Design and preparation of neutral substituted fluorene- and carbazole-based platinum(ii)–acetylide complexes

Abstract

Various combinations of mono-or diethynyl-substituted fluorene or carbazole building blocks were connected via a r-bonded ethynyl linkage to ortho-metallated Pt(II) fragments, giving rise to phosphorescent mono-and dinuclear complexes for which the solubility and extent of delocalization could be tuned by the chemistry on the acidic methylene position of the fluorene.

Electronic structures and optical properties of neutral substituted fluorene-based cyclometalated platinum(II)–acetylide complexes: A DFT exploration

“…The geometries of the complexes all show a nonplanar structure. The lowest energy absorption transitions exhibit LLCT/MLCT character since the electron-rich fluorene moieties possess the stronger [63], the experimental values of 4 and 5 are from the dimethyl derivatives of 4 and 5, respectively.…”

“…Compared to N^N^N (or tpy, 2,2 0 ,6 0 ,2 00 -terpyridine) and C^N^C (HC^N^CH = 2,6-diphenylpyridine) congeners [59][60][61][62], two advantages of the C^N^N ligand have emerged: the strongly r-donating carbanion would increase the energy difference between the ligand field and the MLCT states with superior emissive properties, and associating with the anionic alkynyl ligand affords neutrality to the cyclometalated Pt(II) r-alkynyl moiety framework. Seneclauze and Ziessel have developed various combinations of mono-or diethynyl-substituted fluorene building blocks connected via a r-bonded ethynyl linkage to ortho-metallated Pt(C^N^N) segments [63]. By the general discussion, the luminescent behaviors of this kind of complexes would be assigned to triplet ligand to ligand charge transfer (LLCT) transition perturbed by some MLCT transition.…”

Vectorial Photoinduced Energy Transfer Between Boron–Dipyrromethene (Bodipy) Chromophores Across a Fluorene Bridge

“…[10] Along these lines, we have previously prepared fluorene derivatives chemically modified in the 2,7-substitution positions by protected alkyne fragments. [11] These stable building blocks appeared interesting in the construction of phosphorescent architectures based on transition metals. In the present contribution, the central fluorene subunit has been modified in the central 9,9'-substitution position to connect a short ethyleneglycol chain and to insure good solvent solubility and to import polarity, a key tenet for purification purposes.…”

X-Ray Structural Characterization of Cyclometalated Luminescent Pt(II) Complexes

“…These complexes, 17a-d, show structureless emissions, with max ranging from 528 to 558 nm in acetonitrile at 298 K, which were assigned to 3 MLCT excited states. Also, dinuclear phosphorescent C^N^N Pt(II) cyclometalated were prepared (also investigated by X-ray crystallography) by using diacetylide -carbazole bridging ligand (Seneclauze et al, 2007).…”