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Strong red emissions induced by Pt–Pt interactions in binuclear cycloplatinated(II) complexes containing bridging diphosphines
Author(s) -
Nazari Morteza,
Shahsavari Hamid R.
Publication year - 2019
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.5020
Subject(s) - chemistry , diphosphines , bridging ligand , bipyridine , luminescence , crystallography , transition metal , metal , pyridine , ligand (biochemistry) , platinum , density functional theory , spectroscopy , photochemistry , computational chemistry , medicinal chemistry , catalysis , crystal structure , organic chemistry , biochemistry , physics , receptor , optoelectronics , quantum mechanics
A series of dinuclear cycloplatinated(II) complexes with general closed formula of [Pt 2 Me 2 (C^N) 2 (μ‐P^P)] (C^N = 2‐vinylpyridine (Vpy), 2,2′‐bipyridine N ‐oxide (O‐bpy), 2‐(2,4‐difluorophenyl)pyridine (dfppy); P^P = 1,1‐bis(diphenylphosphino)methane (dppm), N , N ‐bis(diphenylphosphino)amine (dppa)) are reported. The complexes were characterized by means of NMR spectroscopy. Due to the presence of dppm and dppa with short backbones as bridging ligands, two platinum centres are located in front of each other in these complexes so a Pt…Pt interaction is established. Because of this Pt…Pt interaction, the complexes have bright orange colour under ambient light and are able to strongly emit red light under UV light exposure. These strong red emissions originate from a 3 MMLCT (metal–metal‐to‐ligand charge transfer) electronic transition. In most of these complexes, the emissions have unstructured bell‐shaped bands, confirming the presence of large amount of 3 MMLCT character in the emissive state. Only the complexes bearing dfppy and dppa ligands reveal dual luminescence: a high‐energy structured emission originating from 3 ILCT/ 3 MLCT (intra‐ligand charge transfer/metal‐to‐ligand charge transfer) and an unstructured low‐energy band associated with 3 MMLCT. In order to describe the nature of the electronic transitions, density functional theory calculations were performed for all the complexes.