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Multifunctional heteropentanuclear Al(3)Ln(2) (Ln = Nd, Eu, Yb) clusters with a novel structure exhibit significantly fluoride-enhanced lanthanide emission intensity and lifetime in both solid state and solution as well as unusual white-light emitting for an Al(3)Eu(2) complex.

Three quinoline-based zinc(ii)–Schiff base complexes were synthesized and characterized by X-ray crystallography. They exhibit remarkable aggregation-induced emission enhancement (AIEE) in acetonitrile/diethyl ether mixtures due to the conversion of weak luminescence in homogeneous solution into strong emission in the nano-aggregated phase after increasing the fractions of diethyl ether. Interestingly, the AIEE performance can be significantly promoted by joining the two quinoline units through an alkoxy chain. Moreover, they show reversible mechanochromic luminescence behavior between dark and bright states during the grinding–fuming cycles, due to the modulation of morphologies between amorphous and crystalline states. Introducing an electron donating group in the para-position of aniline significantly improves the mechanochromic luminescence effect with a more accessible and distinct emission colour contrast. The molecular packing in the crystalline phase and time-dependent density functional theory (TD-DFT) calculations demonstrate that multiple intermolecular C–H…π and π–π interactions significantly strengthen the molecular rigidity and enhance the intramolecular charge-transfer (ICT) characteristics, leading to the effective emission enhancement in crystalline/nano-aggregated states. The novel AIEE and reversible mechanochromic luminescence properties point to the promising potential applications of these complexes in smart fluorescent materials. [ABSTRACT FROM AUTHOR]

A series of platinum(II) complexes bearing 1,3-bis(2-pyridylimino)isoindoline (BPI) derivatives as ligand have been prepared by substitution of the coordinated Cl in precursors [Pt(L)Cl] [L = L1 ( 1), L2 ( 2), L3 ( 3)] by a monodentate strong-field ligand such as CN-, CN-cyclohexyl, PPh3, NCS-, PhS-, or N(CN)2-. Most of these compounds display orange-to-red luminescence in both the solid state and solution at ambient temperature. Compared with precursors 1- 3, both low-energy absorption and emission bands in ligand-substituted platinum(II) complexes 4- 13 exhibit distinct blueshifts. The emission of platinum(II) complexes with CN-containing monodentate ligands shows progressive blueshifts with increasing ligand field strength: 609 ( 10, NCS-) → 603 [ 12, N(CN)2-] → 590 ( 4, CN-) → 581 nm ( 7, C≡N-cyclohexyl). The emission of complexes 4- 9 originates mainly from the 3[π → π*(BPI)] 3IL triplet excited state, mixed with some 3[dπ(Pt) → π*(BPI)] 3MLCT character. In contrast, the emission of 10- 13 arises from a clearly increased 3[π(L) → π*(BPI)] 3LLCT state with reduced 3[π → π*(BPI)] 3IL and 3[5d(Pt) → π*(BPI)] 3MLCT character. Noticeably, dicyanamido-linked dinuclear complex 13 displays a significant ligand-ligand electronic interaction between the two BPI across the Pt-N≡C-N-C≡N-Pt bridge with remarkable LLCT character from one BPI to the other. [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]

Multifunctional heteropentanuclear Al3Ln2(Ln = Nd, Eu, Yb) clusters with a novel structure exhibit significantly fluoride-enhanced lanthanide emission intensity and lifetime in both solid state and solution as well as unusual white-light emitting for an Al3Eu2complex. [ABSTRACT FROM AUTHOR]

Abstract: Reaction of cyclometallated iridium(III) complex Ir(ppy)2(PPh3)Cl (2, ppy=2-phenylpyridine) with dicyanamide or tricyanomethanide gave neutral mononuclear complexes Ir(ppy)2(PPh3)N(CN)2 (3a) or Ir(ppy)2(PPh3)C(CN)3 (3b), and dicyanamide/tricyanomethanide-linked binuclear iridium(III) complexes [{Ir(ppy)2(PPh3)}2N(CN)2]+ (4a) or [{Ir(ppy)2(PPh3)}2C(CN)3]+ (4b). Substitution of coordinated chloride in the precursor 2 with dicyanamide or tricyanomethanide improved significantly the luminescence properties of 3a–4b. Compared with that in the precursor 2 (1.6%), 2.2 to 9.3-fold enhancement of emission quantum yields was detected in 3a–4b. [Copyright &y& Elsevier]

A platinum(ii) complex of 5,5′-bis(trimethylsilylethynyl)-2,2′-bipyridine displays unusually reversible colour and luminescence changes when exposed to specific organic vapours, correlated well with PtPt distances as well as π–π and C–H(CC) interactions in the stacking of square-planar platinum(ii) moieties. [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]