Crystal structure of 2,3-bis-(4-methyl-phen-yl)benzo[g]quinoxaline.

The title compound, C26H20N2, was obtained during a search for new π-extended ligands with the potential to generate efficient phosphors with iridium(III) for organic light-emitting devices (OLEDs). The benzoquinoxaline ring system is almost planar (r.m.s. deviation = 0.076 Å). A pseudo-twofold rotation axis runs through the midpoints of the C2-C3 and C9-C10 bonds. The two phenyl rings are twisted relative to the benzoquinoxaline ring system, making dihedral angles of 53.91 (4) and 36.86 (6)°. In the crystal, C-H⋯π (arene) inter-actions link the mol-ecules, but no π-π inter-actions between aromatic rings are observed.

Photoluminescence properties of a cationic trinuclear zinc(II) complex with the tetradentate Schiff base ligand 6-methyl-2-({[(pyridin-2-yl)methyl]imino}methyl)phenolate.

Metal complexes with Schiff base ligands have been suggested as potential phosphors in electroluminescent devices. In the title complex, tetrakis[6-methyl-2-({[(pyridin-2-yl)methyl]imino}methyl)phenolato-1:2κ(8)N,N',O:O;3:2κ(8)N,N',O:O]trizinc(II) hexafluoridophosphate methanol monosolvate, [Zn3(C14H13N2O)4](PF6)2·CH3OH, the Zn(II) cations adopt both six- and four-coordinate geometries involving the N and O atoms of tetradentate 6-methyl-2-({[(pyridin-2-yl)methyl]imino}methyl)phenolate ligands. Two terminal Zn(II) cations adopt distorted octahedral geometries and the central Zn(II) cation adopts a distorted tetrahedral geometry. The O atoms of the phenolate ligands bridge three Zn(II) cations, forming a dicationic trinuclear metal cluster. The title complex exhibits a strong emission at 469 nm with a quantum yield of 15.5%.

Synthesis and characterization of phenylpyridine-based iridium(III) complex for solution-processed phosphorescent organic light-emitting diode.

A novel main ligand 2-(2,4-dimethoxyphenyl)-5-trifluoromethylpyridine (MeO2CF3ppy) and its complex bis[2-(2,4-dimethoxy-phenyl)-5-trifluoromethyl pyridinato-N,C2]iridium acetylacetonate (MeO2CF3ppy)2Ir(acac) was synthesized. 2,4-Dimethoxy and 5-trifluoromethyl group were incorporated into main ligand to tune luminescence color. The phosphorescence organic light-emitting diodes (PhOLEDs) based on this complex with the configuration of ITO/PEDOT:PSS (40 nm)/PVK:CBP:Ir(III) complex (50 nm)/BCP (20 nm)/LiF (0.7 nm)/Al (100 nm) were fabricated. The solution-processed PhOLEDs based on (MeO2CF3ppy)2Ir(acac) exhibited a maximum quantum efficiency of 4.18% and luminance efficiency 9.04 cd/A with CIE coordinate of (0.32, 0.64).

(5-Methyl-pyrazine-2-carboxyl-ato-κ(2) N (1),O)bis-[2-(4-methyl-pyridin-2-yl-κN)-3,5-bis-(tri-fluoro-meth-yl)phenyl-κC (1)]iridium(III) chloro-form hemisolvate.

In the title complex, [Ir(C14H8F6N)2(C6H5N2O2)]·0.5CHCl3, the Ir(III) atom adopts a distorted octa-hedral geometry, being coordinated by three N atoms (arranged meridionally), two C atoms and one O atom of three bidentate ligands. The complex mol-ecules pack with no specific inter-molecular inter-actions between them. The SQUEEZE procedure in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155] was used to model a disordered chloro-form solvent mol-ecule; the calculated unit-cell data allow for the presence of half of this mol-ecule in the asymmetric unit.

Synthesis of mononuclear copper(II) complexes of acyclic Schiff's base ligands: spectral, structural, electrochemical, antibacterial, DNA binding and cleavage activity.

The mononuclear copper(II) complexes (1&2) of ligands L(1) [N,N'-bis(2-hydroxy-5-methylbenzyl)-1,4-bis(3-iminopropyl)piperazine] or L(2) [N,N'-bis(2-hydroxy-5-bromobenzyl)-1,4-bis(3-iminopropyl) piperazine] have been synthesized and characterised. The single crystal X-ray study had shown that ligands L(1) and L(2) crystallize in a monoclinic crystal system with P21/c space group. The mononuclear copper(II) complexes show one quasireversible cyclic voltammetric response near cathodic region (-0.77 to -0.85 V) in DMF assignable to the Cu(II)/Cu(I) couple. Binding interaction of the complexes with calf thymus DNA (CT DNA) investigated by absorption studies and fluorescence spectral studies show good binding affinity to CT DNA, which imply both the copper(II) complexes can strongly interact with DNA efficiently. The copper(II) complexes showed efficient oxidative cleavage of plasmid pBR322 DNA in the presence of 3-mercaptopropionic acid as reducing agent through a mechanistic pathway involving formation of singlet oxygen as the reactive species. The Schiff bases and their Cu(II) complexes have been screened for antibacterial activities which indicates that the complexes exhibited higher antimicrobial activity than the free ligands.

Different Zn(II) cation coordination geometries in di-µ-acetato-bis{2-chloro-6-[(pyridine-2-ylmethylimino)methyl]phenol}dizinc(II) chloroform monosolvate.

In the title compound, di-µ-acetato-κ(2)O:O;κ(2)O:O'-bis[(6-chloro-2-{(E)-[(pyridin-2-yl)methylimino]methyl}phenolato-κ(3)N,N',O)zinc(II)], [Zn2(C13H10ClN2O)2(C2H3O2)2]·CHCl3, the Zn(II) cation adopts a five-coordinate geometry and is coordinated by two N atoms and one O atom of a tridentate 6-chloro-2-{(E)-[(pyridin-2-yl)methylimino]methyl}phenolate ligand and two O atoms of two bridging acetate groups, but their coordination geometries differ. One Zn(II) cation adopts a distorted trigonal bipyramidal geometry and the other a square-pyramidal geometry. The two acetate ligands bridge two Zn(II) cations with mono- and bidentate coordination modes. The title compound exhibits a strong emission at 460 nm upon excitation at 325 nm with a quantum yield of 23.1%.

Bis[2-(1,3-benzo-thia-zol-2-yl)phenyl-κ(2) C (1),N][1,3-bis-(4-bromo-phen-yl)propane-1,3-dionato-κ(2) O,O']iridium(III).

The title complex, [Ir(C15H9Br2O2)(C13H8NS)2], lies about a crystallographic twofold rotation axis passing through the Ir(III) atom and the central C atom of the bis-(bromo-phen-yl)propane-1,3-dionate ligand. The Ir(III) atom adopts a distorted octa-hedral geometry coordinated by two N atoms in the axial positions, and two C and two O atoms in the equatorial plane. The dihedral angle between the two thia-zole ring systems in the complex is 77.45 (10)°.

Bis(2-{[(9H-fluoren-2-yl)methyl-idene]amino}-phenolato-κ(2)N,O)zinc methanol disolvate.

In the title compound, [Zn(C(20)H(14)NO)(2)]·2CH(3)OH, the Zn(II) atom lies on a crystallographic twofold rotation axis and is coordinated by two O atoms and two N atoms from two bidentate 2-{[(9H-fluoren-2-yl)methyl-idene]amino}-phenolate ligands within a distorted tetra-hedral geometry. The dihedral angle between the two chelate rings is 82.92 (5)°. In the coordinated ligand, the phenol ring is twisted at 30.22 (9)° from the mean plane of the fluorene ring. In the crystal, O-H⋯O hydrogen bonds link the complex mol-ecules to the methanol solvent mol-ecules.

Bis(2-amino-1,3-benzothia-zole-κN)dichloridozinc(II) ethanol hemisolvate.

In the title compound, [ZnCl(2)(C(7)H(6)N(2)S)(2)]·0.5CH(3)CH(2)OH, the Zn(II) atom is coordinated by two N atoms of two 2-amino-benzothia-zole ligands and two Cl atoms within a distorted tetra-hedral geometry. The dihedral angle between the N/Zn/N and Cl/Zn/Cl planes is 86.22 (7)°. The benzothia-zole mol-ecules are almost perpendicular to each other, forming a dihedral angle of 80.20 (8)°. The mol-ecular structure is stabilized by intra-molecular N-H⋯Cl hydrogen bonds. In the crystal, inter-molecular N-H⋯Cl hydrogen bonds link the mol-ecules into a three-dimensional network. The SQUEEZE procedure in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155] was used to model a disordered ethanol solvent mol-ecule; the calculated unit-cell data allow for the presence of half of this mol-ecule in the asymmetric unit.

Bis[3,5-difluoro-2-(4-methyl-pyridin-2-yl)phenyl-κC,N](picolinato-κN,O)iridium(III) chloro-form monosolvate.

In the title complex, [Ir(C(12)H(8)F(2)N)(2)(C(6)H(4)NO(2))]·CHCl(3), two similar mol-ecules of each component comprise the asymmetric unit. The independent complex mol-ecules are linked by inter-molecular π-π inter-actions [centroid-centroid distance = 3.830 (4) Å]. The Ir(III) ion adopts a distorted octa-hedral geometry, being coordinated by three N atoms, two C atoms, and one O atom of three bidentate ligands, with the N atoms arranged meridionally.

Bis(3-methyl-pyridinium) tetra-(chlorido/bromido)cuprate(II).

The structure of the title salt, (C(6)H(8)N)(2)[CuCl(3.4)Br(0.6)], consists of two 3-methyl-pyridinium cations and a distorted tetra-hedral [CuCl(3.4)Br(0.6)](2-) dianion. Substitutional disorder with Br is exhibited for three of the Cl atoms of the anion, giving a mixed chloride/bromide cuprate(II) anion. In the crystal, inter-molecular N-H⋯Cl hydrogen bonds link two cations to one anion, forming a three-ion aggregate. These are connected into a supra-molecular chain along the b axis via π-π inter-actions between the pyridinium rings [centroid-centroid distance = 3.743 (3) Å].

Dichlorido[N,N-diethyl-N'-(2-pyridyl-methyl-ene)ethane-1,2-diamine]mercury(II).

The Hg atom in the title compound, [HgCl(2)(C(12)H(19)N(3))], adopts a distorted trigonal-bipyramidal geometry, being ligated by two Cl atoms and three N atoms of the N,N-diethyl-N'-(2-pyridylmethyl-ene)ethane-1,2-diamine ligand. The dihedral angle between the HgN(3) and HgCl(2 )least-squares planes is 88.6 (1)°. The Hg-N distances including the pyridine N and the ammonium N atom are about 0.20 Šlonger than the Hg-N distance including the imino N atom.

[Benz-yl(2-pyridyl-methyl-idene)amine]-dichloridomercury(II).

The Hg(II) ion in the title complex, [HgCl(2)(C(13)H(12)N(2))], adopts a distorted tetra-hedral geometry being coordinated by two Cl anions and by two N atoms of the benz-yl(2-pyridyl-methyl-ene)amine ligand. The Cl-Hg-Cl plane is twisted at 70.1 (1)° from the mean plane of the chelate ring. In the crystal structure, inter-molecular π-π inter-actions [centroid-centroid distance = 3.793 (3) Å] between the aromatic rings link the mol-ecules into zigzag chains extending along [010].

Diacetato-(N,N-diethyl-ethylenediamine)-zinc(II).

In the title compound, [Zn(CH(3)COO)(2)(C(6)H(16)N(2))], the Zn(II) atom is coordinated by two N atoms of one bidentate diethyl-ethylenediamine ligand and two O atoms of two acetate anions in a distorted tetra-hedral geometry. The acetate ligands are asymmetrically coordinated to the Zn atom with two different C-O distances of 1.234 (4) and 1.275 (4) Å. The dihedral angle between the N/Zn/N and O/Zn/O planes is 83.11 (8)°. There are two independent mol-ecules in the asymmetric unit. N-H⋯O hydrogen bonding links mol-ecules into a three-dimensional network.

Di-µ-chlorido-bis-{[2-(benzyl-imino-meth-yl)pyridine-κN,N']chloridomercury(II)} dichloridomercury(II).

The Hg(II) ion in the title centrosymmetric dinuclear complex, [Hg(2)Cl(4)(C(13)H(12)N(2))(2)]·[HgCl(2)], adopts a distorted square-pyramidal geometry, being coordinated by the bis-chelating N-heterocyclic ligand, two bridging Cl atoms and one terminal Cl atom. One of the bridging Hg-Cl bonds [2.8428 (11) Å] is significantly longer than the other [2.5327 (10) Å]. In the crystal, there are weak π-π inter-actions [centroid-centroid distance = 3.630 (3) Å] between the aromatic rings of the discrete units. The HgCl(2) adduct molecule is located on an inversion centre and has an Hg-Cl bond length of 2.2875 (11) Å.

Selective complexation of 3d metal(II) ions with multidentate and chiral isomers derived from condensation of 2-pyridinecarboxaldehyde with triethylenetetramine.

Condensation of 2-pyridinecarboxaldehyde with a stoichiometric amount of triethylenetetramine in isopropyl alcohol yields a mixture of at least two products, a Schiff dibase L(1) and a cyclization product with two imidazolidine rings L(2), and possibly a Schiff monobase with one imidazolidine ring L(3). The 3d metal(II) salts, Mn(SCN)(2), MnCl(2), CuBr(2), MnI(2) and ZnBr(2), react selectively with L(1) or L(2) in this mixture solution to produce Mn(L(2))(NCS)(2) 1, Mn(L(2))Cl(2) 2, [Cu(L(2))Br]Br x H(2)O 3, [Mn(L(1))]I(2) 4, and [Zn(L(1))][ZnBr(4)] 5 , respectively. The presence of the two imidazolidine rings in the coordinated ligand L(2) of 1-2 generates two chiral carbon centers. The Mn(II) ion coordinates stereo-selectively to the [R,R] or [S,S] form of the L(2) in hexa-coordinate Mn(II) compounds 1 and 2, whereas the Cu(II) ion coordinates with the meso [R,S] form of L(2) in 3.

Methano-ldinitrato[N-(2-pyridylmethyl-ene)aniline]copper(II).

The Cu atom in the title compound, [Cu(NO(3))(2)(C(12)H(10)N(2))(CH(3)OH)], adopts a square-pyramidal geometry, being ligated by two N atoms of the bidentate N-(2-pyridylmethyl-ene)-aniline (ppma) ligand, two O atoms of NO(3) ligands and one O atom of a methanol molecule, which occupies the apical position. The phenyl ring on the ppma ligand is twisted out of the pyridine plane, forming a dihedral angle of 42.9 (1)°. In the crystal, inter-molecular O-H⋯O hydrogen bonds between methanol and NO(3) ligands form an extensive one-dimensional network extending parallel to [100].

Bis(3-methyl-pyridinium) tetra-chlorido-cuprate(II).

The title compound, (C(6)H(8)N)(2)[CuCl(4)], is composed of two 3-methyl-pyridinium cation and one tetra-chloridocuprate(II) anion. The geometry around the copper(II) ion is that of a distorted tetra-hedron. In the crystal structure, the anions and cations are linked by three different N-H⋯Cl hydrogen bonds. In addition, the crystal structure exhibits aromatic π-π inter-actions between the pyridinium rings of two discrete units [centroid-centroid distance = 3.704 (2) Å].

[Bis(2-pyridylmeth-yl)amine]dichloridomercury(II).

The Hg atom in the title complex, [HgCl(2)(C(12)H(13)N(3))], adopts a square-pyramidal geometry, being ligated by three N atoms of the tridentate bis-(2-pyridylmeth-yl)amine ligand and two Cl atoms, with one of the latter occupying the apical position. Disorder is noted in the amine portion of the ligand and this was modelled over two sites, with the major component having a site-occupancy factor of 0.794 (14).

[Benzyl(2-pyridylmeth-yl)amine]dichloridomercury(II).

The Hg atom in the title compound, [HgCl(2)(C(13)H(14)N(2))], adopts a distorted tetra-hedral geometry, being ligated by two N atoms of the benzyl(2-pyridylmeth-yl)amine (bpma) ligand and two Cl atoms. The dihedral angle between the least-squares planes through the chelate ring and Cl-Hg-Cl atoms is 85.4 (1)°. The phenyl ring on the bpma ligand is twisted out of the pyridine plane, forming a dihedral angle of 76.0 (3)°. Disorder in this ring is also noted with two coplanar conformations having equal site occupancies.