Screening Electronic Communication through ortho‐, meta‐ and para‐Substituted Linkers Separating Subphthalocyanines and C₆₀

Abstract

We have prepared two complementary series of SubPc-C(60) (SubPc=subphthalocyanine) electron/energy donor-acceptor systems, in which the two constituents are linked through ortho-, meta-, or para-substituted phenoxy spacers. In one of the series (1 a) the SubPc units bear iodine atoms, while in the other series (1 b) diphenylamino groups are linked to the SubPc macrocycles. The iodine atoms and diphenylamino groups both influence the resulting oxidation potentials of the electron-donating SubPc. They also modulate the outcome of excited state interactions, namely, energy and/or charge transfer. In addition, we have studied the impact that the substitution pattern in the phenoxy spacer exerts onto intramolecular processes in the ground and excited states. Although some of these processes are governed by the spatial separation between both components, the different electronic coupling through ortho-, meta-, or para- connections also plays decisive roles in some cases.

Triazole Bridges as Versatile Linkers in Electron Donor–Acceptor Conjugates

“…The shorter distance between ZnP and C 60 in m4m -ZnP-Tri-C 60 17 , ~ 10 Å, compared to the other conjugates, > 14 Å, facilitates the electronic interaction in the ground state. This trend resembles with that previously reported in similar short-distance porphyrin-fullerene dyads, 24a,44 in which donor-acceptor separations shorter than 10 Å are crucial for the CT state formation.…”

“…For m4m -ZnP-Tri-C 60 17 , the fact that the CT emission band was only detected in toluene suggests weak coupling between the active units. CT emission has been reported to occur in ZnP-C 60 conjugates with similar donor-acceptor distances in a variety of solvents, 24a,44 which suggests that non-favorable orientations in our ZnP-Tri-C 60 conjugates might prevent the formation of CT states.…”

“…Differences have been observed in past work both in attachment sites on phenyl rings and orientation of a conjugated linker. 24 By combining the structural variations of these three moieties, we hoped to be able to fine-tune rates of CS and CR processes, and to extend the charge-separated state lifetimes beyond that of current fully-conjugated systems. 7 Copper-catalyzed Huisgen 1,3-dipolar cycloaddition was used to selectively synthesize 1,4-disubstituted 1,2,3-triazoles, which then serve as covalent linkers between the photo- and redoxactive porphyrins and fullerenes.…”

Self-assembly of thioether functionalized fullerenes on gold and their activity in electropolymerization of styrene

“…Self-assembly of sulphide I on the surface of gold leads to a significant change in the S2p region of XPS spectra (Fig. 26,27 After series of experiments under the same conditions as for thioethers I-IV we can conclude that metoxylated fullerene neither form stable monolayers nor selfassembles on the gold surface, in contrast to all investigated thioethers. The doublet has two peaks centered at 162.2 and 163.4eV, hence shifted by 1.2 eV towards lower binding energies, implying notable S-Au interactions.…”

“…5B), as well as for other thioethers II-IV (see Fig. 27. The electron transfer processes are shifted towards more negative potentials, when compared to those of unmodified C 60 (Tab.…”