Synthesis, crystal structure, DFT studies and photophysical properties of a copper(I)-triphenylphosphane complex based on trans-(±)-2,4,5-tris(pyridin-2-yl)-2-imidazoline.

The possibility of using less expensive and nontoxic metals, such as copper, as substitutes for more expensive heavy metals in the synthesis of new transition-metal complexes to be used as sensitizers in dye-sensitized solar cells (DSSCs) has stimulated research in this field. The novel photoluminescent copper(I) complex bis(triphenylphosphane-κP)[trans-(±)-2,4,5-tris(pyridin-2-yl)-2-imidazoline-κ2N2,N3]copper(I) hexafluorophosphate, [CuI(C18H15N5)(C18H15P)2]PF6, has been successfully synthesized and characterized by IR and 1H NMR spectroscopy, as well as by single-crystal X-ray diffraction and thermogravimetric analysis. The complex showed interesting photophysical properties, which were studied experimentally in solution and in the solid state by UV-Vis and fluorescence spectroscopy. Density functional theory (DFT) calculations with dichloromethane as solvent reproduced reasonably well the HOMO and LUMO orbitals of the title compound.

Bis[(1RS,2RS)-4,4'-(1-aza-niumyl-2-hy-droxy-ethane-1,2-di-yl)dipyridinium] tris-[tetra-chloridopalladate(II)].

The asymmetric unit of the title compound, (C12H16N3O)2[PdCl4]3, consists of a 4,4'-(1-aza-niumyl-2-hy-droxy-ethane-1,2-di-yl)dipyridinium dication and one and a half tetra-chloridopalladate(II) anions; the latter has inversion symmetry. In the cation, the pyridinium rings attached to the central 1-aza-niumyl-2-hy-droxy-ethane fragment show an anti conformation, as indicated by the central C-C-C-C torsion angle of -178.1 (4)°, and they are inclined to one another by 25.7 (2)°. In the crystal, the cations and anions are linked through N-H⋯Cl and O-H⋯Cl hydrogen bonds. There are also π-π contacts [centroid-centroid distance = 3.788 (3) Å] and a number of C-H⋯O and C-H⋯Cl inter-actions are present, consolidating the formation of a three-dimensional structure.

Dichloridobis(methanol-κO)[cis-(±)-2,4,5-tris-(pyridin-2-yl)-2-imidazoline-κ(3)N(2),N(3),N(4)]ytterbium(III) chloride.

In the crystal structure of the title complex, [YbCl(2)(C(18)H(15)N(5))(CH(3)OH)(2)]Cl, the pseudo-penta-gonal-bipyramidal coordination geometry of the Yb(III) cation is composed of three N atoms from one cis-(±)-2,4,5-tris-(pyridin-2-yl)imidazoline (HL) ligand, two O atoms from two methanol mol-ecules and two Cl(-) anions. Chains are formed along [010] through N-H⋯Cl, O-H⋯Cl and O-H⋯N hydrogen bonds.

Tetra-kis(µ-acetato-κ(2)O:O')-bis-[(3-pyridine-carboxaldehyde-κN')]dicopper(II)(Cu-Cu).

The binuclear title compound, [Cu(2)(CH(3)CO(2))(4)(C(6)H(5)NO)], is located about a center of inversion. The Cu(II) atoms are connected [Cu-Cu = 2.6134 (5) Å] and bridged by four acetate ligands. Their distorted octa-hedral coordination geometry is completed by a terminal pyridine N atom of a 3-pyridincarboxaldehyde ligand. In the crystal, the complex mol-ecules are linked by C-H⋯O hydrogen bonds, forming two-dimensional networks lying parallel to the ab plane. These networks are linked via C-H⋯O hydrogen bonds involving inversion-related 3-pyridinecarboxaldehyde ligands, forming a three dimensional supra-molecular architecture.