Platinum-Conjugated Homo- and Heterobichromophoric Complexes of Tetracene and Pentacene

Abstract

Homobichromophoric platinum(II) complexes containing tetracenyl rings (T-Pt-T) and pentacenyl rings (P-Pt-P) were synthesized by Sonogashira coupling between trans-[Pt(PEt 3 ) 2 I 2 ] and 5-ethynyl-12-[(triisopropylsilyl)ethynyl]tetracene (T-SiH) and 6-ethynyl-13-[(triisopropylsilyl)ethynyl]pentacene (P-SiH), respectively. A heterobichromophoric complex consisting of tetracenyl and pentacenyl rings (T-Pt-P) was generated by coupling P-SiH and platinated T-SiH. The homobichromophoric complexes were characterized by singlecrystal X-ray diffraction. The electronic absorption and emission spectra of the complexes were investigated. All the complexes displayed acene-based fluorescence. The emission spectrum of T-Pt-P showed dual emissions of the tetracenyl and pentacenyl rings. Monitoring the pentacenyl emission gave an excitation spectrum which resembled the absorption spectrum, suggesting the presence of intramolecular energy transfer from the singlet excited state of the tetracenyl ring to the singlet excited state of the pentacenyl ring.

Influence of the heavy-atom effect on singlet fission: a study of platinum-bridged pentacene dimers

“…The synthesis of Pt-acetylide complexes is well-documented in the literature. [41][42][43][44] They are typically formed via the reaction of a terminal acetylene with cis-or trans-PtCl 2 (R 3 P) 2 , giving the thermodynamically more stable trans-isomer in both cases when the reaction is conducted at room temperature. Thus, terminal acetylene 1 (ref.…”

“…This nding is in sound agreement with the absorption spectra reported by Nguyen and Yip. 41 Upon cooling to 85 K, an overall sharpening of the absorption features allows for determining the precise position of the maxima in PrCN: 510, 553, 604, 652 and 709 nm for mono-Pt; 510, 555, 608, 658 and 715 nm for trans-Pt; and 510, 553, 592, 640 and 694 nm for cis-Pt. Of particular interest is the 709 nm maximum for mono-Pt, which red-shis to 715 nm in the case of trans-Pt and blue-shis to 694 nm in the case of cis-Pt.…”

“…In 2012, Nguyen and Yip presented pentacene and tetracene dimers and monomers linked to a platinum atom. 41 They observed a strong uorescence quenching for all pentaceneplatinum compounds; however, the quenching was stronger in the dimers. The tetracene-platinum monomers did not show uorescence quenching, while the uorescence of the platinum-bridged tetracene dimer was strongly quenched.…”

Singlet Fission in Enantiomerically Pure Pentacene Dimers

“…Much less attention has been placed on incorporation of transition metals as a component of the molecular spacer in order to dissect the role of the heavy atom effect in SF. [40] Recently, we reported on a set of transand cis-platinum bridged pentacene dimers. We demonstrated that the presence of platinum does not perturb the 1 (T 1 T 1 ) generation.…”

Turning-On of Coumarin Phosphorescence in Acetylacetonato Platinum Complexes of Cyclometalated Pyridyl-Substituted Coumarins

“…Vibrational structuring is a characteristic asset of a 3 IL-based emission arising from a ligand-centered excited state where the heavy metal atom has only small contributions but efficiently triggers the otherwise forbidden S1→T1 intersystem crossing (ISC) of a coordinated ligand owing to its large spin-orbit coupling constant [19]. Typical examples of such behavior are Pt alkynyl complexes [57][58][59][60][61][62][63][64][65][66][67]. The latter notion is further supported by the computed spin density surface for the T1 state of complex 2 as it is depicted in Figure 10a.…”