Organic Memory Devices Based on a Bis-Cyclometalated Alkynylgold(III) Complex

A bis-cyclometalated alkynylgold­(III) complex, [Au­(^<i>t</i>BuC^N^C^<i>t</i>Bu)­(CC–C₆H₄N­(C₆H₅)₂-<i>p</i>)] (^<i>t</i>BuHC^N^CH^<i>t</i>Bu = 2,6-bis­(4-<i>tert</i>-butylphenyl)­pyridine), has been synthesized and characterized. The complex was found to exhibit rich photophysical and electrochemical properties. More interestingly, the complex has been employed in the fabrication of organic memory devices. The as-fabricated memory devices exhibited good performances with low operating voltage, high ON/OFF ratio, long retention time, and good stability

Luminescent Metallogels of Bis-Cyclometalated Alkynylgold(III) Complexes

A series of luminescent bis-cyclometalated alkynylgold­(III) complexes have been synthesized and characterized. Some of the complexes have been demonstrated to exhibit gelation properties driven by π–π stacking and hydrophobic–hydrophobic interactions. The gelation properties have been investigated in detail through variable-temperature UV–vis absorption and emission studies, and the morphology of the gels has also been characterized by scanning electron microscopy and transmission electron microscopy

Luminescent Metallogels of Bis-Cyclometalated Alkynylgold(III) Complexes

A series of luminescent bis-cyclometalated alkynylgold­(III) complexes have been synthesized and characterized. Some of the complexes have been demonstrated to exhibit gelation properties driven by π–π stacking and hydrophobic–hydrophobic interactions. The gelation properties have been investigated in detail through variable-temperature UV–vis absorption and emission studies, and the morphology of the gels has also been characterized by scanning electron microscopy and transmission electron microscopy

Luminescent Metallogels of Bis-Cyclometalated Alkynylgold(III) Complexes

A series of luminescent bis-cyclometalated alkynylgold­(III) complexes have been synthesized and characterized. Some of the complexes have been demonstrated to exhibit gelation properties driven by π–π stacking and hydrophobic–hydrophobic interactions. The gelation properties have been investigated in detail through variable-temperature UV–vis absorption and emission studies, and the morphology of the gels has also been characterized by scanning electron microscopy and transmission electron microscopy

Luminescent Cyclometalated Alkynylgold(III) Complexes with 6-Phenyl-2,2′-Bipyridine Derivatives: Synthesis, Characterization, Electrochemistry, Photophysics, and Computational Studies

A novel class of luminescent gold­(III) complexes containing various tridentate cyclometalating ligands derived from 6-phenyl-2,2′-bipyridine and alkynyl ligands, [Au­(RC^∧N^∧N)­(CC–R′)]­PF₆, has been successfully synthesized and characterized. One of the complexes has also been determined by X-ray crystallography. Electrochemical studies show a ligand-centered reduction originated from the cyclometalating RC^∧N^∧N ligands as well as an alkynyl-centered oxidation. The electronic absorption and photoluminescence properties of the complexes have also been investigated. In acetonitrile at room temperature, the complexes show intense absorption at higher energy region with wavelength shorter than 320 nm, and a moderately intense broad absorption band at 374–406 nm, assigned as the metal-perturbed intraligand π–π* transition of the cyclometalating RC^∧N^∧N ligand, with some charge transfer character from the aryl ring to the bipyridine moiety. Most of the complexes have been observed to show vibronic-structured emission bands at 469–550 nm in butyronitile glass at 77 K, assigned to an intraligand excited state of the RC^∧N^∧N ligand, with some charge transfer character from the aryl to the bipyridyine moiety. Insights into the origin of the absorption and emission have also been provided by density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations

Functionalized Bis-Cyclometalated Alkynylgold(III) Complexes: Synthesis, Characterization, Electrochemistry, Photophysics, Photochemistry, and Electroluminescence Studies

A series of luminescent alkynylgold­(III) complexes containing various tridentate bis-cyclometalating ligands derived from 2,6-diphenylpyridine (R-C^∧N^∧C), [Au­(R-C^∧N^∧C)­(CCC₆H₄R′)] has been successfully synthesized and characterized. Complexes <b>1</b> and <b>6</b> have been determined by X-ray crystallography. Electrochemical studies show a ligand-centered reduction that originated from the tridentate R-C^∧N^∧C pincer ligands and an alkynyl-centered oxidation. The photophysical properties of the complexes have been studied in detail by electronic absorption and emission studies. Tunable photoluminescence behaviors have been observed, with the emission maxima spanning through the visible region from 476 to 669 nm in dichloromethane at room temperature, and the complexes were also found to be emissive in various media at both room and low temperatures. Transient absorption studies have been conducted to investigate the excited state properties of the complexes. Furthermore, selected complexes have been incorporated into the emissive layer (EML) of organic light-emitting devices (OLEDs) and have demonstrated interesting electroluminescence

Functionalized Bis-Cyclometalated Alkynylgold(III) Complexes: Synthesis, Characterization, Electrochemistry, Photophysics, Photochemistry, and Electroluminescence Studies

A series of luminescent alkynylgold­(III) complexes containing various tridentate bis-cyclometalating ligands derived from 2,6-diphenylpyridine (R-C^∧N^∧C), [Au­(R-C^∧N^∧C)­(CCC₆H₄R′)] has been successfully synthesized and characterized. Complexes <b>1</b> and <b>6</b> have been determined by X-ray crystallography. Electrochemical studies show a ligand-centered reduction that originated from the tridentate R-C^∧N^∧C pincer ligands and an alkynyl-centered oxidation. The photophysical properties of the complexes have been studied in detail by electronic absorption and emission studies. Tunable photoluminescence behaviors have been observed, with the emission maxima spanning through the visible region from 476 to 669 nm in dichloromethane at room temperature, and the complexes were also found to be emissive in various media at both room and low temperatures. Transient absorption studies have been conducted to investigate the excited state properties of the complexes. Furthermore, selected complexes have been incorporated into the emissive layer (EML) of organic light-emitting devices (OLEDs) and have demonstrated interesting electroluminescence

Luminescence color switching of supramolecular assemblies of discrete molecular decanuclear gold(I) sulfido complexes

A series of discrete decanuclear gold(I) μ 3 -sulfido complexes with alkyl chains of various lengths on the aminodiphosphine ligands, [Au 10 {Ph 2 PN(C n H 2n+1 )PPh 2 } 4 (μ 3 -S) 4 ](ClO 4 ) 2 , has been synthesized and characterized. These complexes have been shown to form supramolecular nanoaggregate assemblies upon solvent modulation. The photoluminescence (PL) colors of the nanoaggregates can be switched from green to yellow to red by varying the solvent systems from which they are formed. The PL color variation was investigated and correlated with the nanostructured morphological transformation from the spherical shape to the cube as observed by transmission electron microscopy and scanning electron microscopy. Such variations in PL colors have not been observed in their analogous complexes with short alkyl chains, suggesting that the long alkyl chains would play a key role in governing the supramolecular nanoaggregate assembly and the emission properties of the decanuclear gold(I) sulfido complexes. The long hydrophobic alkyl chains are believed to induce the formation of supramolecular nanoaggregate assemblies with different morphologies and packing densities under different solvent systems, leading to a change in the extent of Au(I)-Au(I) interactions, rigidity, and emission properties. luminescence | color switching | nanoaggregate | gold cluster G old(I) complexes are one of the fascinating classes of complexes that reveal photophysical properties that are highly sensitive to the nuclearity of the metal centers and the metalmetal distances (1-59). In a certain sense, they bear an analogy or resemblance to the interesting classes of metal nanoparticles (NPs) (60-69) and quantum dots (QDs) Based on our interests and experience in the study of gold(I) chalcogenido clusters Herein, we report the preparation and tunable spectroscopic properties of a series of decanuclear gold(I) μ 3 -sulfido complexes with alkyl chains of different lengths on the aminophosphine ligands, [Au 10 {Ph 2 PN(C n H 2n+1 )PPh 2 } 4 (μ 3 -S) 4 ](ClO 4 ) 2 [n = 8 (1), 12 (2), 14 (3), 18 (4)] and their supramolecular assembly to form nanoaggregates. The emission colors of the nanoaggregates of 2−4 can be switched from green to yellow to red by varying the solvent systems from which they are formed. These results have been compared with their short alkyl chain-containing counterparts, 1 and a related [Au 10 {Ph 2 PN(C 3 H 7 )PPh 2 } 4 (μ 3 -S) 4 ](ClO 4 ) 2 (45). The present work demonstrates that polynuclear gold(I) chalcogenides, with the introduction of appropriate functional Significance Polynuclear gold(I) complexes have attracted enormous attention over the past decades owing to their intriguing luminescence behavior and their interesting structural and bonding properties, especially with regard to their propensity to form noncovalent short gold-gold contacts. Most works in polynuclear gold(I) clusters involve structural studies in the solid state, with less attention focused on supramolecular assembly in solution. Herein, discrete decanuclear gold(I) μ 3 -sulfido complexes with long alkyl chains are found to form supramolecular assemblies with different luminescence and morphologies that are tunable by solvent modulation. This has demonstrated the importance of the control and manipulation of intercluster assembly in influencing the photophysical properties and morphologies of the clusters. Such findings have not been previously reported in discrete molecular gold(I) systems. groups, can serve as building blocks for the construction of novel hierarchical nanostructured materials with environment-responsive properties, and it represents a rare example in which nanoaggregates have been assembled with the use of discrete molecular metal clusters as building blocks. Results and Discussion The syntheses and isolation of the discrete propeller-like decanuclear gold(I) μ 3 -sulfido complexes, 1−4 ( Interestingly, the emission colors of complexes 2−4 are found to depend significantly on the solvent systems from which they are prepared. The solvent-induced emission changes of complex 3 are illustrated by the emission spectra ( To establish the identity of the aggregate species in the presence of methanol and methanol−water mixture, respectively, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to probe the morphological changes in various methanol−water compositions. Surprisingly, interesting morphological changes have been observed in the presence of various methanol−water compositions. The TEM images of 4 injected into 100% aqueous solutions showed spheres with diameters of about 70 nm It is remarkable that the size of the nanoaggregates generated from the acetone−methanol−water mixture is found to be generally larger than those obtained from the acetone−water mixture, as revealed by DLS, TEM, and SEM experiments, and the aggregate patterns are also found to be different, indicating that they are packed in different ways. The proposed packing patterns of the nanoaggregates of 2−4 under different conditions are illustrated in In summary, a series of discrete molecular Au 10 clusters with alkyl chains of different lengths on the aminodiphosphine ligands has been synthesized and demonstrated to show intercluster supramolecular nanoaggregate assembly to afford nanoaggregates of different emission colors and morphologies that are dependent on the alkyl chain lengths and the solvent environment. Correlation of the emission color to the morphological transformation has been made. The unique photophysical properties of this class of compounds should form the basis for the future design and development of luminescent nanomaterials and supramolecular assemblies. Materials and Methods Materials and Reagents. Potassium tetrachloroaurate(III) (Strem), iron(II) sulfide (FeS, Acros), and lithium perchlorate trihydrate (LiClO 4 , Strem) were purchased and used as received. Hydrogen sulfide (H 2 S) was freshly generated by reaction of solid FeS with dilute HCl using the Kipp&apos;s apparatus. Pyridine (Acros) was distilled over KOH and stored in the presence of KOH before use. The corresponding ligands of bis(diphenylphosphino)amine derivatives were obtained according to modification of a reported procedure (81). The gold(I) chloride precursors were prepared according to modification of literature procedures (82). Physical Measurements and Instrumentation. Elemental analyses of the complexes were preformed on a Flash EA 1112 elemental analyzer at the Institute of Chemistry, Chinese Academy of Sciences in Beijing. The electronic absorption spectra were obtained on a Hewlett-Packard 8452A diode array spectrophotometer. Steady-state emission spectra recorded at ambient temperature obtained on a Spex Fluorolog-3 Model FL3-211 fluorescence spectrophotometer with Corning filters. The degassed solutions for photophysical studies were deaerated on a high-vacuum line in a two-compartment cell consisting of a 10-cm 3 round-bottomed flask equipped with a side-arm 1-cm fluorescence cuvette and sealed from the atmosphere by a Rotaflo HP6/6 quick-release Teflon stopper. Solutions were rigorously degassed with no less than four successive freeze−pump−thaw cycles. Luminescence lifetime measurements were performed using a conventional laser system. The excitation source was the 355-nm output (third harmonic) of a Spectra-Physics Quanta-Ray Q-switched GCR-150-10 pulsed Nd-YAG laser. Luminescence decay signals were detected by a Hamamatsu R928 photomultiplier tube and recorded on a Tektronix Model TDS-620A (500 MHz, 2 GS/s) digital oscilloscope, and analyzed using a program for exponential fits on a PC computer. Dynamic light-scattering experiments were performed with a Malvern ZetaSizer 3000HSA. TEM experiments were performed on a Philips Tecnai G2 20 S-TWIN transmission electron microscope with an accelerating voltage of 200 kV. SEM experiments were performed on a Leo 1530 field emission gun (FEG) scanning electron microscope operating at 4.0-6.0 kV