Counteranion-Triggered and Excitation-Dependent Chemopalette Effect in a Supramolecular Dual-Emissive System Based on Cu3Pz3

Structural trends in a series of bulky dialkylbiarylphosphane complexes of CuI

Cu^I complexes containing the bulky dialkylbiarylphosphane 2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl (^tBuXPhos, L) and an ancillary ligand (Cl^-, Br^-, I^-, MeCN, ClO₄^- or SCN^-) have been structurally characterized, namely, chlorido[2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]copper(I), [CuCl(C₂₉H₄₅P)], 1, bromido[2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]copper(I), [CuBr(C₂₉H₄₅P)], 2, [2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]iodidocopper(I), [CuI(C₂₉H₄₅P)], 3, (acetonitrile-κN)[2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]copper(I) hexafluoridophosphate, [Cu(CH₃CN)(C₂₉H₄₅P)]PF₆, 4, [2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP](perchlorato-κO)copper(I), [Cu(ClO₄)(C₂₉H₄₅P)], 5, and di-μ-thiocyanato-κ²S:N;κ²N:S-bis{[2-(di-tert-butylphosphanyl)-2',4',6'-triisopropylbiphenyl-κP]copper(I)}, [Cu₂(NCS)₂(C₂₉H₄₅P)₂], 6. Iodide complex 3 shows significant Cu^I-arene interactions, in contrast to its chloride 1 and bromide 2 counterparts, which is attributed to the weaker interaction between the iodide ion and the Cu^I centre. When replacing iodide with an acetonitrile (in 4) or perchlorate (in 5) ligand, the reduced interaction between the Cu^I atom and the ancillary ligand results in stronger Cu^I-arene interactions. No Cu^I-arene interactions are observed in dimer 6, due to the tricoordinated Cu^I centre having sufficient electron density from the coordinated ligands.

Luminescent polymorphic aggregates of trinuclear Cu(I)-pyrazolate tuned by intertrimeric CuNPy weak coordination bonds

Five luminescent polymorphic aggregates of trinuclear Cu(i)-pyrazolate, namely [anti-Cu3L3]2 (1), [syn-Cu3L3·C2H5OH]2 (2), [anti-Cu3L3·C2H5OH]n (3), [anti-Cu3L3·0.5C7H8]n (4) and [syn-Cu3L3·C8H10]n (5) (HL = 4-(pyridin-4-ylthio)-3,5-dimethyl-1H-pyrazole), were reported. The trimeric Cu3L3 fragments present syn- and anti-conformations dependent on the dangled direction of 4-pyridyl groups on the two sides of the Cu3Pz3 plane (Pz = pyrazolate). Intertrimeric NPyCu weak coordination bonds associate these Cu3L3 fragments together to form dimeric or polymeric structures, which are further stabilized by crystallized solvent molecules or intertrimeric CuCu interactions. The solvated complexes (3-5) may be transformed into the unsolvated complex 1 by evacuation of the crystallized solvents upon heating. All these complexes emit from green to yellow under UV irradiation, which originated from the triplet excited states of metal to ligand charge transfer (3MLCT) mixed with intertrimeric CuCu interactions. This work provides a novel kind of supramolecular aggregate based on Cu3Pz3 beyond the classical π-acidbase adducts and metallophilicity-dependent dimers/oligomers.

Visible-light excited luminescent trigonal prismatic metallocages from a template-directed assembly

Trigonal prismatic metallocages based on Cu₃Pz₃ and Cu₂I₂/Cu₂Br₂ with 24-component were assembled via a template-directed strategy. They showed rare visible-light responsive red emissions based on Cu₂I₂/Cu₂Br₂ coordination chromophores.

White Light from Blue Fluorescence and Sensitized Yellow Long-Afterglow Phosphorescence of o-Terphenyl in Its π-Acid···Base Adduct with Ag3Pz3

White-light emission with CIE (0.32, 0.34) was realized for an o-terphenyl (oTP) molecule in its Ag₃[3,5-(CF₃)₂Pz]₃ (Pz = pyrazolate) sandwiching adduct, originating from the hybrid of fluorescence and sensitized long-afterglow phosphorescence of oTP. Density functional theory (DFT) and time-dependent DFT calculations revealed that heavy-atom effects of Ag play a crucial role in sensitization of the triplet of oTP, giving off its ultralong phosphorescence.

Synthesis, structures and luminescence of multinuclear silver(i) pyrazolate adducts with 1,10-phenanthroline derivatives

A set of silver(i) 3,5-bis(trifluoromethyl) pyrazolate adducts with 1,10-phenanthroline (L²), 2,9-dimethyl-1,10-phenanthroline (neocuproine, L³) and 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine, L⁴) was synthesized starting from trimeric silver pyrazolate Ag₃Pz₃. Reactions with sterically hindered L³ and L⁴ cause the destruction of the original trimeric core, yielding a dinuclear Ag₂Pz₂ cycle with an unprecedented chair configuration for L³, while bathocuproine L⁴ leads to the drastic rearrangement of the silver pyrazolate core into cationic Ag(L⁴)₂ and anionic Ag₅Pz₆ subunits. All complexes obtained exhibit phosphorescence in the solid state. Time-dependent density functional theory calculations demonstrate their different possible emission processes, explaining their emission behavior as well as their lifetimes.

The π-acidity/basicity of cyclic trinuclear units (CTUs): from a theoretical perspective to potential applications

Cyclic trinuclear units (CTUs) based on Au(i), Ag(i) and Cu(i) cations, featuring near planar nine-membered coordination rings, represent an important class of metal-organic π-acids/bases with highly adjustable π-acidity/basicity. Their superior π-acidity/basicity coupled with Lewis-acidic and metalmetal bonding sites offers excellent attraction for a wide range of acidic/basic species, and usually followed by noticeable changes of luminescence or charge transfer behaviors. A series of representative cases from the past two decades have been selected herein for such cyclic trinuclear units in both oligomeric and polymeric systems. Their fascinating and profound potential applications related to π-acidity/basicity are highlighted, including molecular absorption and separation, luminescence sensing and detection, organic light-emitting diodes (OLEDs), metal-organic field-effect transistors (MOFETs), molecular wires, and catalysis. The challenges in improving the performance for practical application will also be discussed.

Luminescence color alteration induced by trapped solvent molecules in crystals of tetrahedral gold(i) complexes: near-unity luminescence mixed with thermally activated delayed fluorescence and phosphorescence

Emission color alteration caused by captured solvent molecules in the crystal lattice of tetrahedral gold(i) complexes.

A luminescent edge-interlocked prismatic heteroleptic metallocage assembled through a ligand replacement reaction

A luminescent edge-interlocked heteroleptic metallocages based on Cu₃(pyrazolate)₃ was prepared through a ligand replacement reaction from a homoleptic metallocage and a new ligand.