Terpyridine isomerism as a tool for tuning red-to-NIR emissive properties in heteronuclear gold(I)-thallium(I) complexes

The polymeric linear chain [AuTl(C6Cl5)2]n reacts with three terpyridine-type ligands substituted with thiophene groups containing N-donor centres in different relative positions (L1, L2 and L3), leading to the Au(I)/Tl(I) complexes [AuTl(C6Cl5)2(L1)]n (1), [{AuTl(C6Cl5)2}2(L2)]n (2) and [AuTl(C6Cl5)2(L3)]n (3). X-Ray diffraction studies reveal that L1 acts as a chelate, while L2 and L3 act as bridging ligands, resulting in different coordination indexes for the thallium(I) centre. These structural differences strongly influence their optical properties, and while compounds 2 and 3 emit near the limit of the visible range, complex 1 emits in the infrared region. DFT calculations have also been carried out in order to determine the origin of the electronic transitions responsible for their optical properties.

Self-Assembled Encapsulation of CuX2- (X = Br, Cl) in a Gold Phosphine Box-like Cavity with Metallophilic Au-Cu Interactions

Synthetic routes to the crystallization of two new box-like complexes, [Au6(Triphos)4(CuBr2)](OTf)5·(CH2Cl2)3·(CH3OH)3·(H2O)4 (1) and [Au6(Triphos)4 (CuCl2)](PF6)5·(CH2Cl2)4 (2) (triphos = bis(2-diphenylphosphinoethyl)phenylphosphine), have been developed. The two centrosymmetric cationic complexes have been structurally characterized through single-crystal X-ray diffraction and shown to contain a CuX2- (X = Br or Cl) unit suspended between two Au(I) centers without the involvement of bridging ligands. These colorless crystals display green luminescence (λem = 527 nm) for (1) and teal luminescence (λem = 464 nm) for (2). Computational results document the metallophilic interactions that are involved in positioning the Cu(I) center between the two Au(I) ions and in the luminescence.

Homoleptic Alkynylphosphonium Au(I) Complexes as Push-Pull Phosphorescent Emitters

A series of compounds P1-P4 bearing terminal alkynyl sites connected with a phosphonium group via different π-conjugated linkers have been synthesized. The compounds themselves are efficient push-pull emitters and exhibit bright fluorescence in blue and near-UV regions. P1-P4 were used as alkynyl ligands to obtain a series of homoleptic bis-alkynyl Au(I) complexes 1-4. The complexes demonstrate bright phosphorescence and dual emission with dominating phosphorescence (2-4). Terphenyl derivative complex 3 exhibits warm white emission in DMSO solution and pure white emission in PMMA films. Time-dependent density functional theory calculations have shown that the T₁ excited state has a hybrid MLCT/ILCT nature with a dominant contribution of charge transfer across a ligand-centered "D-π-A" system. The variation of linker allows tuning the effect of intermolecular charge transfer and thus changing the electronic and photophysical properties of the organogold "D-π-A" system. The results presented unambiguously display the advances of the conception of organometallic "D-π-A" construction.

Homo- and hetero-metallophilicity-driven synthesis of highly emissive and stimuli-responsive Au(i)–Cu(i) double salts

Discrete complex salts having Au···Au and Au···Cu interactions were obtained as three crystalline polymorphs exhibiting various emission colors with high efficiency. Solvent vapor caused crystal-to-crystal transition, changing the emission color.

Keep it tight: a crucial role of bridging phosphine ligands in the design and optical properties of multinuclear coinage metal complexes

Copper subgroup metal ions in the +1 oxidation state are classical candidates for aggregation via non-covalent metal-metal interactions, which are supported by a number of bridging ligands. The bridging phosphines, soft donors with a relatively labile coordination to coinage metals, serve as convenient and essential components of the ligand environment that allow for efficient self-assembly of discrete polynuclear aggregates. Simultaneously, accessible and rich modification of the organic spacer of such P-donors has been used to generate many fascinating structures with attractive photoluminescent behavior. In this work we consider the development of di- and polynuclear complexes of M(i) (M = Cu, Ag, Au) and their photophysical properties, focusing on the effect of phosphine bridging ligands, their flexibility and denticity.

Solution versus solid-state dual emission of the Au(i)-alkynyl diphosphine complexes via modification of polyaromatic spacers

Single molecule luminophores capable of multiple emissions are essential for the development of new materials with unconventional photophysical behavior.

New Au(i)–Cu(i) heterometallic complexes: the role of bridging pyridazine ligands in the presence of unsupported metallophilic interactions

The use of N-donor pyridazine ligands in different amounts in the reaction with a Au(i)/Cu(i) precursor allows the control of metallophilic interactions in the solid state.