Fullerene Polypyridine Ligands: Synthesis, Ruthenium Complexes, and Electrochemical and Photophysical Properties

Abstract

Fullerene coordination ligands bearing one bipyridine or terpyridine unit were synthesized, and their coordination to ruthenium(II) formed linear rod-like donor-acceptor systems. Steady-state fluorescence of [Ru(bpy)(2)(bpy-C(60))](2+) showed a rapid solvent-dependent, intramolecular quenching of the ruthenium(II) MLCT excited state. Time-resolved flash photolysis in CH(3)CN revealed characteristic transient absorption changes that have been ascribed to the formation of the C(60) triplet state, suggesting that photoexcitation of [Ru(bpy)(2)(bpy-C(60))](2+) results in a rapid intramolecular transduction of triplet excited state energy. The electrochemical studies on both [Ru(bpy)(2)(bpy-C(60))](2+) and [Ru(tpy)(tpy-C(60))](2+) indicated electronic coupling between the metal center and the fullerene core.

Synthesis and Preliminary Characterization of a PPE-Type Polymer Containing Substituted Fullerenes and Transition Metal Ligation Sites

“…Absorption spectra of precursor 2 and polymers 5-7 in 2-MTHF at optically dilute concentrations are shown in Figure 1. For the fullerenecontaining precursor, the spectrum is very similar to previously reported substituted fullerene 1 [4,6] with intense absorption bands below 350 nm typically associated with aromatic , * transitions [1,[46][47][48][49][50]. We do not observe the longer wavelength features typically associated with fullerenes, likely due to the intense absorption associated with the aromatic "hub" structure.…”

4′‐Hydrazone Derivatives of 2,2′:6′,2"‐Terpyridine: Protonation and Substituent Effects

“…4Ј-Hydrazino-2,2Ј:6Ј,2ЈЈ-terpyridine was prepared as previously reported, and spectroscopic data were consistent with those in the literature. [25][26][27] In the 1 H NMR spectra listed below, data at 360 K are given whenever the spectrum at 295 K contains very broad or unresolved signals.…”

“…The synthetic route to hydrazones 1-4 (Scheme 1) was by the well established acid-catalysed condensation of a hydrazine (4Ј-hydrazino-2,2Ј:6Ј,2ЈЈ-terpyridine or 4Ј-(1-methylhydrazino)-2,2Ј:6Ј,2ЈЈ-terpyridine [25][26][27] ) and an aldehyde or ketone (benzaldehyde for 1 and 4, acetophenone for 2, and benzophenone for 3). The reaction of 4Ј-hydrazino-2,2Ј:6Ј,2ЈЈ-terpyridine and benzaldehyde in methanol in the presence of a few drops of concentrated H 2 SO 4 resulted in the formation of a bright yellow solid, elemental analysis of which was consistent with the methyl sulfate salt of [H 2 1] 2+ (Scheme 2).…”

The Marriage of Terpyridines and Inorganic Nanoparticles: Synthetic Aspects, Characterization Techniques, and Potential Applications

“…No energy transfer between the excited singlet methanofullerene moieties and the central metal complexes was detectable; however, indications for a quenching of the excited triplet state of the fullerene by the Fe II complex could be obtained by transient absorption spectroscopy. Moreover, terpyridyl glycine was used for the functionalization of fullerenes, resulting in fullerenopyrrolidines bearing a tpy moiety ( 15 );135 this approach was also applied for the synthesis of tetra kis ‐ and hexa kis terpyridyl fullerenes 136. The heteroleptic complex [(tpy)Ru( 15 )] 2+ revealed an electronic coupling between the fullerene and the Ru II complex 135…”