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In this study, a new iridium(III) complex containing coumarin derivative as the cyclometalated ligand (L) and 7-allyl-8-hydroxyquinoline (Hq-allyl) as the ancillary ligand, Ir(III)bis(3-(pyridin-2-yl)coumarinato N,C 4 )(7-allyl-8-hydroxyquinolinolato) [Ir(L) 2 (q-allyl)], was firstly synthesized as the emissive iridium complex. Then a macromolecule consisting of the emissive iridium complex and carbazole moieties covalently attached to a polyhedral oligomeric silsesquioxane (POSS) core, 7Cz-Ir(L) 2 (q)-POSS, was successfully synthesized by hydrosilylation reaction in the presence of platinum(0)-1,3-divinyl-1,1,3,3-tetramethyldisiloxane (Pt-dvs) as the catalyst. The macromolecule has good thermal stability due to the significant effect of the POSS core, and its photoluminescence performance is improved because the POSS core reduced interactions among the emissive units and diminished concentration quenching in the solid state.

Two mononuclear Cu (I) complexes based on a 2-(2-pyridyl)benzimidazolyl derivative ligand containing the hole-transporting ligand 1-[4-(9-carbazolyl)butyl]-2-(2-pyridyl)benzimidazole (L), [Cu(L)(PPh3)2](BF4) (1) and [Cu(L)(DPEphos)](BF4) (2), where DPEphos is bis[2-(diphenylphosphino)phenyl]ether, were synthesized and characterized by elemental analysis, 1H NMR and FT-IR spectra. The structure of complex 2 was determined by X-ray single crystal analysis. It was demonstrated that the central Cu (I) ion in the complex has a distorted tetrahedral geometry and is tetra-coordinated by the two nitrogen atoms from L ligand and two phosphorus atoms from DPEphos ancillary ligand. The photophysical properties of the complexes were examined by using UV–Vis, photoluminescence spectroscopic analysis. The complexes exhibit weak MLCT absorption bands at 410 and 490 nm, and display strong phosphorescence in the solid states at T = 298 K, which is completely quenched in solution.

Novel iridium complex containing coumarin derivative as a cyclometalated ligand (L) and picolinate (pic) as the ancillary ligand, Ir(III) bis (3-(pyridin-2-yl)coumarinato N,C 4 )(picolinate) [Ir(L) 2 (pic)], was synthesized and characterized. It was demonstrated that the iridium (III) ion in Ir(L) 2 (pic) is hexacoordinated by two C atoms and two N atoms from 3-(pyridin-2-yl)coumarin ligands and one N atom and one O atom from picolinate ligand, displaying a distorted octahedral coordination geometry. The Ir(L) 2 (pic) has very strong absorption and intensive emission at 532 nm. These results show the promising future of that Ir(L) 2 (pic) in fabrication organic light-emitting diodes.

An aromatic bridged Schiff base ligand, N,n′-bis((4,4′-diethylamino)salicylidene)-1,2-phenylenediamine (H2L3), and its trinuclear Zinc(II) complex, Zn 3 L 2 3 ( CH 3 COO ) 2 , were synthesized and characterized by means of elemental analyses, FT-IR and UV–Vis absorption spectra, and single crystal X-ray crystallography. The X-ray crystal structure of the complex reveals that the zinc ion (Zn1 or Zn1A) is coordinated by two oxygen atoms in phenolate and two nitrogen atoms in imines of the ligand and one oxygen atom of the acetate, the zinc ion (Zn2) is coordinated by four oxygen atoms in phenolate of the ligands and two oxygen atoms of the acetates. Two acetates coordinate to three zinc ions through Zn–O–C–O–Zn bridges. The complex exhibits blue-green emission as the result of the fluorescence from the intraligand emission excited state. In addition, the ground-state geometries, the lowest energy transition and the UV–Vis spectrum of the ligand have been studied with density functional theory (DFT) and time-dependent density functional theory (TD-DFT) at B3LYP/6-31G(d) level, showing that the calculation outcomes are in good agreement with experimental data.

A new complex of zinc with a Schiff base, zinc(N,N′-bis(salicylidene)-3, 6-dioxa-1, 8-diaminooctane monohydrate) (ZnBSO · H2O), was synthesized and characterized by means of elemental analyses, IR spectra and DTA-TG. Its structure was determined by X-ray single crystal analysis. It was demonstrated that the zinc atom is coordinated by the two oxygen atoms in phenolate and two nitrogen atoms in imine of the ligand in a slightly distorted tetrahedral geometry, while the two oxygen atoms from the oxa-alkyl chain are not coordinated to Zn(II) atom. The energy levels of the HOMO, LUMO and the electrochemical band gap were determined by cyclic voltammeter. The electroluminescent devices with the complex as the emitter showed bright blue emission with a peak at 450 nm, which is same as the fluorescence of the complex in both solution and solid states.