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Reaction of [Au(tht)2](ClO4) (tht = tetrahydrothiophene), [Cu(CH3CN)4](ClO4), 3,6-di-tert-butyl-1,8-diethynyl-9H-carbazole (H3decz), and bis(2-diphenylphosphinophenyl)ether (POP) in the presence of triethylamine (NEt3) gave the cluster complex Au4Cu2(decz)2(POP)2 as yellow crystals. As revealed by X-ray crystallography, the Au4Cu2 cluster exhibits scissor-like structure sustained by two decz and two POP ligands and stabilized by Au-Cu and Au-Au interactions. The Au4Cu2 cluster shows bright yellow to orange photoluminescence upon irradiation at >300 nm, arising from 3[π (decz)→5d (Au)] 3LMCT (ligand-to-metal charge transfer) and 3[π→π* (decz)] 3IL (intraligand) triplet states as revealed by theoretical and computational studies. When it is mechanically ground, reversible phosphorescence conversion from yellow to red is observed owing to more compact molecular packing and thus stronger intermetallic interaction. Variable-temperature luminescence studies reveal that it displays distinct red-shifts of the emission whether the temperature is elevated or lowered from ambient temperature, suggestive of exceptional thermochromic phosphorescence characteristics. [ABSTRACT FROM AUTHOR]

Two heteroctanuclear Au4Ag4 cluster complexes of 4,5-diethynylacridin-9-one (H2L) were prepared through the self-assembly reactions of [Au(tht)2](CF3SO3), Ag(tht)(CF3SO3), H2L and PPh3 or PPh2Py (2-(diphenylphosphino)pyridine). The Au4Ag4 cluster consists of a [Au4L4]4− and four [Ag(PPh3)]+ or [Ag(PPh2Py)]+ units with Au4L4 framework exhibiting a twisted paper clip structure. In CH2Cl2 solutions at ambient temperature, both compounds show ligand fluorescence at ca. 463 nm as well as phosphorescence at 650 nm for 1 and 630 nm for 2 resulting from admixture of 3IL (intraligand) of L ligand, 3LMCT (from L ligand to Au4Ag4) and 3MC (metal-cluster) triplet states. Crystals or crystalline powders manifest bright yellow-green phosphorescence with vibronic-structured emission bands at 530 (568sh) nm for complex 1 and 536 (576sh) nm for complex 2. Upon mechanical grinding, yellow-green emission in the crystalline state is dramatically converted to red luminescence centered at ca. 610 nm with a drastic redshift of the emission after crystal packing is destroyed. [ABSTRACT FROM AUTHOR]

The title compound, C18H12N4O·H2O, adopts the keto tautomeric form and the azomethine C=N double bond is in the E configuration. The dihedral angle between the planes of the di­aza­fluorene moiety and the phenyl ring is 11.3 (1)°. In the solid state, the mol­ecules form infinite chain-like structures via O-H⋯N hydrogen bonds involving the water mol­ecules and di­aza­fluorene moieties. [ABSTRACT FROM AUTHOR]

As versatile ligands with extraordinary coordination capabilities, RPH 2 (R = alkyl or aryl) are rarely used in constructing metal nanoclusters due to their volatility, toxicity, spontaneous flammability, and susceptibility to oxidation. In this work, we designed a primary and tertiary phosphorus-bound diphosphine chelator (2-Ph 2 PC 6 H 4 PH 2 ) to create ultrastable silver nanoclusters with metallic aromaticity. By controlling the deprotonation rate of 2-Ph 2 PC 6 H 4 PH 2 and adjusting the templates, we successfully synthesized two near-infrared emissive nanoclusters, Ag30 and Ag32 , which have analogous icosidodecahedral Ag 30 shells with an I h symmetry. Deprotonated ligand (2-Ph 2 P α C 6 H 4 P β 2- ) exhibits a coordination mode of μ 5 -η 1 (P β ),η 2 (P α ,P β ), which endows a unique metallic aromaticity to Ag30 and Ag32 . The solution-processed organic light-emitting diodes based on Ag30 achieve an external quantum efficiency of 15.1%, representing the breakthrough in application of silver nanoclusters to near-infrared-emitting devices. This work represents a special ligand system for synthesizing ligand-protected coinage metal nanoclusters and opens up horizons of creating nanoclusters with distinct geometries and metal aromaticity.

Fabricating electron transport layers at low temperatures is challenging but highly desired in the field of flexible perovskite solar cells (f-PSCs). In this study, highly uniform cerium oxide (CeO x ) films prepared by the UV-O 3 treatment have been successfully applied as the electron transport layer (ETL) in methylammonium lead halide (CH 3 NH 3 PbI 3 ) perovskite-based f-PSCs. Under AM 1.5 G sunlight with 100 mW cm -2 , these cells exhibited an open-circuit voltage ( V oc ) of 0.98 V, a short-circuit current density ( J sc ) of 19.42 mA cm -2 , a fill factor (FF) of 0.72 and power conversion efficiency (PCE) of 14.63%. The PCE was much higher than that of the control planar CeO x ETL (PCE ∼ 9.08%) prepared at a low temperature (80 °C) without the UV-O 3 treatment, and this was ascribed to the improved CeO x film, enhanced light absorption and suppressed charge recombination. The cells that bend at 15 mm of radius showed excellent stability with less than 10% reduction in PCE after 500 cycles of repeated bending at ambient temperature. The charge-transmission kinetic parameters and long-term stability of the CeO x -based f-PSCs were analyzed as well., Competing Interests: The authors declare no competing financial and nonfinancial interests., (This journal is © The Royal Society of Chemistry.)

The process of molecular recognition is the assembly of two or more molecules through weak interactions. Information in the process of molecular recognition can be transmitted to us via physical signals, which may find applications in sensing and switching. The conventional signals are mainly limited to light signal. Here, we describe the recognition of diols with Cu(1,10-phenlothroline) 2 SeO 4 and the transduction of discrete recognition events into dielectric and/or ferroelectric signals. We observe that systems of Cu(1,10-phenlothroline) 2 SeO 4 ·(diol) exhibit significant dielectric and/or ferroelectric dependence on different diol molecules. The compounds including ethane-1,2-diol or propane-1,2-diol just show small temperature-dependent dielectric anomalies and no reversible polarization, while the compound including ethane-1,3-diol shows giant temperature-dependent dielectric anomalies as well as ferroelectric reversible spontaneous polarization. This finding shows that dielectricity and/or ferroelectricity has the potential to be used for signalling molecular recognition.