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A series of highly phosphorescent PtAg2 heterotrinu-clear alkynyl complexes with bis(diphenylphosphinomethyl)-phenylphosphine (dpmp) were prepared and characterized structurally. The solution phosphorescence with various emitting colors is systematically modulated by modifying substituents as well as n-conjugated systems in aromatic acetylides. The crystals, powders, or films exhibit reversible stimuli-responsive phosphorescence changes upon exposure to vapor of MeCN, pyridine, DMF, etc., resulting from perturbation of d8-d10 metallophilic interaction in the excited states as a consequence of the formation/disruption of Ag--solvent bonds. Both experimental and time-dependent density functional theory (TD-DFT) studies demonstrate that d8-d10 metallophilic interaction exerts a crucial role on phosphorescent characteristics due to the PtAg2 cluster-based ³[d → p] state. This study affords a paradigm for phosphorescence modulation in d8--d10 heteronuclear complexes. [ABSTRACT FROM AUTHOR]

A series of platinum(ii) complexes with 1,3-bis(2-pyridylimino)isoindoline (BPI) derivatives were prepared by substitution of the coordinated Cl in the precursor complex Pt(BPI)Cl with a N-heterocyclic ligand such as pyridine, phthalazine or phenanthridine. These complexes display orange to red luminescence in fluid dichloromethane solutions and in the solid states at room temperature. The photophysical properties were tuned by introducing electron-withdrawing -NO2or electron-donating -NH2to the BPI ligand. The DFT computational studies suggest that the emission in the N-heterocyclic ligand substituted platinum(ii) complexes originates mainly from the 3[π→π*(BPI)] 3IL triplet excited state, mixed with some 3[dπ(Pt)→π*(BPI)] 3MLCT character. Compared with the precursor Pt(BPI)Cl, both the low-energy absorption and the emission in the N-heterocyclic ligand substituted platinum(ii) complexes exhibits a distinct blue-shift due to an obviously enhanced contribution from the 3IL state and a reduced 3MLCT character. [ABSTRACT FROM AUTHOR]

Abstract: The preparation, characterization and photophysical properties of heterobinuclear complexes {Pt(C^N^N)(Chfac)3 (C^N^N=2-(6-(naphthalen-3-yl)-4-phenylpyridin-2-yl)pyridine; HCsp sp="0.25" />=5-ethynyl-2,2′-bipyridine; Ln=Nd, Eu, Yb; hfac=hexafluoroacetylacetonate) are described. With excitation at 390⩽ λ ex ⩽500nm which is the MLCT/LLCT absorption region of the Pt(C^N^N)(Comophore, lanthanide luminescence is successfully attained by Pt→Ln energy transfer from the platinum(II) antenna chromophore to the lanthanide center across the bridging Cnd. [Copyright &y& Elsevier]

Abstract: A series of cyclometallated iridium(III) acetylide complexes Ir(ppy)2(PPh3)(C:hsp sp="0.12" />=C6H5 3, C6H4But-4 4, C6F5 5, C6H4COMe-4 6, SiMe3 7) were synthesized by substitution of coordination chloride in precursor Ir(ppy)2(PPh3)Cl (2, ppy=2-phenylpyridine) with an acetylide ligand. These complexes are brightly luminescent in fluid dichloromethane at ambient temperature, originating from 3MLCT/3LLCT/3IL states as supported by TD-DFT studies. It is demonstrated that substitution of coordination chloride in precursor 2 (λ em =456 and 485nm, Φ em =1.6%) with an acetylide ligand results in obvious red-shift of the emission as well as significant enhancement of the luminescence efficiency in 3–7 (λ em =480–510nm, Φ em =9.5%–19%) since the energy level of non-emissive d–d transition is highly raised and thus d–d state deactivation is significantly suppressed. [Copyright &y& Elsevier]