The Role of Substituent Effects in Tuning Metallophilic Interactions and Emission Energy of Bis‐4‐(2‐pyridyl)‐1,2,3‐triazolatoplatinum(II) Complexes

Abstract

The photoluminescence spectra of a series of 5-substituted pyridyl-1,2,3-triazolato Pt(II) homoleptic complexes show weak emission tunability (ranging from λ=397-408 nm) in dilute (10(-6) M) ethanolic solutions at the monomer level and strong tunability in concentrated solutions (10(-4) M) and thin films (ranging from λ=487-625 nm) from dimeric excited states (excimers). The results of density functional calculations (PBE0) attribute this "turn-on" sensitivity and intensity in the excimer to strong Pt-Pt metallophilic interactions and a change in the excited-state character from singlet metal-to-ligand charge transfer ((1)MLCT) to singlet metal-metal-to-ligand charge transfer ((1)MMLCT) emissions in agreement with lifetime measurements.

Metallophilic Mercuraazamacrocycles Derived from Bis{6‐formyl‐(2,3,4‐trimethoxy)phenyl}mercury: Reactivity with d10and d8Metal Ions

“…The geometries of the precursors 12 and 14 , macrocycles 15 – 17 , metal complexes 24 – 29 were optimized at PBE0 level of theory using 6‐31G(d) basis set for C, H, N, O, Cl atoms and SDD basis set for Hg, Cu, Ag and Pt with the corresponding quasi‐relativistic pseudopotentials. PBE0 functional has been earlier successfully used by several groups to study metallophilic interactions …”

A single-step acid catalyzed reaction for rapid assembly of NH-1,2,3-triazoles

“…and purified by column chromatography (silica gel), at first with CH 2 Cl 2 as eluent to remove all 4-nitroaniline 4 formed during the reaction followed by using a mixture of heptane and ethyl acetate as eluent to afford the corresponding NH-1,2,3-triazole as off-white solids or semi-solids. 6,7,8,9-tetrahydro-5Hbenzo [7]annulen-5-one (75 mg, 0.47 mmol), Ammonium acetate (180 mg, 2.35 mmol), 4-nitrophenyl azide (100 mg, 0.61 mmol), and DMF (1 mL). Reaction time is 12 h. The product was purified by flash column chromatography (CH 2 Cl 2 followed by heptane/EtOAc = 5:2) afforded 3b (70 mg, 81% yield) as an off-white solid.…”

Novel gold(i) diphosphine-based dimers with aurophilicity triggered multistimuli light-emitting properties

“…9 The starting complex [Au2(dpephos)2](NO3)2 (1) was obtained in high yield by ball-milling equimolar amounts of (Me2S)AuCl with dpephos and AgNO3. Anion exchange was carried out by ball-milling 1 with NaX (X = CF3SO3, BF4, PF6 and SbF6) in a 1:3 molar ratio with addition of few drops of dichloromethane.…”

“…7 In contrast, stimuli-responsive luminescence often requires flexible molecular conformations that can be altered by external physical or chemical stimuli. 8 Molecular flexibility becomes an emerging strategy in the design of stimuli-responsive material properties, 9 whereas systematic structural modification of the ligands has been demonstrated to be effective in tuning the emission energy. 10 Specifically, dinuclear complexes [Au2(diphos)2](X)2 with a diphosphine ligand (diphos, Chart 1) having short intramolecular aurophilic Au···Au interactions are a remarkable class of materials where the structural diversity of the ligand accounts for the tunability of their emission energy.…”

“…10 Within this context we have previously studied the photophysical properties of two complexes, [Au2(xantphos)2](X)2 (xantphos = 9,9'-dimethyl-4,5-bis(diphenylphosphino)-xanthene, Chart 1) and [Au2(nixantphos)2](X)2 (nixantphos = 4,6-bis(diphenylphosphino)phenoxazine, Chart 1), and their relation to the nature of the substituents (Me2C versus NH). 9 In these dinuclear gold(I)-diphosphine compounds, the triplet intraligand transition of the bridging diphosphine ligands occurs at much higher energy than the triplet metal-centered transition originating from an Au···Au interaction. 11 These xantphos-and nixantphos-based [Au2(diphos)2](X)2 complexes have stimuli-responsive emission as their luminescence can be switched by temperature, mechanical grinding and solvent vapors.…”