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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]

We demonstrate a proof-of-concept design of a new platform for proton recognition and modulation. The new proton receptors are derived from a unique class of synthetic supercontainers that exhibit exceptional proton binding capacity (over 50 equiv.) and intriguing proton-dependent fluorescent switching behavior. Experimental and computational studies suggest that the proton-responsive event involves a two-step mechanism pertaining to proton binding by both amino and pyrenyl moieties of the supercontainer constructs. The high proton binding capacity of the supercontainers can be further modulated via small-molecule “regulators” that compete for the proton-binding sites, opening exiting new opportunities for proton manipulation in both chemistry and biology. [ABSTRACT FROM AUTHOR]

A new sulfonylcalix[4]arene-based dinuclear terbium molecular container (1) was conveniently synthesized and utilized as a fluorescence probe for the detection of a well-known biomarker 1-hydroxypyrene (1-OHP), which is used for the evaluation of polycyclic aromatic hydrocarbons (PAHs). The sulfonylcalix[4]arene ligand could not only serve as an efficient antenna ligand to promote the ligand-to-metal energy transfer but also provide a suitable cavity to accommodate 1-OHP. Promising fluorescence quenching effects were well established during the titration of the compound 1 with 1-OHP, and these effects were due to the enhancement in the host–guest intermolecular charge transfer and the decrease in the ligand-to-metal energy transfer after the formation of the stable host–guest complex. The fluorescence sensing mechanism was clearly understood through the titration experiments, and the data could be fit with the Benesi–Hildebrand and Stern–Volmer models. The TbIII-TBSC-based luminescent sensor exhibited quick response, high sensitivity, and specific selectivity to 1-OHP, even in the presence of other constituents in urine, thus providing a new sensing platform for the clinical diagnosis of human exposure to PAHs. [ABSTRACT FROM AUTHOR]

Cationic PtAu2 heterotrinuclear complexes [PtAu2(dpmp)2(C≡CR)2]2+ (dpmp = bis(diphenylphosphinomethyl)phenylphosphine, R = aryl) of aromatic acetylides were prepared. The PtAu2 structures are supported through doubly bridging dpmp and stabilized by a significant Pt–Au interaction. They are highly phosphorescent in fluid CH2Cl2 solution (Φem = 23.5%–78.9%), the solid state (Φem = 15.4%–70.2%), the PMMA film (Φem = 39.9%–71.7%) and the doping film of 61% TCTA : 31% OXD-7 : 8% PtAu2 complex (Φem = 16.9%–67.9%). The phosphorescence arises mainly from 3[π (C≡CR) →π* (dpmp)] 3LLCT and 3[π (C≡CR) → s/p (PtAu2)] 3LMCT triplet excited states for carbazole-acetylide complexes, whereas other complexes display a 3LLCT character mixed with noticeable PtAu2 centered 3[d → s/p] parentage. Utilizing a mixed host composed of hole-transporting TCTA and electron-transporting OXD-7 doped with 8% PtAu2 species as a light-emitting layer and CuSCN as a hole-transporting layer through an orthogonal solution process, the devices exhibit highly efficient electrophosphorescence with the highest current efficiency (CEmax) of 51.7 cd A−1 and external quantum efficiency (EQEmax) of 14.5%. The efficiency roll-off is small in the practical brightness range of 500–5000 cd m−2. The PtAu2 complexes with carbazole-acetylides display a higher electroluminescence efficiency ascribed to their better hole-transporting character as well as more facile energy transfer from mixed host materials. [ABSTRACT FROM AUTHOR]

Heterodimetallic Ru–Fe complexes [(tppz)(PPh3)2RuL](ClO4) (L = C≡CFc, [1](ClO4); C≡C–C6H4–C≡CFc), [2](ClO4); C≡C–C6H4–C6H4–C≡CFc, [3](ClO4)) were synthesized by the reactions of [(tppz)(PPh3)2RuCl](ClO4) (tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine) with ferrocence-acetylide ligands and characterized by ESI-MS, and 1H and 31P NMR spectroscopies. The structure of [1](PF6) was determined by X-ray crystallography. The electrochemical studies show that compounds [1](ClO4)–[3](ClO4) possess two widely separated anodic peaks, ascribable to one-electron oxidation of Fc and RuII, respectively. This assignment is further corroborated by the results of UV-vis-NIR, XPS, and theoretical calculation studies. Compound [1](ClO4) exhibits significant Ru…Fe metal–metal interactions across the Ru–C≡C–Fc backbone. As revealed by electrochemical, spectroscopic and theoretical computational studies, one-electron oxidized species [1a](ClO4)2 is between the electronically delocalized and valence-trapped state and shows a typical Robin–Day class II mixed-valence behavior. [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]

A series of oxo-centred triruthenium-acetate complexes with valence iii,iii,iiwere prepared by reactions of [Ru3III,III,III]+precursor [Ru3O(OAc)6(py)2(CH3OH)]+(1) with 3-chloro-6-(pyrazol-1-yl)pyridazine (cppd), 3-chloro-6-(3,5-dimethylpyrazol-1-yl)pyridazine (cmppd), 3,6-bis(pyrazol-1-yl)pyridazine (ppd), 3,6-bis(3,5-dimethylpyrazol-1-yl)pyridazine (mppd) or 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine (bptz). When neutral Ru3III,III,IIprecursor Ru3O(OAc)6(CO)(CH3OH)2(2) was utilized, a stable low-valence Ru3III,II,IIderivative complex was successfully isolated. As established through crystal structural analyses, they were derived from 1or 2by substitution of the axial methanol and one of six bridging acetates in the parent Ru3(μ3-O)(μ-OAc)6cluster core as well as one axial pyridine in some cases. As revealed by electrochemical and spectroscopic studies, substituting one of the six bridging acetates in the parent Ru3(μ3-O)(μ-OAc)6cluster core significantly modifies the electronic and redox characteristics. Compared with those for the parent compound [Ru3O(OAc)6(py)3]+, triruthenium-based redox potentials of these derivatives show remarkable positive shifts. [ABSTRACT FROM AUTHOR]