Glenna So Ming Tong

Luminescent Organogold(III) Complexes with Long‐Lived Triplet Excited States for Light‐Induced Oxidative CH Bond Functionalization and Hydrogen Production

All that glitters is gold: highly phosphorescent gold(III) complexes with extended π-conjugated cyclometalating ligands exhibit rich photophysical and photochemical properties. They act as efficient photocatalysts/photosensitizers for oxidative functionalizations of secondary and tertiary benzylic amines and homogeneous hydrogen production from a water/acetonitrile mixture.

Cyclometalated Platinum(II) Complexes as Highly Sensitive Luminescent Switch‐On Probes for Practical Application in Protein Staining and Cell Imaging

Protein-staining platinum: The luminescent switch-on characteristic of the platinum(II) complex can be utilized for staining a series of proteins in sodium dodecyl sulfate-polyarcylamide gels, to give emissive gel images directly under UV light (see figure). The detection sensitivity for BSA protein is down to 6.0 ng, revealing potential practical applications of luminescent platinum(II) complexes in the luminescent signaling of biomolecules.

Semiconducting and electroluminescent nanowires self-assembled from organoplatinum(II) complexes

Organometallic nanowires with luminescent and current‐modulating properties were self‐assembled from cyclometalated/terpyridyl platinum(II) complexes with auxiliary arylisocyanide/arylacetylide ligands and incorporated into a compact organic light‐emitting field‐effect transistor (see picture) by solution‐processable protocols. The nanowires exhibit both electron and hole mobilities of 0.1 cm2 V−1 s−1.

Strongly Luminescent Gold(III) Complexes with Long‐Lived Excited States: High Emission Quantum Yields, Energy Up‐Conversion, and Nonlinear Optical Properties

Strongly Luminescent Gold(III) Complexes with Long-Lived Excited States: High Emission Quantum Yields, Energy Up-Conversion, and Nonlinear Optical Properties Photochemistry : A series of emissive gold(III) complexes with fluorene-containing cyclometalating ligands exhibits strong phosphorescence and long-lived excited states with emission quantum yields and lifetimes up to 58 % and 305 ms, respectively. These complexes can sensitize energy up-conversion of 9,10-diphenylanthracene (DPA; see picture) and display rich two-photon absorption properties (TPA; TTA = triplet–triplet annihilation). Angewandte Chemie

Robust Phosphorescent Platinum(II) Complexes Containing Tetradentate O^N^C^N Ligands: Excimeric Excited State and Application in Organic White‐Light‐Emitting Diodes

The bright white lights: A series of highly robust platinum(II) complexes supported by tetradentate O N C N ligands with high emission quantum yields (0.72-0.93) and high T(d) (>400 °C) have been synthesized. Among the complexes, that shown in the figure has strong excimer emission attributed to the monomer triplet excited state with a localized structure. The application of this low band-gap material on single-dopant organic or polymer white-light-emitting diodes (WOLED) is highlighted.

Highly selective metal catalysts for intermolecular carbenoid insertion into primary C-H bonds and enantioselective C-C bond formation.

Direct functionalization of C H bonds is an appealing strategy in organic synthesis but its practical application has so far been difficult to realize. The selective functionalization of primary C H bonds of alkanes that also contain secondary and/or tertiary C H bonds is a great challenge, as C H bond energy follows an order primary> secondary> tertiary. In seminal works by Bergman, Jones, and their respective co-workers, stoichiometric reactions of alkanes with [Cp*(Me3P)M] (Cp* = C5Me5; M = Rh, Ir) resulted in the formation of C M bonds by selective activation of primary C H bonds. Subsequent work by Hartwig and coworkers 2] demonstrated C B bond formation by stoichiometric and catalytic functionalization of primary C H bonds mediated by tungsten, rhodium, or ruthenium complexes. The high selectivity for primary C H bond functionalization in these C M or C B bond-formation reactions (Scheme S1 in the Supporting Information) is considered to result from kinetic factors or steric interaction between the metal complexes and alkanes. 3] A well-established process in C C bond formation by direct C H bond functionalization is the metal-catalyzed intraand intermolecular carbenoid insertion into C H bonds, with diazo compounds as the carbene source. 4] These catalytic C C bond-formation reactions generally feature lower selectivity for primary C H bonds than for secondary and tertiary C H bonds. For example, a selectivity order of primary< secondary< tertiary C H bonds has been observed for the extensively investigated carbene insertion catalyzed by rhodium complexes, 5] possibly because of the electron density order of primary< secondary< tertiary C H bonds, which renders primary C H bonds the least susceptible to attack by electrophilic rhodium–carbene intermediates. By manipulating the steric or electronic properties of the metal catalysts, a selectivity for primary C H bonds of alkanes comparable to that for secondary or tertiary C H bonds was observed, with the highest primary/secondary and primary/tertiary ratio per C H bond being 1.17:1.0 and 1.0:0.9, respectively. Herein we report a highly selective primary C H bond functionalization by metal-catalyzed carbenoid insertion into the C H bonds of alkanes (Scheme 1), which features a

The 3[ndσ*(n+1)pσ] Emissions of Linear Silver(I) and Gold(I) Chains with Bridging Phosphine Ligands

The complexes [Au(3)(dcmp)(2)][X](3) {dcmp=bis(dicyclohexylphosphinomethyl)cyclohexylphosphine; X=Cl(-) (1), ClO(4) (-) (2), OTf(-) (3), PF(6) (-) (4), SCN(-)(5)}, [Ag(3)(dcmp)(2)][ClO(4)](3) (6), and [Ag(3)(dcmp)(2)Cl(2)][ClO(4)] (7) were prepared and their structures were determined by X-ray crystallography. Complexes 2-4 display a high-energy emission band with lambda(max) at 442-452 nm, whereas 1 and 5 display a low-energy emission with lambda(max) at 558-634 nm in both solid state and in dichloromethane at 298 K. The former is assigned to the (3)[5dsigma*6psigma] excited state of [Au(3)(dcmp)(2)](3+), whereas the latter is attributed to an exciplex formed between the (3)[5dsigma*6psigma] excited state of [Au(3)(dcmp)(2)](3+) and the counterions. In solid state, complex [Ag(3)(dcmp)(2)][ClO(4)](3) (6) displays an intense emission band at 375 nm with a Stokes shift of approximately 7200 cm(-1) from the (1)[4dsigma*-->5psigma] absorption band at 295 nm. The 375 nm emission band is assigned to the emission directly from the (3)[4dsigma(*)5psigma] excited state of 6. Density functional theory (DFT) calculations revealed that the absorption and emission energies are inversely proportional to the number of metal ions (n) in polynuclear Au(I) and Ag(I) linear chain complexes without close metalanion contacts. The emission energies are extrapolated to be 715 and 446 nm for the infinite linear Au(I) and Ag(I) chains, respectively, at metalmetal distances of about 2.93-3.02 A. A QM/MM calculation on the model [Au(3)(dcmp)(2)Cl(2)](+) system, with Au...Cl contacts of 2.90-3.10 A, gave optimized Au...Au distances of 2.99-3.11 A in its lowest triplet excited state and the emission energies were calculated to be at approximately 600-690 nm, which are assigned to a three-coordinate Au(I) site with its spectroscopic properties affected by Au(I)...Au(I) interactions.

Spectacular luminescent behaviour of tandem terpyridyl platinum(II) acetylide complexes attributed to solvent effect on ordering of excited states, “ion-pair” formation and molecular conformations

A series of oligomeric tandem terpyridyl platinum(II) complexes, namely [(tBu3tpy)Pt(CCtpy)PtCl](OTf)2 (3), [(tBu3tpy)Pt(CCtpy)PtCCtBu](OTf)2 (4), [(tBu3tpy)Pt(CCtpy)PtCCtpy](OTf)2 (5), and [(tBu3tpy)Pt(CCtpy)Pt(CCtpy)PtCl](OTf)3 (6), were prepared and their spectroscopic properties and self-aggregating behaviour were examined. In particular, complex 4 exhibits unusually higher emission quantum yield in CH2Cl2 (ϕ = 0.43) than that in CH3CN (ϕ < 0.1), which is attributed to the formation of a “contact ion pair” in chlorinated solvents, such as CHCl3, CH2Cl2 and C6H5Cl. DFT calculations revealed that both intersystem crossing (ISC) and radiative decay of this complex are less effective in CH3CN than in CH2Cl2, thus accounting for the low emission quantum yield in CH3CN.

Theoretical studies of the first-row transition metal phosphides

The electronic structures and spectroscopic parameters of the ground and some low-lying excited states of the first-row transition metal phosphides have been calculated with the density functional theory using the Becke three-parameter hybrid exchange functional with the Lee–Yang–Parr correlation functional (B3LYP). The ground states of the transition metal phosphides are found to be 1Σ+ (ScP), 2Δ (TiP), 3Δ (VP), 4Σ− (CrP), 5Π (MnP), 6Σ+ (FeP), 5Δ (CoP), 4Δ (NiP), and 3Σ− (CuP). The B3LYP functional predicts an increase in covalent character in the bonds between the metal and the phosphorus across the transition metal series. The energies of the low-lying excited states relative to the ground state for TiP, FeP, and CoP have been found to be so small that many low-lying states are possible candidates to be the ground state.

Highly Luminescent Pincer Gold(III) Aryl Emitters: Thermally Activated Delayed Fluorescence and Solution-Processed OLEDs

Herein are described the synthesis, photophysical properties and applications of a series of luminescent cyclometalated AuIII complexes having an auxiliary aryl ligand. These complexes show photoluminescence with emission quantum yields of up to 0.79 in solution and 0.84 in thin films (4 wt % in PMMA) at room temperature, both of which are the highest reported values among AuIII complexes. Thermally activated delayed fluorescence (TADF) is the emission origin for some of these complexes. Solution-processed OLEDs made with these complexes showed sky-blue to green electroluminescence with external quantum efficiencies (EQEs) of up to 23.8 %, current efficiencies of up to 70.4 cd A-1 , and roll-off of down to 1 %, highlighting the bright prospect of AuIII -TADF emitters in OLEDs.