Improvement of the photophysical performance of platinum-cyclometalated complexes in halogen-bonded adducts
Journal
Chemistry - A European Journal
Journal Volume
24
Journal Issue
44
Pages
11475-11484
Date Issued
2018
Author(s)
Sivchik, V.
Sarker, R.K.
Liu, Z.-Y.
Chung, K.-Y.
Grachova, E.V.
Karttunen, A.J.
Koshevoy, I.O.
Abstract
AbstractThree groups of luminescent platinum complexes [Pt(C^N)(L)(Y)] [C^N=benzothienyl‐pyridine (1), bezofuryl‐pyridine (2), phenyl‐pyridine (3); L/Y=DMSO/Cl (a), PPh3/Cl (b), PPh3/CN (c)] have been probed as halogen‐bond (XB) acceptors towards iodofluorobenzenes (IC6F5 and I2C6F4). Compounds 1 a and 2 a (L/Y=DMSO/Cl) afford the adducts 1 a⋅⋅⋅I2C6F4 and 2 a⋅⋅⋅I2C6F4, which feature I⋅⋅⋅Sbtpy/I⋅⋅⋅πbtpy and I⋅⋅⋅ODMSO/I⋅⋅⋅Cl short contacts, respectively. The phosphane‐cyanide derivatives 1 c and 2 c (L/Y=PPh3/CN) co‐crystallise with both IC6F5 and I2C6F4. None of the phpy‐based species 3 a–3 c participated in XB interactions. Although the native complexes are rather poor luminophores in the solid state (Φem=0.023–0.089), the adducts exhibit an up to 10‐fold increase of the intensity with a minor alteration of the emission energy. The observed gain in the quantum efficiency is mainly attributed to the joint influence of non‐covalent interactions (halogen/hydrogen bonding, π–π stacking), which govern the crystal‐packing mode and diminish the radiationless pathways for the T1→S0 transition by providing a rigid environment around the chromophore.
SDGs
Type
journal article