Tracking Intramolecular Interactions in Flexibly Linked Binuclear Platinum(II) Complexes

Abstract

In this work we describe the synthesis and the photophysical and electrochemical characterization of binuclear PtII complexes. Using a modular click chemistry approach, we decorated different flexible bridging units with (bpy)PtII bisacetylides (bpy = 2,2′-bipyridine). Intramolecular excimer formation originating from PtII–PtII and π–π interactions was investigated by steady-state and time-resolved emission spectroscopy in dilute solution. We observed that linkers bringing the metallic centers in close proximity favor both ground-state coupling and excimer formation. These interactions lead to changes in the photophysical and electrochemical properties, which can be tuned by the choice of solvent.

A Phosphorescent Platinum(II) Bipyridyl Supramolecular Polymer Based on Quadruple Hydrogen Bonds

“…Based on the long lifetime,t his emission is believed to be phosphorescencef rom an admixed state, 3 MLCT [d(Pt)! [11,14] Most likely,t he strong spin-orbit coupling imparted by the heavy metal centers in Pt-bisUPy facilitated the intersystem crossing (ISC) from the singlet excited state to the triplet state. [11,14] Most likely,t he strong spin-orbit coupling imparted by the heavy metal centers in Pt-bisUPy facilitated the intersystem crossing (ISC) from the singlet excited state to the triplet state.…”

Control over the Self‐Assembly Modes of PtII Complexes by Alkyl Chain Variation: From Slipped to Parallel π‐Stacks

“…[21][22][23][24][25][26][27][28][29][30] These systems have a strong propensity to aggregate in solution and in the solid state via Pt•••Pt and/or other secondary forces, as recently shown for various classes of complexes in a comprehensive review by Yam and co-workers. 31 Among them, the self-assembly features of hydrophobic Pt(II) complexes with acetylide, [32][33][34][35][36] bidentate, [37][38][39] tridentate N-donor, [40][41][42] and cyclometalating ligands [43][44][45] are relatively well understood. 31 In contrast, their hydrophobic counterparts featuring non-chelating ligands and, in particular, bis(pyridyl) Pt(II) complexes have been limited to liquid crystalline materials [46][47][48] and hydrogen-bonded metallogelators.…”

A Dinuclear (bpy)PtII‐Decorated Crownophane

“…[23] Generally, square-planar (bpy)Pt II bis(acetylide)s display distinct metal-to-ligand charge transfer (MLCT) absorption and emission bands with high photoluminescence quantum yields (PLQY). [12,26] The shorter the Pt II -Pt II distance, the stronger the interaction, the more redshifted appears the emission colour, as the lowest-energy excited state changes from 3 MLCT to excimeric states. [12,26] The shorter the Pt II -Pt II distance, the stronger the interaction, the more redshifted appears the emission colour, as the lowest-energy excited state changes from 3 MLCT to excimeric states.…”

“…[11,24,25] Furthermore, the emission colour of such complexes can be tuned by taking advantage of ππ and Pt II -Pt II interactions. The photophysical properties of dinuclear Pt II crownophane 2 were investigated in comparison to analogous mononuclear complex 18 [11] and flexibly linked dinuclear compound 19 [12] (Figure 3a). The photophysical properties of dinuclear Pt II crownophane 2 were investigated in comparison to analogous mononuclear complex 18 [11] and flexibly linked dinuclear compound 19 [12] (Figure 3a).…”

“…The oxygen atoms of the ether chain in the crowno-introduces the feature of varying the opening angle of the cyclophane triggered by cation complexation. [12] Inspired by the above described work on crownophanes, we decided to design and synthesize a functionalized crownophane as a backbone for a dinuclear Pt II complex. Redrawn from ref.…”