ion and simultaneously bridge a neighbouring Pb(II) ion to form a polymeric chain along [100] comprising Pb-linked Pb(2)O(2) distorted rhombi. These chains pack to form a square grid, with the channels thus defined occupied by the disordered solvent mol-ecules.

Poly[(µ(4)-3-carb-oxy-benzoato-κO:O,O:O:O)(quinolin-8-olato-κN,O)lead(II)].

The asymmetric unit of the title complex, [Pb(C(8)H(5)O(4))(C(9)H(6)NO)](n), comprises a Pb(II) cation, a quinolin-8-olate anion and a 3-carb-oxy-benzoate anion. The coordination geometry of the Pb(II) atom is defined by one N and six O atoms, as well as a stereochemically active lone pair of electrons, and is based on a Ψ-dodeca-hedron. The quinolin-8-olate is chelating and the 3-carb-oxy-benzoate anion forms bonds to four different Pb(II) atoms. The benzoate end of the 3-carb-oxy-benzoate ligand chelates one Pb(II) atom and simultaneously bridges two Pb(II) atoms on either side, forming a chain along the b axis. The carboxyl end of the 3-carb-oxy-benzoate connects to a neighbouring chain by employing its carbonyl atom to form a bond to a Pb(II) atom and the hydroxyl group to form a hydrogen bond to a quinolin-8-olate O atom. Thereby, a layer is formed in the bc plane.

Bis(µ-azido-κN:N)bis-{(acetato-κO,O')[2,4,6-tris-(2-pyrid-yl)-1,3,5-triazine-κN,N,N]lead(II)}.

The complete dinuclear title complex, [Pb(2)(C(2)H(3)O(2))(2)(N(3))(2)(C(18)H(12)N(6))(2)], is generated by the application of a crystallographic centre of inversion. The Pb(II) atom is coordinated by three N atoms of the tridentate ligand, two O atoms derived from an asymmetrically coordinating acetate ligand, and two azido-N atoms derived from two asymmetrically bridging azido ligands. The metal coordination geometry can be described as a square anti-prism with one position occupied by an unseen lone pair of electrons. In the ligand, the two coordinating pyridine rings are almost co-planar with the central pyrazine ring [dihedral angles = 0.47 (17) and 0.83 (18)°], but the terminal ring is twisted [dihedral angle = 19.76 (18)°]. In the crystal, the presence of π-π inter-actions [ring centroid distance between pyridyl rings = 3.581 (2) Å] leads to supra-molecular chains along the a-axis direction.

{5,5'-Dimeth-oxy-2,2'-[1,1'-(2,2-dimethyl-propane-1,3-diyldinitrilo)-diethyl-idyne]diphenolato-κO,N,N',O'}copper(II) monohydrate.

The tetra-dentate dianion in the title complex hydrate, [Cu(C(23)H(28)N(2)O(4))]·H(2)O, provides the Cu(II) atom with a cis-N(2)O(2) donor set. There is a significant twist from a regular square-planar geometry with the dihedral angle formed between the two six-membered CuOC(3)N chelate rings being 32.14 (8)°. The water mol-ecule forms hydrogen bonds to each of the coordinating O atoms of a given complex mol-ecule. Supra-molecular layers in the bc plane are formed in the crystal packing through C-H⋯O and C-H⋯π inter-actions.

2-{(1E)-1-[(3-{(E)-[1-(2-Hy-droxy-4-meth-oxy-phen-yl)ethyl-idene]amino}-2,2-di-methyl-prop-yl)imino]-eth-yl}-5-meth-oxy-phenol.

Mol-ecules of the title compound, C(23)H(30)N(2)O(4), are located on a crystallographic mirror plane. The mol-ecule has a curved shape with the dihedral angle formed between the two benzene rings being 55.26 (5)°. Intra-molecular O-H⋯N hydrogen bonds are noted. In the crystal, supra-molecular layers are formed in the ac plane owing to the presence of C-H⋯π inter-actions.

Diiodido(1,10-phenanthroline-5,6-dione-κN,N')mercury(II).

The Hg(II) atom in the title complex, [HgI(2)(C(12)H(6)N(2)O(2))], is tetra-hedrally coordinated by the N atoms of the chelating 1,10-phenanthroline-5,6-dione ligand and two I atoms. The range of tetra-hedral angles is broad, viz. 68.94 (17)° for the chelate angle to a wide 132.627 (15)° for the I-Hg-I angle. The ligand mol-ecule is non-planar with the O atoms lying 0.422 (5) and -0.325 (5) Šout of the plane through the remaining atoms [r.m.s. deviation = 0.068 Å]. Mol-ecules are consolidated in the crystal packing by C-H⋯O inter-actions.

{4,4'-Dibromo-2,2'-[2,2-dimethyl-propane-1,3-diylbis(nitrilo-methanylyl-idene)]diphenolato-κO,N,N',O'}nickel(II).

In the title compound, [Ni(C(19)H(18)Br(2)N(2)O(2))], the Ni(II) ion, lying on a twofold rotation axis, is coordinated by two N atoms and two O atoms from the Schiff base ligand in a distorted square-planar geometry. Weak inter-molecular C-H⋯O hydrogen bonds stabilize the crystal structure.

{2,2'-[o-Phenyl-enebis(nitrilo-methanylyl-idene)]diphenolato-κO,N,N',O'}nickel(II) monohydrate.

The Ni(II) atom in the title monohydrate, [Ni(C(20)H(14)N(2)O(2))]·H(2)O, is coordinated within a cis-N(2)O(2) square-planar donor set provided by the tetra-dentate Schiff base ligand. Overall, the mol-ecule has a curved shape with the dihedral angle formed between the planes of the outer benzene rings being 13.92 (18)°. The water mol-ecule was found to be disordered over two positions [ratio 0.80 (1):0.20 (1)] and the major component is linked to the complex via an O-H⋯O hydrogen bond.